use crate::app_backtrack::BacktrackState;
use crate::app_event::AppEvent;
use crate::app_event::ExitMode;
use crate::app_event::RealtimeAudioDeviceKind;
#[cfg(target_os = "windows")]
use crate::app_event::WindowsSandboxEnableMode;
use crate::app_event_sender::AppEventSender;
use crate::bottom_pane::ApprovalRequest;
use crate::bottom_pane::FeedbackAudience;
use crate::bottom_pane::SelectionItem;
use crate::bottom_pane::SelectionViewParams;
use crate::bottom_pane::popup_consts::standard_popup_hint_line;
use crate::chatwidget::ChatWidget;
use crate::chatwidget::ExternalEditorState;
use crate::cwd_prompt::CwdPromptAction;
use crate::diff_render::DiffSummary;
use crate::exec_command::strip_bash_lc_and_escape;
use crate::external_editor;
use crate::file_search::FileSearchManager;
use crate::history_cell;
use crate::history_cell::HistoryCell;
#[cfg(not(debug_assertions))]
use crate::history_cell::UpdateAvailableHistoryCell;
use crate::model_migration::ModelMigrationOutcome;
use crate::model_migration::migration_copy_for_models;
use crate::model_migration::run_model_migration_prompt;
use crate::multi_agents::AgentPickerThreadEntry;
use crate::multi_agents::agent_picker_status_dot_spans;
use crate::multi_agents::format_agent_picker_item_name;
use crate::multi_agents::sort_agent_picker_threads;
use crate::pager_overlay::Overlay;
use crate::render::highlight::highlight_bash_to_lines;
use crate::render::renderable::Renderable;
use crate::resume_picker::SessionSelection;
use crate::tui;
use crate::tui::TuiEvent;
use crate::update_action::UpdateAction;
use crate::version::CODEX_CLI_VERSION;
use codex_ansi_escape::ansi_escape_line;
use codex_app_server_protocol::ConfigLayerSource;
use codex_core::AuthManager;
use codex_core::CodexAuth;
use codex_core::ThreadManager;
use codex_core::config::Config;
use codex_core::config::ConfigBuilder;
use codex_core::config::ConfigOverrides;
use codex_core::config::edit::ConfigEdit;
use codex_core::config::edit::ConfigEditsBuilder;
use codex_core::config::types::ModelAvailabilityNuxConfig;
use codex_core::config_loader::ConfigLayerStackOrdering;
use codex_core::features::Feature;
use codex_core::models_manager::collaboration_mode_presets::CollaborationModesConfig;
use codex_core::models_manager::manager::RefreshStrategy;
use codex_core::models_manager::model_presets::HIDE_GPT_5_1_CODEX_MAX_MIGRATION_PROMPT_CONFIG;
use codex_core::models_manager::model_presets::HIDE_GPT5_1_MIGRATION_PROMPT_CONFIG;
#[cfg(target_os = "windows")]
use codex_core::windows_sandbox::WindowsSandboxLevelExt;
use codex_otel::OtelManager;
use codex_otel::TelemetryAuthMode;
use codex_protocol::ThreadId;
use codex_protocol::config_types::Personality;
#[cfg(target_os = "windows")]
use codex_protocol::config_types::WindowsSandboxLevel;
use codex_protocol::items::TurnItem;
use codex_protocol::openai_models::ModelAvailabilityNux;
use codex_protocol::openai_models::ModelPreset;
use codex_protocol::openai_models::ModelUpgrade;
use codex_protocol::openai_models::ReasoningEffort as ReasoningEffortConfig;
use codex_protocol::protocol::AskForApproval;
use codex_protocol::protocol::Event;
use codex_protocol::protocol::EventMsg;
use codex_protocol::protocol::FinalOutput;
use codex_protocol::protocol::ListSkillsResponseEvent;
use codex_protocol::protocol::Op;
use codex_protocol::protocol::SandboxPolicy;
use codex_protocol::protocol::SessionConfiguredEvent;
use codex_protocol::protocol::SessionSource;
use codex_protocol::protocol::SkillErrorInfo;
use codex_protocol::protocol::TokenUsage;
use codex_utils_absolute_path::AbsolutePathBuf;
use color_eyre::eyre::Result;
use color_eyre::eyre::WrapErr;
use crossterm::event::KeyCode;
use crossterm::event::KeyEvent;
use crossterm::event::KeyEventKind;
use ratatui::style::Stylize;
use ratatui::text::Line;
use ratatui::widgets::Paragraph;
use ratatui::widgets::Wrap;
use std::collections::BTreeMap;
use std::collections::HashMap;
use std::collections::HashSet;
use std::collections::VecDeque;
use std::path::Path;
use std::path::PathBuf;
use std::sync::Arc;
use std::sync::atomic::AtomicBool;
use std::sync::atomic::Ordering;
use std::thread;
use std::time::Duration;
use std::time::Instant;
use tokio::select;
use tokio::sync::Mutex;
use tokio::sync::broadcast;
use tokio::sync::mpsc;
use tokio::sync::mpsc::error::TryRecvError;
use tokio::sync::mpsc::error::TrySendError;
use tokio::sync::mpsc::unbounded_channel;
use tokio::task::JoinHandle;
use toml::Value as TomlValue;

mod pending_interactive_replay;

use self::pending_interactive_replay::PendingInteractiveReplayState;

const EXTERNAL_EDITOR_HINT: &str = "Save and close external editor to continue.";
const THREAD_EVENT_CHANNEL_CAPACITY: usize = 32768;
/// Baseline cadence for periodic stream commit animation ticks.
///
/// Smooth-mode streaming drains one line per tick, so this interval controls
/// perceived typing speed for non-backlogged output.
const COMMIT_ANIMATION_TICK: Duration = tui::TARGET_FRAME_INTERVAL;

#[derive(Debug, Clone)]
pub struct AppExitInfo {
    pub token_usage: TokenUsage,
    pub thread_id: Option<ThreadId>,
    pub thread_name: Option<String>,
    pub update_action: Option<UpdateAction>,
    pub exit_reason: ExitReason,
}

impl AppExitInfo {
    pub fn fatal(message: impl Into<String>) -> Self {
        Self {
            token_usage: TokenUsage::default(),
            thread_id: None,
            thread_name: None,
            update_action: None,
            exit_reason: ExitReason::Fatal(message.into()),
        }
    }
}

#[derive(Debug)]
pub(crate) enum AppRunControl {
    Continue,
    Exit(ExitReason),
}

#[derive(Debug, Clone)]
pub enum ExitReason {
    UserRequested,
    Fatal(String),
}

fn session_summary(
    token_usage: TokenUsage,
    thread_id: Option<ThreadId>,
    thread_name: Option<String>,
) -> Option<SessionSummary> {
    if token_usage.is_zero() {
        return None;
    }

    let usage_line = FinalOutput::from(token_usage).to_string();
    let resume_command = codex_core::util::resume_command(thread_name.as_deref(), thread_id);
    Some(SessionSummary {
        usage_line,
        resume_command,
    })
}

fn errors_for_cwd(cwd: &Path, response: &ListSkillsResponseEvent) -> Vec<SkillErrorInfo> {
    response
        .skills
        .iter()
        .find(|entry| entry.cwd.as_path() == cwd)
        .map(|entry| entry.errors.clone())
        .unwrap_or_default()
}

fn emit_skill_load_warnings(app_event_tx: &AppEventSender, errors: &[SkillErrorInfo]) {
    if errors.is_empty() {
        return;
    }

    let error_count = errors.len();
    app_event_tx.send(AppEvent::InsertHistoryCell(Box::new(
        crate::history_cell::new_warning_event(format!(
            "Skipped loading {error_count} skill(s) due to invalid SKILL.md files."
        )),
    )));

    for error in errors {
        let path = error.path.display();
        let message = error.message.as_str();
        app_event_tx.send(AppEvent::InsertHistoryCell(Box::new(
            crate::history_cell::new_warning_event(format!("{path}: {message}")),
        )));
    }
}

fn emit_project_config_warnings(app_event_tx: &AppEventSender, config: &Config) {
    let mut disabled_folders = Vec::new();

    for layer in config
        .config_layer_stack
        .get_layers(ConfigLayerStackOrdering::LowestPrecedenceFirst, true)
    {
        let ConfigLayerSource::Project { dot_codex_folder } = &layer.name else {
            continue;
        };
        if layer.disabled_reason.is_none() {
            continue;
        }
        disabled_folders.push((
            dot_codex_folder.as_path().display().to_string(),
            layer
                .disabled_reason
                .as_ref()
                .map(ToString::to_string)
                .unwrap_or_else(|| "config.toml is disabled.".to_string()),
        ));
    }

    if disabled_folders.is_empty() {
        return;
    }

    let mut message = concat!(
        "Project config.toml files are disabled in the following folders. ",
        "Settings in those files are ignored, but skills and exec policies still load.\n",
    )
    .to_string();
    for (index, (folder, reason)) in disabled_folders.iter().enumerate() {
        let display_index = index + 1;
        message.push_str(&format!("    {display_index}. {folder}\n"));
        message.push_str(&format!("       {reason}\n"));
    }

    app_event_tx.send(AppEvent::InsertHistoryCell(Box::new(
        history_cell::new_warning_event(message),
    )));
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct SessionSummary {
    usage_line: String,
    resume_command: Option<String>,
}

#[derive(Debug, Clone)]
struct ThreadEventSnapshot {
    session_configured: Option<Event>,
    events: Vec<Event>,
}

#[derive(Debug)]
struct ThreadEventStore {
    session_configured: Option<Event>,
    buffer: VecDeque<Event>,
    user_message_ids: HashSet<String>,
    pending_interactive_replay: PendingInteractiveReplayState,
    capacity: usize,
    active: bool,
}

impl ThreadEventStore {
    fn new(capacity: usize) -> Self {
        Self {
            session_configured: None,
            buffer: VecDeque::new(),
            user_message_ids: HashSet::new(),
            pending_interactive_replay: PendingInteractiveReplayState::default(),
            capacity,
            active: false,
        }
    }

    fn new_with_session_configured(capacity: usize, event: Event) -> Self {
        let mut store = Self::new(capacity);
        store.session_configured = Some(event);
        store
    }

    fn push_event(&mut self, event: Event) {
        self.pending_interactive_replay.note_event(&event);
        match &event.msg {
            EventMsg::SessionConfigured(_) => {
                self.session_configured = Some(event);
                return;
            }
            EventMsg::ItemCompleted(completed) => {
                if let TurnItem::UserMessage(item) = &completed.item {
                    if !event.id.is_empty() && self.user_message_ids.contains(&event.id) {
                        return;
                    }
                    let legacy = Event {
                        id: event.id,
                        msg: item.as_legacy_event(),
                    };
                    self.push_legacy_event(legacy);
                    return;
                }
            }
            _ => {}
        }

        self.push_legacy_event(event);
    }

    fn push_legacy_event(&mut self, event: Event) {
        if let EventMsg::UserMessage(_) = &event.msg
            && !event.id.is_empty()
            && !self.user_message_ids.insert(event.id.clone())
        {
            return;
        }
        self.buffer.push_back(event);
        if self.buffer.len() > self.capacity
            && let Some(removed) = self.buffer.pop_front()
        {
            self.pending_interactive_replay.note_evicted_event(&removed);
            if matches!(removed.msg, EventMsg::UserMessage(_)) && !removed.id.is_empty() {
                self.user_message_ids.remove(&removed.id);
            }
        }
    }

    fn snapshot(&self) -> ThreadEventSnapshot {
        ThreadEventSnapshot {
            session_configured: self.session_configured.clone(),
            // Thread switches replay buffered events into a rebuilt ChatWidget. Only replay
            // interactive prompts that are still pending, or answered approvals/input will reappear.
            events: self
                .buffer
                .iter()
                .filter(|event| {
                    self.pending_interactive_replay
                        .should_replay_snapshot_event(event)
                })
                .cloned()
                .collect(),
        }
    }

    fn note_outbound_op(&mut self, op: &Op) {
        self.pending_interactive_replay.note_outbound_op(op);
    }

    fn op_can_change_pending_replay_state(op: &Op) -> bool {
        PendingInteractiveReplayState::op_can_change_state(op)
    }

    fn event_can_change_pending_thread_approvals(event: &Event) -> bool {
        PendingInteractiveReplayState::event_can_change_pending_thread_approvals(event)
    }

    fn has_pending_thread_approvals(&self) -> bool {
        self.pending_interactive_replay
            .has_pending_thread_approvals()
    }
}

#[derive(Debug)]
struct ThreadEventChannel {
    sender: mpsc::Sender<Event>,
    receiver: Option<mpsc::Receiver<Event>>,
    store: Arc<Mutex<ThreadEventStore>>,
}

impl ThreadEventChannel {
    fn new(capacity: usize) -> Self {
        let (sender, receiver) = mpsc::channel(capacity);
        Self {
            sender,
            receiver: Some(receiver),
            store: Arc::new(Mutex::new(ThreadEventStore::new(capacity))),
        }
    }

    fn new_with_session_configured(capacity: usize, event: Event) -> Self {
        let (sender, receiver) = mpsc::channel(capacity);
        Self {
            sender,
            receiver: Some(receiver),
            store: Arc::new(Mutex::new(ThreadEventStore::new_with_session_configured(
                capacity, event,
            ))),
        }
    }
}

fn should_show_model_migration_prompt(
    current_model: &str,
    target_model: &str,
    seen_migrations: &BTreeMap<String, String>,
    available_models: &[ModelPreset],
) -> bool {
    if target_model == current_model {
        return false;
    }

    if let Some(seen_target) = seen_migrations.get(current_model)
        && seen_target == target_model
    {
        return false;
    }

    if !available_models
        .iter()
        .any(|preset| preset.model == target_model && preset.show_in_picker)
    {
        return false;
    }

    if available_models
        .iter()
        .any(|preset| preset.model == current_model && preset.upgrade.is_some())
    {
        return true;
    }

    if available_models
        .iter()
        .any(|preset| preset.upgrade.as_ref().map(|u| u.id.as_str()) == Some(target_model))
    {
        return true;
    }

    false
}

fn migration_prompt_hidden(config: &Config, migration_config_key: &str) -> bool {
    match migration_config_key {
        HIDE_GPT_5_1_CODEX_MAX_MIGRATION_PROMPT_CONFIG => config
            .notices
            .hide_gpt_5_1_codex_max_migration_prompt
            .unwrap_or(false),
        HIDE_GPT5_1_MIGRATION_PROMPT_CONFIG => {
            config.notices.hide_gpt5_1_migration_prompt.unwrap_or(false)
        }
        _ => false,
    }
}

fn target_preset_for_upgrade<'a>(
    available_models: &'a [ModelPreset],
    target_model: &str,
) -> Option<&'a ModelPreset> {
    available_models
        .iter()
        .find(|preset| preset.model == target_model && preset.show_in_picker)
}

const MODEL_AVAILABILITY_NUX_MAX_SHOW_COUNT: u32 = 4;

#[derive(Debug, Clone, PartialEq, Eq)]
struct StartupTooltipOverride {
    model_slug: String,
    message: String,
}

fn select_model_availability_nux(
    available_models: &[ModelPreset],
    nux_config: &ModelAvailabilityNuxConfig,
) -> Option<StartupTooltipOverride> {
    available_models.iter().find_map(|preset| {
        let ModelAvailabilityNux { message } = preset.availability_nux.as_ref()?;
        let shown_count = nux_config
            .shown_count
            .get(&preset.model)
            .copied()
            .unwrap_or_default();
        (shown_count < MODEL_AVAILABILITY_NUX_MAX_SHOW_COUNT).then(|| StartupTooltipOverride {
            model_slug: preset.model.clone(),
            message: message.clone(),
        })
    })
}

async fn prepare_startup_tooltip_override(
    config: &mut Config,
    available_models: &[ModelPreset],
    is_first_run: bool,
) -> Option<String> {
    if is_first_run || !config.show_tooltips {
        return None;
    }

    let tooltip_override =
        select_model_availability_nux(available_models, &config.model_availability_nux)?;

    let shown_count = config
        .model_availability_nux
        .shown_count
        .get(&tooltip_override.model_slug)
        .copied()
        .unwrap_or_default();
    let next_count = shown_count.saturating_add(1);
    let mut updated_shown_count = config.model_availability_nux.shown_count.clone();
    updated_shown_count.insert(tooltip_override.model_slug.clone(), next_count);

    if let Err(err) = ConfigEditsBuilder::new(&config.codex_home)
        .set_model_availability_nux_count(&updated_shown_count)
        .apply()
        .await
    {
        tracing::error!(
            error = %err,
            model = %tooltip_override.model_slug,
            "failed to persist model availability nux count"
        );
        return Some(tooltip_override.message);
    }

    config.model_availability_nux.shown_count = updated_shown_count;
    Some(tooltip_override.message)
}

async fn handle_model_migration_prompt_if_needed(
    tui: &mut tui::Tui,
    config: &mut Config,
    model: &str,
    app_event_tx: &AppEventSender,
    available_models: &[ModelPreset],
) -> Option<AppExitInfo> {
    let upgrade = available_models
        .iter()
        .find(|preset| preset.model == model)
        .and_then(|preset| preset.upgrade.as_ref());

    if let Some(ModelUpgrade {
        id: target_model,
        reasoning_effort_mapping,
        migration_config_key,
        model_link,
        upgrade_copy,
        migration_markdown,
    }) = upgrade
    {
        if migration_prompt_hidden(config, migration_config_key.as_str()) {
            return None;
        }

        let target_model = target_model.to_string();
        if !should_show_model_migration_prompt(
            model,
            &target_model,
            &config.notices.model_migrations,
            available_models,
        ) {
            return None;
        }

        let current_preset = available_models.iter().find(|preset| preset.model == model);
        let target_preset = target_preset_for_upgrade(available_models, &target_model);
        let target_preset = target_preset?;
        let target_display_name = target_preset.display_name.clone();
        let heading_label = if target_display_name == model {
            target_model.clone()
        } else {
            target_display_name.clone()
        };
        let target_description =
            (!target_preset.description.is_empty()).then(|| target_preset.description.clone());
        let can_opt_out = current_preset.is_some();
        let prompt_copy = migration_copy_for_models(
            model,
            &target_model,
            model_link.clone(),
            upgrade_copy.clone(),
            migration_markdown.clone(),
            heading_label,
            target_description,
            can_opt_out,
        );
        match run_model_migration_prompt(tui, prompt_copy).await {
            ModelMigrationOutcome::Accepted => {
                app_event_tx.send(AppEvent::PersistModelMigrationPromptAcknowledged {
                    from_model: model.to_string(),
                    to_model: target_model.clone(),
                });

                let mapped_effort = if let Some(reasoning_effort_mapping) = reasoning_effort_mapping
                    && let Some(reasoning_effort) = config.model_reasoning_effort
                {
                    reasoning_effort_mapping
                        .get(&reasoning_effort)
                        .cloned()
                        .or(config.model_reasoning_effort)
                } else {
                    config.model_reasoning_effort
                };

                config.model = Some(target_model.clone());
                config.model_reasoning_effort = mapped_effort;
                app_event_tx.send(AppEvent::UpdateModel(target_model.clone()));
                app_event_tx.send(AppEvent::UpdateReasoningEffort(mapped_effort));
                app_event_tx.send(AppEvent::PersistModelSelection {
                    model: target_model.clone(),
                    effort: mapped_effort,
                });
            }
            ModelMigrationOutcome::Rejected => {
                app_event_tx.send(AppEvent::PersistModelMigrationPromptAcknowledged {
                    from_model: model.to_string(),
                    to_model: target_model.clone(),
                });
            }
            ModelMigrationOutcome::Exit => {
                return Some(AppExitInfo {
                    token_usage: TokenUsage::default(),
                    thread_id: None,
                    thread_name: None,
                    update_action: None,
                    exit_reason: ExitReason::UserRequested,
                });
            }
        }
    }

    None
}

pub(crate) struct App {
    pub(crate) server: Arc<ThreadManager>,
    pub(crate) otel_manager: OtelManager,
    pub(crate) app_event_tx: AppEventSender,
    pub(crate) chat_widget: ChatWidget,
    pub(crate) auth_manager: Arc<AuthManager>,
    /// Config is stored here so we can recreate ChatWidgets as needed.
    pub(crate) config: Config,
    pub(crate) active_profile: Option<String>,
    cli_kv_overrides: Vec<(String, TomlValue)>,
    harness_overrides: ConfigOverrides,
    runtime_approval_policy_override: Option<AskForApproval>,
    runtime_sandbox_policy_override: Option<SandboxPolicy>,

    pub(crate) file_search: FileSearchManager,

    pub(crate) transcript_cells: Vec<Arc<dyn HistoryCell>>,

    // Pager overlay state (Transcript or Static like Diff)
    pub(crate) overlay: Option<Overlay>,
    pub(crate) deferred_history_lines: Vec<Line<'static>>,
    has_emitted_history_lines: bool,

    pub(crate) enhanced_keys_supported: bool,

    /// Controls the animation thread that sends CommitTick events.
    pub(crate) commit_anim_running: Arc<AtomicBool>,
    // Shared across ChatWidget instances so invalid status-line config warnings only emit once.
    status_line_invalid_items_warned: Arc<AtomicBool>,

    // Esc-backtracking state grouped
    pub(crate) backtrack: crate::app_backtrack::BacktrackState,
    /// When set, the next draw re-renders the transcript into terminal scrollback once.
    ///
    /// This is used after a confirmed thread rollback to ensure scrollback reflects the trimmed
    /// transcript cells.
    pub(crate) backtrack_render_pending: bool,
    pub(crate) feedback: codex_feedback::CodexFeedback,
    feedback_audience: FeedbackAudience,
    /// Set when the user confirms an update; propagated on exit.
    pub(crate) pending_update_action: Option<UpdateAction>,

    /// One-shot guard used while switching threads.
    ///
    /// We set this when intentionally stopping the current thread before moving
    /// to another one, then ignore exactly one `ShutdownComplete` so it is not
    /// misclassified as an unexpected sub-agent death.
    suppress_shutdown_complete: bool,
    /// Tracks the thread we intentionally shut down while exiting the app.
    ///
    /// When this matches the active thread, its `ShutdownComplete` should lead to
    /// process exit instead of being treated as an unexpected sub-agent death that
    /// triggers failover to the primary thread.
    ///
    /// This is thread-scoped state (`Option<ThreadId>`) instead of a global bool
    /// so shutdown events from other threads still take the normal failover path.
    pending_shutdown_exit_thread_id: Option<ThreadId>,

    windows_sandbox: WindowsSandboxState,

    thread_event_channels: HashMap<ThreadId, ThreadEventChannel>,
    thread_event_listener_tasks: HashMap<ThreadId, JoinHandle<()>>,
    agent_picker_threads: HashMap<ThreadId, AgentPickerThreadEntry>,
    active_thread_id: Option<ThreadId>,
    active_thread_rx: Option<mpsc::Receiver<Event>>,
    primary_thread_id: Option<ThreadId>,
    primary_session_configured: Option<SessionConfiguredEvent>,
    pending_primary_events: VecDeque<Event>,
}

