package core

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"
	"unicode/utf8"
)

const maxPlatformMessageLen = 4000

const (
	defaultThinkingMaxLen = 300
	defaultToolMaxLen     = 500
)

// Slow-operation thresholds. Operations exceeding these durations produce a
// slog.Warn so operators can quickly pinpoint bottlenecks.
const (
	slowPlatformSend    = 2 * time.Second  // platform Reply / Send
	slowAgentStart      = 5 * time.Second  // agent.StartSession
	slowAgentClose      = 3 * time.Second  // agentSession.Close
	slowAgentSend       = 2 * time.Second  // agentSession.Send
	slowAgentFirstEvent = 15 * time.Second // time from send to first agent event
)

// VersionInfo is set by main at startup so that /version works.
var VersionInfo string

// CurrentVersion is the semver tag (e.g. "v1.2.0-beta.1"), set by main.
var CurrentVersion string

// RestartRequest carries info needed to send a post-restart notification.
type RestartRequest struct {
	SessionKey string `json:"session_key"`
	Platform   string `json:"platform"`
}

// SaveRestartNotify persists restart info so the new process can send
// a "restart successful" message after startup.
func SaveRestartNotify(dataDir string, req RestartRequest) error {
	dir := filepath.Join(dataDir, "run")
	os.MkdirAll(dir, 0o755)
	data, _ := json.Marshal(req)
	return os.WriteFile(filepath.Join(dir, "restart_notify"), data, 0o644)
}

// ConsumeRestartNotify reads and deletes the restart notification file.
// Returns nil if no notification is pending.
func ConsumeRestartNotify(dataDir string) *RestartRequest {
	p := filepath.Join(dataDir, "run", "restart_notify")
	data, err := os.ReadFile(p)
	if err != nil {
		return nil
	}
	os.Remove(p)
	var req RestartRequest
	if json.Unmarshal(data, &req) != nil {
		return nil
	}
	return &req
}

// SendRestartNotification sends a "restart successful" message to the
// platform/session that initiated the restart.
func (e *Engine) SendRestartNotification(platformName, sessionKey string) {
	for _, p := range e.platforms {
		if p.Name() != platformName {
			continue
		}
		rc, ok := p.(ReplyContextReconstructor)
		if !ok {
			slog.Debug("restart notify: platform does not support ReconstructReplyCtx", "platform", platformName)
			return
		}
		rctx, err := rc.ReconstructReplyCtx(sessionKey)
		if err != nil {
			slog.Debug("restart notify: reconstruct failed", "error", err)
			return
		}
		msg := e.i18n.T(MsgRestartSuccess)
		if err := p.Send(e.ctx, rctx, msg); err != nil {
			slog.Debug("restart notify: send failed", "error", err)
		}
		return
	}
}

// RestartCh is signaled when /restart is invoked. main listens on it
// to perform a graceful shutdown followed by syscall.Exec.
var RestartCh = make(chan RestartRequest, 1)

// DisplayCfg controls truncation of intermediate messages.
// A value of -1 means "use default", 0 means "no truncation".
type DisplayCfg struct {
	ThinkingMaxLen int // max runes for thinking preview; 0 = no truncation
	ToolMaxLen     int // max runes for tool use preview; 0 = no truncation
}

// RateLimitCfg controls per-session message rate limiting.
type RateLimitCfg struct {
	MaxMessages int           // max messages per window; 0 = disabled
	Window      time.Duration // sliding window size
}

// Engine routes messages between platforms and the agent for a single project.
type Engine struct {
	name      string
	agent     Agent
	platforms []Platform
	sessions  *SessionManager
	ctx       context.Context
	cancel    context.CancelFunc
	i18n      *I18n
	speech       SpeechCfg
	display      DisplayCfg
	defaultQuiet bool
	startedAt    time.Time

	providerSaveFunc       func(providerName string) error
	providerAddSaveFunc    func(p ProviderConfig) error
	providerRemoveSaveFunc func(name string) error

	commandSaveAddFunc func(name, description, prompt string) error
	commandSaveDelFunc func(name string) error

	displaySaveFunc  func(thinkingMaxLen, toolMaxLen *int) error
	configReloadFunc func() (*ConfigReloadResult, error)

	cronScheduler *CronScheduler

	commands *CommandRegistry
	skills   *SkillRegistry
	aliases  map[string]string // trigger → command (e.g. "帮助" → "/help")
	aliasMu  sync.RWMutex

	aliasSaveAddFunc func(name, command string) error
	aliasSaveDelFunc func(name string) error

	bannedWords []string
	bannedMu    sync.RWMutex

	disabledCmds map[string]bool

	rateLimiter   *RateLimiter
	streamPreview StreamPreviewCfg

	// Interactive agent session management
	interactiveMu     sync.Mutex
	interactiveStates map[string]*interactiveState // key = sessionKey
}

