// Package cli provides the CLI runtime and utilities.
package cli

import (
	"os"

	"golang.org/x/term"
)

// Mode represents the CLI execution mode.
type Mode int

const (
	// ModeInteractive indicates TTY attached with coloured output.
	ModeInteractive Mode = iota
	// ModePipe indicates stdout is piped, colours disabled.
	ModePipe
	// ModeDaemon indicates headless execution, log-only output.
	ModeDaemon
)

// String returns the string representation of the Mode.
func (m Mode) String() string {
	switch m {
	case ModeInteractive:
		return "interactive"
	case ModePipe:
		return "pipe"
	case ModeDaemon:
		return "daemon"
	default:
		return "unknown"
	}
}

// DetectMode determines the execution mode based on environment.
// Checks CORE_DAEMON env var first, then TTY status.
func DetectMode() Mode {
	if os.Getenv("CORE_DAEMON") == "1" {
		return ModeDaemon
	}
	if !IsTTY() {
		return ModePipe
	}
	return ModeInteractive
}

// IsTTY returns true if stdout is a terminal.
func IsTTY() bool {
	return term.IsTerminal(int(os.Stdout.Fd()))
}

// IsStdinTTY returns true if stdin is a terminal.
func IsStdinTTY() bool {
	return term.IsTerminal(int(os.Stdin.Fd()))
}

// IsStderrTTY returns true if stderr is a terminal.
func IsStderrTTY() bool {
	return term.IsTerminal(int(os.Stderr.Fd()))
}