// SPDX-License-Identifier: EUPL-1.2

// Package agentic provides MCP tools for agent orchestration.
// Prepares sandboxed workspaces and dispatches subagents.
package agentic

import (
	"context"
	"encoding/base64"
	"encoding/json"
	goio "io"
	"net/http"
	"os/exec"
	"sync"
	"time"

	"dappco.re/go/agent/pkg/lib"
	core "dappco.re/go/core"
	coremcp "forge.lthn.ai/core/mcp/pkg/mcp"
	"github.com/modelcontextprotocol/go-sdk/mcp"
	"gopkg.in/yaml.v3"
)

// CompletionNotifier is called when an agent completes, to trigger
// immediate notifications to connected clients.
//
//	prep.SetCompletionNotifier(monitor)
type CompletionNotifier interface {
	Poke()
}

// PrepSubsystem provides agentic MCP tools for workspace orchestration.
//
//	sub := agentic.NewPrep()
//	sub.RegisterTools(server)
type PrepSubsystem struct {
	forgeURL   string
	forgeToken string
	brainURL   string
	brainKey   string
	specsPath  string
	codePath   string
	client     *http.Client
	onComplete CompletionNotifier
	drainMu    sync.Mutex // protects drainQueue from concurrent execution
}

var _ coremcp.Subsystem = (*PrepSubsystem)(nil)

// NewPrep creates an agentic subsystem.
//
//	sub := agentic.NewPrep()
//	sub.SetCompletionNotifier(monitor)
//	sub.RegisterTools(server)
func NewPrep() *PrepSubsystem {
	home := core.Env("DIR_HOME")

	forgeToken := core.Env("FORGE_TOKEN")
	if forgeToken == "" {
		forgeToken = core.Env("GITEA_TOKEN")
	}

	brainKey := core.Env("CORE_BRAIN_KEY")
	if brainKey == "" {
		if r := fs.Read(core.JoinPath(home, ".claude", "brain.key")); r.OK {
			brainKey = core.Trim(r.Value.(string))
		}
	}

	return &PrepSubsystem{
		forgeURL:   envOr("FORGE_URL", "https://forge.lthn.ai"),
		forgeToken: forgeToken,
		brainURL:   envOr("CORE_BRAIN_URL", "https://api.lthn.sh"),
		brainKey:   brainKey,
		specsPath:  envOr("SPECS_PATH", core.JoinPath(home, "Code", "specs")),
		codePath:   envOr("CODE_PATH", core.JoinPath(home, "Code")),
		client:     &http.Client{Timeout: 30 * time.Second},
	}
}

// SetCompletionNotifier wires up the monitor for immediate push on agent completion.
//
//	prep.SetCompletionNotifier(monitor)
func (s *PrepSubsystem) SetCompletionNotifier(n CompletionNotifier) {
	s.onComplete = n
}

func envOr(key, fallback string) string {
	if v := core.Env(key); v != "" {
		return v
	}
	return fallback
}

// Name implements mcp.Subsystem.
//
//	name := prep.Name() // "agentic"
func (s *PrepSubsystem) Name() string { return "agentic" }

// RegisterTools implements mcp.Subsystem.
//
//	prep.RegisterTools(server)
func (s *PrepSubsystem) RegisterTools(server *mcp.Server) {
	mcp.AddTool(server, &mcp.Tool{
		Name:        "agentic_prep_workspace",
		Description: "Prepare a sandboxed agent workspace with TODO.md, CLAUDE.md, CONTEXT.md, CONSUMERS.md, RECENT.md, and a git clone of the target repo in src/.",
	}, s.prepWorkspace)

	s.registerDispatchTool(server)
	s.registerStatusTool(server)
	s.registerResumeTool(server)
	s.registerCreatePRTool(server)
	s.registerListPRsTool(server)
	s.registerEpicTool(server)
	s.registerMirrorTool(server)
	s.registerRemoteDispatchTool(server)
	s.registerRemoteStatusTool(server)
	s.registerReviewQueueTool(server)

	mcp.AddTool(server, &mcp.Tool{
		Name:        "agentic_scan",
		Description: "Scan Forge repos for open issues with actionable labels (agentic, help-wanted, bug).",
	}, s.scan)

	s.registerPlanTools(server)
	s.registerWatchTool(server)
}

// Shutdown implements mcp.SubsystemWithShutdown.
//
//	_ = prep.Shutdown(context.Background())
func (s *PrepSubsystem) Shutdown(_ context.Context) error { return nil }