#[derive(Default)]
struct WindowsSandboxState {
    setup_started_at: Option<Instant>,
    // One-shot suppression of the next world-writable scan after user confirmation.
    skip_world_writable_scan_once: bool,
}

fn normalize_harness_overrides_for_cwd(
    mut overrides: ConfigOverrides,
    base_cwd: &Path,
) -> Result<ConfigOverrides> {
    if overrides.additional_writable_roots.is_empty() {
        return Ok(overrides);
    }

    let mut normalized = Vec::with_capacity(overrides.additional_writable_roots.len());
    for root in overrides.additional_writable_roots.drain(..) {
        let absolute = AbsolutePathBuf::resolve_path_against_base(root, base_cwd)?;
        normalized.push(absolute.into_path_buf());
    }
    overrides.additional_writable_roots = normalized;
    Ok(overrides)
}

impl App {
    pub fn chatwidget_init_for_forked_or_resumed_thread(
        &self,
        tui: &mut tui::Tui,
        cfg: codex_core::config::Config,
    ) -> crate::chatwidget::ChatWidgetInit {
        crate::chatwidget::ChatWidgetInit {
            config: cfg,
            frame_requester: tui.frame_requester(),
            app_event_tx: self.app_event_tx.clone(),
            // Fork/resume bootstraps here don't carry any prefilled message content.
            initial_user_message: None,
            enhanced_keys_supported: self.enhanced_keys_supported,
            auth_manager: self.auth_manager.clone(),
            models_manager: self.server.get_models_manager(),
            feedback: self.feedback.clone(),
            is_first_run: false,
            feedback_audience: self.feedback_audience,
            model: Some(self.chat_widget.current_model().to_string()),
            startup_tooltip_override: None,
            status_line_invalid_items_warned: self.status_line_invalid_items_warned.clone(),
            otel_manager: self.otel_manager.clone(),
        }
    }

    async fn rebuild_config_for_cwd(&self, cwd: PathBuf) -> Result<Config> {
        let mut overrides = self.harness_overrides.clone();
        overrides.cwd = Some(cwd.clone());
        let cwd_display = cwd.display().to_string();
        ConfigBuilder::default()
            .codex_home(self.config.codex_home.clone())
            .cli_overrides(self.cli_kv_overrides.clone())
            .harness_overrides(overrides)
            .build()
            .await
            .wrap_err_with(|| format!("Failed to rebuild config for cwd {cwd_display}"))
    }

    async fn refresh_in_memory_config_from_disk(&mut self) -> Result<()> {
        let mut config = self.rebuild_config_for_cwd(self.config.cwd.clone()).await?;
        self.apply_runtime_policy_overrides(&mut config);
        self.config = config;
        Ok(())
    }

    fn apply_runtime_policy_overrides(&mut self, config: &mut Config) {
        if let Some(policy) = self.runtime_approval_policy_override.as_ref()
            && let Err(err) = config.permissions.approval_policy.set(*policy)
        {
            tracing::warn!(%err, "failed to carry forward approval policy override");
            self.chat_widget.add_error_message(format!(
                "Failed to carry forward approval policy override: {err}"
            ));
        }
        if let Some(policy) = self.runtime_sandbox_policy_override.as_ref()
            && let Err(err) = config.permissions.sandbox_policy.set(policy.clone())
        {
            tracing::warn!(%err, "failed to carry forward sandbox policy override");
            self.chat_widget.add_error_message(format!(
                "Failed to carry forward sandbox policy override: {err}"
            ));
        }
    }

    fn open_url_in_browser(&mut self, url: String) {
        if let Err(err) = webbrowser::open(&url) {
            self.chat_widget
                .add_error_message(format!("Failed to open browser for {url}: {err}"));
            return;
        }

        self.chat_widget
            .add_info_message(format!("Opened {url} in your browser."), None);
    }

    fn clear_ui_header_lines_with_version(
        &self,
        width: u16,
        version: &'static str,
    ) -> Vec<Line<'static>> {
        history_cell::SessionHeaderHistoryCell::new(
            self.chat_widget.current_model().to_string(),
            self.chat_widget.current_reasoning_effort(),
            self.config.cwd.clone(),
            version,
        )
        .display_lines(width)
    }

    fn clear_ui_header_lines(&self, width: u16) -> Vec<Line<'static>> {
        self.clear_ui_header_lines_with_version(width, CODEX_CLI_VERSION)
    }

    fn queue_clear_ui_header(&mut self, tui: &mut tui::Tui) {
        let width = tui.terminal.last_known_screen_size.width;
        let header_lines = self.clear_ui_header_lines(width);
        if !header_lines.is_empty() {
            tui.insert_history_lines(header_lines);
            self.has_emitted_history_lines = true;
        }
    }

    fn clear_terminal_ui(&mut self, tui: &mut tui::Tui, redraw_header: bool) -> Result<()> {
        let is_alt_screen_active = tui.is_alt_screen_active();

        // Drop queued history insertions so stale transcript lines cannot be flushed after /clear.
        tui.clear_pending_history_lines();

        if is_alt_screen_active {
            tui.terminal.clear_visible_screen()?;
        } else {
            // Some terminals (Terminal.app, Warp) do not reliably drop scrollback when purge and
            // clear are emitted as separate backend commands. Prefer a single ANSI sequence.
            tui.terminal.clear_scrollback_and_visible_screen_ansi()?;
        }

        let mut area = tui.terminal.viewport_area;
        if area.y > 0 {
            // After a full clear, anchor the inline viewport at the top and redraw a fresh header
            // box. `insert_history_lines()` will shift the viewport down by the rendered height.
            area.y = 0;
            tui.terminal.set_viewport_area(area);
        }
        self.has_emitted_history_lines = false;

        if redraw_header {
            self.queue_clear_ui_header(tui);
        }
        Ok(())
    }

    fn reset_app_ui_state_after_clear(&mut self) {
        self.overlay = None;
        self.transcript_cells.clear();
        self.deferred_history_lines.clear();
        self.has_emitted_history_lines = false;
        self.backtrack = BacktrackState::default();
        self.backtrack_render_pending = false;
    }

    async fn shutdown_current_thread(&mut self) {
        if let Some(thread_id) = self.chat_widget.thread_id() {
            // Clear any in-flight rollback guard when switching threads.
            self.backtrack.pending_rollback = None;
            self.suppress_shutdown_complete = true;
            self.chat_widget.submit_op(Op::Shutdown);
            self.server.remove_thread(&thread_id).await;
            self.abort_thread_event_listener(thread_id);
        }
    }

    fn abort_thread_event_listener(&mut self, thread_id: ThreadId) {
        if let Some(handle) = self.thread_event_listener_tasks.remove(&thread_id) {
            handle.abort();
        }
    }

    fn abort_all_thread_event_listeners(&mut self) {
        for handle in self
            .thread_event_listener_tasks
            .drain()
            .map(|(_, handle)| handle)
        {
            handle.abort();
        }
    }

    fn ensure_thread_channel(&mut self, thread_id: ThreadId) -> &mut ThreadEventChannel {
        self.thread_event_channels
            .entry(thread_id)
            .or_insert_with(|| ThreadEventChannel::new(THREAD_EVENT_CHANNEL_CAPACITY))
    }

    async fn set_thread_active(&mut self, thread_id: ThreadId, active: bool) {
        if let Some(channel) = self.thread_event_channels.get_mut(&thread_id) {
            let mut store = channel.store.lock().await;
            store.active = active;
        }
    }

    async fn activate_thread_channel(&mut self, thread_id: ThreadId) {
        if self.active_thread_id.is_some() {
            return;
        }
        self.set_thread_active(thread_id, true).await;
        let receiver = if let Some(channel) = self.thread_event_channels.get_mut(&thread_id) {
            channel.receiver.take()
        } else {
            None
        };
        self.active_thread_id = Some(thread_id);
        self.active_thread_rx = receiver;
        self.refresh_pending_thread_approvals().await;
    }

    async fn store_active_thread_receiver(&mut self) {
        let Some(active_id) = self.active_thread_id else {
            return;
        };
        let Some(receiver) = self.active_thread_rx.take() else {
            return;
        };
        if let Some(channel) = self.thread_event_channels.get_mut(&active_id) {
            let mut store = channel.store.lock().await;
            store.active = false;
            channel.receiver = Some(receiver);
        }
    }

    async fn activate_thread_for_replay(
        &mut self,
        thread_id: ThreadId,
    ) -> Option<(mpsc::Receiver<Event>, ThreadEventSnapshot)> {
        let channel = self.thread_event_channels.get_mut(&thread_id)?;
        let receiver = channel.receiver.take()?;
        let mut store = channel.store.lock().await;
        store.active = true;
        let snapshot = store.snapshot();
        Some((receiver, snapshot))
    }

    async fn clear_active_thread(&mut self) {
        if let Some(active_id) = self.active_thread_id.take() {
            self.set_thread_active(active_id, false).await;
        }
        self.active_thread_rx = None;
        self.refresh_pending_thread_approvals().await;
    }

    async fn note_thread_outbound_op(&mut self, thread_id: ThreadId, op: &Op) {
        let Some(channel) = self.thread_event_channels.get(&thread_id) else {
            return;
        };
        let mut store = channel.store.lock().await;
        store.note_outbound_op(op);
    }

    async fn note_active_thread_outbound_op(&mut self, op: &Op) {
        if !ThreadEventStore::op_can_change_pending_replay_state(op) {
            return;
        }
        let Some(thread_id) = self.active_thread_id else {
            return;
        };
        self.note_thread_outbound_op(thread_id, op).await;
    }

    fn thread_label(&self, thread_id: ThreadId) -> String {
        let is_primary = self.primary_thread_id == Some(thread_id);
        let fallback_label = if is_primary {
            "Main [default]".to_string()
        } else {
            let thread_id = thread_id.to_string();
            let short_id: String = thread_id.chars().take(8).collect();
            format!("Agent ({short_id})")
        };
        if let Some(entry) = self.agent_picker_threads.get(&thread_id) {
            let label = format_agent_picker_item_name(
                entry.agent_nickname.as_deref(),
                entry.agent_role.as_deref(),
                is_primary,
            );
            if label == "Agent" {
                let thread_id = thread_id.to_string();
                let short_id: String = thread_id.chars().take(8).collect();
                format!("{label} ({short_id})")
            } else {
                label
            }
        } else {
            fallback_label
        }
    }

    async fn thread_cwd(&self, thread_id: ThreadId) -> Option<PathBuf> {
        let channel = self.thread_event_channels.get(&thread_id)?;
        let store = channel.store.lock().await;
        match store.session_configured.as_ref().map(|event| &event.msg) {
            Some(EventMsg::SessionConfigured(session)) => Some(session.cwd.clone()),
            _ => None,
        }
    }

    async fn approval_request_for_thread_event(
        &self,
        thread_id: ThreadId,
        event: &Event,
    ) -> Option<ApprovalRequest> {
        let thread_label = Some(self.thread_label(thread_id));
        match &event.msg {
            EventMsg::ExecApprovalRequest(ev) => Some(ApprovalRequest::Exec {
                thread_id,
                thread_label,
                id: ev.effective_approval_id(),
                command: ev.command.clone(),
                reason: ev.reason.clone(),
                available_decisions: ev.effective_available_decisions(),
                network_approval_context: ev.network_approval_context.clone(),
                additional_permissions: ev.additional_permissions.clone(),
            }),
            EventMsg::ApplyPatchApprovalRequest(ev) => Some(ApprovalRequest::ApplyPatch {
                thread_id,
                thread_label,
                id: ev.call_id.clone(),
                reason: ev.reason.clone(),
                cwd: self
                    .thread_cwd(thread_id)
                    .await
                    .unwrap_or_else(|| self.config.cwd.clone()),
                changes: ev.changes.clone(),
            }),
            EventMsg::ElicitationRequest(ev) => Some(ApprovalRequest::McpElicitation {
                thread_id,
                thread_label,
                server_name: ev.server_name.clone(),
                request_id: ev.id.clone(),
                message: ev.message.clone(),
            }),
            _ => None,
        }
    }

    async fn submit_op_to_thread(&mut self, thread_id: ThreadId, op: Op) {
        let replay_state_op =
            ThreadEventStore::op_can_change_pending_replay_state(&op).then(|| op.clone());
        let submitted = if self.active_thread_id == Some(thread_id) {
            self.chat_widget.submit_op(op)
        } else {
            crate::session_log::log_outbound_op(&op);
            match self.server.get_thread(thread_id).await {
                Ok(thread) => match thread.submit(op).await {
                    Ok(_) => true,
                    Err(err) => {
                        self.chat_widget.add_error_message(format!(
                            "Failed to submit op to thread {thread_id}: {err}"
                        ));
                        false
                    }
                },
                Err(err) => {
                    self.chat_widget.add_error_message(format!(
                        "Failed to find thread {thread_id} for approval response: {err}"
                    ));
                    false
                }
            }
        };
        if submitted && let Some(op) = replay_state_op.as_ref() {
            self.note_thread_outbound_op(thread_id, op).await;
            self.refresh_pending_thread_approvals().await;
        }
    }

    async fn refresh_pending_thread_approvals(&mut self) {
        let channels: Vec<(ThreadId, Arc<Mutex<ThreadEventStore>>)> = self
            .thread_event_channels
            .iter()
            .map(|(thread_id, channel)| (*thread_id, Arc::clone(&channel.store)))
            .collect();

        let mut pending_thread_ids = Vec::new();
        for (thread_id, store) in channels {
            if Some(thread_id) == self.active_thread_id {
                continue;
            }

            let store = store.lock().await;
            if store.has_pending_thread_approvals() {
                pending_thread_ids.push(thread_id);
            }
        }

        pending_thread_ids.sort_by_key(ThreadId::to_string);

        let threads = pending_thread_ids
            .into_iter()
            .map(|thread_id| self.thread_label(thread_id))
            .collect();

        self.chat_widget.set_pending_thread_approvals(threads);
    }

    async fn enqueue_thread_event(&mut self, thread_id: ThreadId, event: Event) -> Result<()> {
        let refresh_pending_thread_approvals =
            ThreadEventStore::event_can_change_pending_thread_approvals(&event);
        let inactive_approval_request = if self.active_thread_id != Some(thread_id) {
            self.approval_request_for_thread_event(thread_id, &event)
                .await
        } else {
            None
        };
        let (sender, store) = {
            let channel = self.ensure_thread_channel(thread_id);
            (channel.sender.clone(), Arc::clone(&channel.store))
        };

        let should_send = {
            let mut guard = store.lock().await;
            guard.push_event(event.clone());
            guard.active
        };

        if should_send {
            // Never await a bounded channel send on the main TUI loop: if the receiver falls behind,
            // `send().await` can block and the UI stops drawing. If the channel is full, wait in a
            // spawned task instead.
            match sender.try_send(event) {
                Ok(()) => {}
                Err(TrySendError::Full(event)) => {
                    tokio::spawn(async move {
                        if let Err(err) = sender.send(event).await {
                            tracing::warn!("thread {thread_id} event channel closed: {err}");
                        }
                    });
                }
                Err(TrySendError::Closed(_)) => {
                    tracing::warn!("thread {thread_id} event channel closed");
                }
            }
        } else if let Some(request) = inactive_approval_request {
            self.chat_widget.push_approval_request(request);
        }
        if refresh_pending_thread_approvals {
            self.refresh_pending_thread_approvals().await;
        }
        Ok(())
    }

    async fn handle_routed_thread_event(
        &mut self,
        thread_id: ThreadId,
        event: Event,
    ) -> Result<()> {
        if !self.thread_event_channels.contains_key(&thread_id) {
            tracing::debug!("dropping stale event for untracked thread {thread_id}");
            return Ok(());
        }

        self.enqueue_thread_event(thread_id, event).await
    }

    async fn enqueue_primary_event(&mut self, event: Event) -> Result<()> {
        if let Some(thread_id) = self.primary_thread_id {
            return self.enqueue_thread_event(thread_id, event).await;
        }

        if let EventMsg::SessionConfigured(session) = &event.msg {
            let thread_id = session.session_id;
            self.primary_thread_id = Some(thread_id);
            self.primary_session_configured = Some(session.clone());
            self.ensure_thread_channel(thread_id);
            self.activate_thread_channel(thread_id).await;
            self.enqueue_thread_event(thread_id, event).await?;

            let pending = std::mem::take(&mut self.pending_primary_events);
            for pending_event in pending {
                self.enqueue_thread_event(thread_id, pending_event).await?;
            }
        } else {
            self.pending_primary_events.push_back(event);
        }
        Ok(())
    }

    async fn open_agent_picker(&mut self) {
        let thread_ids: Vec<ThreadId> = self.thread_event_channels.keys().cloned().collect();
        for thread_id in thread_ids {
            match self.server.get_thread(thread_id).await {
                Ok(thread) => {
                    let session_source = thread.config_snapshot().await.session_source;
                    self.upsert_agent_picker_thread(
                        thread_id,
                        session_source.get_nickname(),
                        session_source.get_agent_role(),
                        false,
                    );
                }
                Err(_) => {
                    self.mark_agent_picker_thread_closed(thread_id);
                }
            }
        }

        let has_non_primary_agent_thread = self
            .agent_picker_threads
            .keys()
            .any(|thread_id| Some(*thread_id) != self.primary_thread_id);
        if !self.config.features.enabled(Feature::Collab) && !has_non_primary_agent_thread {
            self.chat_widget.open_multi_agent_enable_prompt();
            return;
        }

        if self.agent_picker_threads.is_empty() {
            self.chat_widget
                .add_info_message("No agents available yet.".to_string(), None);
            return;
        }

        let mut agent_threads: Vec<(ThreadId, AgentPickerThreadEntry)> = self
            .agent_picker_threads
            .iter()
            .map(|(thread_id, entry)| (*thread_id, entry.clone()))
            .collect();
        sort_agent_picker_threads(&mut agent_threads);

        let mut initial_selected_idx = None;
        let items: Vec<SelectionItem> = agent_threads
            .iter()
            .enumerate()
            .map(|(idx, (thread_id, entry))| {
                if self.active_thread_id == Some(*thread_id) {
                    initial_selected_idx = Some(idx);
                }
                let id = *thread_id;
                let is_primary = self.primary_thread_id == Some(*thread_id);
                let name = format_agent_picker_item_name(
                    entry.agent_nickname.as_deref(),
                    entry.agent_role.as_deref(),
                    is_primary,
                );
                let uuid = thread_id.to_string();
                SelectionItem {
                    name: name.clone(),
                    name_prefix_spans: agent_picker_status_dot_spans(entry.is_closed),
                    description: Some(uuid.clone()),
                    is_current: self.active_thread_id == Some(*thread_id),
                    actions: vec![Box::new(move |tx| {
                        tx.send(AppEvent::SelectAgentThread(id));
                    })],
                    dismiss_on_select: true,
                    search_value: Some(format!("{name} {uuid}")),
                    ..Default::default()
                }
            })
            .collect();

        self.chat_widget.show_selection_view(SelectionViewParams {
            title: Some("Multi-agents".to_string()),
            subtitle: Some("Select an agent to watch".to_string()),
            footer_hint: Some(standard_popup_hint_line()),
            items,
            initial_selected_idx,
            ..Default::default()
        });
    }

    fn upsert_agent_picker_thread(
        &mut self,
        thread_id: ThreadId,
        agent_nickname: Option<String>,
        agent_role: Option<String>,
        is_closed: bool,
    ) {
        self.agent_picker_threads.insert(
            thread_id,
            AgentPickerThreadEntry {
                agent_nickname,
                agent_role,
                is_closed,
            },
        );
    }

    fn mark_agent_picker_thread_closed(&mut self, thread_id: ThreadId) {
        if let Some(entry) = self.agent_picker_threads.get_mut(&thread_id) {
            entry.is_closed = true;
        } else {
            self.upsert_agent_picker_thread(thread_id, None, None, true);
        }
    }

    async fn select_agent_thread(&mut self, tui: &mut tui::Tui, thread_id: ThreadId) -> Result<()> {
        if self.active_thread_id == Some(thread_id) {
            return Ok(());
        }

        let live_thread = match self.server.get_thread(thread_id).await {
            Ok(thread) => Some(thread),
            Err(err) => {
                if self.thread_event_channels.contains_key(&thread_id) {
                    self.mark_agent_picker_thread_closed(thread_id);
                    None
                } else {
                    self.chat_widget.add_error_message(format!(
                        "Failed to attach to agent thread {thread_id}: {err}"
                    ));
                    return Ok(());
                }
            }
        };
        let is_replay_only = live_thread.is_none();

        let previous_thread_id = self.active_thread_id;
        self.store_active_thread_receiver().await;
        self.active_thread_id = None;
        let Some((receiver, snapshot)) = self.activate_thread_for_replay(thread_id).await else {
            self.chat_widget
                .add_error_message(format!("Agent thread {thread_id} is already active."));
            if let Some(previous_thread_id) = previous_thread_id {
                self.activate_thread_channel(previous_thread_id).await;
            }
            return Ok(());
        };

        self.active_thread_id = Some(thread_id);
        self.active_thread_rx = Some(receiver);

        let init = self.chatwidget_init_for_forked_or_resumed_thread(tui, self.config.clone());
        let codex_op_tx = if let Some(thread) = live_thread {
            crate::chatwidget::spawn_op_forwarder(thread)
        } else {
            let (tx, _rx) = unbounded_channel();
            tx
        };
        self.chat_widget = ChatWidget::new_with_op_sender(init, codex_op_tx);

        self.reset_for_thread_switch(tui)?;
        self.replay_thread_snapshot(snapshot);
        if is_replay_only {
            self.chat_widget.add_info_message(
                format!("Agent thread {thread_id} is closed. Replaying saved transcript."),
                None,
            );
        }
        self.drain_active_thread_events(tui).await?;
        self.refresh_pending_thread_approvals().await;