// interactiveState tracks a running interactive agent session and its permission state.
type interactiveState struct {
	agentSession AgentSession
	platform     Platform
	replyCtx     any
	mu           sync.Mutex
	pending      *pendingPermission
	approveAll   bool // when true, auto-approve all permission requests for this session
	quiet        bool // when true, suppress thinking and tool progress messages
}

// pendingPermission represents a permission request waiting for user response.
type pendingPermission struct {
	RequestID    string
	ToolName     string
	ToolInput    map[string]any
	InputPreview string
	Resolved     chan struct{} // closed when user responds
	resolveOnce  sync.Once
}

// resolve safely closes the Resolved channel exactly once.
func (pp *pendingPermission) resolve() {
	pp.resolveOnce.Do(func() { close(pp.Resolved) })
}

func NewEngine(name string, ag Agent, platforms []Platform, sessionStorePath string, lang Language) *Engine {
	ctx, cancel := context.WithCancel(context.Background())
	e := &Engine{
		name:              name,
		agent:             ag,
		platforms:         platforms,
		sessions:          NewSessionManager(sessionStorePath),
		ctx:               ctx,
		cancel:            cancel,
		i18n:              NewI18n(lang),
		display:           DisplayCfg{ThinkingMaxLen: defaultThinkingMaxLen, ToolMaxLen: defaultToolMaxLen},
		commands:          NewCommandRegistry(),
		skills:            NewSkillRegistry(),
		aliases:           make(map[string]string),
		interactiveStates: make(map[string]*interactiveState),
		startedAt:         time.Now(),
		streamPreview:     DefaultStreamPreviewCfg(),
	}

	if cp, ok := ag.(CommandProvider); ok {
		e.commands.SetAgentDirs(cp.CommandDirs())
	}
	if sp, ok := ag.(SkillProvider); ok {
		e.skills.SetDirs(sp.SkillDirs())
	}

	return e
}

// SetSpeechConfig configures the speech-to-text subsystem.
func (e *Engine) SetSpeechConfig(cfg SpeechCfg) {
	e.speech = cfg
}

// SetDisplayConfig overrides the default truncation settings.
func (e *Engine) SetDisplayConfig(cfg DisplayCfg) {
	e.display = cfg
}

// SetDefaultQuiet sets whether new sessions start in quiet mode.
func (e *Engine) SetDefaultQuiet(q bool) {
	e.defaultQuiet = q
}

func (e *Engine) SetLanguageSaveFunc(fn func(Language) error) {
	e.i18n.SetSaveFunc(fn)
}

func (e *Engine) SetProviderSaveFunc(fn func(providerName string) error) {
	e.providerSaveFunc = fn
}

func (e *Engine) SetProviderAddSaveFunc(fn func(ProviderConfig) error) {
	e.providerAddSaveFunc = fn
}

func (e *Engine) SetProviderRemoveSaveFunc(fn func(string) error) {
	e.providerRemoveSaveFunc = fn
}

func (e *Engine) SetCronScheduler(cs *CronScheduler) {
	e.cronScheduler = cs
}

func (e *Engine) SetCommandSaveAddFunc(fn func(name, description, prompt string) error) {
	e.commandSaveAddFunc = fn
}

func (e *Engine) SetCommandSaveDelFunc(fn func(name string) error) {
	e.commandSaveDelFunc = fn
}

func (e *Engine) SetDisplaySaveFunc(fn func(thinkingMaxLen, toolMaxLen *int) error) {
	e.displaySaveFunc = fn
}

// ConfigReloadResult describes what was updated by a config reload.
type ConfigReloadResult struct {
	DisplayUpdated   bool
	ProvidersUpdated int
	CommandsUpdated  int
}

func (e *Engine) SetConfigReloadFunc(fn func() (*ConfigReloadResult, error)) {
	e.configReloadFunc = fn
}

// GetAgent returns the engine's agent (for type assertions like ProviderSwitcher).
func (e *Engine) GetAgent() Agent {
	return e.agent
}

// AddCommand registers a custom slash command.
func (e *Engine) AddCommand(name, description, prompt, source string) {
	e.commands.Add(name, description, prompt, source)
}

// ClearCommands removes all commands from the given source.
func (e *Engine) ClearCommands(source string) {
	e.commands.ClearSource(source)
}

// AddAlias registers a command alias.
func (e *Engine) AddAlias(name, command string) {
	e.aliasMu.Lock()
	defer e.aliasMu.Unlock()
	e.aliases[name] = command
}

func (e *Engine) SetAliasSaveAddFunc(fn func(name, command string) error) {
	e.aliasSaveAddFunc = fn
}

func (e *Engine) SetAliasSaveDelFunc(fn func(name string) error) {
	e.aliasSaveDelFunc = fn
}

// ClearAliases removes all aliases (for config reload).
func (e *Engine) ClearAliases() {
	e.aliasMu.Lock()
	defer e.aliasMu.Unlock()
	e.aliases = make(map[string]string)
}