// --- Input/Output types ---

// PrepInput is the input for agentic_prep_workspace.
//
//	input := agentic.PrepInput{Repo: "go-io", Task: "Migrate pkg/fs to Core primitives"}
type PrepInput struct {
	Repo         string            `json:"repo"`                    // e.g. "go-io"
	Org          string            `json:"org,omitempty"`           // default "core"
	Issue        int               `json:"issue,omitempty"`         // Forge issue number
	Task         string            `json:"task,omitempty"`          // Task description (if no issue)
	Template     string            `json:"template,omitempty"`      // Prompt template: conventions, security, coding (default: coding)
	PlanTemplate string            `json:"plan_template,omitempty"` // Plan template slug: bug-fix, code-review, new-feature, refactor, feature-port
	Variables    map[string]string `json:"variables,omitempty"`     // Template variable substitution
	Persona      string            `json:"persona,omitempty"`       // Persona slug: engineering/backend-architect, testing/api-tester, etc.
}

// PrepOutput is the output for agentic_prep_workspace.
//
//	out := agentic.PrepOutput{Success: true, WorkspaceDir: ".core/workspace/go-io-123", Branch: "agent/migrate-fs"}
type PrepOutput struct {
	Success      bool   `json:"success"`
	WorkspaceDir string `json:"workspace_dir"`
	Branch       string `json:"branch"`
	WikiPages    int    `json:"wiki_pages"`
	SpecFiles    int    `json:"spec_files"`
	Memories     int    `json:"memories"`
	Consumers    int    `json:"consumers"`
	ClaudeMd     bool   `json:"claude_md"`
	GitLog       int    `json:"git_log_entries"`
}

func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolRequest, input PrepInput) (*mcp.CallToolResult, PrepOutput, error) {
	if input.Repo == "" {
		return nil, PrepOutput{}, core.E("prepWorkspace", "repo is required", nil)
	}
	if input.Org == "" {
		input.Org = "core"
	}
	if input.Template == "" {
		input.Template = "coding"
	}

	// Workspace root: .core/workspace/{repo}-{timestamp}/
	wsRoot := WorkspaceRoot()
	wsName := core.Sprintf("%s-%d", input.Repo, time.Now().UnixNano())
	wsDir := core.JoinPath(wsRoot, wsName)

	// Create workspace structure
	// kb/ and specs/ will be created inside src/ after clone

	// Ensure workspace directory exists
	if r := fs.EnsureDir(wsDir); !r.OK {
		return nil, PrepOutput{}, core.E("prep", "failed to create workspace dir", nil)
	}

	out := PrepOutput{WorkspaceDir: wsDir}

	// Source repo path — sanitise to prevent path traversal
	repoName := core.PathBase(input.Repo) // strips ../ and absolute paths
	if repoName == "." || repoName == ".." || repoName == "" {
		return nil, PrepOutput{}, core.E("prep", "invalid repo name: "+input.Repo, nil)
	}
	repoPath := core.JoinPath(s.codePath, "core", repoName)

	// 1. Clone repo into src/ and create feature branch
	srcDir := core.JoinPath(wsDir, "src")
	cloneCmd := exec.CommandContext(ctx, "git", "clone", repoPath, srcDir)
	if err := cloneCmd.Run(); err != nil {
		return nil, PrepOutput{}, core.E("prep", "git clone failed for "+input.Repo, err)
	}

	// Create feature branch
	taskSlug := sanitiseBranchSlug(input.Task, 40)
	if taskSlug == "" {
		// Fallback for issue-only dispatches with no task text
		taskSlug = core.Sprintf("issue-%d", input.Issue)
		if input.Issue == 0 {
			taskSlug = core.Sprintf("work-%d", time.Now().Unix())
		}
	}
	branchName := core.Sprintf("agent/%s", taskSlug)

	branchCmd := exec.CommandContext(ctx, "git", "checkout", "-b", branchName)
	branchCmd.Dir = srcDir
	if err := branchCmd.Run(); err != nil {
		return nil, PrepOutput{}, core.E("prep.branch", core.Sprintf("failed to create branch %q", branchName), err)
	}
	out.Branch = branchName

	// Create context dirs inside src/
	fs.EnsureDir(core.JoinPath(wsDir, "kb"))
	fs.EnsureDir(core.JoinPath(wsDir, "specs"))

	// Remote stays as local clone origin — agent cannot push to forge.
	// Reviewer pulls changes from workspace and pushes after verification.