        Ok(())
    }

    fn reset_for_thread_switch(&mut self, tui: &mut tui::Tui) -> Result<()> {
        self.overlay = None;
        self.transcript_cells.clear();
        self.deferred_history_lines.clear();
        self.has_emitted_history_lines = false;
        self.backtrack = BacktrackState::default();
        self.backtrack_render_pending = false;
        tui.terminal.clear_scrollback()?;
        tui.terminal.clear()?;
        Ok(())
    }

    fn reset_thread_event_state(&mut self) {
        self.abort_all_thread_event_listeners();
        self.thread_event_channels.clear();
        self.agent_picker_threads.clear();
        self.active_thread_id = None;
        self.active_thread_rx = None;
        self.primary_thread_id = None;
        self.pending_primary_events.clear();
        self.chat_widget.set_pending_thread_approvals(Vec::new());
    }

    async fn start_fresh_session_with_summary_hint(&mut self, tui: &mut tui::Tui) {
        // Start a fresh in-memory session while preserving resumability via persisted rollout
        // history.
        let model = self.chat_widget.current_model().to_string();
        let config = self.fresh_session_config();
        let summary = session_summary(
            self.chat_widget.token_usage(),
            self.chat_widget.thread_id(),
            self.chat_widget.thread_name(),
        );
        self.shutdown_current_thread().await;
        if let Err(err) = self.server.remove_and_close_all_threads().await {
            tracing::warn!(error = %err, "failed to close all threads");
        }
        let init = crate::chatwidget::ChatWidgetInit {
            config,
            frame_requester: tui.frame_requester(),
            app_event_tx: self.app_event_tx.clone(),
            // New sessions start without prefilled message content.
            initial_user_message: None,
            enhanced_keys_supported: self.enhanced_keys_supported,
            auth_manager: self.auth_manager.clone(),
            models_manager: self.server.get_models_manager(),
            feedback: self.feedback.clone(),
            is_first_run: false,
            feedback_audience: self.feedback_audience,
            model: Some(model),
            startup_tooltip_override: None,
            status_line_invalid_items_warned: self.status_line_invalid_items_warned.clone(),
            otel_manager: self.otel_manager.clone(),
        };
        self.chat_widget = ChatWidget::new(init, self.server.clone());
        self.reset_thread_event_state();
        if let Some(summary) = summary {
            let mut lines: Vec<Line<'static>> = vec![summary.usage_line.clone().into()];
            if let Some(command) = summary.resume_command {
                let spans = vec!["To continue this session, run ".into(), command.cyan()];
                lines.push(spans.into());
            }
            self.chat_widget.add_plain_history_lines(lines);
        }
        tui.frame_requester().schedule_frame();
    }

    fn fresh_session_config(&self) -> Config {
        let mut config = self.config.clone();
        config.service_tier = self.chat_widget.current_service_tier();
        config
    }

    async fn drain_active_thread_events(&mut self, tui: &mut tui::Tui) -> Result<()> {
        let Some(mut rx) = self.active_thread_rx.take() else {
            return Ok(());
        };

        let mut disconnected = false;
        loop {
            match rx.try_recv() {
                Ok(event) => self.handle_codex_event_now(event),
                Err(TryRecvError::Empty) => break,
                Err(TryRecvError::Disconnected) => {
                    disconnected = true;
                    break;
                }
            }
        }

        if !disconnected {
            self.active_thread_rx = Some(rx);
        } else {
            self.clear_active_thread().await;
        }

        if self.backtrack_render_pending {
            tui.frame_requester().schedule_frame();
        }
        Ok(())
    }

    /// Returns `(closed_thread_id, primary_thread_id)` when a non-primary active
    /// thread has died and we should fail over to the primary thread.
    ///
    /// A user-requested shutdown (`ExitMode::ShutdownFirst`) sets
    /// `pending_shutdown_exit_thread_id`; matching shutdown completions are ignored
    /// here so Ctrl+C-like exits don't accidentally resurrect the main thread.
    ///
    /// Failover is only eligible when all of these are true:
    /// 1. the event is `ShutdownComplete`;
    /// 2. the active thread differs from the primary thread;
    /// 3. the active thread is not the pending shutdown-exit thread.
    fn active_non_primary_shutdown_target(&self, msg: &EventMsg) -> Option<(ThreadId, ThreadId)> {
        if !matches!(msg, EventMsg::ShutdownComplete) {
            return None;
        }
        let active_thread_id = self.active_thread_id?;
        let primary_thread_id = self.primary_thread_id?;
        if self.pending_shutdown_exit_thread_id == Some(active_thread_id) {
            return None;
        }
        (active_thread_id != primary_thread_id).then_some((active_thread_id, primary_thread_id))
    }

    fn replay_thread_snapshot(&mut self, snapshot: ThreadEventSnapshot) {
        if let Some(event) = snapshot.session_configured {
            self.handle_codex_event_replay(event);
        }
        for event in snapshot.events {
            self.handle_codex_event_replay(event);
        }
        self.refresh_status_line();
    }

    fn should_wait_for_initial_session(session_selection: &SessionSelection) -> bool {
        matches!(
            session_selection,
            SessionSelection::StartFresh | SessionSelection::Exit
        )
    }

    fn should_handle_active_thread_events(
        waiting_for_initial_session_configured: bool,
        has_active_thread_receiver: bool,
    ) -> bool {
        has_active_thread_receiver && !waiting_for_initial_session_configured
    }

    fn should_stop_waiting_for_initial_session(
        waiting_for_initial_session_configured: bool,
        primary_thread_id: Option<ThreadId>,
    ) -> bool {
        waiting_for_initial_session_configured && primary_thread_id.is_some()
    }

    #[allow(clippy::too_many_arguments)]
    pub async fn run(
        tui: &mut tui::Tui,
        auth_manager: Arc<AuthManager>,
        mut config: Config,
        cli_kv_overrides: Vec<(String, TomlValue)>,
        harness_overrides: ConfigOverrides,
        active_profile: Option<String>,
        initial_prompt: Option<String>,
        initial_images: Vec<PathBuf>,
        session_selection: SessionSelection,
        feedback: codex_feedback::CodexFeedback,
        is_first_run: bool,
        should_prompt_windows_sandbox_nux_at_startup: bool,
    ) -> Result<AppExitInfo> {
        use tokio_stream::StreamExt;
        let (app_event_tx, mut app_event_rx) = unbounded_channel();
        let app_event_tx = AppEventSender::new(app_event_tx);
        emit_project_config_warnings(&app_event_tx, &config);
        tui.set_notification_method(config.tui_notification_method);

        let harness_overrides =
            normalize_harness_overrides_for_cwd(harness_overrides, &config.cwd)?;
        let thread_manager = Arc::new(ThreadManager::new(
            config.codex_home.clone(),
            auth_manager.clone(),
            SessionSource::Cli,
            config.model_catalog.clone(),
            CollaborationModesConfig {
                default_mode_request_user_input: config
                    .features
                    .enabled(codex_core::features::Feature::DefaultModeRequestUserInput),
            },
        ));
        let mut model = thread_manager
            .get_models_manager()
            .get_default_model(&config.model, RefreshStrategy::Offline)
            .await;
        let available_models = thread_manager
            .get_models_manager()
            .list_models(RefreshStrategy::Offline)
            .await;
        let exit_info = handle_model_migration_prompt_if_needed(
            tui,
            &mut config,
            model.as_str(),
            &app_event_tx,
            &available_models,
        )
        .await;
        if let Some(exit_info) = exit_info {
            return Ok(exit_info);
        }
        if let Some(updated_model) = config.model.clone() {
            model = updated_model;
        }
        let auth = auth_manager.auth().await;
        let auth_ref = auth.as_ref();
        // Determine who should see internal Slack routing. We treat
        // `@openai.com` emails as employees and default to `External` when the
        // email is unavailable (for example, API key auth).
        let feedback_audience = if auth_ref
            .and_then(CodexAuth::get_account_email)
            .is_some_and(|email| email.ends_with("@openai.com"))
        {
            FeedbackAudience::OpenAiEmployee
        } else {
            FeedbackAudience::External
        };
        let auth_mode = auth_ref
            .map(CodexAuth::auth_mode)
            .map(TelemetryAuthMode::from);
        let otel_manager = OtelManager::new(
            ThreadId::new(),
            model.as_str(),
            model.as_str(),
            auth_ref.and_then(CodexAuth::get_account_id),
            auth_ref.and_then(CodexAuth::get_account_email),
            auth_mode,
            codex_core::default_client::originator().value,
            config.otel.log_user_prompt,
            codex_core::terminal::user_agent(),
            SessionSource::Cli,
        );
        if config
            .tui_status_line
            .as_ref()
            .is_some_and(|cmd| !cmd.is_empty())
        {
            otel_manager.counter("codex.status_line", 1, &[]);
        }

        let status_line_invalid_items_warned = Arc::new(AtomicBool::new(false));

        let enhanced_keys_supported = tui.enhanced_keys_supported();
        let wait_for_initial_session_configured =
            Self::should_wait_for_initial_session(&session_selection);
        let mut chat_widget = match session_selection {
            SessionSelection::StartFresh | SessionSelection::Exit => {
                let startup_tooltip_override =
                    prepare_startup_tooltip_override(&mut config, &available_models, is_first_run)
                        .await;
                let init = crate::chatwidget::ChatWidgetInit {
                    config: config.clone(),
                    frame_requester: tui.frame_requester(),
                    app_event_tx: app_event_tx.clone(),
                    initial_user_message: crate::chatwidget::create_initial_user_message(
                        initial_prompt.clone(),
                        initial_images.clone(),
                        // CLI prompt args are plain strings, so they don't provide element ranges.
                        Vec::new(),
                    ),
                    enhanced_keys_supported,
                    auth_manager: auth_manager.clone(),
                    models_manager: thread_manager.get_models_manager(),
                    feedback: feedback.clone(),
                    is_first_run,
                    feedback_audience,
                    model: Some(model.clone()),
                    startup_tooltip_override,
                    status_line_invalid_items_warned: status_line_invalid_items_warned.clone(),
                    otel_manager: otel_manager.clone(),
                };
                ChatWidget::new(init, thread_manager.clone())
            }
            SessionSelection::Resume(target_session) => {
                let resumed = thread_manager
                    .resume_thread_from_rollout(
                        config.clone(),
                        target_session.path.clone(),
                        auth_manager.clone(),
                    )
                    .await
                    .wrap_err_with(|| {
                        let path_display = target_session.path.display();
                        format!("Failed to resume session from {path_display}")
                    })?;
                let init = crate::chatwidget::ChatWidgetInit {
                    config: config.clone(),
                    frame_requester: tui.frame_requester(),
                    app_event_tx: app_event_tx.clone(),
                    initial_user_message: crate::chatwidget::create_initial_user_message(
                        initial_prompt.clone(),
                        initial_images.clone(),
                        // CLI prompt args are plain strings, so they don't provide element ranges.
                        Vec::new(),
                    ),
                    enhanced_keys_supported,
                    auth_manager: auth_manager.clone(),
                    models_manager: thread_manager.get_models_manager(),
                    feedback: feedback.clone(),
                    is_first_run,
                    feedback_audience,
                    model: config.model.clone(),
                    startup_tooltip_override: None,
                    status_line_invalid_items_warned: status_line_invalid_items_warned.clone(),
                    otel_manager: otel_manager.clone(),
                };
                ChatWidget::new_from_existing(init, resumed.thread, resumed.session_configured)
            }
            SessionSelection::Fork(target_session) => {
                otel_manager.counter("codex.thread.fork", 1, &[("source", "cli_subcommand")]);
                let forked = thread_manager
                    .fork_thread(
                        usize::MAX,
                        config.clone(),
                        target_session.path.clone(),
                        false,
                    )
                    .await
                    .wrap_err_with(|| {
                        let path_display = target_session.path.display();
                        format!("Failed to fork session from {path_display}")
                    })?;
                let init = crate::chatwidget::ChatWidgetInit {
                    config: config.clone(),
                    frame_requester: tui.frame_requester(),
                    app_event_tx: app_event_tx.clone(),
                    initial_user_message: crate::chatwidget::create_initial_user_message(
                        initial_prompt.clone(),
                        initial_images.clone(),
                        // CLI prompt args are plain strings, so they don't provide element ranges.
                        Vec::new(),
                    ),
                    enhanced_keys_supported,
                    auth_manager: auth_manager.clone(),
                    models_manager: thread_manager.get_models_manager(),
                    feedback: feedback.clone(),
                    is_first_run,
                    feedback_audience,
                    model: config.model.clone(),
                    startup_tooltip_override: None,
                    status_line_invalid_items_warned: status_line_invalid_items_warned.clone(),
                    otel_manager: otel_manager.clone(),
                };
                ChatWidget::new_from_existing(init, forked.thread, forked.session_configured)
            }
        };

        chat_widget
            .maybe_prompt_windows_sandbox_enable(should_prompt_windows_sandbox_nux_at_startup);

        let file_search = FileSearchManager::new(config.cwd.clone(), app_event_tx.clone());
        #[cfg(not(debug_assertions))]
        let upgrade_version = crate::updates::get_upgrade_version(&config);

        let mut app = Self {
            server: thread_manager.clone(),
            otel_manager: otel_manager.clone(),
            app_event_tx,
            chat_widget,
            auth_manager: auth_manager.clone(),
            config,
            active_profile,
            cli_kv_overrides,
            harness_overrides,
            runtime_approval_policy_override: None,
            runtime_sandbox_policy_override: None,
            file_search,
            enhanced_keys_supported,
            transcript_cells: Vec::new(),
            overlay: None,
            deferred_history_lines: Vec::new(),
            has_emitted_history_lines: false,
            commit_anim_running: Arc::new(AtomicBool::new(false)),
            status_line_invalid_items_warned: status_line_invalid_items_warned.clone(),
            backtrack: BacktrackState::default(),
            backtrack_render_pending: false,
            feedback: feedback.clone(),
            feedback_audience,
            pending_update_action: None,
            suppress_shutdown_complete: false,
            pending_shutdown_exit_thread_id: None,
            windows_sandbox: WindowsSandboxState::default(),
            thread_event_channels: HashMap::new(),
            thread_event_listener_tasks: HashMap::new(),
            agent_picker_threads: HashMap::new(),
            active_thread_id: None,
            active_thread_rx: None,
            primary_thread_id: None,
            primary_session_configured: None,
            pending_primary_events: VecDeque::new(),
        };

        // On startup, if Agent mode (workspace-write) or ReadOnly is active, warn about world-writable dirs on Windows.
        #[cfg(target_os = "windows")]
        {
            let should_check = WindowsSandboxLevel::from_config(&app.config)
                != WindowsSandboxLevel::Disabled
                && matches!(
                    app.config.permissions.sandbox_policy.get(),
                    codex_protocol::protocol::SandboxPolicy::WorkspaceWrite { .. }
                        | codex_protocol::protocol::SandboxPolicy::ReadOnly { .. }
                )
                && !app
                    .config
                    .notices
                    .hide_world_writable_warning
                    .unwrap_or(false);
            if should_check {
                let cwd = app.config.cwd.clone();
                let env_map: std::collections::HashMap<String, String> = std::env::vars().collect();
                let tx = app.app_event_tx.clone();
                let logs_base_dir = app.config.codex_home.clone();
                let sandbox_policy = app.config.permissions.sandbox_policy.get().clone();
                Self::spawn_world_writable_scan(cwd, env_map, logs_base_dir, sandbox_policy, tx);
            }
        }

        #[cfg(not(debug_assertions))]
        if let Some(latest_version) = upgrade_version {
            let control = app
                .handle_event(
                    tui,
                    AppEvent::InsertHistoryCell(Box::new(UpdateAvailableHistoryCell::new(
                        latest_version,
                        crate::update_action::get_update_action(),
                    ))),
                )
                .await?;
            if let AppRunControl::Exit(exit_reason) = control {
                return Ok(AppExitInfo {
                    token_usage: app.token_usage(),
                    thread_id: app.chat_widget.thread_id(),
                    thread_name: app.chat_widget.thread_name(),
                    update_action: app.pending_update_action,
                    exit_reason,
                });
            }
        }

        let tui_events = tui.event_stream();
        tokio::pin!(tui_events);

        tui.frame_requester().schedule_frame();

        let mut thread_created_rx = thread_manager.subscribe_thread_created();
        let mut listen_for_threads = true;
        let mut waiting_for_initial_session_configured = wait_for_initial_session_configured;

        let exit_reason = loop {
            let control = select! {
                Some(event) = app_event_rx.recv() => {
                    app.handle_event(tui, event).await?
                }
                active = async {
                    if let Some(rx) = app.active_thread_rx.as_mut() {
                        rx.recv().await
                    } else {
                        None
                    }
                }, if App::should_handle_active_thread_events(
                    waiting_for_initial_session_configured,
                    app.active_thread_rx.is_some()
                ) => {
                    if let Some(event) = active {
                        app.handle_active_thread_event(tui, event).await?;
                    } else {
                        app.clear_active_thread().await;
                    }
                    AppRunControl::Continue
                }
                Some(event) = tui_events.next() => {
                    app.handle_tui_event(tui, event).await?
                }
                // Listen on new thread creation due to collab tools.
                created = thread_created_rx.recv(), if listen_for_threads => {
                    match created {
                        Ok(thread_id) => {
                            app.handle_thread_created(thread_id).await?;
                        }
                        Err(broadcast::error::RecvError::Lagged(_)) => {
                            tracing::warn!("thread_created receiver lagged; skipping resync");
                        }
                        Err(broadcast::error::RecvError::Closed) => {
                            listen_for_threads = false;
                        }
                    }
                    AppRunControl::Continue
                }
            };
            if App::should_stop_waiting_for_initial_session(
                waiting_for_initial_session_configured,
                app.primary_thread_id,
            ) {
                waiting_for_initial_session_configured = false;
            }
            match control {
                AppRunControl::Continue => {}
                AppRunControl::Exit(reason) => break reason,
            }
        };
        tui.terminal.clear()?;
        Ok(AppExitInfo {
            token_usage: app.token_usage(),
            thread_id: app.chat_widget.thread_id(),
            thread_name: app.chat_widget.thread_name(),
            update_action: app.pending_update_action,
            exit_reason,
        })
    }

    pub(crate) async fn handle_tui_event(
        &mut self,
        tui: &mut tui::Tui,
        event: TuiEvent,
    ) -> Result<AppRunControl> {
        if matches!(event, TuiEvent::Draw) {
            let size = tui.terminal.size()?;
            if size != tui.terminal.last_known_screen_size {
                self.refresh_status_line();
            }
        }

        if self.overlay.is_some() {
            let _ = self.handle_backtrack_overlay_event(tui, event).await?;
        } else {
            match event {
                TuiEvent::Key(key_event) => {
                    self.handle_key_event(tui, key_event).await;
                }
                TuiEvent::Paste(pasted) => {
                    // Many terminals convert newlines to \r when pasting (e.g., iTerm2),
                    // but tui-textarea expects \n. Normalize CR to LF.
                    // [tui-textarea]: https://github.com/rhysd/tui-textarea/blob/4d18622eeac13b309e0ff6a55a46ac6706da68cf/src/textarea.rs#L782-L783
                    // [iTerm2]: https://github.com/gnachman/iTerm2/blob/5d0c0d9f68523cbd0494dad5422998964a2ecd8d/sources/iTermPasteHelper.m#L206-L216
                    let pasted = pasted.replace("\r", "\n");
                    self.chat_widget.handle_paste(pasted);
                }
                TuiEvent::Draw => {
                    if self.backtrack_render_pending {
                        self.backtrack_render_pending = false;
                        self.render_transcript_once(tui);
                    }
                    self.chat_widget.maybe_post_pending_notification(tui);
                    if self
                        .chat_widget
                        .handle_paste_burst_tick(tui.frame_requester())
                    {
                        return Ok(AppRunControl::Continue);
                    }
                    // Allow widgets to process any pending timers before rendering.
                    self.chat_widget.pre_draw_tick();
                    tui.draw(
                        self.chat_widget.desired_height(tui.terminal.size()?.width),
                        |frame| {
                            self.chat_widget.render(frame.area(), frame.buffer);
                            if let Some((x, y)) = self.chat_widget.cursor_pos(frame.area()) {
                                frame.set_cursor_position((x, y));
                            }
                        },
                    )?;
                    if self.chat_widget.external_editor_state() == ExternalEditorState::Requested {
                        self.chat_widget
                            .set_external_editor_state(ExternalEditorState::Active);
                        self.app_event_tx.send(AppEvent::LaunchExternalEditor);
                    }
                }
            }
        }
        Ok(AppRunControl::Continue)
    }

    async fn handle_event(&mut self, tui: &mut tui::Tui, event: AppEvent) -> Result<AppRunControl> {
        match event {
            AppEvent::NewSession => {
                self.start_fresh_session_with_summary_hint(tui).await;
            }
            AppEvent::ClearUi => {
                self.clear_terminal_ui(tui, false)?;
                self.reset_app_ui_state_after_clear();

                self.start_fresh_session_with_summary_hint(tui).await;
            }
            AppEvent::OpenResumePicker => {
                match crate::resume_picker::run_resume_picker(tui, &self.config, false).await? {
                    SessionSelection::Resume(target_session) => {
                        let current_cwd = self.config.cwd.clone();
                        let resume_cwd = match crate::resolve_cwd_for_resume_or_fork(
                            tui,
                            &self.config,
                            &current_cwd,
                            target_session.thread_id,
                            &target_session.path,
                            CwdPromptAction::Resume,
                            true,
                        )
                        .await?
                        {
                            crate::ResolveCwdOutcome::Continue(Some(cwd)) => cwd,
                            crate::ResolveCwdOutcome::Continue(None) => current_cwd.clone(),
                            crate::ResolveCwdOutcome::Exit => {
                                return Ok(AppRunControl::Exit(ExitReason::UserRequested));
                            }
                        };
                        let mut resume_config = if crate::cwds_differ(&current_cwd, &resume_cwd) {
                            match self.rebuild_config_for_cwd(resume_cwd).await {
                                Ok(cfg) => cfg,
                                Err(err) => {
                                    self.chat_widget.add_error_message(format!(
                                        "Failed to rebuild configuration for resume: {err}"
                                    ));
                                    return Ok(AppRunControl::Continue);
                                }
                            }
                        } else {
                            // No rebuild needed: current_cwd comes from self.config.cwd.
                            self.config.clone()
                        };
                        self.apply_runtime_policy_overrides(&mut resume_config);
                        let summary = session_summary(
                            self.chat_widget.token_usage(),
                            self.chat_widget.thread_id(),
                            self.chat_widget.thread_name(),
                        );
                        match self
                            .server
                            .resume_thread_from_rollout(
                                resume_config.clone(),
                                target_session.path.clone(),
                                self.auth_manager.clone(),
                            )
                            .await
                        {
                            Ok(resumed) => {
                                self.shutdown_current_thread().await;
                                self.config = resume_config;
                                tui.set_notification_method(self.config.tui_notification_method);
                                self.file_search.update_search_dir(self.config.cwd.clone());
                                let init = self.chatwidget_init_for_forked_or_resumed_thread(
                                    tui,
                                    self.config.clone(),
                                );
                                self.chat_widget = ChatWidget::new_from_existing(
                                    init,
                                    resumed.thread,
                                    resumed.session_configured,
                                );
                                self.reset_thread_event_state();
                                if let Some(summary) = summary {
                                    let mut lines: Vec<Line<'static>> =
                                        vec![summary.usage_line.clone().into()];
                                    if let Some(command) = summary.resume_command {
                                        let spans = vec![
                                            "To continue this session, run ".into(),
                                            command.cyan(),
                                        ];
                                        lines.push(spans.into());
                                    }
                                    self.chat_widget.add_plain_history_lines(lines);
                                }
                            }
                            Err(err) => {
                                let path_display = target_session.path.display();
                                self.chat_widget.add_error_message(format!(
                                    "Failed to resume session from {path_display}: {err}"
                                ));
                            }
                        }
                    }
                    SessionSelection::Exit
                    | SessionSelection::StartFresh
                    | SessionSelection::Fork(_) => {}
                }