// SetDisabledCommands sets the list of command IDs that are disabled for this project.
func (e *Engine) SetDisabledCommands(cmds []string) {
	m := make(map[string]bool, len(cmds))
	for _, c := range cmds {
		c = strings.ToLower(strings.TrimPrefix(c, "/"))
		// Resolve alias names to canonical IDs
		id := matchPrefix(c, builtinCommands)
		if id != "" {
			m[id] = true
		} else {
			m[c] = true
		}
	}
	e.disabledCmds = m
}

// SetBannedWords replaces the banned words list.
func (e *Engine) SetBannedWords(words []string) {
	e.bannedMu.Lock()
	defer e.bannedMu.Unlock()
	lower := make([]string, len(words))
	for i, w := range words {
		lower[i] = strings.ToLower(w)
	}
	e.bannedWords = lower
}

// SetRateLimitCfg configures per-session message rate limiting.
func (e *Engine) SetRateLimitCfg(cfg RateLimitCfg) {
	e.rateLimiter = NewRateLimiter(cfg.MaxMessages, cfg.Window)
}

// SetStreamPreviewCfg configures the streaming preview behavior.
func (e *Engine) SetStreamPreviewCfg(cfg StreamPreviewCfg) {
	e.streamPreview = cfg
}

// RemoveCommand removes a custom command by name. Returns false if not found.
func (e *Engine) RemoveCommand(name string) bool {
	return e.commands.Remove(name)
}

func (e *Engine) ProjectName() string {
	return e.name
}

// ExecuteCronJob runs a cron job by injecting a synthetic message into the engine.
// It finds the platform that owns the session key, reconstructs a reply context,
// and processes the message as if the user sent it.
func (e *Engine) ExecuteCronJob(job *CronJob) error {
	sessionKey := job.SessionKey
	platformName := ""
	if idx := strings.Index(sessionKey, ":"); idx > 0 {
		platformName = sessionKey[:idx]
	}

	var targetPlatform Platform
	for _, p := range e.platforms {
		if p.Name() == platformName {
			targetPlatform = p
			break
		}
	}
	if targetPlatform == nil {
		return fmt.Errorf("platform %q not found for session %q", platformName, sessionKey)
	}

	rc, ok := targetPlatform.(ReplyContextReconstructor)
	if !ok {
		return fmt.Errorf("platform %q does not support proactive messaging (cron)", platformName)
	}

	replyCtx, err := rc.ReconstructReplyCtx(sessionKey)
	if err != nil {
		return fmt.Errorf("reconstruct reply context: %w", err)
	}

	// Notify user that a cron job is executing
	desc := job.Description
	if desc == "" {
		desc = truncateStr(job.Prompt, 40)
	}
	e.send(targetPlatform, replyCtx, fmt.Sprintf("⏰ %s", desc))

	msg := &Message{
		SessionKey: sessionKey,
		Platform:   platformName,
		UserID:     "cron",
		UserName:   "cron",
		Content:    job.Prompt,
		ReplyCtx:   replyCtx,
	}

	session := e.sessions.GetOrCreateActive(sessionKey)
	if !session.TryLock() {
		return fmt.Errorf("session %q is busy", sessionKey)
	}

	e.processInteractiveMessage(targetPlatform, msg, session)
	return nil
}

func (e *Engine) Start() error {
	for _, p := range e.platforms {
		if err := p.Start(e.handleMessage); err != nil {
			return fmt.Errorf("[%s] start platform %s: %w", e.name, p.Name(), err)
		}
		slog.Info("platform started", "project", e.name, "platform", p.Name())
	}
	slog.Info("engine started", "project", e.name, "agent", e.agent.Name(), "platforms", len(e.platforms))
	return nil
}

func (e *Engine) Stop() error {
	// Stop platforms first to prevent new incoming messages
	var errs []error
	for _, p := range e.platforms {
		if err := p.Stop(); err != nil {
			errs = append(errs, fmt.Errorf("stop platform %s: %w", p.Name(), err))
		}
	}

	// Now cancel context and clean up sessions
	e.cancel()

	e.interactiveMu.Lock()
	states := make(map[string]*interactiveState, len(e.interactiveStates))
	for k, v := range e.interactiveStates {
		states[k] = v
		delete(e.interactiveStates, k)
	}
	e.interactiveMu.Unlock()

	for key, state := range states {
		if state.agentSession != nil {
			slog.Debug("engine.Stop: closing agent session", "session", key)
			state.agentSession.Close()
		}
	}

	if err := e.agent.Stop(); err != nil {
		errs = append(errs, fmt.Errorf("stop agent %s: %w", e.agent.Name(), err))
	}
	if len(errs) > 0 {
		return fmt.Errorf("engine stop errors: %v", errs)
	}
	return nil
}

// matchBannedWord returns the first banned word found in content, or "".
func (e *Engine) matchBannedWord(content string) string {
	e.bannedMu.RLock()
	defer e.bannedMu.RUnlock()
	if len(e.bannedWords) == 0 {
		return ""
	}
	lower := strings.ToLower(content)
	for _, w := range e.bannedWords {
		if strings.Contains(lower, w) {
			return w
		}
	}
	return ""
}