	// 2. Extract workspace template — default first, then overlay
	wsTmpl := ""
	if input.Template == "security" {
		wsTmpl = "security"
	} else if input.Template == "review" || input.Template == "verify" || input.Template == "conventions" {
		wsTmpl = "review"
	}

	promptContent := ""
	if r := lib.Prompt(input.Template); r.OK {
		promptContent = r.Value.(string)
	}
	personaContent := ""
	if input.Persona != "" {
		if r := lib.Persona(input.Persona); r.OK {
			personaContent = r.Value.(string)
		}
	}
	flowContent := ""
	if r := lib.Flow(detectLanguage(repoPath)); r.OK {
		flowContent = r.Value.(string)
	}

	wsData := &lib.WorkspaceData{
		Repo:     input.Repo,
		Branch:   branchName,
		Task:     input.Task,
		Agent:    "agent",
		Language: detectLanguage(repoPath),
		Prompt:   promptContent,
		Persona:  personaContent,
		Flow:     flowContent,
		BuildCmd: detectBuildCmd(repoPath),
		TestCmd:  detectTestCmd(repoPath),
	}

	lib.ExtractWorkspace("default", wsDir, wsData)
	if wsTmpl != "" {
		lib.ExtractWorkspace(wsTmpl, wsDir, wsData)
	}

	// 3. Generate TODO.md from issue (overrides template)
	if input.Issue > 0 {
		s.generateTodo(ctx, input.Org, input.Repo, input.Issue, wsDir)
	}

	// 4. Generate CONTEXT.md from OpenBrain
	out.Memories = s.generateContext(ctx, input.Repo, wsDir)

	// 5. Generate CONSUMERS.md
	out.Consumers = s.findConsumers(input.Repo, wsDir)

	// 6. Generate RECENT.md
	out.GitLog = s.gitLog(repoPath, wsDir)

	// 7. Pull wiki pages into kb/
	out.WikiPages = s.pullWiki(ctx, input.Org, input.Repo, wsDir)

	// 8. Copy spec files into specs/
	out.SpecFiles = s.copySpecs(wsDir)

	// 9. Write PLAN.md from template (if specified)
	if input.PlanTemplate != "" {
		s.writePlanFromTemplate(input.PlanTemplate, input.Variables, input.Task, wsDir)
	}

	// 10. Write prompt template
	s.writePromptTemplate(input.Template, wsDir)

	out.Success = true
	return nil, out, nil
}

// --- Prompt templates ---

func (s *PrepSubsystem) writePromptTemplate(template, wsDir string) {
	r := lib.Template(template)
	if !r.OK {
		r = lib.Template("default")
	}
	prompt := "Read TODO.md and complete the task. Work in src/.\n"
	if r.OK {
		prompt = r.Value.(string)
	}

	fs.Write(core.JoinPath(wsDir, "src", "PROMPT.md"), prompt)
}

// --- Plan template rendering ---

// writePlanFromTemplate loads a YAML plan template, substitutes variables,
// and writes PLAN.md into the workspace src/ directory.
func (s *PrepSubsystem) writePlanFromTemplate(templateSlug string, variables map[string]string, task string, wsDir string) {
	// Load template from embedded prompts package
	r := lib.Template(templateSlug)
	if !r.OK {
		return // Template not found, skip silently
	}

	content := r.Value.(string)

	// Substitute variables ({{variable_name}} → value)
	for key, value := range variables {
		content = core.Replace(content, "{{"+key+"}}", value)
		content = core.Replace(content, "{{ "+key+" }}", value)
	}

	// Parse the YAML to render as markdown
	var tmpl struct {
		Name        string   `yaml:"name"`
		Description string   `yaml:"description"`
		Guidelines  []string `yaml:"guidelines"`
		Phases      []struct {
			Name        string `yaml:"name"`
			Description string `yaml:"description"`
			Tasks       []any  `yaml:"tasks"`
		} `yaml:"phases"`
	}

	if err := yaml.Unmarshal([]byte(content), &tmpl); err != nil {
		return
	}

	// Render as PLAN.md
	plan := core.NewBuilder()
	plan.WriteString("# Plan: " + tmpl.Name + "\n\n")
	if task != "" {
		plan.WriteString("**Task:** " + task + "\n\n")
	}
	if tmpl.Description != "" {
		plan.WriteString(tmpl.Description + "\n\n")
	}

	if len(tmpl.Guidelines) > 0 {
		plan.WriteString("## Guidelines\n\n")
		for _, g := range tmpl.Guidelines {
			plan.WriteString("- " + g + "\n")
		}
		plan.WriteString("\n")
	}