                // Leaving alt-screen may blank the inline viewport; force a redraw either way.
                tui.frame_requester().schedule_frame();
            }
            AppEvent::ForkCurrentSession => {
                self.otel_manager
                    .counter("codex.thread.fork", 1, &[("source", "slash_command")]);
                let summary = session_summary(
                    self.chat_widget.token_usage(),
                    self.chat_widget.thread_id(),
                    self.chat_widget.thread_name(),
                );
                self.chat_widget
                    .add_plain_history_lines(vec!["/fork".magenta().into()]);
                if let Some(path) = self.chat_widget.rollout_path() {
                    // Fresh threads expose a precomputed path, but the file is
                    // materialized lazily on first user message.
                    if path.exists() {
                        match self
                            .server
                            .fork_thread(usize::MAX, self.config.clone(), path.clone(), false)
                            .await
                        {
                            Ok(forked) => {
                                self.shutdown_current_thread().await;
                                let init = self.chatwidget_init_for_forked_or_resumed_thread(
                                    tui,
                                    self.config.clone(),
                                );
                                self.chat_widget = ChatWidget::new_from_existing(
                                    init,
                                    forked.thread,
                                    forked.session_configured,
                                );
                                self.reset_thread_event_state();
                                if let Some(summary) = summary {
                                    let mut lines: Vec<Line<'static>> =
                                        vec![summary.usage_line.clone().into()];
                                    if let Some(command) = summary.resume_command {
                                        let spans = vec![
                                            "To continue this session, run ".into(),
                                            command.cyan(),
                                        ];
                                        lines.push(spans.into());
                                    }
                                    self.chat_widget.add_plain_history_lines(lines);
                                }
                            }
                            Err(err) => {
                                let path_display = path.display();
                                self.chat_widget.add_error_message(format!(
                                    "Failed to fork current session from {path_display}: {err}"
                                ));
                            }
                        }
                    } else {
                        self.chat_widget.add_error_message(
                            "A thread must contain at least one turn before it can be forked."
                                .to_string(),
                        );
                    }
                } else {
                    self.chat_widget.add_error_message(
                        "A thread must contain at least one turn before it can be forked."
                            .to_string(),
                    );
                }

                tui.frame_requester().schedule_frame();
            }
            AppEvent::InsertHistoryCell(cell) => {
                let cell: Arc<dyn HistoryCell> = cell.into();
                if let Some(Overlay::Transcript(t)) = &mut self.overlay {
                    t.insert_cell(cell.clone());
                    tui.frame_requester().schedule_frame();
                }
                self.transcript_cells.push(cell.clone());
                let mut display = cell.display_lines(tui.terminal.last_known_screen_size.width);
                if !display.is_empty() {
                    // Only insert a separating blank line for new cells that are not
                    // part of an ongoing stream. Streaming continuations should not
                    // accrue extra blank lines between chunks.
                    if !cell.is_stream_continuation() {
                        if self.has_emitted_history_lines {
                            display.insert(0, Line::from(""));
                        } else {
                            self.has_emitted_history_lines = true;
                        }
                    }
                    if self.overlay.is_some() {
                        self.deferred_history_lines.extend(display);
                    } else {
                        tui.insert_history_lines(display);
                    }
                }
            }
            AppEvent::ApplyThreadRollback { num_turns } => {
                if self.apply_non_pending_thread_rollback(num_turns) {
                    tui.frame_requester().schedule_frame();
                }
            }
            AppEvent::StartCommitAnimation => {
                if self
                    .commit_anim_running
                    .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
                    .is_ok()
                {
                    let tx = self.app_event_tx.clone();
                    let running = self.commit_anim_running.clone();
                    thread::spawn(move || {
                        while running.load(Ordering::Relaxed) {
                            thread::sleep(COMMIT_ANIMATION_TICK);
                            tx.send(AppEvent::CommitTick);
                        }
                    });
                }
            }
            AppEvent::StopCommitAnimation => {
                self.commit_anim_running.store(false, Ordering::Release);
            }
            AppEvent::CommitTick => {
                self.chat_widget.on_commit_tick();
            }
            AppEvent::CodexEvent(event) => {
                self.enqueue_primary_event(event).await?;
            }
            AppEvent::ThreadEvent { thread_id, event } => {
                self.handle_routed_thread_event(thread_id, event).await?;
            }
            AppEvent::Exit(mode) => {
                return Ok(self.handle_exit_mode(mode));
            }
            AppEvent::FatalExitRequest(message) => {
                return Ok(AppRunControl::Exit(ExitReason::Fatal(message)));
            }
            AppEvent::CodexOp(op) => {
                let replay_state_op =
                    ThreadEventStore::op_can_change_pending_replay_state(&op).then(|| op.clone());
                let submitted = self.chat_widget.submit_op(op);
                if submitted && let Some(op) = replay_state_op.as_ref() {
                    self.note_active_thread_outbound_op(op).await;
                    self.refresh_pending_thread_approvals().await;
                }
            }
            AppEvent::SubmitThreadOp { thread_id, op } => {
                self.submit_op_to_thread(thread_id, op).await;
            }
            AppEvent::DiffResult(text) => {
                // Clear the in-progress state in the bottom pane
                self.chat_widget.on_diff_complete();
                // Enter alternate screen using TUI helper and build pager lines
                let _ = tui.enter_alt_screen();
                let pager_lines: Vec<ratatui::text::Line<'static>> = if text.trim().is_empty() {
                    vec!["No changes detected.".italic().into()]
                } else {
                    text.lines().map(ansi_escape_line).collect()
                };
                self.overlay = Some(Overlay::new_static_with_lines(
                    pager_lines,
                    "D I F F".to_string(),
                ));
                tui.frame_requester().schedule_frame();
            }
            AppEvent::OpenAppLink {
                app_id,
                title,
                description,
                instructions,
                url,
                is_installed,
                is_enabled,
            } => {
                self.chat_widget
                    .open_app_link_view(crate::bottom_pane::AppLinkViewParams {
                        app_id,
                        title,
                        description,
                        instructions,
                        url,
                        is_installed,
                        is_enabled,
                    });
            }
            AppEvent::OpenUrlInBrowser { url } => {
                self.open_url_in_browser(url);
            }
            AppEvent::RefreshConnectors { force_refetch } => {
                self.chat_widget.refresh_connectors(force_refetch);
            }
            AppEvent::StartFileSearch(query) => {
                self.file_search.on_user_query(query);
            }
            AppEvent::FileSearchResult { query, matches } => {
                self.chat_widget.apply_file_search_result(query, matches);
            }
            AppEvent::RateLimitSnapshotFetched(snapshot) => {
                self.chat_widget.on_rate_limit_snapshot(Some(snapshot));
            }
            AppEvent::ConnectorsLoaded { result, is_final } => {
                self.chat_widget.on_connectors_loaded(result, is_final);
            }
            AppEvent::UpdateReasoningEffort(effort) => {
                self.on_update_reasoning_effort(effort);
                self.refresh_status_line();
            }
            AppEvent::UpdateModel(model) => {
                self.chat_widget.set_model(&model);
                self.refresh_status_line();
            }
            AppEvent::UpdateCollaborationMode(mask) => {
                self.chat_widget.set_collaboration_mask(mask);
                self.refresh_status_line();
            }
            AppEvent::UpdatePersonality(personality) => {
                self.on_update_personality(personality);
            }
            AppEvent::OpenRealtimeAudioDeviceSelection { kind } => {
                self.chat_widget.open_realtime_audio_device_selection(kind);
            }
            AppEvent::OpenReasoningPopup { model } => {
                self.chat_widget.open_reasoning_popup(model);
            }
            AppEvent::OpenPlanReasoningScopePrompt { model, effort } => {
                self.chat_widget
                    .open_plan_reasoning_scope_prompt(model, effort);
            }
            AppEvent::OpenAllModelsPopup { models } => {
                self.chat_widget.open_all_models_popup(models);
            }
            AppEvent::OpenFullAccessConfirmation {
                preset,
                return_to_permissions,
            } => {
                self.chat_widget
                    .open_full_access_confirmation(preset, return_to_permissions);
            }
            AppEvent::OpenWorldWritableWarningConfirmation {
                preset,
                sample_paths,
                extra_count,
                failed_scan,
            } => {
                self.chat_widget.open_world_writable_warning_confirmation(
                    preset,
                    sample_paths,
                    extra_count,
                    failed_scan,
                );
            }
            AppEvent::OpenFeedbackNote {
                category,
                include_logs,
            } => {
                self.chat_widget.open_feedback_note(category, include_logs);
            }
            AppEvent::OpenFeedbackConsent { category } => {
                self.chat_widget.open_feedback_consent(category);
            }
            AppEvent::LaunchExternalEditor => {
                if self.chat_widget.external_editor_state() == ExternalEditorState::Active {
                    self.launch_external_editor(tui).await;
                }
            }
            AppEvent::OpenWindowsSandboxEnablePrompt { preset } => {
                self.chat_widget.open_windows_sandbox_enable_prompt(preset);
            }
            AppEvent::OpenWindowsSandboxFallbackPrompt { preset } => {
                self.otel_manager
                    .counter("codex.windows_sandbox.fallback_prompt_shown", 1, &[]);
                self.chat_widget.clear_windows_sandbox_setup_status();
                if let Some(started_at) = self.windows_sandbox.setup_started_at.take() {
                    self.otel_manager.record_duration(
                        "codex.windows_sandbox.elevated_setup_duration_ms",
                        started_at.elapsed(),
                        &[("result", "failure")],
                    );
                }
                self.chat_widget
                    .open_windows_sandbox_fallback_prompt(preset);
            }
            AppEvent::BeginWindowsSandboxElevatedSetup { preset } => {
                #[cfg(target_os = "windows")]
                {
                    let policy = preset.sandbox.clone();
                    let policy_cwd = self.config.cwd.clone();
                    let command_cwd = policy_cwd.clone();
                    let env_map: std::collections::HashMap<String, String> =
                        std::env::vars().collect();
                    let codex_home = self.config.codex_home.clone();
                    let tx = self.app_event_tx.clone();

                    // If the elevated setup already ran on this machine, don't prompt for
                    // elevation again - just flip the config to use the elevated path.
                    if codex_core::windows_sandbox::sandbox_setup_is_complete(codex_home.as_path())
                    {
                        tx.send(AppEvent::EnableWindowsSandboxForAgentMode {
                            preset,
                            mode: WindowsSandboxEnableMode::Elevated,
                        });
                        return Ok(AppRunControl::Continue);
                    }

                    self.chat_widget.show_windows_sandbox_setup_status();
                    self.windows_sandbox.setup_started_at = Some(Instant::now());
                    let otel_manager = self.otel_manager.clone();
                    tokio::task::spawn_blocking(move || {
                        let result = codex_core::windows_sandbox::run_elevated_setup(
                            &policy,
                            policy_cwd.as_path(),
                            command_cwd.as_path(),
                            &env_map,
                            codex_home.as_path(),
                        );
                        let event = match result {
                            Ok(()) => {
                                otel_manager.counter(
                                    "codex.windows_sandbox.elevated_setup_success",
                                    1,
                                    &[],
                                );
                                AppEvent::EnableWindowsSandboxForAgentMode {
                                    preset: preset.clone(),
                                    mode: WindowsSandboxEnableMode::Elevated,
                                }
                            }
                            Err(err) => {
                                let mut code_tag: Option<String> = None;
                                let mut message_tag: Option<String> = None;
                                if let Some((code, message)) =
                                    codex_core::windows_sandbox::elevated_setup_failure_details(
                                        &err,
                                    )
                                {
                                    code_tag = Some(code);
                                    message_tag = Some(message);
                                }
                                let mut tags: Vec<(&str, &str)> = Vec::new();
                                if let Some(code) = code_tag.as_deref() {
                                    tags.push(("code", code));
                                }
                                if let Some(message) = message_tag.as_deref() {
                                    tags.push(("message", message));
                                }
                                otel_manager.counter(
                                    codex_core::windows_sandbox::elevated_setup_failure_metric_name(
                                        &err,
                                    ),
                                    1,
                                    &tags,
                                );
                                tracing::error!(
                                    error = %err,
                                    "failed to run elevated Windows sandbox setup"
                                );
                                AppEvent::OpenWindowsSandboxFallbackPrompt { preset }
                            }
                        };
                        tx.send(event);
                    });
                }
                #[cfg(not(target_os = "windows"))]
                {
                    let _ = preset;
                }
            }
            AppEvent::BeginWindowsSandboxLegacySetup { preset } => {
                #[cfg(target_os = "windows")]
                {
                    let policy = preset.sandbox.clone();
                    let policy_cwd = self.config.cwd.clone();
                    let command_cwd = policy_cwd.clone();
                    let env_map: std::collections::HashMap<String, String> =
                        std::env::vars().collect();
                    let codex_home = self.config.codex_home.clone();
                    let tx = self.app_event_tx.clone();
                    let otel_manager = self.otel_manager.clone();

                    self.chat_widget.show_windows_sandbox_setup_status();
                    tokio::task::spawn_blocking(move || {
                        if let Err(err) = codex_core::windows_sandbox::run_legacy_setup_preflight(
                            &policy,
                            policy_cwd.as_path(),
                            command_cwd.as_path(),
                            &env_map,
                            codex_home.as_path(),
                        ) {
                            otel_manager.counter(
                                "codex.windows_sandbox.legacy_setup_preflight_failed",
                                1,
                                &[],
                            );
                            tracing::warn!(
                                error = %err,
                                "failed to preflight non-admin Windows sandbox setup"
                            );
                        }
                        tx.send(AppEvent::EnableWindowsSandboxForAgentMode {
                            preset,
                            mode: WindowsSandboxEnableMode::Legacy,
                        });
                    });
                }
                #[cfg(not(target_os = "windows"))]
                {
                    let _ = preset;
                }
            }
            AppEvent::BeginWindowsSandboxGrantReadRoot { path } => {
                #[cfg(target_os = "windows")]
                {
                    self.chat_widget
                        .add_to_history(history_cell::new_info_event(
                            format!("Granting sandbox read access to {path} ..."),
                            None,
                        ));

                    let policy = self.config.permissions.sandbox_policy.get().clone();
                    let policy_cwd = self.config.cwd.clone();
                    let command_cwd = self.config.cwd.clone();
                    let env_map: std::collections::HashMap<String, String> =
                        std::env::vars().collect();
                    let codex_home = self.config.codex_home.clone();
                    let tx = self.app_event_tx.clone();

                    tokio::task::spawn_blocking(move || {
                        let requested_path = PathBuf::from(path);
                        let event = match codex_core::windows_sandbox_read_grants::grant_read_root_non_elevated(
                            &policy,
                            policy_cwd.as_path(),
                            command_cwd.as_path(),
                            &env_map,
                            codex_home.as_path(),
                            requested_path.as_path(),
                        ) {
                            Ok(canonical_path) => AppEvent::WindowsSandboxGrantReadRootCompleted {
                                path: canonical_path,
                                error: None,
                            },
                            Err(err) => AppEvent::WindowsSandboxGrantReadRootCompleted {
                                path: requested_path,
                                error: Some(err.to_string()),
                            },
                        };
                        tx.send(event);
                    });
                }
                #[cfg(not(target_os = "windows"))]
                {
                    let _ = path;
                }
            }
            AppEvent::WindowsSandboxGrantReadRootCompleted { path, error } => match error {
                Some(err) => {
                    self.chat_widget
                        .add_to_history(history_cell::new_error_event(format!("Error: {err}")));
                }
                None => {
                    self.chat_widget
                        .add_to_history(history_cell::new_info_event(
                            format!("Sandbox read access granted for {}", path.display()),
                            None,
                        ));
                }
            },
            AppEvent::EnableWindowsSandboxForAgentMode { preset, mode } => {
                #[cfg(target_os = "windows")]
                {
                    self.chat_widget.clear_windows_sandbox_setup_status();
                    if let Some(started_at) = self.windows_sandbox.setup_started_at.take() {
                        self.otel_manager.record_duration(
                            "codex.windows_sandbox.elevated_setup_duration_ms",
                            started_at.elapsed(),
                            &[("result", "success")],
                        );
                    }
                    let profile = self.active_profile.as_deref();
                    let elevated_enabled = matches!(mode, WindowsSandboxEnableMode::Elevated);
                    let builder = ConfigEditsBuilder::new(&self.config.codex_home)
                        .with_profile(profile)
                        .set_windows_sandbox_mode(if elevated_enabled {
                            "elevated"
                        } else {
                            "unelevated"
                        })
                        .clear_legacy_windows_sandbox_keys();
                    match builder.apply().await {
                        Ok(()) => {
                            if elevated_enabled {
                                self.config.set_windows_sandbox_enabled(false);
                                self.config.set_windows_elevated_sandbox_enabled(true);
                            } else {
                                self.config.set_windows_sandbox_enabled(true);
                                self.config.set_windows_elevated_sandbox_enabled(false);
                            }
                            self.chat_widget.set_windows_sandbox_mode(
                                self.config.permissions.windows_sandbox_mode,
                            );
                            let windows_sandbox_level =
                                WindowsSandboxLevel::from_config(&self.config);
                            if let Some((sample_paths, extra_count, failed_scan)) =
                                self.chat_widget.world_writable_warning_details()
                            {
                                self.app_event_tx.send(AppEvent::CodexOp(
                                    Op::OverrideTurnContext {
                                        cwd: None,
                                        approval_policy: None,
                                        sandbox_policy: None,
                                        windows_sandbox_level: Some(windows_sandbox_level),
                                        model: None,
                                        effort: None,
                                        summary: None,
                                        service_tier: None,
                                        collaboration_mode: None,
                                        personality: None,
                                    },
                                ));
                                self.app_event_tx.send(
                                    AppEvent::OpenWorldWritableWarningConfirmation {
                                        preset: Some(preset.clone()),
                                        sample_paths,
                                        extra_count,
                                        failed_scan,
                                    },
                                );
                            } else {
                                self.app_event_tx.send(AppEvent::CodexOp(
                                    Op::OverrideTurnContext {
                                        cwd: None,
                                        approval_policy: Some(preset.approval),
                                        sandbox_policy: Some(preset.sandbox.clone()),
                                        windows_sandbox_level: Some(windows_sandbox_level),
                                        model: None,
                                        effort: None,
                                        summary: None,
                                        service_tier: None,
                                        collaboration_mode: None,
                                        personality: None,
                                    },
                                ));
                                self.app_event_tx
                                    .send(AppEvent::UpdateAskForApprovalPolicy(preset.approval));
                                self.app_event_tx
                                    .send(AppEvent::UpdateSandboxPolicy(preset.sandbox.clone()));
                                let _ = mode;
                                self.chat_widget.add_plain_history_lines(vec![
                                    Line::from(vec!["• ".dim(), "Sandbox ready".into()]),
                                    Line::from(vec![
                                        "  ".into(),
                                        "Codex can now safely edit files and execute commands in your computer"
                                            .dark_gray(),
                                    ]),
                                ]);
                            }
                        }
                        Err(err) => {
                            tracing::error!(
                                error = %err,
                                "failed to enable Windows sandbox feature"
                            );
                            self.chat_widget.add_error_message(format!(
                                "Failed to enable the Windows sandbox feature: {err}"
                            ));
                        }
                    }
                }
                #[cfg(not(target_os = "windows"))]
                {
                    let _ = (preset, mode);
                }
            }
            AppEvent::PersistModelSelection { model, effort } => {
                let profile = self.active_profile.as_deref();
                match ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_profile(profile)
                    .set_model(Some(model.as_str()), effort)
                    .apply()
                    .await
                {
                    Ok(()) => {
                        let effort_label = effort
                            .map(|selected_effort| selected_effort.to_string())
                            .unwrap_or_else(|| "default".to_string());
                        tracing::info!("Selected model: {model}, Selected effort: {effort_label}");
                        let mut message = format!("Model changed to {model}");
                        if let Some(label) = Self::reasoning_label_for(&model, effort) {
                            message.push(' ');
                            message.push_str(label);
                        }
                        if let Some(profile) = profile {
                            message.push_str(" for ");
                            message.push_str(profile);
                            message.push_str(" profile");
                        }
                        self.chat_widget.add_info_message(message, None);
                    }
                    Err(err) => {
                        tracing::error!(
                            error = %err,
                            "failed to persist model selection"
                        );
                        if let Some(profile) = profile {
                            self.chat_widget.add_error_message(format!(
                                "Failed to save model for profile `{profile}`: {err}"
                            ));
                        } else {
                            self.chat_widget
                                .add_error_message(format!("Failed to save default model: {err}"));
                        }
                    }
                }
            }
            AppEvent::PersistPersonalitySelection { personality } => {
                let profile = self.active_profile.as_deref();
                match ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_profile(profile)
                    .set_personality(Some(personality))
                    .apply()
                    .await
                {
                    Ok(()) => {
                        let label = Self::personality_label(personality);
                        let mut message = format!("Personality set to {label}");
                        if let Some(profile) = profile {
                            message.push_str(" for ");
                            message.push_str(profile);
                            message.push_str(" profile");
                        }
                        self.chat_widget.add_info_message(message, None);
                    }
                    Err(err) => {
                        tracing::error!(
                            error = %err,
                            "failed to persist personality selection"
                        );
                        if let Some(profile) = profile {
                            self.chat_widget.add_error_message(format!(
                                "Failed to save personality for profile `{profile}`: {err}"
                            ));
                        } else {
                            self.chat_widget.add_error_message(format!(
                                "Failed to save default personality: {err}"
                            ));
                        }
                    }
                }
            }
            AppEvent::PersistServiceTierSelection { service_tier } => {
                self.refresh_status_line();
                let profile = self.active_profile.as_deref();
                match ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_profile(profile)
                    .set_service_tier(service_tier)
                    .apply()
                    .await
                {
                    Ok(()) => {
                        let status = if service_tier.is_some() { "on" } else { "off" };
                        let mut message = format!("Fast mode set to {status}");
                        if let Some(profile) = profile {
                            message.push_str(" for ");
                            message.push_str(profile);
                            message.push_str(" profile");
                        }
                        self.chat_widget.add_info_message(message, None);
                    }
                    Err(err) => {
                        tracing::error!(error = %err, "failed to persist fast mode selection");
                        if let Some(profile) = profile {
                            self.chat_widget.add_error_message(format!(
                                "Failed to save Fast mode for profile `{profile}`: {err}"
                            ));
                        } else {
                            self.chat_widget.add_error_message(format!(
                                "Failed to save default Fast mode: {err}"
                            ));
                        }
                    }
                }
            }
            AppEvent::PersistRealtimeAudioDeviceSelection { kind, name } => {
                let builder = match kind {
                    RealtimeAudioDeviceKind::Microphone => {
                        ConfigEditsBuilder::new(&self.config.codex_home)
                            .set_realtime_microphone(name.as_deref())
                    }
                    RealtimeAudioDeviceKind::Speaker => {
                        ConfigEditsBuilder::new(&self.config.codex_home)
                            .set_realtime_speaker(name.as_deref())
                    }
                };

                match builder.apply().await {
                    Ok(()) => {
                        match kind {
                            RealtimeAudioDeviceKind::Microphone => {
                                self.config.realtime_audio.microphone = name.clone();
                            }
                            RealtimeAudioDeviceKind::Speaker => {
                                self.config.realtime_audio.speaker = name.clone();
                            }
                        }
                        self.chat_widget
                            .set_realtime_audio_device(kind, name.clone());