// resolveAlias checks if the content (or its first word) matches an alias and replaces it.
func (e *Engine) resolveAlias(content string) string {
	e.aliasMu.RLock()
	defer e.aliasMu.RUnlock()

	if len(e.aliases) == 0 {
		return content
	}

	// Exact match on full content
	if cmd, ok := e.aliases[content]; ok {
		return cmd
	}

	// Match first word, append remaining args
	parts := strings.SplitN(content, " ", 2)
	if cmd, ok := e.aliases[parts[0]]; ok {
		if len(parts) > 1 {
			return cmd + " " + parts[1]
		}
		return cmd
	}
	return content
}

func (e *Engine) handleMessage(p Platform, msg *Message) {
	// Voice message: transcribe to text first
	if msg.Audio != nil {
		e.handleVoiceMessage(p, msg)
		return
	}

	content := strings.TrimSpace(msg.Content)
	if content == "" && len(msg.Images) == 0 {
		return
	}

	// Resolve aliases: check if the first word (or whole content) matches an alias
	content = e.resolveAlias(content)
	msg.Content = content

	// Rate limit check
	if e.rateLimiter != nil && !e.rateLimiter.Allow(msg.SessionKey) {
		slog.Info("message rate limited", "session", msg.SessionKey, "user", msg.UserName)
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgRateLimited))
		return
	}

	// Banned words check (skip for slash commands)
	if !strings.HasPrefix(content, "/") {
		if word := e.matchBannedWord(content); word != "" {
			slog.Info("message blocked by banned word", "word", word, "user", msg.UserName)
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgBannedWordBlocked))
			return
		}
	}

	if len(msg.Images) == 0 && strings.HasPrefix(content, "/") {
		if e.handleCommand(p, msg, content) {
			return
		}
		// Unrecognized slash command — fall through to agent as normal message
	}

	// Permission responses bypass the session lock
	if e.handlePendingPermission(p, msg, content) {
		return
	}

	session := e.sessions.GetOrCreateActive(msg.SessionKey)
	if !session.TryLock() {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPreviousProcessing))
		return
	}

	slog.Info("processing message",
		"platform", msg.Platform,
		"user", msg.UserName,
		"session", session.ID,
	)

	go e.processInteractiveMessage(p, msg, session)
}

// ──────────────────────────────────────────────────────────────
// Voice message handling
// ──────────────────────────────────────────────────────────────

func (e *Engine) handleVoiceMessage(p Platform, msg *Message) {
	if !e.speech.Enabled || e.speech.STT == nil {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgVoiceNotEnabled))
		return
	}

	audio := msg.Audio
	if NeedsConversion(audio.Format) && !HasFFmpeg() {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgVoiceNoFFmpeg))
		return
	}

	slog.Info("transcribing voice message",
		"platform", msg.Platform, "user", msg.UserName,
		"format", audio.Format, "size", len(audio.Data),
	)
	e.send(p, msg.ReplyCtx, e.i18n.T(MsgVoiceTranscribing))

	text, err := TranscribeAudio(e.ctx, e.speech.STT, audio, e.speech.Language)
	if err != nil {
		slog.Error("speech transcription failed", "error", err)
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgVoiceTranscribeFailed), err))
		return
	}

	text = strings.TrimSpace(text)
	if text == "" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgVoiceEmpty))
		return
	}

	slog.Info("voice transcribed", "text_len", len(text))
	e.send(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgVoiceTranscribed), text))

	// Replace audio with transcribed text and re-dispatch
	msg.Audio = nil
	msg.Content = text
	e.handleMessage(p, msg)
}

// ──────────────────────────────────────────────────────────────
// Permission handling
// ──────────────────────────────────────────────────────────────

func (e *Engine) handlePendingPermission(p Platform, msg *Message, content string) bool {
	e.interactiveMu.Lock()
	state, ok := e.interactiveStates[msg.SessionKey]
	e.interactiveMu.Unlock()
	if !ok || state == nil {
		return false
	}

	state.mu.Lock()
	pending := state.pending
	state.mu.Unlock()
	if pending == nil {
		return false
	}

	lower := strings.ToLower(strings.TrimSpace(content))

	if isApproveAllResponse(lower) {
		state.mu.Lock()
		state.approveAll = true
		state.mu.Unlock()

		if err := state.agentSession.RespondPermission(pending.RequestID, PermissionResult{
			Behavior:     "allow",
			UpdatedInput: pending.ToolInput,
		}); err != nil {
			slog.Error("failed to send permission response", "error", err)
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgError), err))
		} else {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPermissionApproveAll))
		}
	} else if isAllowResponse(lower) {
		if err := state.agentSession.RespondPermission(pending.RequestID, PermissionResult{
			Behavior:     "allow",
			UpdatedInput: pending.ToolInput,
		}); err != nil {
			slog.Error("failed to send permission response", "error", err)
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgError), err))
		} else {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPermissionAllowed))
		}
	} else if isDenyResponse(lower) {
		if err := state.agentSession.RespondPermission(pending.RequestID, PermissionResult{
			Behavior: "deny",
			Message:  "User denied this tool use.",
		}); err != nil {
			slog.Error("failed to send deny response", "error", err)
		}
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPermissionDenied))
	} else {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPermissionHint))
		return true
	}