	for i, phase := range tmpl.Phases {
		plan.WriteString(core.Sprintf("## Phase %d: %s\n\n", i+1, phase.Name))
		if phase.Description != "" {
			plan.WriteString(phase.Description + "\n\n")
		}
		for _, task := range phase.Tasks {
			switch t := task.(type) {
			case string:
				plan.WriteString("- [ ] " + t + "\n")
			case map[string]any:
				if name, ok := t["name"].(string); ok {
					plan.WriteString("- [ ] " + name + "\n")
				}
			}
		}
		plan.WriteString("\n**Commit after completing this phase.**\n\n---\n\n")
	}

	fs.Write(core.JoinPath(wsDir, "src", "PLAN.md"), plan.String())
}

// --- Helpers (unchanged) ---

func (s *PrepSubsystem) pullWiki(ctx context.Context, org, repo, wsDir string) int {
	if s.forgeToken == "" {
		return 0
	}

	url := core.Sprintf("%s/api/v1/repos/%s/%s/wiki/pages", s.forgeURL, org, repo)
	req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)
	req.Header.Set("Authorization", "token "+s.forgeToken)

	resp, err := s.client.Do(req)
	if err != nil {
		return 0
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return 0
	}

	var pages []struct {
		Title  string `json:"title"`
		SubURL string `json:"sub_url"`
	}
	json.NewDecoder(resp.Body).Decode(&pages)

	count := 0
	for _, page := range pages {
		subURL := page.SubURL
		if subURL == "" {
			subURL = page.Title
		}

		pageURL := core.Sprintf("%s/api/v1/repos/%s/%s/wiki/page/%s", s.forgeURL, org, repo, subURL)
		pageReq, _ := http.NewRequestWithContext(ctx, "GET", pageURL, nil)
		pageReq.Header.Set("Authorization", "token "+s.forgeToken)

		pageResp, err := s.client.Do(pageReq)
		if err != nil {
			continue
		}
		if pageResp.StatusCode != 200 {
			pageResp.Body.Close()
			continue
		}

		var pageData struct {
			ContentBase64 string `json:"content_base64"`
		}
		json.NewDecoder(pageResp.Body).Decode(&pageData)
		pageResp.Body.Close()

		if pageData.ContentBase64 == "" {
			continue
		}

		content, _ := base64.StdEncoding.DecodeString(pageData.ContentBase64)
		filename := sanitiseFilename(page.Title) + ".md"

		fs.Write(core.JoinPath(wsDir, "src", "kb", filename), string(content))
		count++
	}

	return count
}

func (s *PrepSubsystem) copySpecs(wsDir string) int {
	specFiles := []string{"AGENT_CONTEXT.md", "TASK_PROTOCOL.md"}
	count := 0

	for _, file := range specFiles {
		src := core.JoinPath(s.specsPath, file)
		if r := fs.Read(src); r.OK {
			fs.Write(core.JoinPath(wsDir, "src", "specs", file), r.Value.(string))
			count++
		}
	}

	return count
}

func (s *PrepSubsystem) generateContext(ctx context.Context, repo, wsDir string) int {
	if s.brainKey == "" {
		return 0
	}

	body, _ := json.Marshal(map[string]any{
		"query":    "architecture conventions key interfaces for " + repo,
		"top_k":    10,
		"project":  repo,
		"agent_id": "cladius",
	})

	req, _ := http.NewRequestWithContext(ctx, "POST", s.brainURL+"/v1/brain/recall", core.NewReader(string(body)))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	req.Header.Set("Authorization", "Bearer "+s.brainKey)

	resp, err := s.client.Do(req)
	if err != nil {
		return 0
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return 0
	}

	respData, _ := goio.ReadAll(resp.Body)
	var result struct {
		Memories []map[string]any `json:"memories"`
	}
	json.Unmarshal(respData, &result)

	content := core.NewBuilder()
	content.WriteString("# Context — " + repo + "\n\n")
	content.WriteString("> Relevant knowledge from OpenBrain.\n\n")

	for i, mem := range result.Memories {
		memType, _ := mem["type"].(string)
		memContent, _ := mem["content"].(string)
		memProject, _ := mem["project"].(string)
		score, _ := mem["score"].(float64)
		content.WriteString(core.Sprintf("### %d. %s [%s] (score: %.3f)\n\n%s\n\n", i+1, memProject, memType, score, memContent))
	}

	fs.Write(core.JoinPath(wsDir, "src", "CONTEXT.md"), content.String())
	return len(result.Memories)
}