                        if self.chat_widget.realtime_conversation_is_live() {
                            self.chat_widget.open_realtime_audio_restart_prompt(kind);
                        } else {
                            let selection = name.unwrap_or_else(|| "System default".to_string());
                            self.chat_widget.add_info_message(
                                format!("Realtime {} set to {selection}", kind.noun()),
                                None,
                            );
                        }
                    }
                    Err(err) => {
                        tracing::error!(
                            error = %err,
                            "failed to persist realtime audio selection"
                        );
                        self.chat_widget.add_error_message(format!(
                            "Failed to save realtime {}: {err}",
                            kind.noun()
                        ));
                    }
                }
            }
            AppEvent::RestartRealtimeAudioDevice { kind } => {
                self.chat_widget.restart_realtime_audio_device(kind);
            }
            AppEvent::UpdateAskForApprovalPolicy(policy) => {
                self.runtime_approval_policy_override = Some(policy);
                if let Err(err) = self.config.permissions.approval_policy.set(policy) {
                    tracing::warn!(%err, "failed to set approval policy on app config");
                    self.chat_widget
                        .add_error_message(format!("Failed to set approval policy: {err}"));
                    return Ok(AppRunControl::Continue);
                }
                self.chat_widget.set_approval_policy(policy);
            }
            AppEvent::UpdateSandboxPolicy(policy) => {
                #[cfg(target_os = "windows")]
                let policy_is_workspace_write_or_ro = matches!(
                    &policy,
                    codex_protocol::protocol::SandboxPolicy::WorkspaceWrite { .. }
                        | codex_protocol::protocol::SandboxPolicy::ReadOnly { .. }
                );
                let policy_for_chat = policy.clone();

                if let Err(err) = self.config.permissions.sandbox_policy.set(policy) {
                    tracing::warn!(%err, "failed to set sandbox policy on app config");
                    self.chat_widget
                        .add_error_message(format!("Failed to set sandbox policy: {err}"));
                    return Ok(AppRunControl::Continue);
                }
                if let Err(err) = self.chat_widget.set_sandbox_policy(policy_for_chat) {
                    tracing::warn!(%err, "failed to set sandbox policy on chat config");
                    self.chat_widget
                        .add_error_message(format!("Failed to set sandbox policy: {err}"));
                    return Ok(AppRunControl::Continue);
                }
                self.runtime_sandbox_policy_override =
                    Some(self.config.permissions.sandbox_policy.get().clone());

                // If sandbox policy becomes workspace-write or read-only, run the Windows world-writable scan.
                #[cfg(target_os = "windows")]
                {
                    // One-shot suppression if the user just confirmed continue.
                    if self.windows_sandbox.skip_world_writable_scan_once {
                        self.windows_sandbox.skip_world_writable_scan_once = false;
                        return Ok(AppRunControl::Continue);
                    }

                    let should_check = WindowsSandboxLevel::from_config(&self.config)
                        != WindowsSandboxLevel::Disabled
                        && policy_is_workspace_write_or_ro
                        && !self.chat_widget.world_writable_warning_hidden();
                    if should_check {
                        let cwd = self.config.cwd.clone();
                        let env_map: std::collections::HashMap<String, String> =
                            std::env::vars().collect();
                        let tx = self.app_event_tx.clone();
                        let logs_base_dir = self.config.codex_home.clone();
                        let sandbox_policy = self.config.permissions.sandbox_policy.get().clone();
                        Self::spawn_world_writable_scan(
                            cwd,
                            env_map,
                            logs_base_dir,
                            sandbox_policy,
                            tx,
                        );
                    }
                }
            }
            AppEvent::UpdateFeatureFlags { updates } => {
                if updates.is_empty() {
                    return Ok(AppRunControl::Continue);
                }
                let windows_sandbox_changed = updates.iter().any(|(feature, _)| {
                    matches!(
                        feature,
                        Feature::WindowsSandbox | Feature::WindowsSandboxElevated
                    )
                });
                let mut builder = ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_profile(self.active_profile.as_deref());
                for (feature, enabled) in &updates {
                    let feature_key = feature.key();
                    if let Err(err) = self.config.features.set_enabled(*feature, *enabled) {
                        tracing::error!(
                            error = %err,
                            feature = feature_key,
                            "failed to update constrained feature flags"
                        );
                        self.chat_widget.add_error_message(format!(
                            "Failed to update experimental feature `{feature_key}`: {err}"
                        ));
                        continue;
                    }
                    let effective_enabled = self.config.features.enabled(*feature);
                    self.chat_widget
                        .set_feature_enabled(*feature, effective_enabled);
                    if effective_enabled {
                        builder = builder.set_feature_enabled(feature_key, true);
                    } else if feature.default_enabled() {
                        builder = builder.set_feature_enabled(feature_key, false);
                    } else {
                        // If the feature already default to `false`, we drop the key
                        // in the config file so that the user does not miss the feature
                        // once it gets globally released.
                        builder = builder.with_edits(vec![ConfigEdit::ClearPath {
                            segments: vec!["features".to_string(), feature_key.to_string()],
                        }]);
                    }
                }
                if windows_sandbox_changed {
                    #[cfg(target_os = "windows")]
                    {
                        let windows_sandbox_level = WindowsSandboxLevel::from_config(&self.config);
                        self.app_event_tx
                            .send(AppEvent::CodexOp(Op::OverrideTurnContext {
                                cwd: None,
                                approval_policy: None,
                                sandbox_policy: None,
                                windows_sandbox_level: Some(windows_sandbox_level),
                                model: None,
                                effort: None,
                                summary: None,
                                service_tier: None,
                                collaboration_mode: None,
                                personality: None,
                            }));
                    }
                }
                if let Err(err) = builder.apply().await {
                    tracing::error!(error = %err, "failed to persist feature flags");
                    self.chat_widget.add_error_message(format!(
                        "Failed to update experimental features: {err}"
                    ));
                }
            }
            AppEvent::SkipNextWorldWritableScan => {
                self.windows_sandbox.skip_world_writable_scan_once = true;
            }
            AppEvent::UpdateFullAccessWarningAcknowledged(ack) => {
                self.chat_widget.set_full_access_warning_acknowledged(ack);
            }
            AppEvent::UpdateWorldWritableWarningAcknowledged(ack) => {
                self.chat_widget
                    .set_world_writable_warning_acknowledged(ack);
            }
            AppEvent::UpdateRateLimitSwitchPromptHidden(hidden) => {
                self.chat_widget.set_rate_limit_switch_prompt_hidden(hidden);
            }
            AppEvent::UpdatePlanModeReasoningEffort(effort) => {
                self.config.plan_mode_reasoning_effort = effort;
                self.chat_widget.set_plan_mode_reasoning_effort(effort);
                self.refresh_status_line();
            }
            AppEvent::PersistFullAccessWarningAcknowledged => {
                if let Err(err) = ConfigEditsBuilder::new(&self.config.codex_home)
                    .set_hide_full_access_warning(true)
                    .apply()
                    .await
                {
                    tracing::error!(
                        error = %err,
                        "failed to persist full access warning acknowledgement"
                    );
                    self.chat_widget.add_error_message(format!(
                        "Failed to save full access confirmation preference: {err}"
                    ));
                }
            }
            AppEvent::PersistWorldWritableWarningAcknowledged => {
                if let Err(err) = ConfigEditsBuilder::new(&self.config.codex_home)
                    .set_hide_world_writable_warning(true)
                    .apply()
                    .await
                {
                    tracing::error!(
                        error = %err,
                        "failed to persist world-writable warning acknowledgement"
                    );
                    self.chat_widget.add_error_message(format!(
                        "Failed to save Agent mode warning preference: {err}"
                    ));
                }
            }
            AppEvent::PersistRateLimitSwitchPromptHidden => {
                if let Err(err) = ConfigEditsBuilder::new(&self.config.codex_home)
                    .set_hide_rate_limit_model_nudge(true)
                    .apply()
                    .await
                {
                    tracing::error!(
                        error = %err,
                        "failed to persist rate limit switch prompt preference"
                    );
                    self.chat_widget.add_error_message(format!(
                        "Failed to save rate limit reminder preference: {err}"
                    ));
                }
            }
            AppEvent::PersistPlanModeReasoningEffort(effort) => {
                let profile = self.active_profile.as_deref();
                let segments = if let Some(profile) = profile {
                    vec![
                        "profiles".to_string(),
                        profile.to_string(),
                        "plan_mode_reasoning_effort".to_string(),
                    ]
                } else {
                    vec!["plan_mode_reasoning_effort".to_string()]
                };
                let edit = if let Some(effort) = effort {
                    ConfigEdit::SetPath {
                        segments,
                        value: effort.to_string().into(),
                    }
                } else {
                    ConfigEdit::ClearPath { segments }
                };
                if let Err(err) = ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_edits([edit])
                    .apply()
                    .await
                {
                    tracing::error!(
                        error = %err,
                        "failed to persist plan mode reasoning effort"
                    );
                    if let Some(profile) = profile {
                        self.chat_widget.add_error_message(format!(
                            "Failed to save Plan mode reasoning effort for profile `{profile}`: {err}"
                        ));
                    } else {
                        self.chat_widget.add_error_message(format!(
                            "Failed to save Plan mode reasoning effort: {err}"
                        ));
                    }
                }
            }
            AppEvent::PersistModelMigrationPromptAcknowledged {
                from_model,
                to_model,
            } => {
                if let Err(err) = ConfigEditsBuilder::new(&self.config.codex_home)
                    .record_model_migration_seen(from_model.as_str(), to_model.as_str())
                    .apply()
                    .await
                {
                    tracing::error!(
                        error = %err,
                        "failed to persist model migration prompt acknowledgement"
                    );
                    self.chat_widget.add_error_message(format!(
                        "Failed to save model migration prompt preference: {err}"
                    ));
                }
            }
            AppEvent::OpenApprovalsPopup => {
                self.chat_widget.open_approvals_popup();
            }
            AppEvent::OpenAgentPicker => {
                self.open_agent_picker().await;
            }
            AppEvent::SelectAgentThread(thread_id) => {
                self.select_agent_thread(tui, thread_id).await?;
            }
            AppEvent::OpenSkillsList => {
                self.chat_widget.open_skills_list();
            }
            AppEvent::OpenManageSkillsPopup => {
                self.chat_widget.open_manage_skills_popup();
            }
            AppEvent::SetSkillEnabled { path, enabled } => {
                let edits = [ConfigEdit::SetSkillConfig {
                    path: path.clone(),
                    enabled,
                }];
                match ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_edits(edits)
                    .apply()
                    .await
                {
                    Ok(()) => {
                        self.chat_widget.update_skill_enabled(path.clone(), enabled);
                        if let Err(err) = self.refresh_in_memory_config_from_disk().await {
                            tracing::warn!(
                                error = %err,
                                "failed to refresh config after skill toggle"
                            );
                        }
                    }
                    Err(err) => {
                        let path_display = path.display();
                        self.chat_widget.add_error_message(format!(
                            "Failed to update skill config for {path_display}: {err}"
                        ));
                    }
                }
            }
            AppEvent::SetAppEnabled { id, enabled } => {
                let edits = if enabled {
                    vec![
                        ConfigEdit::ClearPath {
                            segments: vec!["apps".to_string(), id.clone(), "enabled".to_string()],
                        },
                        ConfigEdit::ClearPath {
                            segments: vec![
                                "apps".to_string(),
                                id.clone(),
                                "disabled_reason".to_string(),
                            ],
                        },
                    ]
                } else {
                    vec![
                        ConfigEdit::SetPath {
                            segments: vec!["apps".to_string(), id.clone(), "enabled".to_string()],
                            value: false.into(),
                        },
                        ConfigEdit::SetPath {
                            segments: vec![
                                "apps".to_string(),
                                id.clone(),
                                "disabled_reason".to_string(),
                            ],
                            value: "user".into(),
                        },
                    ]
                };
                match ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_edits(edits)
                    .apply()
                    .await
                {
                    Ok(()) => {
                        self.chat_widget.update_connector_enabled(&id, enabled);
                        if let Err(err) = self.refresh_in_memory_config_from_disk().await {
                            tracing::warn!(error = %err, "failed to refresh config after app toggle");
                        }
                        self.chat_widget.submit_op(Op::ReloadUserConfig);
                    }
                    Err(err) => {
                        self.chat_widget.add_error_message(format!(
                            "Failed to update app config for {id}: {err}"
                        ));
                    }
                }
            }
            AppEvent::OpenPermissionsPopup => {
                self.chat_widget.open_permissions_popup();
            }
            AppEvent::OpenReviewBranchPicker(cwd) => {
                self.chat_widget.show_review_branch_picker(&cwd).await;
            }
            AppEvent::OpenReviewCommitPicker(cwd) => {
                self.chat_widget.show_review_commit_picker(&cwd).await;
            }
            AppEvent::OpenReviewCustomPrompt => {
                self.chat_widget.show_review_custom_prompt();
            }
            AppEvent::SubmitUserMessageWithMode {
                text,
                collaboration_mode,
            } => {
                self.chat_widget
                    .submit_user_message_with_mode(text, collaboration_mode);
            }
            AppEvent::ManageSkillsClosed => {
                self.chat_widget.handle_manage_skills_closed();
            }
            AppEvent::FullScreenApprovalRequest(request) => match request {
                ApprovalRequest::ApplyPatch { cwd, changes, .. } => {
                    let _ = tui.enter_alt_screen();
                    let diff_summary = DiffSummary::new(changes, cwd);
                    self.overlay = Some(Overlay::new_static_with_renderables(
                        vec![diff_summary.into()],
                        "P A T C H".to_string(),
                    ));
                }
                ApprovalRequest::Exec { command, .. } => {
                    let _ = tui.enter_alt_screen();
                    let full_cmd = strip_bash_lc_and_escape(&command);
                    let full_cmd_lines = highlight_bash_to_lines(&full_cmd);
                    self.overlay = Some(Overlay::new_static_with_lines(
                        full_cmd_lines,
                        "E X E C".to_string(),
                    ));
                }
                ApprovalRequest::McpElicitation {
                    server_name,
                    message,
                    ..
                } => {
                    let _ = tui.enter_alt_screen();
                    let paragraph = Paragraph::new(vec![
                        Line::from(vec!["Server: ".into(), server_name.bold()]),
                        Line::from(""),
                        Line::from(message),
                    ])
                    .wrap(Wrap { trim: false });
                    self.overlay = Some(Overlay::new_static_with_renderables(
                        vec![Box::new(paragraph)],
                        "E L I C I T A T I O N".to_string(),
                    ));
                }
            },
            #[cfg(not(target_os = "linux"))]
            AppEvent::TranscriptionComplete { id, text } => {
                self.chat_widget.replace_transcription(&id, &text);
            }
            #[cfg(not(target_os = "linux"))]
            AppEvent::TranscriptionFailed { id, error: _ } => {
                self.chat_widget.remove_transcription_placeholder(&id);
            }
            #[cfg(not(target_os = "linux"))]
            AppEvent::UpdateRecordingMeter { id, text } => {
                // Update in place to preserve the element id for subsequent frames.
                let updated = self.chat_widget.update_transcription_in_place(&id, &text);
                if updated {
                    tui.frame_requester().schedule_frame();
                }
            }
            AppEvent::StatusLineSetup { items } => {
                let ids = items.iter().map(ToString::to_string).collect::<Vec<_>>();
                let edit = codex_core::config::edit::status_line_items_edit(&ids);
                let apply_result = ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_edits([edit])
                    .apply()
                    .await;
                match apply_result {
                    Ok(()) => {
                        self.config.tui_status_line = Some(ids.clone());
                        self.chat_widget.setup_status_line(items);
                    }
                    Err(err) => {
                        tracing::error!(error = %err, "failed to persist status line items; keeping previous selection");
                        self.chat_widget
                            .add_error_message(format!("Failed to save status line items: {err}"));
                    }
                }
            }
            AppEvent::StatusLineBranchUpdated { cwd, branch } => {
                self.chat_widget.set_status_line_branch(cwd, branch);
                self.refresh_status_line();
            }
            AppEvent::StatusLineSetupCancelled => {
                self.chat_widget.cancel_status_line_setup();
            }
            AppEvent::SyntaxThemeSelected { name } => {
                let edit = codex_core::config::edit::syntax_theme_edit(&name);
                let apply_result = ConfigEditsBuilder::new(&self.config.codex_home)
                    .with_edits([edit])
                    .apply()
                    .await;
                match apply_result {
                    Ok(()) => {
                        // Ensure the selected theme is active in the current
                        // session.  The preview callback covers arrow-key
                        // navigation, but if the user presses Enter without
                        // navigating, the runtime theme must still be applied.
                        if let Some(theme) = crate::render::highlight::resolve_theme_by_name(
                            &name,
                            Some(&self.config.codex_home),
                        ) {
                            crate::render::highlight::set_syntax_theme(theme);
                        }
                        self.sync_tui_theme_selection(name);
                    }
                    Err(err) => {
                        self.restore_runtime_theme_from_config();
                        tracing::error!(error = %err, "failed to persist theme selection");
                        self.chat_widget
                            .add_error_message(format!("Failed to save theme: {err}"));
                    }
                }
            }
        }
        Ok(AppRunControl::Continue)
    }

    fn handle_exit_mode(&mut self, mode: ExitMode) -> AppRunControl {
        match mode {
            ExitMode::ShutdownFirst => {
                // Mark the thread we are explicitly shutting down for exit so
                // its shutdown completion does not trigger agent failover.
                self.pending_shutdown_exit_thread_id =
                    self.active_thread_id.or(self.chat_widget.thread_id());
                if self.chat_widget.submit_op(Op::Shutdown) {
                    AppRunControl::Continue
                } else {
                    self.pending_shutdown_exit_thread_id = None;
                    AppRunControl::Exit(ExitReason::UserRequested)
                }
            }
            ExitMode::Immediate => {
                self.pending_shutdown_exit_thread_id = None;
                AppRunControl::Exit(ExitReason::UserRequested)
            }
        }
    }

    fn handle_codex_event_now(&mut self, event: Event) {
        let needs_refresh = matches!(
            event.msg,
            EventMsg::SessionConfigured(_) | EventMsg::TokenCount(_)
        );
        // This guard is only for intentional thread-switch shutdowns.
        // App-exit shutdowns are tracked by `pending_shutdown_exit_thread_id`
        // and resolved in `handle_active_thread_event`.
        if self.suppress_shutdown_complete && matches!(event.msg, EventMsg::ShutdownComplete) {
            self.suppress_shutdown_complete = false;
            return;
        }
        if let EventMsg::ListSkillsResponse(response) = &event.msg {
            let cwd = self.chat_widget.config_ref().cwd.clone();
            let errors = errors_for_cwd(&cwd, response);
            emit_skill_load_warnings(&self.app_event_tx, &errors);
        }
        self.handle_backtrack_event(&event.msg);
        self.chat_widget.handle_codex_event(event);

        if needs_refresh {
            self.refresh_status_line();
        }
    }

    fn handle_codex_event_replay(&mut self, event: Event) {
        self.chat_widget.handle_codex_event_replay(event);
    }

    /// Handles an event emitted by the currently active thread.
    ///
    /// This function enforces shutdown intent routing: unexpected non-primary
    /// thread shutdowns fail over to the primary thread, while user-requested
    /// app exits consume only the tracked shutdown completion and then proceed.
    async fn handle_active_thread_event(&mut self, tui: &mut tui::Tui, event: Event) -> Result<()> {
        // Capture this before any potential thread switch: we only want to clear
        // the exit marker when the currently active thread acknowledges shutdown.
        let pending_shutdown_exit_completed = matches!(&event.msg, EventMsg::ShutdownComplete)
            && self.pending_shutdown_exit_thread_id == self.active_thread_id;