	state.mu.Lock()
	state.pending = nil
	state.mu.Unlock()
	pending.resolve()

	return true
}

func isApproveAllResponse(s string) bool {
	for _, w := range []string{
		"allow all", "allowall", "approve all", "yes all",
		"允许所有", "允许全部", "全部允许", "所有允许", "都允许", "全部同意",
	} {
		if s == w {
			return true
		}
	}
	return false
}

func isAllowResponse(s string) bool {
	for _, w := range []string{"allow", "yes", "y", "ok", "允许", "同意", "可以", "好", "好的", "是", "确认", "approve"} {
		if s == w {
			return true
		}
	}
	return false
}

func isDenyResponse(s string) bool {
	for _, w := range []string{"deny", "no", "n", "reject", "拒绝", "不允许", "不行", "不", "否", "取消", "cancel"} {
		if s == w {
			return true
		}
	}
	return false
}

// ──────────────────────────────────────────────────────────────
// Interactive agent processing
// ──────────────────────────────────────────────────────────────

func (e *Engine) processInteractiveMessage(p Platform, msg *Message, session *Session) {
	defer session.Unlock()

	if e.ctx.Err() != nil {
		return
	}

	turnStart := time.Now()

	e.i18n.DetectAndSet(msg.Content)
	session.AddHistory("user", msg.Content)

	state := e.getOrCreateInteractiveState(msg.SessionKey, p, msg.ReplyCtx, session)

	// Update reply context for this turn
	state.mu.Lock()
	state.platform = p
	state.replyCtx = msg.ReplyCtx
	state.mu.Unlock()

	if state.agentSession == nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgError), "failed to start agent session"))
		return
	}

	sendStart := time.Now()
	if err := state.agentSession.Send(msg.Content, msg.Images); err != nil {
		slog.Error("failed to send prompt", "error", err)

		if !state.agentSession.Alive() {
			e.cleanupInteractiveState(msg.SessionKey)
			e.send(p, msg.ReplyCtx, e.i18n.T(MsgSessionRestarting))

			state = e.getOrCreateInteractiveState(msg.SessionKey, p, msg.ReplyCtx, session)
			if state.agentSession == nil {
				e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgError), "failed to restart agent session"))
				return
			}
			sendStart = time.Now()
			if err := state.agentSession.Send(msg.Content, msg.Images); err != nil {
				e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgError), err))
				return
			}
		} else {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgError), err))
			return
		}
	}
	if elapsed := time.Since(sendStart); elapsed >= slowAgentSend {
		slog.Warn("slow agent send", "elapsed", elapsed, "session", msg.SessionKey, "content_len", len(msg.Content))
	}

	e.processInteractiveEvents(state, session, msg.SessionKey, turnStart)
}

func (e *Engine) getOrCreateInteractiveState(sessionKey string, p Platform, replyCtx any, session *Session) *interactiveState {
	e.interactiveMu.Lock()
	defer e.interactiveMu.Unlock()

	state, ok := e.interactiveStates[sessionKey]
	if ok && state.agentSession != nil && state.agentSession.Alive() {
		return state
	}

	// Inject per-session env vars so the agent subprocess can call `cc-connect cron add` etc.
	if inj, ok := e.agent.(SessionEnvInjector); ok {
		envVars := []string{
			"CC_PROJECT=" + e.name,
			"CC_SESSION_KEY=" + sessionKey,
		}
		if exePath, err := os.Executable(); err == nil {
			binDir := filepath.Dir(exePath)
			if curPath := os.Getenv("PATH"); curPath != "" {
				envVars = append(envVars, "PATH="+binDir+string(filepath.ListSeparator)+curPath)
			} else {
				envVars = append(envVars, "PATH="+binDir)
			}
		}
		inj.SetSessionEnv(envVars)
	}

	// Check if context is already canceled (e.g. during shutdown/restart)
	if e.ctx.Err() != nil {
		slog.Debug("skipping session start: context canceled", "session_key", sessionKey)
		state = &interactiveState{platform: p, replyCtx: replyCtx, quiet: e.defaultQuiet}
		e.interactiveStates[sessionKey] = state
		return state
	}

	startAt := time.Now()
	agentSession, err := e.agent.StartSession(e.ctx, session.AgentSessionID)
	startElapsed := time.Since(startAt)
	if err != nil {
		slog.Error("failed to start interactive session", "error", err, "elapsed", startElapsed)
		state = &interactiveState{platform: p, replyCtx: replyCtx, quiet: e.defaultQuiet}
		e.interactiveStates[sessionKey] = state
		return state
	}
	if startElapsed >= slowAgentStart {
		slog.Warn("slow agent session start", "elapsed", startElapsed, "agent", e.agent.Name(), "session_id", session.AgentSessionID)
	}