func (s *PrepSubsystem) findConsumers(repo, wsDir string) int {
	goWorkPath := core.JoinPath(s.codePath, "go.work")
	modulePath := "forge.lthn.ai/core/" + repo

	r := fs.Read(goWorkPath)
	if !r.OK {
		return 0
	}
	workData := r.Value.(string)

	var consumers []string
	for _, line := range core.Split(workData, "\n") {
		line = core.Trim(line)
		if !core.HasPrefix(line, "./") {
			continue
		}
		dir := core.JoinPath(s.codePath, core.TrimPrefix(line, "./"))
		goMod := core.JoinPath(dir, "go.mod")
		mr := fs.Read(goMod)
		if !mr.OK {
			continue
		}
		modData := mr.Value.(string)
		if core.Contains(modData, modulePath) && !core.HasPrefix(modData, "module "+modulePath) {
			consumers = append(consumers, core.PathBase(dir))
		}
	}

	if len(consumers) > 0 {
		content := "# Consumers of " + repo + "\n\n"
		content += "These modules import `" + modulePath + "`:\n\n"
		for _, c := range consumers {
			content += "- " + c + "\n"
		}
		content += core.Sprintf("\n**Breaking change risk: %d consumers.**\n", len(consumers))
		fs.Write(core.JoinPath(wsDir, "src", "CONSUMERS.md"), content)
	}

	return len(consumers)
}

func (s *PrepSubsystem) gitLog(repoPath, wsDir string) int {
	cmd := exec.Command("git", "log", "--oneline", "-20")
	cmd.Dir = repoPath
	output, err := cmd.Output()
	if err != nil {
		return 0
	}

	lines := core.Split(core.Trim(string(output)), "\n")
	if len(lines) > 0 && lines[0] != "" {
		content := "# Recent Changes\n\n```\n" + string(output) + "```\n"
		fs.Write(core.JoinPath(wsDir, "src", "RECENT.md"), content)
	}

	return len(lines)
}

func (s *PrepSubsystem) generateTodo(ctx context.Context, org, repo string, issue int, wsDir string) {
	if s.forgeToken == "" {
		return
	}

	url := core.Sprintf("%s/api/v1/repos/%s/%s/issues/%d", s.forgeURL, org, repo, issue)
	req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)
	req.Header.Set("Authorization", "token "+s.forgeToken)

	resp, err := s.client.Do(req)
	if err != nil {
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return
	}

	var issueData struct {
		Title string `json:"title"`
		Body  string `json:"body"`
	}
	json.NewDecoder(resp.Body).Decode(&issueData)

	content := core.Sprintf("# TASK: %s\n\n", issueData.Title)
	content += core.Sprintf("**Status:** ready\n")
	content += core.Sprintf("**Source:** %s/%s/%s/issues/%d\n", s.forgeURL, org, repo, issue)
	content += core.Sprintf("**Repo:** %s/%s\n\n---\n\n", org, repo)
	content += "## Objective\n\n" + issueData.Body + "\n"

	fs.Write(core.JoinPath(wsDir, "src", "TODO.md"), content)
}

// detectLanguage guesses the primary language from repo contents.
// Checks in priority order (Go first) to avoid nondeterministic results.
func detectLanguage(repoPath string) string {
	checks := []struct {
		file string
		lang string
	}{
		{"go.mod", "go"},
		{"composer.json", "php"},
		{"package.json", "ts"},
		{"Cargo.toml", "rust"},
		{"requirements.txt", "py"},
		{"CMakeLists.txt", "cpp"},
		{"Dockerfile", "docker"},
	}
	for _, c := range checks {
		if fs.IsFile(core.JoinPath(repoPath, c.file)) {
			return c.lang
		}
	}
	return "go"
}

func detectBuildCmd(repoPath string) string {
	switch detectLanguage(repoPath) {
	case "go":
		return "go build ./..."
	case "php":
		return "composer install"
	case "ts":
		return "npm run build"
	case "py":
		return "pip install -e ."
	case "rust":
		return "cargo build"
	case "cpp":
		return "cmake --build ."
	default:
		return "go build ./..."
	}
}

func detectTestCmd(repoPath string) string {
	switch detectLanguage(repoPath) {
	case "go":
		return "go test ./..."
	case "php":
		return "composer test"
	case "ts":
		return "npm test"
	case "py":
		return "pytest"
	case "rust":
		return "cargo test"
	case "cpp":
		return "ctest"
	default:
		return "go test ./..."
	}
}