        // Processing order matters:
        //
        // 1. handle unexpected non-primary shutdown failover first;
        // 2. clear pending exit marker for matching shutdown;
        // 3. forward the event through normal handling.
        //
        // This preserves the mental model that user-requested exits do not trigger
        // failover, while true sub-agent deaths still do.
        if let Some((closed_thread_id, primary_thread_id)) =
            self.active_non_primary_shutdown_target(&event.msg)
        {
            self.mark_agent_picker_thread_closed(closed_thread_id);
            self.select_agent_thread(tui, primary_thread_id).await?;
            if self.active_thread_id == Some(primary_thread_id) {
                self.chat_widget.add_info_message(
                    format!(
                        "Agent thread {closed_thread_id} closed. Switched back to main thread."
                    ),
                    None,
                );
            } else {
                self.clear_active_thread().await;
                self.chat_widget.add_error_message(format!(
                    "Agent thread {closed_thread_id} closed. Failed to switch back to main thread {primary_thread_id}.",
                ));
            }
            return Ok(());
        }

        if pending_shutdown_exit_completed {
            // Clear only after seeing the shutdown completion for the tracked
            // thread, so unrelated shutdowns cannot consume this marker.
            self.pending_shutdown_exit_thread_id = None;
        }
        self.handle_codex_event_now(event);
        if self.backtrack_render_pending {
            tui.frame_requester().schedule_frame();
        }
        Ok(())
    }

    async fn handle_thread_created(&mut self, thread_id: ThreadId) -> Result<()> {
        if self.thread_event_channels.contains_key(&thread_id) {
            return Ok(());
        }
        let thread = match self.server.get_thread(thread_id).await {
            Ok(thread) => thread,
            Err(err) => {
                tracing::warn!("failed to attach listener for thread {thread_id}: {err}");
                return Ok(());
            }
        };
        let config_snapshot = thread.config_snapshot().await;
        self.upsert_agent_picker_thread(
            thread_id,
            config_snapshot.session_source.get_nickname(),
            config_snapshot.session_source.get_agent_role(),
            false,
        );
        let event = Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id: thread_id,
                forked_from_id: None,
                thread_name: None,
                model: config_snapshot.model,
                model_provider_id: config_snapshot.model_provider_id,
                service_tier: config_snapshot.service_tier,
                approval_policy: config_snapshot.approval_policy,
                sandbox_policy: config_snapshot.sandbox_policy,
                cwd: config_snapshot.cwd,
                reasoning_effort: config_snapshot.reasoning_effort,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: thread.rollout_path(),
            }),
        };
        let channel =
            ThreadEventChannel::new_with_session_configured(THREAD_EVENT_CHANNEL_CAPACITY, event);
        let app_event_tx = self.app_event_tx.clone();
        self.thread_event_channels.insert(thread_id, channel);
        let listener_handle = tokio::spawn(async move {
            loop {
                let event = match thread.next_event().await {
                    Ok(event) => event,
                    Err(err) => {
                        tracing::debug!("external thread {thread_id} listener stopped: {err}");
                        break;
                    }
                };
                app_event_tx.send(AppEvent::ThreadEvent { thread_id, event });
            }
        });
        self.thread_event_listener_tasks
            .insert(thread_id, listener_handle);
        Ok(())
    }

    fn reasoning_label(reasoning_effort: Option<ReasoningEffortConfig>) -> &'static str {
        match reasoning_effort {
            Some(ReasoningEffortConfig::Minimal) => "minimal",
            Some(ReasoningEffortConfig::Low) => "low",
            Some(ReasoningEffortConfig::Medium) => "medium",
            Some(ReasoningEffortConfig::High) => "high",
            Some(ReasoningEffortConfig::XHigh) => "xhigh",
            None | Some(ReasoningEffortConfig::None) => "default",
        }
    }

    fn reasoning_label_for(
        model: &str,
        reasoning_effort: Option<ReasoningEffortConfig>,
    ) -> Option<&'static str> {
        (!model.starts_with("codex-auto-")).then(|| Self::reasoning_label(reasoning_effort))
    }

    pub(crate) fn token_usage(&self) -> codex_protocol::protocol::TokenUsage {
        self.chat_widget.token_usage()
    }

    fn on_update_reasoning_effort(&mut self, effort: Option<ReasoningEffortConfig>) {
        // TODO(aibrahim): Remove this and don't use config as a state object.
        // Instead, explicitly pass the stored collaboration mode's effort into new sessions.
        self.config.model_reasoning_effort = effort;
        self.chat_widget.set_reasoning_effort(effort);
    }

    fn on_update_personality(&mut self, personality: Personality) {
        self.config.personality = Some(personality);
        self.chat_widget.set_personality(personality);
    }

    fn sync_tui_theme_selection(&mut self, name: String) {
        self.config.tui_theme = Some(name.clone());
        self.chat_widget.set_tui_theme(Some(name));
    }

    fn restore_runtime_theme_from_config(&self) {
        if let Some(name) = self.config.tui_theme.as_deref()
            && let Some(theme) =
                crate::render::highlight::resolve_theme_by_name(name, Some(&self.config.codex_home))
        {
            crate::render::highlight::set_syntax_theme(theme);
            return;
        }

        let auto_theme_name = crate::render::highlight::adaptive_default_theme_name();
        if let Some(theme) = crate::render::highlight::resolve_theme_by_name(
            auto_theme_name,
            Some(&self.config.codex_home),
        ) {
            crate::render::highlight::set_syntax_theme(theme);
        }
    }

    fn personality_label(personality: Personality) -> &'static str {
        match personality {
            Personality::None => "None",
            Personality::Friendly => "Friendly",
            Personality::Pragmatic => "Pragmatic",
        }
    }

    async fn launch_external_editor(&mut self, tui: &mut tui::Tui) {
        let editor_cmd = match external_editor::resolve_editor_command() {
            Ok(cmd) => cmd,
            Err(external_editor::EditorError::MissingEditor) => {
                self.chat_widget
                    .add_to_history(history_cell::new_error_event(
                    "Cannot open external editor: set $VISUAL or $EDITOR before starting Codex."
                        .to_string(),
                ));
                self.reset_external_editor_state(tui);
                return;
            }
            Err(err) => {
                self.chat_widget
                    .add_to_history(history_cell::new_error_event(format!(
                        "Failed to open editor: {err}",
                    )));
                self.reset_external_editor_state(tui);
                return;
            }
        };

        let seed = self.chat_widget.composer_text_with_pending();
        let editor_result = tui
            .with_restored(tui::RestoreMode::KeepRaw, || async {
                external_editor::run_editor(&seed, &editor_cmd).await
            })
            .await;
        self.reset_external_editor_state(tui);

        match editor_result {
            Ok(new_text) => {
                // Trim trailing whitespace
                let cleaned = new_text.trim_end().to_string();
                self.chat_widget.apply_external_edit(cleaned);
            }
            Err(err) => {
                self.chat_widget
                    .add_to_history(history_cell::new_error_event(format!(
                        "Failed to open editor: {err}",
                    )));
            }
        }
        tui.frame_requester().schedule_frame();
    }

    fn request_external_editor_launch(&mut self, tui: &mut tui::Tui) {
        self.chat_widget
            .set_external_editor_state(ExternalEditorState::Requested);
        self.chat_widget.set_footer_hint_override(Some(vec![(
            EXTERNAL_EDITOR_HINT.to_string(),
            String::new(),
        )]));
        tui.frame_requester().schedule_frame();
    }

    fn reset_external_editor_state(&mut self, tui: &mut tui::Tui) {
        self.chat_widget
            .set_external_editor_state(ExternalEditorState::Closed);
        self.chat_widget.set_footer_hint_override(None);
        tui.frame_requester().schedule_frame();
    }

    async fn handle_key_event(&mut self, tui: &mut tui::Tui, key_event: KeyEvent) {
        match key_event {
            KeyEvent {
                code: KeyCode::Char('t'),
                modifiers: crossterm::event::KeyModifiers::CONTROL,
                kind: KeyEventKind::Press,
                ..
            } => {
                // Enter alternate screen and set viewport to full size.
                let _ = tui.enter_alt_screen();
                self.overlay = Some(Overlay::new_transcript(self.transcript_cells.clone()));
                tui.frame_requester().schedule_frame();
            }
            KeyEvent {
                code: KeyCode::Char('l'),
                modifiers: crossterm::event::KeyModifiers::CONTROL,
                kind: KeyEventKind::Press,
                ..
            } => {
                if !self.chat_widget.can_run_ctrl_l_clear_now() {
                    return;
                }
                if let Err(err) = self.clear_terminal_ui(tui, false) {
                    tracing::warn!(error = %err, "failed to clear terminal UI");
                    self.chat_widget
                        .add_error_message(format!("Failed to clear terminal UI: {err}"));
                } else {
                    self.reset_app_ui_state_after_clear();
                    self.queue_clear_ui_header(tui);
                    tui.frame_requester().schedule_frame();
                }
            }
            KeyEvent {
                code: KeyCode::Char('g'),
                modifiers: crossterm::event::KeyModifiers::CONTROL,
                kind: KeyEventKind::Press,
                ..
            } => {
                // Only launch the external editor if there is no overlay and the bottom pane is not in use.
                // Note that it can be launched while a task is running to enable editing while the previous turn is ongoing.
                if self.overlay.is_none()
                    && self.chat_widget.can_launch_external_editor()
                    && self.chat_widget.external_editor_state() == ExternalEditorState::Closed
                {
                    self.request_external_editor_launch(tui);
                }
            }
            // Esc primes/advances backtracking only in normal (not working) mode
            // with the composer focused and empty. In any other state, forward
            // Esc so the active UI (e.g. status indicator, modals, popups)
            // handles it.
            KeyEvent {
                code: KeyCode::Esc,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                if self.chat_widget.is_normal_backtrack_mode()
                    && self.chat_widget.composer_is_empty()
                {
                    self.handle_backtrack_esc_key(tui);
                } else {
                    self.chat_widget.handle_key_event(key_event);
                }
            }
            // Enter confirms backtrack when primed + count > 0. Otherwise pass to widget.
            KeyEvent {
                code: KeyCode::Enter,
                kind: KeyEventKind::Press,
                ..
            } if self.backtrack.primed
                && self.backtrack.nth_user_message != usize::MAX
                && self.chat_widget.composer_is_empty() =>
            {
                if let Some(selection) = self.confirm_backtrack_from_main() {
                    self.apply_backtrack_selection(tui, selection);
                }
            }
            KeyEvent {
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                // Any non-Esc key press should cancel a primed backtrack.
                // This avoids stale "Esc-primed" state after the user starts typing
                // (even if they later backspace to empty).
                if key_event.code != KeyCode::Esc && self.backtrack.primed {
                    self.reset_backtrack_state();
                }
                self.chat_widget.handle_key_event(key_event);
            }
            _ => {
                self.chat_widget.handle_key_event(key_event);
            }
        };
    }

    fn refresh_status_line(&mut self) {
        self.chat_widget.refresh_status_line();
    }

    #[cfg(target_os = "windows")]
    fn spawn_world_writable_scan(
        cwd: PathBuf,
        env_map: std::collections::HashMap<String, String>,
        logs_base_dir: PathBuf,
        sandbox_policy: codex_protocol::protocol::SandboxPolicy,
        tx: AppEventSender,
    ) {
        tokio::task::spawn_blocking(move || {
            let result = codex_windows_sandbox::apply_world_writable_scan_and_denies(
                &logs_base_dir,
                &cwd,
                &env_map,
                &sandbox_policy,
                Some(logs_base_dir.as_path()),
            );
            if result.is_err() {
                // Scan failed: warn without examples.
                tx.send(AppEvent::OpenWorldWritableWarningConfirmation {
                    preset: None,
                    sample_paths: Vec::new(),
                    extra_count: 0usize,
                    failed_scan: true,
                });
            }
        });
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::app_backtrack::BacktrackSelection;
    use crate::app_backtrack::BacktrackState;
    use crate::app_backtrack::user_count;
    use crate::chatwidget::tests::make_chatwidget_manual_with_sender;
    use crate::file_search::FileSearchManager;
    use crate::history_cell::AgentMessageCell;
    use crate::history_cell::HistoryCell;
    use crate::history_cell::UserHistoryCell;
    use crate::history_cell::new_session_info;
    use assert_matches::assert_matches;
    use codex_core::CodexAuth;
    use codex_core::config::ConfigBuilder;
    use codex_core::config::ConfigOverrides;
    use codex_core::config::types::ModelAvailabilityNuxConfig;
    use codex_otel::OtelManager;
    use codex_protocol::ThreadId;
    use codex_protocol::openai_models::ModelAvailabilityNux;
    use codex_protocol::protocol::AskForApproval;
    use codex_protocol::protocol::Event;
    use codex_protocol::protocol::EventMsg;
    use codex_protocol::protocol::SandboxPolicy;
    use codex_protocol::protocol::SessionConfiguredEvent;
    use codex_protocol::protocol::SessionSource;
    use codex_protocol::protocol::ThreadRolledBackEvent;
    use codex_protocol::protocol::UserMessageEvent;
    use codex_protocol::user_input::TextElement;
    use codex_protocol::user_input::UserInput;
    use crossterm::event::KeyModifiers;
    use insta::assert_snapshot;
    use pretty_assertions::assert_eq;
    use ratatui::prelude::Line;
    use std::path::PathBuf;
    use std::sync::Arc;
    use std::sync::atomic::AtomicBool;
    use tempfile::tempdir;
    use tokio::time;

    #[test]
    fn normalize_harness_overrides_resolves_relative_add_dirs() -> Result<()> {
        let temp_dir = tempdir()?;
        let base_cwd = temp_dir.path().join("base");
        std::fs::create_dir_all(&base_cwd)?;

        let overrides = ConfigOverrides {
            additional_writable_roots: vec![PathBuf::from("rel")],
            ..Default::default()
        };
        let normalized = normalize_harness_overrides_for_cwd(overrides, &base_cwd)?;

        assert_eq!(
            normalized.additional_writable_roots,
            vec![base_cwd.join("rel")]
        );
        Ok(())
    }

    #[test]
    fn startup_waiting_gate_is_only_for_fresh_or_exit_session_selection() {
        assert_eq!(
            App::should_wait_for_initial_session(&SessionSelection::StartFresh),
            true
        );
        assert_eq!(
            App::should_wait_for_initial_session(&SessionSelection::Exit),
            true
        );
        assert_eq!(
            App::should_wait_for_initial_session(&SessionSelection::Resume(
                crate::resume_picker::SessionTarget {
                    path: PathBuf::from("/tmp/restore"),
                    thread_id: ThreadId::new(),
                }
            )),
            false
        );
        assert_eq!(
            App::should_wait_for_initial_session(&SessionSelection::Fork(
                crate::resume_picker::SessionTarget {
                    path: PathBuf::from("/tmp/fork"),
                    thread_id: ThreadId::new(),
                }
            )),
            false
        );
    }

    #[test]
    fn startup_waiting_gate_holds_active_thread_events_until_primary_thread_configured() {
        let mut wait_for_initial_session =
            App::should_wait_for_initial_session(&SessionSelection::StartFresh);
        assert_eq!(wait_for_initial_session, true);
        assert_eq!(
            App::should_handle_active_thread_events(wait_for_initial_session, true),
            false
        );

        assert_eq!(
            App::should_stop_waiting_for_initial_session(wait_for_initial_session, None),
            false
        );
        if App::should_stop_waiting_for_initial_session(
            wait_for_initial_session,
            Some(ThreadId::new()),
        ) {
            wait_for_initial_session = false;
        }
        assert_eq!(wait_for_initial_session, false);

        assert_eq!(
            App::should_handle_active_thread_events(wait_for_initial_session, true),
            true
        );
    }

    #[test]
    fn startup_waiting_gate_not_applied_for_resume_or_fork_session_selection() {
        let wait_for_resume = App::should_wait_for_initial_session(&SessionSelection::Resume(
            crate::resume_picker::SessionTarget {
                path: PathBuf::from("/tmp/restore"),
                thread_id: ThreadId::new(),
            },
        ));
        assert_eq!(
            App::should_handle_active_thread_events(wait_for_resume, true),
            true
        );
        let wait_for_fork = App::should_wait_for_initial_session(&SessionSelection::Fork(
            crate::resume_picker::SessionTarget {
                path: PathBuf::from("/tmp/fork"),
                thread_id: ThreadId::new(),
            },
        ));
        assert_eq!(
            App::should_handle_active_thread_events(wait_for_fork, true),
            true
        );
    }

    #[tokio::test]
    async fn enqueue_primary_event_delivers_session_configured_before_buffered_approval()
    -> Result<()> {
        let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;
        let thread_id = ThreadId::new();
        let approval_event = Event {
            id: "approval-event".to_string(),
            msg: EventMsg::ExecApprovalRequest(
                codex_protocol::protocol::ExecApprovalRequestEvent {
                    call_id: "call-1".to_string(),
                    approval_id: None,
                    turn_id: "turn-1".to_string(),
                    command: vec!["echo".to_string(), "hello".to_string()],
                    cwd: PathBuf::from("/tmp/project"),
                    reason: Some("needs approval".to_string()),
                    network_approval_context: None,
                    proposed_execpolicy_amendment: None,
                    proposed_network_policy_amendments: None,
                    additional_permissions: None,
                    available_decisions: None,
                    parsed_cmd: Vec::new(),
                },
            ),
        };
        let session_configured_event = Event {
            id: "session-configured".to_string(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id: thread_id,
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/tmp/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            }),
        };

        app.enqueue_primary_event(approval_event.clone()).await?;
        app.enqueue_primary_event(session_configured_event.clone())
            .await?;

        let rx = app
            .active_thread_rx
            .as_mut()
            .expect("primary thread receiver should be active");
        let first_event = time::timeout(Duration::from_millis(50), rx.recv())
            .await
            .expect("timed out waiting for session configured event")
            .expect("channel closed unexpectedly");
        let second_event = time::timeout(Duration::from_millis(50), rx.recv())
            .await
            .expect("timed out waiting for buffered approval event")
            .expect("channel closed unexpectedly");

        assert!(matches!(first_event.msg, EventMsg::SessionConfigured(_)));
        assert!(matches!(second_event.msg, EventMsg::ExecApprovalRequest(_)));

        app.handle_codex_event_now(first_event);
        app.handle_codex_event_now(second_event);
        app.chat_widget
            .handle_key_event(KeyEvent::new(KeyCode::Char('y'), KeyModifiers::NONE));

        while let Ok(app_event) = app_event_rx.try_recv() {
            if let AppEvent::SubmitThreadOp {
                thread_id: op_thread_id,
                ..
            } = app_event
            {
                assert_eq!(op_thread_id, thread_id);
                return Ok(());
            }
        }

        panic!("expected approval action to submit a thread-scoped op");
    }

    #[tokio::test]
    async fn routed_thread_event_does_not_recreate_channel_after_reset() -> Result<()> {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.thread_event_channels.insert(
            thread_id,
            ThreadEventChannel::new(THREAD_EVENT_CHANNEL_CAPACITY),
        );

        app.reset_thread_event_state();
        app.handle_routed_thread_event(
            thread_id,
            Event {
                id: "stale-event".to_string(),
                msg: EventMsg::ShutdownComplete,
            },
        )
        .await?;

        assert!(
            !app.thread_event_channels.contains_key(&thread_id),
            "stale routed events should not recreate cleared thread channels"
        );
        assert_eq!(app.active_thread_id, None);
        assert_eq!(app.primary_thread_id, None);
        Ok(())
    }

    #[tokio::test]
    async fn reset_thread_event_state_aborts_listener_tasks() {
        struct NotifyOnDrop(Option<tokio::sync::oneshot::Sender<()>>);

        impl Drop for NotifyOnDrop {
            fn drop(&mut self) {
                if let Some(tx) = self.0.take() {
                    let _ = tx.send(());
                }
            }
        }

        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        let (started_tx, started_rx) = tokio::sync::oneshot::channel();
        let (dropped_tx, dropped_rx) = tokio::sync::oneshot::channel();
        let handle = tokio::spawn(async move {
            let _notify_on_drop = NotifyOnDrop(Some(dropped_tx));
            let _ = started_tx.send(());
            std::future::pending::<()>().await;
        });
        app.thread_event_listener_tasks.insert(thread_id, handle);
        started_rx
            .await
            .expect("listener task should report it started");

        app.reset_thread_event_state();

        assert_eq!(app.thread_event_listener_tasks.is_empty(), true);
        time::timeout(Duration::from_millis(50), dropped_rx)
            .await
            .expect("timed out waiting for listener task abort")
            .expect("listener task drop notification should succeed");
    }

    #[tokio::test]
    async fn enqueue_thread_event_does_not_block_when_channel_full() -> Result<()> {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.thread_event_channels
            .insert(thread_id, ThreadEventChannel::new(1));
        app.set_thread_active(thread_id, true).await;

        let event = Event {
            id: String::new(),
            msg: EventMsg::ShutdownComplete,
        };

        app.enqueue_thread_event(thread_id, event.clone()).await?;
        time::timeout(
            Duration::from_millis(50),
            app.enqueue_thread_event(thread_id, event),
        )
        .await
        .expect("enqueue_thread_event blocked on a full channel")?;

        let mut rx = app
            .thread_event_channels
            .get_mut(&thread_id)
            .expect("missing thread channel")
            .receiver
            .take()
            .expect("missing receiver");

        time::timeout(Duration::from_millis(50), rx.recv())
            .await
            .expect("timed out waiting for first event")
            .expect("channel closed unexpectedly");
        time::timeout(Duration::from_millis(50), rx.recv())
            .await
            .expect("timed out waiting for second event")
            .expect("channel closed unexpectedly");

        Ok(())
    }

    #[tokio::test]
    async fn open_agent_picker_keeps_missing_threads_for_replay() -> Result<()> {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.thread_event_channels
            .insert(thread_id, ThreadEventChannel::new(1));

        app.open_agent_picker().await;

        assert_eq!(app.thread_event_channels.contains_key(&thread_id), true);
        assert_eq!(
            app.agent_picker_threads.get(&thread_id),
            Some(&AgentPickerThreadEntry {
                agent_nickname: None,
                agent_role: None,
                is_closed: true,
            })
        );
        Ok(())
    }

    #[tokio::test]
    async fn open_agent_picker_keeps_cached_closed_threads() -> Result<()> {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.thread_event_channels
            .insert(thread_id, ThreadEventChannel::new(1));
        app.agent_picker_threads.insert(
            thread_id,
            AgentPickerThreadEntry {
                agent_nickname: Some("Robie".to_string()),
                agent_role: Some("explorer".to_string()),
                is_closed: false,
            },
        );

        app.open_agent_picker().await;

        assert_eq!(app.thread_event_channels.contains_key(&thread_id), true);
        assert_eq!(
            app.agent_picker_threads.get(&thread_id),
            Some(&AgentPickerThreadEntry {
                agent_nickname: Some("Robie".to_string()),
                agent_role: Some("explorer".to_string()),
                is_closed: true,
            })
        );
        Ok(())
    }

    #[tokio::test]
    async fn open_agent_picker_prompts_to_enable_multi_agent_when_disabled() -> Result<()> {
        let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;

        app.open_agent_picker().await;
        app.chat_widget
            .handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));

        assert_matches!(
            app_event_rx.try_recv(),
            Ok(AppEvent::UpdateFeatureFlags { updates }) if updates == vec![(Feature::Collab, true)]
        );
        let cell = match app_event_rx.try_recv() {
            Ok(AppEvent::InsertHistoryCell(cell)) => cell,
            other => panic!("expected InsertHistoryCell event, got {other:?}"),
        };
        let rendered = cell
            .display_lines(120)
            .into_iter()
            .map(|line| line.to_string())
            .collect::<Vec<_>>()
            .join("\n");
        assert!(rendered.contains("Multi-agent will be enabled in the next session."));
        Ok(())
    }

    #[tokio::test]
    async fn open_agent_picker_allows_existing_agent_threads_when_feature_is_disabled() -> Result<()>
    {
        let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;
        let thread_id = ThreadId::new();
        app.thread_event_channels
            .insert(thread_id, ThreadEventChannel::new(1));

        app.open_agent_picker().await;
        app.chat_widget
            .handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));

        assert_matches!(
            app_event_rx.try_recv(),
            Ok(AppEvent::SelectAgentThread(selected_thread_id)) if selected_thread_id == thread_id
        );
        Ok(())
    }

    #[tokio::test]
    async fn refresh_pending_thread_approvals_only_lists_inactive_threads() {
        let mut app = make_test_app().await;
        let main_thread_id =
            ThreadId::from_string("00000000-0000-0000-0000-000000000001").expect("valid thread");
        let agent_thread_id =
            ThreadId::from_string("00000000-0000-0000-0000-000000000002").expect("valid thread");

        app.primary_thread_id = Some(main_thread_id);
        app.active_thread_id = Some(main_thread_id);
        app.thread_event_channels
            .insert(main_thread_id, ThreadEventChannel::new(1));

        let agent_channel = ThreadEventChannel::new(1);
        {
            let mut store = agent_channel.store.lock().await;
            store.push_event(Event {
                id: "ev-1".to_string(),
                msg: EventMsg::ExecApprovalRequest(
                    codex_protocol::protocol::ExecApprovalRequestEvent {
                        call_id: "call-1".to_string(),
                        approval_id: None,
                        turn_id: "turn-1".to_string(),
                        command: vec!["echo".to_string(), "hi".to_string()],
                        cwd: PathBuf::from("/tmp"),
                        reason: None,
                        network_approval_context: None,
                        proposed_execpolicy_amendment: None,
                        proposed_network_policy_amendments: None,
                        additional_permissions: None,
                        available_decisions: None,
                        parsed_cmd: Vec::new(),
                    },
                ),
            });
        }
        app.thread_event_channels
            .insert(agent_thread_id, agent_channel);
        app.agent_picker_threads.insert(
            agent_thread_id,
            AgentPickerThreadEntry {
                agent_nickname: Some("Robie".to_string()),
                agent_role: Some("explorer".to_string()),
                is_closed: false,
            },
        );

        app.refresh_pending_thread_approvals().await;
        assert_eq!(
            app.chat_widget.pending_thread_approvals(),
            &["Robie [explorer]".to_string()]
        );

        app.active_thread_id = Some(agent_thread_id);
        app.refresh_pending_thread_approvals().await;
        assert!(app.chat_widget.pending_thread_approvals().is_empty());
    }