	state = &interactiveState{
		agentSession: agentSession,
		platform:     p,
		replyCtx:     replyCtx,
		quiet:        e.defaultQuiet,
	}
	e.interactiveStates[sessionKey] = state

	slog.Info("interactive session started", "session_key", sessionKey, "agent_session", session.AgentSessionID, "elapsed", startElapsed)
	return state
}

func (e *Engine) cleanupInteractiveState(sessionKey string) {
	e.interactiveMu.Lock()
	state, ok := e.interactiveStates[sessionKey]
	delete(e.interactiveStates, sessionKey)
	e.interactiveMu.Unlock()

	if ok && state != nil && state.agentSession != nil {
		slog.Debug("cleanupInteractiveState: closing agent session", "session", sessionKey)
		closeStart := time.Now()

		done := make(chan struct{})
		go func() {
			state.agentSession.Close()
			close(done)
		}()

		select {
		case <-done:
			if elapsed := time.Since(closeStart); elapsed >= slowAgentClose {
				slog.Warn("slow agent session close", "elapsed", elapsed, "session", sessionKey)
			}
		case <-time.After(10 * time.Second):
			slog.Error("agent session close timed out (10s), abandoning", "session", sessionKey)
		}
	}
}

func (e *Engine) processInteractiveEvents(state *interactiveState, session *Session, sessionKey string, turnStart time.Time) {
	var textParts []string
	toolCount := 0
	waitStart := time.Now()
	firstEventLogged := false

	state.mu.Lock()
	sp := newStreamPreview(e.streamPreview, state.platform, state.replyCtx, e.ctx)
	state.mu.Unlock()

	for event := range state.agentSession.Events() {
		if e.ctx.Err() != nil {
			return
		}

		if !firstEventLogged {
			firstEventLogged = true
			if elapsed := time.Since(waitStart); elapsed >= slowAgentFirstEvent {
				slog.Warn("slow agent first event", "elapsed", elapsed, "session", sessionKey, "event_type", event.Type)
			}
		}

		state.mu.Lock()
		p := state.platform
		replyCtx := state.replyCtx
		quiet := state.quiet
		state.mu.Unlock()

		switch event.Type {
		case EventThinking:
			if !quiet && event.Content != "" {
				preview := truncateIf(event.Content, e.display.ThinkingMaxLen)
				e.send(p, replyCtx, fmt.Sprintf(e.i18n.T(MsgThinking), preview))
			}

		case EventToolUse:
			toolCount++
			if !quiet {
				inputPreview := truncateIf(event.ToolInput, e.display.ToolMaxLen)
				e.send(p, replyCtx, fmt.Sprintf(e.i18n.T(MsgTool), toolCount, event.ToolName, inputPreview))
			}

		case EventText:
			if event.Content != "" {
				textParts = append(textParts, event.Content)
				if sp.canPreview() {
					sp.appendText(event.Content)
				}
			}
			if event.SessionID != "" {
				session.mu.Lock()
				if session.AgentSessionID == "" {
					session.AgentSessionID = event.SessionID
					pendingName := session.Name
					session.mu.Unlock()
					if pendingName != "" && pendingName != "session" && pendingName != "default" {
						e.sessions.SetSessionName(event.SessionID, pendingName)
					}
					e.sessions.Save()
				} else {
					session.mu.Unlock()
				}
			}

		case EventPermissionRequest:
			state.mu.Lock()
			autoApprove := state.approveAll
			state.mu.Unlock()

			if autoApprove {
				slog.Debug("auto-approving (approve-all)", "request_id", event.RequestID, "tool", event.ToolName)
				_ = state.agentSession.RespondPermission(event.RequestID, PermissionResult{
					Behavior:     "allow",
					UpdatedInput: event.ToolInputRaw,
				})
				continue
			}

			slog.Info("permission request",
				"request_id", event.RequestID,
				"tool", event.ToolName,
			)

			permLimit := e.display.ToolMaxLen
			if permLimit > 0 {
				permLimit = permLimit * 8 / 5 // permission prompts get ~1.6x more room
			}
			prompt := fmt.Sprintf(e.i18n.T(MsgPermissionPrompt), event.ToolName, truncateIf(event.ToolInput, permLimit))
			e.sendPermissionPrompt(p, replyCtx, prompt)

			pending := &pendingPermission{
				RequestID:    event.RequestID,
				ToolName:     event.ToolName,
				ToolInput:    event.ToolInputRaw,
				InputPreview: event.ToolInput,
				Resolved:     make(chan struct{}),
			}
			state.mu.Lock()
			state.pending = pending
			state.mu.Unlock()