    #[tokio::test]
    async fn inactive_thread_approval_bubbles_into_active_view() -> Result<()> {
        let mut app = make_test_app().await;
        let main_thread_id =
            ThreadId::from_string("00000000-0000-0000-0000-000000000011").expect("valid thread");
        let agent_thread_id =
            ThreadId::from_string("00000000-0000-0000-0000-000000000022").expect("valid thread");

        app.primary_thread_id = Some(main_thread_id);
        app.active_thread_id = Some(main_thread_id);
        app.thread_event_channels
            .insert(main_thread_id, ThreadEventChannel::new(1));
        app.thread_event_channels.insert(
            agent_thread_id,
            ThreadEventChannel::new_with_session_configured(
                1,
                Event {
                    id: String::new(),
                    msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                        session_id: agent_thread_id,
                        forked_from_id: None,
                        thread_name: None,
                        model: "gpt-5".to_string(),
                        model_provider_id: "test-provider".to_string(),
                        service_tier: None,
                        approval_policy: AskForApproval::OnRequest,
                        sandbox_policy: SandboxPolicy::new_workspace_write_policy(),
                        cwd: PathBuf::from("/tmp/agent"),
                        reasoning_effort: None,
                        history_log_id: 0,
                        history_entry_count: 0,
                        initial_messages: None,
                        network_proxy: None,
                        rollout_path: Some(PathBuf::from("/tmp/agent-rollout.jsonl")),
                    }),
                },
            ),
        );
        app.agent_picker_threads.insert(
            agent_thread_id,
            AgentPickerThreadEntry {
                agent_nickname: Some("Robie".to_string()),
                agent_role: Some("explorer".to_string()),
                is_closed: false,
            },
        );

        app.enqueue_thread_event(
            agent_thread_id,
            Event {
                id: "ev-approval".to_string(),
                msg: EventMsg::ExecApprovalRequest(
                    codex_protocol::protocol::ExecApprovalRequestEvent {
                        call_id: "call-approval".to_string(),
                        approval_id: None,
                        turn_id: "turn-approval".to_string(),
                        command: vec!["echo".to_string(), "hi".to_string()],
                        cwd: PathBuf::from("/tmp/agent"),
                        reason: Some("need approval".to_string()),
                        network_approval_context: None,
                        proposed_execpolicy_amendment: None,
                        proposed_network_policy_amendments: None,
                        additional_permissions: None,
                        available_decisions: None,
                        parsed_cmd: Vec::new(),
                    },
                ),
            },
        )
        .await?;

        assert_eq!(app.chat_widget.has_active_view(), true);
        assert_eq!(
            app.chat_widget.pending_thread_approvals(),
            &["Robie [explorer]".to_string()]
        );

        Ok(())
    }

    #[test]
    fn agent_picker_item_name_snapshot() {
        let thread_id =
            ThreadId::from_string("00000000-0000-0000-0000-000000000123").expect("valid thread id");
        let snapshot = [
            format!(
                "{} | {}",
                format_agent_picker_item_name(Some("Robie"), Some("explorer"), true),
                thread_id
            ),
            format!(
                "{} | {}",
                format_agent_picker_item_name(Some("Robie"), Some("explorer"), false),
                thread_id
            ),
            format!(
                "{} | {}",
                format_agent_picker_item_name(Some("Robie"), None, false),
                thread_id
            ),
            format!(
                "{} | {}",
                format_agent_picker_item_name(None, Some("explorer"), false),
                thread_id
            ),
            format!(
                "{} | {}",
                format_agent_picker_item_name(None, None, false),
                thread_id
            ),
        ]
        .join("\n");
        assert_snapshot!("agent_picker_item_name", snapshot);
    }

    #[tokio::test]
    async fn active_non_primary_shutdown_target_returns_none_for_non_shutdown_event() -> Result<()>
    {
        let mut app = make_test_app().await;
        app.active_thread_id = Some(ThreadId::new());
        app.primary_thread_id = Some(ThreadId::new());

        assert_eq!(
            app.active_non_primary_shutdown_target(&EventMsg::SkillsUpdateAvailable),
            None
        );
        Ok(())
    }

    #[tokio::test]
    async fn active_non_primary_shutdown_target_returns_none_for_primary_thread_shutdown()
    -> Result<()> {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.active_thread_id = Some(thread_id);
        app.primary_thread_id = Some(thread_id);

        assert_eq!(
            app.active_non_primary_shutdown_target(&EventMsg::ShutdownComplete),
            None
        );
        Ok(())
    }

    #[tokio::test]
    async fn active_non_primary_shutdown_target_returns_ids_for_non_primary_shutdown() -> Result<()>
    {
        let mut app = make_test_app().await;
        let active_thread_id = ThreadId::new();
        let primary_thread_id = ThreadId::new();
        app.active_thread_id = Some(active_thread_id);
        app.primary_thread_id = Some(primary_thread_id);

        assert_eq!(
            app.active_non_primary_shutdown_target(&EventMsg::ShutdownComplete),
            Some((active_thread_id, primary_thread_id))
        );
        Ok(())
    }

    #[tokio::test]
    async fn active_non_primary_shutdown_target_returns_none_when_shutdown_exit_is_pending()
    -> Result<()> {
        let mut app = make_test_app().await;
        let active_thread_id = ThreadId::new();
        let primary_thread_id = ThreadId::new();
        app.active_thread_id = Some(active_thread_id);
        app.primary_thread_id = Some(primary_thread_id);
        app.pending_shutdown_exit_thread_id = Some(active_thread_id);

        assert_eq!(
            app.active_non_primary_shutdown_target(&EventMsg::ShutdownComplete),
            None
        );
        Ok(())
    }

    #[tokio::test]
    async fn active_non_primary_shutdown_target_still_switches_for_other_pending_exit_thread()
    -> Result<()> {
        let mut app = make_test_app().await;
        let active_thread_id = ThreadId::new();
        let primary_thread_id = ThreadId::new();
        app.active_thread_id = Some(active_thread_id);
        app.primary_thread_id = Some(primary_thread_id);
        app.pending_shutdown_exit_thread_id = Some(ThreadId::new());

        assert_eq!(
            app.active_non_primary_shutdown_target(&EventMsg::ShutdownComplete),
            Some((active_thread_id, primary_thread_id))
        );
        Ok(())
    }

    async fn render_clear_ui_header_after_long_transcript_for_snapshot() -> String {
        let mut app = make_test_app().await;
        app.config.cwd = PathBuf::from("/tmp/project");
        app.chat_widget.set_model("gpt-test");
        app.chat_widget
            .set_reasoning_effort(Some(ReasoningEffortConfig::High));
        let story_part_one = "In the cliffside town of Bracken Ferry, the lighthouse had been dark for \
            nineteen years, and the children were told it was because the sea no longer wanted a \
            guide. Mara, who repaired clocks for a living, found that hard to believe. Every dawn she \
            heard the gulls circling the empty tower, and every dusk she watched ships hesitate at the \
            mouth of the bay as if listening for a signal that never came. When an old brass key fell \
            out of a cracked parcel in her workshop, tagged only with the words 'for the lamp room,' \
            she decided to climb the hill and see what the town had forgotten.";
        let story_part_two = "Inside the lighthouse she found gears wrapped in oilcloth, logbooks filled \
            with weather notes, and a lens shrouded beneath salt-stiff canvas. The mechanism was not \
            broken, only unfinished. Someone had removed the governor spring and hidden it in a false \
            drawer, along with a letter from the last keeper admitting he had darkened the light on \
            purpose after smugglers threatened his family. Mara spent the night rebuilding the clockwork \
            from spare watch parts, her fingers blackened with soot and grease, while a storm gathered \
            over the water and the harbor bells began to ring.";
        let story_part_three = "At midnight the first squall hit, and the fishing boats returned early, \
            blind in sheets of rain. Mara wound the mechanism, set the teeth by hand, and watched the \
            great lens begin to turn in slow, certain arcs. The beam swept across the bay, caught the \
            whitecaps, and reached the boats just as they were drifting toward the rocks below the \
            eastern cliffs. In the morning the town square was crowded with wet sailors, angry elders, \
            and wide-eyed children, but when the oldest captain placed the keeper's log on the fountain \
            and thanked Mara for relighting the coast, nobody argued. By sunset, Bracken Ferry had a \
            lighthouse again, and Mara had more clocks to mend than ever because everyone wanted \
            something in town to keep better time.";

        let user_cell = |text: &str| -> Arc<dyn HistoryCell> {
            Arc::new(UserHistoryCell {
                message: text.to_string(),
                text_elements: Vec::new(),
                local_image_paths: Vec::new(),
                remote_image_urls: Vec::new(),
            }) as Arc<dyn HistoryCell>
        };
        let agent_cell = |text: &str| -> Arc<dyn HistoryCell> {
            Arc::new(AgentMessageCell::new(
                vec![Line::from(text.to_string())],
                true,
            )) as Arc<dyn HistoryCell>
        };
        let make_header = |is_first| -> Arc<dyn HistoryCell> {
            let event = SessionConfiguredEvent {
                session_id: ThreadId::new(),
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/tmp/project"),
                reasoning_effort: Some(ReasoningEffortConfig::High),
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            };
            Arc::new(new_session_info(
                app.chat_widget.config_ref(),
                app.chat_widget.current_model(),
                event,
                is_first,
                None,
                None,
            )) as Arc<dyn HistoryCell>
        };

        app.transcript_cells = vec![
            make_header(true),
            Arc::new(crate::history_cell::new_info_event(
                "startup tip that used to replay".to_string(),
                None,
            )) as Arc<dyn HistoryCell>,
            user_cell("Tell me a long story about a town with a dark lighthouse."),
            agent_cell(story_part_one),
            user_cell("Continue the story and reveal why the light went out."),
            agent_cell(story_part_two),
            user_cell("Finish the story with a storm and a resolution."),
            agent_cell(story_part_three),
        ];
        app.has_emitted_history_lines = true;

        let rendered = app
            .clear_ui_header_lines_with_version(80, "<VERSION>")
            .iter()
            .map(|line| {
                line.spans
                    .iter()
                    .map(|span| span.content.as_ref())
                    .collect::<String>()
            })
            .collect::<Vec<_>>()
            .join("\n");

        assert!(
            !rendered.contains("startup tip that used to replay"),
            "clear header should not replay startup notices"
        );
        assert!(
            !rendered.contains("Bracken Ferry"),
            "clear header should not replay prior conversation turns"
        );
        rendered
    }

    #[tokio::test]
    async fn clear_ui_after_long_transcript_snapshots_fresh_header_only() {
        let rendered = render_clear_ui_header_after_long_transcript_for_snapshot().await;
        assert_snapshot!("clear_ui_after_long_transcript_fresh_header_only", rendered);
    }

    #[tokio::test]
    async fn ctrl_l_clear_ui_after_long_transcript_reuses_clear_header_snapshot() {
        let rendered = render_clear_ui_header_after_long_transcript_for_snapshot().await;
        assert_snapshot!("clear_ui_after_long_transcript_fresh_header_only", rendered);
    }

    async fn make_test_app() -> App {
        let (chat_widget, app_event_tx, _rx, _op_rx) = make_chatwidget_manual_with_sender().await;
        let config = chat_widget.config_ref().clone();
        let server = Arc::new(
            codex_core::test_support::thread_manager_with_models_provider(
                CodexAuth::from_api_key("Test API Key"),
                config.model_provider.clone(),
            ),
        );
        let auth_manager = codex_core::test_support::auth_manager_from_auth(
            CodexAuth::from_api_key("Test API Key"),
        );
        let file_search = FileSearchManager::new(config.cwd.clone(), app_event_tx.clone());
        let model = codex_core::test_support::get_model_offline(config.model.as_deref());
        let otel_manager = test_otel_manager(&config, model.as_str());

        App {
            server,
            otel_manager,
            app_event_tx,
            chat_widget,
            auth_manager,
            config,
            active_profile: None,
            cli_kv_overrides: Vec::new(),
            harness_overrides: ConfigOverrides::default(),
            runtime_approval_policy_override: None,
            runtime_sandbox_policy_override: None,
            file_search,
            transcript_cells: Vec::new(),
            overlay: None,
            deferred_history_lines: Vec::new(),
            has_emitted_history_lines: false,
            enhanced_keys_supported: false,
            commit_anim_running: Arc::new(AtomicBool::new(false)),
            status_line_invalid_items_warned: Arc::new(AtomicBool::new(false)),
            backtrack: BacktrackState::default(),
            backtrack_render_pending: false,
            feedback: codex_feedback::CodexFeedback::new(),
            feedback_audience: FeedbackAudience::External,
            pending_update_action: None,
            suppress_shutdown_complete: false,
            pending_shutdown_exit_thread_id: None,
            windows_sandbox: WindowsSandboxState::default(),
            thread_event_channels: HashMap::new(),
            thread_event_listener_tasks: HashMap::new(),
            agent_picker_threads: HashMap::new(),
            active_thread_id: None,
            active_thread_rx: None,
            primary_thread_id: None,
            primary_session_configured: None,
            pending_primary_events: VecDeque::new(),
        }
    }

    async fn make_test_app_with_channels() -> (
        App,
        tokio::sync::mpsc::UnboundedReceiver<AppEvent>,
        tokio::sync::mpsc::UnboundedReceiver<Op>,
    ) {
        let (chat_widget, app_event_tx, rx, op_rx) = make_chatwidget_manual_with_sender().await;
        let config = chat_widget.config_ref().clone();
        let server = Arc::new(
            codex_core::test_support::thread_manager_with_models_provider(
                CodexAuth::from_api_key("Test API Key"),
                config.model_provider.clone(),
            ),
        );
        let auth_manager = codex_core::test_support::auth_manager_from_auth(
            CodexAuth::from_api_key("Test API Key"),
        );
        let file_search = FileSearchManager::new(config.cwd.clone(), app_event_tx.clone());
        let model = codex_core::test_support::get_model_offline(config.model.as_deref());
        let otel_manager = test_otel_manager(&config, model.as_str());

        (
            App {
                server,
                otel_manager,
                app_event_tx,
                chat_widget,
                auth_manager,
                config,
                active_profile: None,
                cli_kv_overrides: Vec::new(),
                harness_overrides: ConfigOverrides::default(),
                runtime_approval_policy_override: None,
                runtime_sandbox_policy_override: None,
                file_search,
                transcript_cells: Vec::new(),
                overlay: None,
                deferred_history_lines: Vec::new(),
                has_emitted_history_lines: false,
                enhanced_keys_supported: false,
                commit_anim_running: Arc::new(AtomicBool::new(false)),
                status_line_invalid_items_warned: Arc::new(AtomicBool::new(false)),
                backtrack: BacktrackState::default(),
                backtrack_render_pending: false,
                feedback: codex_feedback::CodexFeedback::new(),
                feedback_audience: FeedbackAudience::External,
                pending_update_action: None,
                suppress_shutdown_complete: false,
                pending_shutdown_exit_thread_id: None,
                windows_sandbox: WindowsSandboxState::default(),
                thread_event_channels: HashMap::new(),
                thread_event_listener_tasks: HashMap::new(),
                agent_picker_threads: HashMap::new(),
                active_thread_id: None,
                active_thread_rx: None,
                primary_thread_id: None,
                primary_session_configured: None,
                pending_primary_events: VecDeque::new(),
            },
            rx,
            op_rx,
        )
    }

    fn test_otel_manager(config: &Config, model: &str) -> OtelManager {
        let model_info = codex_core::test_support::construct_model_info_offline(model, config);
        OtelManager::new(
            ThreadId::new(),
            model,
            model_info.slug.as_str(),
            None,
            None,
            None,
            "test_originator".to_string(),
            false,
            "test".to_string(),
            SessionSource::Cli,
        )
    }

    fn app_enabled_in_effective_config(config: &Config, app_id: &str) -> Option<bool> {
        config
            .config_layer_stack
            .effective_config()
            .as_table()
            .and_then(|table| table.get("apps"))
            .and_then(TomlValue::as_table)
            .and_then(|apps| apps.get(app_id))
            .and_then(TomlValue::as_table)
            .and_then(|app| app.get("enabled"))
            .and_then(TomlValue::as_bool)
    }

    fn all_model_presets() -> Vec<ModelPreset> {
        codex_core::test_support::all_model_presets().clone()
    }

    fn model_availability_nux_config(shown_count: &[(&str, u32)]) -> ModelAvailabilityNuxConfig {
        ModelAvailabilityNuxConfig {
            shown_count: shown_count
                .iter()
                .map(|(model, count)| ((*model).to_string(), *count))
                .collect(),
        }
    }

    fn model_migration_copy_to_plain_text(
        copy: &crate::model_migration::ModelMigrationCopy,
    ) -> String {
        if let Some(markdown) = copy.markdown.as_ref() {
            return markdown.clone();
        }
        let mut s = String::new();
        for span in &copy.heading {
            s.push_str(&span.content);
        }
        s.push('\n');
        s.push('\n');
        for line in &copy.content {
            for span in &line.spans {
                s.push_str(&span.content);
            }
            s.push('\n');
        }
        s
    }

    #[tokio::test]
    async fn model_migration_prompt_only_shows_for_deprecated_models() {
        let seen = BTreeMap::new();
        assert!(should_show_model_migration_prompt(
            "gpt-5",
            "gpt-5.2-codex",
            &seen,
            &all_model_presets()
        ));
        assert!(should_show_model_migration_prompt(
            "gpt-5-codex",
            "gpt-5.2-codex",
            &seen,
            &all_model_presets()
        ));
        assert!(should_show_model_migration_prompt(
            "gpt-5-codex-mini",
            "gpt-5.2-codex",
            &seen,
            &all_model_presets()
        ));
        assert!(should_show_model_migration_prompt(
            "gpt-5.1-codex",
            "gpt-5.2-codex",
            &seen,
            &all_model_presets()
        ));
        assert!(!should_show_model_migration_prompt(
            "gpt-5.1-codex",
            "gpt-5.1-codex",
            &seen,
            &all_model_presets()
        ));
    }

    #[test]
    fn select_model_availability_nux_picks_only_eligible_model() {
        let mut presets = all_model_presets();
        presets.iter_mut().for_each(|preset| {
            preset.availability_nux = None;
        });
        let target = presets
            .iter_mut()
            .find(|preset| preset.model == "gpt-5")
            .expect("target preset present");
        target.availability_nux = Some(ModelAvailabilityNux {
            message: "gpt-5 is available".to_string(),
        });

        let selected = select_model_availability_nux(&presets, &model_availability_nux_config(&[]));

        assert_eq!(
            selected,
            Some(StartupTooltipOverride {
                model_slug: "gpt-5".to_string(),
                message: "gpt-5 is available".to_string(),
            })
        );
    }

    #[test]
    fn select_model_availability_nux_skips_missing_and_exhausted_models() {
        let mut presets = all_model_presets();
        presets.iter_mut().for_each(|preset| {
            preset.availability_nux = None;
        });
        let gpt_5 = presets
            .iter_mut()
            .find(|preset| preset.model == "gpt-5")
            .expect("gpt-5 preset present");
        gpt_5.availability_nux = Some(ModelAvailabilityNux {
            message: "gpt-5 is available".to_string(),
        });
        let gpt_5_2 = presets
            .iter_mut()
            .find(|preset| preset.model == "gpt-5.2")
            .expect("gpt-5.2 preset present");
        gpt_5_2.availability_nux = Some(ModelAvailabilityNux {
            message: "gpt-5.2 is available".to_string(),
        });

        let selected = select_model_availability_nux(
            &presets,
            &model_availability_nux_config(&[("gpt-5", MODEL_AVAILABILITY_NUX_MAX_SHOW_COUNT)]),
        );

        assert_eq!(
            selected,
            Some(StartupTooltipOverride {
                model_slug: "gpt-5.2".to_string(),
                message: "gpt-5.2 is available".to_string(),
            })
        );
    }

    #[test]
    fn select_model_availability_nux_uses_existing_model_order_as_priority() {
        let mut presets = all_model_presets();
        presets.iter_mut().for_each(|preset| {
            preset.availability_nux = None;
        });
        let first = presets
            .iter_mut()
            .find(|preset| preset.model == "gpt-5")
            .expect("gpt-5 preset present");
        first.availability_nux = Some(ModelAvailabilityNux {
            message: "first".to_string(),
        });
        let second = presets
            .iter_mut()
            .find(|preset| preset.model == "gpt-5.2")
            .expect("gpt-5.2 preset present");
        second.availability_nux = Some(ModelAvailabilityNux {
            message: "second".to_string(),
        });

        let selected = select_model_availability_nux(&presets, &model_availability_nux_config(&[]));

        assert_eq!(
            selected,
            Some(StartupTooltipOverride {
                model_slug: "gpt-5.2".to_string(),
                message: "second".to_string(),
            })
        );
    }

    #[test]
    fn select_model_availability_nux_returns_none_when_all_models_are_exhausted() {
        let mut presets = all_model_presets();
        presets.iter_mut().for_each(|preset| {
            preset.availability_nux = None;
        });
        let target = presets
            .iter_mut()
            .find(|preset| preset.model == "gpt-5")
            .expect("target preset present");
        target.availability_nux = Some(ModelAvailabilityNux {
            message: "gpt-5 is available".to_string(),
        });

        let selected = select_model_availability_nux(
            &presets,
            &model_availability_nux_config(&[("gpt-5", MODEL_AVAILABILITY_NUX_MAX_SHOW_COUNT)]),
        );

        assert_eq!(selected, None);
    }

    #[tokio::test]
    async fn model_migration_prompt_respects_hide_flag_and_self_target() {
        let mut seen = BTreeMap::new();
        seen.insert("gpt-5".to_string(), "gpt-5.1".to_string());
        assert!(!should_show_model_migration_prompt(
            "gpt-5",
            "gpt-5.1",
            &seen,
            &all_model_presets()
        ));
        assert!(!should_show_model_migration_prompt(
            "gpt-5.1",
            "gpt-5.1",
            &seen,
            &all_model_presets()
        ));
    }

    #[tokio::test]
    async fn model_migration_prompt_skips_when_target_missing_or_hidden() {
        let mut available = all_model_presets();
        let mut current = available
            .iter()
            .find(|preset| preset.model == "gpt-5-codex")
            .cloned()
            .expect("preset present");
        current.upgrade = Some(ModelUpgrade {
            id: "missing-target".to_string(),
            reasoning_effort_mapping: None,
            migration_config_key: HIDE_GPT5_1_MIGRATION_PROMPT_CONFIG.to_string(),
            model_link: None,
            upgrade_copy: None,
            migration_markdown: None,
        });
        available.retain(|preset| preset.model != "gpt-5-codex");
        available.push(current.clone());

        assert!(!should_show_model_migration_prompt(
            &current.model,
            "missing-target",
            &BTreeMap::new(),
            &available,
        ));

        assert!(target_preset_for_upgrade(&available, "missing-target").is_none());

        let mut with_hidden_target = all_model_presets();
        let target = with_hidden_target
            .iter_mut()
            .find(|preset| preset.model == "gpt-5.2-codex")
            .expect("target preset present");
        target.show_in_picker = false;

        assert!(!should_show_model_migration_prompt(
            "gpt-5-codex",
            "gpt-5.2-codex",
            &BTreeMap::new(),
            &with_hidden_target,
        ));
        assert!(target_preset_for_upgrade(&with_hidden_target, "gpt-5.2-codex").is_none());
    }

    #[tokio::test]
    async fn model_migration_prompt_shows_for_hidden_model() {
        let codex_home = tempdir().expect("temp codex home");
        let config = ConfigBuilder::default()
            .codex_home(codex_home.path().to_path_buf())
            .build()
            .await
            .expect("config");

        let mut available_models = all_model_presets();
        let current = available_models
            .iter()
            .find(|preset| preset.model == "gpt-5.1-codex")
            .cloned()
            .expect("gpt-5.1-codex preset present");
        assert!(
            !current.show_in_picker,
            "expected gpt-5.1-codex to be hidden from picker for this test"
        );

        let upgrade = current.upgrade.as_ref().expect("upgrade configured");
        // Test "hidden current model still prompts" even if bundled
        // catalog data changes the target model's picker visibility.
        available_models
            .iter_mut()
            .find(|preset| preset.model == upgrade.id)
            .expect("upgrade target present")
            .show_in_picker = true;
        assert!(
            should_show_model_migration_prompt(
                &current.model,
                &upgrade.id,
                &config.notices.model_migrations,
                &available_models,
            ),
            "expected migration prompt to be eligible for hidden model"
        );

        let target = target_preset_for_upgrade(&available_models, &upgrade.id)
            .expect("upgrade target present");
        let target_description =
            (!target.description.is_empty()).then(|| target.description.clone());
        let can_opt_out = true;
        let copy = migration_copy_for_models(
            &current.model,
            &upgrade.id,
            upgrade.model_link.clone(),
            upgrade.upgrade_copy.clone(),
            upgrade.migration_markdown.clone(),
            target.display_name.clone(),
            target_description,
            can_opt_out,
        );

        // Snapshot the copy we would show; rendering is covered by model_migration snapshots.
        assert_snapshot!(
            "model_migration_prompt_shows_for_hidden_model",
            model_migration_copy_to_plain_text(&copy)
        );
    }

    #[tokio::test]
    async fn update_reasoning_effort_updates_collaboration_mode() {
        let mut app = make_test_app().await;
        app.chat_widget
            .set_reasoning_effort(Some(ReasoningEffortConfig::Medium));

        app.on_update_reasoning_effort(Some(ReasoningEffortConfig::High));

        assert_eq!(
            app.chat_widget.current_reasoning_effort(),
            Some(ReasoningEffortConfig::High)
        );
        assert_eq!(
            app.config.model_reasoning_effort,
            Some(ReasoningEffortConfig::High)
        );
    }

    #[tokio::test]
    async fn refresh_in_memory_config_from_disk_loads_latest_apps_state() -> Result<()> {
        let mut app = make_test_app().await;
        let codex_home = tempdir()?;
        app.config.codex_home = codex_home.path().to_path_buf();
        let app_id = "unit_test_refresh_in_memory_config_connector".to_string();

        assert_eq!(app_enabled_in_effective_config(&app.config, &app_id), None);

        ConfigEditsBuilder::new(&app.config.codex_home)
            .with_edits([
                ConfigEdit::SetPath {
                    segments: vec!["apps".to_string(), app_id.clone(), "enabled".to_string()],
                    value: false.into(),
                },
                ConfigEdit::SetPath {
                    segments: vec![
                        "apps".to_string(),
                        app_id.clone(),
                        "disabled_reason".to_string(),
                    ],
                    value: "user".into(),
                },
            ])
            .apply()
            .await
            .expect("persist app toggle");

        assert_eq!(app_enabled_in_effective_config(&app.config, &app_id), None);

        app.refresh_in_memory_config_from_disk().await?;

        assert_eq!(
            app_enabled_in_effective_config(&app.config, &app_id),
            Some(false)
        );
        Ok(())
    }

    #[tokio::test]
    async fn sync_tui_theme_selection_updates_chat_widget_config_copy() {
        let mut app = make_test_app().await;

        app.sync_tui_theme_selection("dracula".to_string());

        assert_eq!(app.config.tui_theme.as_deref(), Some("dracula"));
        assert_eq!(
            app.chat_widget.config_ref().tui_theme.as_deref(),
            Some("dracula")
        );
    }

    #[tokio::test]
    async fn fresh_session_config_uses_current_service_tier() {
        let mut app = make_test_app().await;
        app.chat_widget
            .set_service_tier(Some(codex_protocol::config_types::ServiceTier::Fast));

        let config = app.fresh_session_config();

        assert_eq!(
            config.service_tier,
            Some(codex_protocol::config_types::ServiceTier::Fast)
        );
    }

    #[tokio::test]
    async fn backtrack_selection_with_duplicate_history_targets_unique_turn() {
        let (mut app, _app_event_rx, mut op_rx) = make_test_app_with_channels().await;

        let user_cell = |text: &str,
                         text_elements: Vec<TextElement>,
                         local_image_paths: Vec<PathBuf>,
                         remote_image_urls: Vec<String>|
         -> Arc<dyn HistoryCell> {
            Arc::new(UserHistoryCell {
                message: text.to_string(),
                text_elements,
                local_image_paths,
                remote_image_urls,
            }) as Arc<dyn HistoryCell>
        };
        let agent_cell = |text: &str| -> Arc<dyn HistoryCell> {
            Arc::new(AgentMessageCell::new(
                vec![Line::from(text.to_string())],
                true,
            )) as Arc<dyn HistoryCell>
        };

        let make_header = |is_first| {
            let event = SessionConfiguredEvent {
                session_id: ThreadId::new(),
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/home/user/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            };
            Arc::new(new_session_info(
                app.chat_widget.config_ref(),
                app.chat_widget.current_model(),
                event,
                is_first,
                None,
                None,
            )) as Arc<dyn HistoryCell>
        };

        let placeholder = "[Image #1]";
        let edited_text = format!("follow-up (edited) {placeholder}");
        let edited_range = edited_text.len().saturating_sub(placeholder.len())..edited_text.len();
        let edited_text_elements = vec![TextElement::new(edited_range.into(), None)];
        let edited_local_image_paths = vec![PathBuf::from("/tmp/fake-image.png")];

        // Simulate a transcript with duplicated history (e.g., from prior backtracks)
        // and an edited turn appended after a session header boundary.
        app.transcript_cells = vec![
            make_header(true),
            user_cell("first question", Vec::new(), Vec::new(), Vec::new()),
            agent_cell("answer first"),
            user_cell("follow-up", Vec::new(), Vec::new(), Vec::new()),
            agent_cell("answer follow-up"),
            make_header(false),
            user_cell("first question", Vec::new(), Vec::new(), Vec::new()),
            agent_cell("answer first"),
            user_cell(
                &edited_text,
                edited_text_elements.clone(),
                edited_local_image_paths.clone(),
                vec!["https://example.com/backtrack.png".to_string()],
            ),
            agent_cell("answer edited"),
        ];

        assert_eq!(user_count(&app.transcript_cells), 2);

        let base_id = ThreadId::new();
        app.chat_widget.handle_codex_event(Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id: base_id,
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/home/user/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            }),
        });

        app.backtrack.base_id = Some(base_id);
        app.backtrack.primed = true;
        app.backtrack.nth_user_message = user_count(&app.transcript_cells).saturating_sub(1);

        let selection = app
            .confirm_backtrack_from_main()
            .expect("backtrack selection");
        assert_eq!(selection.nth_user_message, 1);
        assert_eq!(selection.prefill, edited_text);
        assert_eq!(selection.text_elements, edited_text_elements);
        assert_eq!(selection.local_image_paths, edited_local_image_paths);
        assert_eq!(
            selection.remote_image_urls,
            vec!["https://example.com/backtrack.png".to_string()]
        );

        app.apply_backtrack_rollback(selection);
        assert_eq!(
            app.chat_widget.remote_image_urls(),
            vec!["https://example.com/backtrack.png".to_string()]
        );

        let mut rollback_turns = None;
        while let Ok(op) = op_rx.try_recv() {
            if let Op::ThreadRollback { num_turns } = op {
                rollback_turns = Some(num_turns);
            }
        }

        assert_eq!(rollback_turns, Some(1));
    }

    #[tokio::test]
    async fn backtrack_remote_image_only_selection_clears_existing_composer_draft() {
        let (mut app, _app_event_rx, mut op_rx) = make_test_app_with_channels().await;

        app.transcript_cells = vec![Arc::new(UserHistoryCell {
            message: "original".to_string(),
            text_elements: Vec::new(),
            local_image_paths: Vec::new(),
            remote_image_urls: Vec::new(),
        }) as Arc<dyn HistoryCell>];
        app.chat_widget
            .set_composer_text("stale draft".to_string(), Vec::new(), Vec::new());

        let remote_image_url = "https://example.com/remote-only.png".to_string();
        app.apply_backtrack_rollback(BacktrackSelection {
            nth_user_message: 0,
            prefill: String::new(),
            text_elements: Vec::new(),
            local_image_paths: Vec::new(),
            remote_image_urls: vec![remote_image_url.clone()],
        });

        assert_eq!(app.chat_widget.composer_text_with_pending(), "");
        assert_eq!(app.chat_widget.remote_image_urls(), vec![remote_image_url]);

        let mut rollback_turns = None;
        while let Ok(op) = op_rx.try_recv() {
            if let Op::ThreadRollback { num_turns } = op {
                rollback_turns = Some(num_turns);
            }
        }
        assert_eq!(rollback_turns, Some(1));
    }

    #[tokio::test]
    async fn backtrack_resubmit_preserves_data_image_urls_in_user_turn() {
        let (mut app, _app_event_rx, mut op_rx) = make_test_app_with_channels().await;

        let thread_id = ThreadId::new();
        app.chat_widget.handle_codex_event(Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id: thread_id,
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/home/user/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            }),
        });

        let data_image_url = "data:image/png;base64,abc123".to_string();
        app.transcript_cells = vec![Arc::new(UserHistoryCell {
            message: "please inspect this".to_string(),
            text_elements: Vec::new(),
            local_image_paths: Vec::new(),
            remote_image_urls: vec![data_image_url.clone()],
        }) as Arc<dyn HistoryCell>];

        app.apply_backtrack_rollback(BacktrackSelection {
            nth_user_message: 0,
            prefill: "please inspect this".to_string(),
            text_elements: Vec::new(),
            local_image_paths: Vec::new(),
            remote_image_urls: vec![data_image_url.clone()],
        });

        app.chat_widget
            .handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));

        let mut saw_rollback = false;
        let mut submitted_items: Option<Vec<UserInput>> = None;
        while let Ok(op) = op_rx.try_recv() {
            match op {
                Op::ThreadRollback { .. } => saw_rollback = true,
                Op::UserTurn { items, .. } => submitted_items = Some(items),
                _ => {}
            }
        }

        assert!(saw_rollback);
        let items = submitted_items.expect("expected user turn after backtrack resubmit");
        assert!(items.iter().any(|item| {
            matches!(
                item,
                UserInput::Image { image_url } if image_url == &data_image_url
            )
        }));
    }

    #[tokio::test]
    async fn replayed_initial_messages_apply_rollback_in_queue_order() {
        let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;

        let session_id = ThreadId::new();
        app.handle_codex_event_replay(Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id,
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/home/user/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: Some(vec![
                    EventMsg::UserMessage(UserMessageEvent {
                        message: "first prompt".to_string(),
                        images: None,
                        local_images: Vec::new(),
                        text_elements: Vec::new(),
                    }),
                    EventMsg::UserMessage(UserMessageEvent {
                        message: "second prompt".to_string(),
                        images: None,
                        local_images: Vec::new(),
                        text_elements: Vec::new(),
                    }),
                    EventMsg::ThreadRolledBack(ThreadRolledBackEvent { num_turns: 1 }),
                    EventMsg::UserMessage(UserMessageEvent {
                        message: "third prompt".to_string(),
                        images: None,
                        local_images: Vec::new(),
                        text_elements: Vec::new(),
                    }),
                ]),
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            }),
        });

        let mut saw_rollback = false;
        while let Ok(event) = app_event_rx.try_recv() {
            match event {
                AppEvent::InsertHistoryCell(cell) => {
                    let cell: Arc<dyn HistoryCell> = cell.into();
                    app.transcript_cells.push(cell);
                }
                AppEvent::ApplyThreadRollback { num_turns } => {
                    saw_rollback = true;
                    crate::app_backtrack::trim_transcript_cells_drop_last_n_user_turns(
                        &mut app.transcript_cells,
                        num_turns,
                    );
                }
                _ => {}
            }
        }

        assert!(saw_rollback);
        let user_messages: Vec<String> = app
            .transcript_cells
            .iter()
            .filter_map(|cell| {
                cell.as_any()
                    .downcast_ref::<UserHistoryCell>()
                    .map(|cell| cell.message.clone())
            })
            .collect();
        assert_eq!(
            user_messages,
            vec!["first prompt".to_string(), "third prompt".to_string()]
        );
    }

    #[tokio::test]
    async fn live_rollback_during_replay_is_applied_in_app_event_order() {
        let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;

        let session_id = ThreadId::new();
        app.handle_codex_event_replay(Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id,
                forked_from_id: None,
                thread_name: None,
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/home/user/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: Some(vec![
                    EventMsg::UserMessage(UserMessageEvent {
                        message: "first prompt".to_string(),
                        images: None,
                        local_images: Vec::new(),
                        text_elements: Vec::new(),
                    }),
                    EventMsg::UserMessage(UserMessageEvent {
                        message: "second prompt".to_string(),
                        images: None,
                        local_images: Vec::new(),
                        text_elements: Vec::new(),
                    }),
                ]),
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            }),
        });

        // Simulate a live rollback arriving before queued replay inserts are drained.
        app.handle_codex_event_now(Event {
            id: "live-rollback".to_string(),
            msg: EventMsg::ThreadRolledBack(ThreadRolledBackEvent { num_turns: 1 }),
        });

        let mut saw_rollback = false;
        while let Ok(event) = app_event_rx.try_recv() {
            match event {
                AppEvent::InsertHistoryCell(cell) => {
                    let cell: Arc<dyn HistoryCell> = cell.into();
                    app.transcript_cells.push(cell);
                }
                AppEvent::ApplyThreadRollback { num_turns } => {
                    saw_rollback = true;
                    crate::app_backtrack::trim_transcript_cells_drop_last_n_user_turns(
                        &mut app.transcript_cells,
                        num_turns,
                    );
                }
                _ => {}
            }
        }

        assert!(saw_rollback);
        let user_messages: Vec<String> = app
            .transcript_cells
            .iter()
            .filter_map(|cell| {
                cell.as_any()
                    .downcast_ref::<UserHistoryCell>()
                    .map(|cell| cell.message.clone())
            })
            .collect();
        assert_eq!(user_messages, vec!["first prompt".to_string()]);
    }

    #[tokio::test]
    async fn queued_rollback_syncs_overlay_and_clears_deferred_history() {
        let mut app = make_test_app().await;
        app.transcript_cells = vec![
            Arc::new(UserHistoryCell {
                message: "first".to_string(),
                text_elements: Vec::new(),
                local_image_paths: Vec::new(),
                remote_image_urls: Vec::new(),
            }) as Arc<dyn HistoryCell>,
            Arc::new(AgentMessageCell::new(
                vec![Line::from("after first")],
                false,
            )) as Arc<dyn HistoryCell>,
            Arc::new(UserHistoryCell {
                message: "second".to_string(),
                text_elements: Vec::new(),
                local_image_paths: Vec::new(),
                remote_image_urls: Vec::new(),
            }) as Arc<dyn HistoryCell>,
            Arc::new(AgentMessageCell::new(
                vec![Line::from("after second")],
                false,
            )) as Arc<dyn HistoryCell>,
        ];
        app.overlay = Some(Overlay::new_transcript(app.transcript_cells.clone()));
        app.deferred_history_lines = vec![Line::from("stale buffered line")];
        app.backtrack.overlay_preview_active = true;
        app.backtrack.nth_user_message = 1;

        let changed = app.apply_non_pending_thread_rollback(1);

        assert!(changed);
        assert!(app.backtrack_render_pending);
        assert!(app.deferred_history_lines.is_empty());
        assert_eq!(app.backtrack.nth_user_message, 0);
        let user_messages: Vec<String> = app
            .transcript_cells
            .iter()
            .filter_map(|cell| {
                cell.as_any()
                    .downcast_ref::<UserHistoryCell>()
                    .map(|cell| cell.message.clone())
            })
            .collect();
        assert_eq!(user_messages, vec!["first".to_string()]);
        let overlay_cell_count = match app.overlay.as_ref() {
            Some(Overlay::Transcript(t)) => t.committed_cell_count(),
            _ => panic!("expected transcript overlay"),
        };
        assert_eq!(overlay_cell_count, app.transcript_cells.len());
    }

    #[tokio::test]
    async fn new_session_requests_shutdown_for_previous_conversation() {
        let (mut app, mut app_event_rx, mut op_rx) = make_test_app_with_channels().await;

        let thread_id = ThreadId::new();
        let event = SessionConfiguredEvent {
            session_id: thread_id,
            forked_from_id: None,
            thread_name: None,
            model: "gpt-test".to_string(),
            model_provider_id: "test-provider".to_string(),
            service_tier: None,
            approval_policy: AskForApproval::Never,
            sandbox_policy: SandboxPolicy::new_read_only_policy(),
            cwd: PathBuf::from("/home/user/project"),
            reasoning_effort: None,
            history_log_id: 0,
            history_entry_count: 0,
            initial_messages: None,
            network_proxy: None,
            rollout_path: Some(PathBuf::new()),
        };

        app.chat_widget.handle_codex_event(Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(event),
        });

        while app_event_rx.try_recv().is_ok() {}
        while op_rx.try_recv().is_ok() {}

        app.shutdown_current_thread().await;

        match op_rx.try_recv() {
            Ok(Op::Shutdown) => {}
            Ok(other) => panic!("expected Op::Shutdown, got {other:?}"),
            Err(_) => panic!("expected shutdown op to be sent"),
        }
    }

    #[tokio::test]
    async fn shutdown_first_exit_returns_immediate_exit_when_shutdown_submit_fails() {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.active_thread_id = Some(thread_id);

        let control = app.handle_exit_mode(ExitMode::ShutdownFirst);

        assert_eq!(app.pending_shutdown_exit_thread_id, None);
        assert!(matches!(
            control,
            AppRunControl::Exit(ExitReason::UserRequested)
        ));
    }

    #[tokio::test]
    async fn shutdown_first_exit_waits_for_shutdown_when_submit_succeeds() {
        let (mut app, _app_event_rx, mut op_rx) = make_test_app_with_channels().await;
        let thread_id = ThreadId::new();
        app.active_thread_id = Some(thread_id);

        let control = app.handle_exit_mode(ExitMode::ShutdownFirst);

        assert_eq!(app.pending_shutdown_exit_thread_id, Some(thread_id));
        assert!(matches!(control, AppRunControl::Continue));
        assert_eq!(op_rx.try_recv(), Ok(Op::Shutdown));
    }

    #[tokio::test]
    async fn clear_only_ui_reset_preserves_chat_session_state() {
        let mut app = make_test_app().await;
        let thread_id = ThreadId::new();
        app.chat_widget.handle_codex_event(Event {
            id: String::new(),
            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                session_id: thread_id,
                forked_from_id: None,
                thread_name: Some("keep me".to_string()),
                model: "gpt-test".to_string(),
                model_provider_id: "test-provider".to_string(),
                service_tier: None,
                approval_policy: AskForApproval::Never,
                sandbox_policy: SandboxPolicy::new_read_only_policy(),
                cwd: PathBuf::from("/tmp/project"),
                reasoning_effort: None,
                history_log_id: 0,
                history_entry_count: 0,
                initial_messages: None,
                network_proxy: None,
                rollout_path: Some(PathBuf::new()),
            }),
        });
        app.chat_widget
            .apply_external_edit("draft prompt".to_string());
        app.transcript_cells = vec![Arc::new(UserHistoryCell {
            message: "old message".to_string(),
            text_elements: Vec::new(),
            local_image_paths: Vec::new(),
            remote_image_urls: Vec::new(),
        }) as Arc<dyn HistoryCell>];
        app.overlay = Some(Overlay::new_transcript(app.transcript_cells.clone()));
        app.deferred_history_lines = vec![Line::from("stale buffered line")];
        app.has_emitted_history_lines = true;
        app.backtrack.primed = true;
        app.backtrack.overlay_preview_active = true;
        app.backtrack.nth_user_message = 0;
        app.backtrack_render_pending = true;

        app.reset_app_ui_state_after_clear();

        assert!(app.overlay.is_none());
        assert!(app.transcript_cells.is_empty());
        assert!(app.deferred_history_lines.is_empty());
        assert!(!app.has_emitted_history_lines);
        assert!(!app.backtrack.primed);
        assert!(!app.backtrack.overlay_preview_active);
        assert!(app.backtrack.pending_rollback.is_none());
        assert!(!app.backtrack_render_pending);
        assert_eq!(app.chat_widget.thread_id(), Some(thread_id));
        assert_eq!(app.chat_widget.composer_text_with_pending(), "draft prompt");
    }

    #[tokio::test]
    async fn session_summary_skip_zero_usage() {
        assert!(session_summary(TokenUsage::default(), None, None).is_none());
    }

    #[tokio::test]
    async fn session_summary_includes_resume_hint() {
        let usage = TokenUsage {
            input_tokens: 10,
            output_tokens: 2,
            total_tokens: 12,
            ..Default::default()
        };
        let conversation = ThreadId::from_string("123e4567-e89b-12d3-a456-426614174000").unwrap();

        let summary = session_summary(usage, Some(conversation), None).expect("summary");
        assert_eq!(
            summary.usage_line,
            "Token usage: total=12 input=10 output=2"
        );
        assert_eq!(
            summary.resume_command,
            Some("codex resume 123e4567-e89b-12d3-a456-426614174000".to_string())
        );
    }

    #[tokio::test]
    async fn session_summary_prefers_name_over_id() {
        let usage = TokenUsage {
            input_tokens: 10,
            output_tokens: 2,
            total_tokens: 12,
            ..Default::default()
        };
        let conversation = ThreadId::from_string("123e4567-e89b-12d3-a456-426614174000").unwrap();

        let summary = session_summary(usage, Some(conversation), Some("my-session".to_string()))
            .expect("summary");
        assert_eq!(
            summary.resume_command,
            Some("codex resume my-session".to_string())
        );
    }
}