			<-pending.Resolved
			slog.Info("permission resolved", "request_id", event.RequestID)

		case EventResult:
			if event.SessionID != "" {
				session.mu.Lock()
				session.AgentSessionID = event.SessionID
				session.mu.Unlock()
			}

			fullResponse := event.Content
			if fullResponse == "" && len(textParts) > 0 {
				fullResponse = strings.Join(textParts, "")
			}
			if fullResponse == "" {
				fullResponse = e.i18n.T(MsgEmptyResponse)
			}

			session.AddHistory("assistant", fullResponse)
			e.sessions.Save()

			turnDuration := time.Since(turnStart)
			slog.Info("turn complete",
				"session", session.ID,
				"agent_session", session.AgentSessionID,
				"tools", toolCount,
				"response_len", len(fullResponse),
				"turn_duration", turnDuration,
			)

			replyStart := time.Now()

			// If streaming preview was active, try to finalize in-place
			if sp.finish(fullResponse) {
				slog.Debug("stream preview: finalized in-place", "response_len", len(fullResponse))
			} else {
				for _, chunk := range splitMessage(fullResponse, maxPlatformMessageLen) {
					if err := p.Send(e.ctx, replyCtx, chunk); err != nil {
						slog.Error("failed to send reply", "error", err)
						return
					}
				}
			}

			if elapsed := time.Since(replyStart); elapsed >= slowPlatformSend {
				slog.Warn("slow final reply send", "platform", p.Name(), "elapsed", elapsed, "response_len", len(fullResponse))
			}
			return

		case EventError:
			sp.finish("") // clean up preview on error
			if event.Error != nil {
				slog.Error("agent error", "error", event.Error)
				e.send(p, replyCtx, fmt.Sprintf(e.i18n.T(MsgError), event.Error))
			}
			return
		}
	}

	// Channel closed - process exited unexpectedly
	slog.Warn("agent process exited", "session_key", sessionKey)
	e.cleanupInteractiveState(sessionKey)

	if len(textParts) > 0 {
		state.mu.Lock()
		p := state.platform
		replyCtx := state.replyCtx
		state.mu.Unlock()

		fullResponse := strings.Join(textParts, "")
		session.AddHistory("assistant", fullResponse)

		if sp.finish(fullResponse) {
			slog.Debug("stream preview: finalized in-place (process exited)")
		} else {
			for _, chunk := range splitMessage(fullResponse, maxPlatformMessageLen) {
				e.send(p, replyCtx, chunk)
			}
		}
	}
}

// ──────────────────────────────────────────────────────────────
// Command handling
// ──────────────────────────────────────────────────────────────

// builtinCommands maps canonical command names to their aliases/full names.
// The first entry is the canonical name used for prefix matching.
var builtinCommands = []struct {
	names []string
	id    string
}{
	{[]string{"new"}, "new"},
	{[]string{"list", "sessions"}, "list"},
	{[]string{"switch"}, "switch"},
	{[]string{"name", "rename"}, "name"},
	{[]string{"current"}, "current"},
	{[]string{"status"}, "status"},
	{[]string{"history"}, "history"},
	{[]string{"allow"}, "allow"},
	{[]string{"model"}, "model"},
	{[]string{"mode"}, "mode"},
	{[]string{"lang"}, "lang"},
	{[]string{"quiet"}, "quiet"},
	{[]string{"provider"}, "provider"},
	{[]string{"memory"}, "memory"},
	{[]string{"cron"}, "cron"},
	{[]string{"compress", "compact"}, "compress"},
	{[]string{"stop"}, "stop"},
	{[]string{"help"}, "help"},
	{[]string{"version"}, "version"},
	{[]string{"commands", "command", "cmd"}, "commands"},
	{[]string{"skills", "skill"}, "skills"},
	{[]string{"config"}, "config"},
	{[]string{"doctor"}, "doctor"},
	{[]string{"upgrade", "update"}, "upgrade"},
	{[]string{"restart"}, "restart"},
	{[]string{"alias"}, "alias"},
	{[]string{"delete", "del", "rm"}, "delete"},
}

// matchPrefix finds a unique command matching the given prefix.
// Returns the command id or "" if no match / ambiguous.
func matchPrefix(prefix string, candidates []struct {
	names []string
	id    string
}) string {
	// Exact match first
	for _, c := range candidates {
		for _, n := range c.names {
			if prefix == n {
				return c.id
			}
		}
	}
	// Prefix match
	var matched string
	for _, c := range candidates {
		for _, n := range c.names {
			if strings.HasPrefix(n, prefix) {
				if matched != "" && matched != c.id {
					return "" // ambiguous
				}
				matched = c.id
				break
			}
		}
	}
	return matched
}

// matchSubCommand does prefix matching against a flat list of subcommand names.
func matchSubCommand(input string, candidates []string) string {
	for _, c := range candidates {
		if input == c {
			return c
		}
	}
	var matched string
	for _, c := range candidates {
		if strings.HasPrefix(c, input) {
			if matched != "" {
				return input // ambiguous → return raw input (will hit default)
			}
			matched = c
		}
	}
	if matched != "" {
		return matched
	}
	return input
}

func (e *Engine) handleCommand(p Platform, msg *Message, raw string) bool {
	parts := strings.Fields(raw)
	cmd := strings.ToLower(strings.TrimPrefix(parts[0], "/"))
	args := parts[1:]

	cmdID := matchPrefix(cmd, builtinCommands)

	if cmdID != "" && e.disabledCmds[cmdID] {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCommandDisabled), "/"+cmdID))
		return true
	}

	switch cmdID {
	case "new":
		e.cmdNew(p, msg, args)
	case "list":
		e.cmdList(p, msg)
	case "switch":
		e.cmdSwitch(p, msg, args)
	case "name":
		e.cmdName(p, msg, args)
	case "current":
		e.cmdCurrent(p, msg)
	case "status":
		e.cmdStatus(p, msg)
	case "history":
		e.cmdHistory(p, msg, args)
	case "allow":
		e.cmdAllow(p, msg, args)
	case "model":
		e.cmdModel(p, msg, args)
	case "mode":
		e.cmdMode(p, msg, args)
	case "lang":
		e.cmdLang(p, msg, args)
	case "quiet":
		e.cmdQuiet(p, msg)
	case "provider":
		e.cmdProvider(p, msg, args)
	case "memory":
		e.cmdMemory(p, msg, args)
	case "cron":
		e.cmdCron(p, msg, args)
	case "compress":
		e.cmdCompress(p, msg)
	case "stop":
		e.cmdStop(p, msg)
	case "help":
		e.cmdHelp(p, msg)
	case "version":
		e.reply(p, msg.ReplyCtx, VersionInfo)
	case "commands":
		e.cmdCommands(p, msg, args)
	case "skills":
		e.cmdSkills(p, msg)
	case "config":
		e.cmdConfig(p, msg, args)
	case "doctor":
		e.cmdDoctor(p, msg)
	case "upgrade":
		e.cmdUpgrade(p, msg, args)
	case "restart":
		e.cmdRestart(p, msg)
	case "alias":
		e.cmdAlias(p, msg, args)
	case "delete":
		e.cmdDelete(p, msg, args)
	default:
		if custom, ok := e.commands.Resolve(cmd); ok {
			e.executeCustomCommand(p, msg, custom, args)
			return true
		}
		if skill := e.skills.Resolve(cmd); skill != nil {
			e.executeSkill(p, msg, skill, args)
			return true
		}
		// Not a cc-connect command — notify user, then fall through to agent
		e.send(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgUnknownCommand), "/"+cmd))
		return false
	}
	return true
}

func (e *Engine) cmdNew(p Platform, msg *Message, args []string) {
	slog.Info("cmdNew: cleaning up old session", "session_key", msg.SessionKey)
	e.cleanupInteractiveState(msg.SessionKey)
	slog.Info("cmdNew: cleanup done, creating new session", "session_key", msg.SessionKey)
	name := ""
	if len(args) > 0 {
		name = strings.Join(args, " ")
	}
	s := e.sessions.NewSession(msg.SessionKey, name)
	if name != "" {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgNewSessionCreatedName), name))
	} else {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNewSessionCreated))
	}
	_ = s
}

func (e *Engine) cmdList(p Platform, msg *Message) {
	agentSessions, err := e.agent.ListSessions(e.ctx)
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgListError), err))
		return
	}
	if len(agentSessions) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgListEmpty))
		return
	}

	agentName := e.agent.Name()
	activeSession := e.sessions.GetOrCreateActive(msg.SessionKey)
	activeAgentID := activeSession.AgentSessionID

	limit := 20
	if len(agentSessions) < limit {
		limit = len(agentSessions)
	}

	var sb strings.Builder
	sb.WriteString(fmt.Sprintf(e.i18n.T(MsgListTitle), agentName, len(agentSessions)))
	for i := 0; i < limit; i++ {
		s := agentSessions[i]
		marker := "◻"
		if s.ID == activeAgentID {
			marker = "▶"
		}
		displayName := e.sessions.GetSessionName(s.ID)
		if displayName != "" {
			displayName = "📌 " + displayName
		} else {
			displayName = strings.ReplaceAll(s.Summary, "\n", " ")
			displayName = strings.Join(strings.Fields(displayName), " ")
			if displayName == "" {
				displayName = "(empty)"
			}
			if len([]rune(displayName)) > 40 {
				displayName = string([]rune(displayName)[:40]) + "…"
			}
		}
		sb.WriteString(fmt.Sprintf("%s **%d.** %s · **%d** msgs · %s\n",
			marker, i+1, displayName, s.MessageCount, s.ModifiedAt.Format("01-02 15:04")))
	}
	if len(agentSessions) > limit {
		sb.WriteString(fmt.Sprintf(e.i18n.T(MsgListMore), len(agentSessions)-limit))
	}
	sb.WriteString(e.i18n.T(MsgListSwitchHint))
	e.reply(p, msg.ReplyCtx, sb.String())
}

func (e *Engine) cmdSwitch(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, "Usage: /switch <number or id_prefix>")
		return
	}
	prefix := strings.TrimSpace(args[0])

	slog.Info("cmdSwitch: listing agent sessions", "session_key", msg.SessionKey)
	agentSessions, err := e.agent.ListSessions(e.ctx)
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
		return
	}

	var matched *AgentSessionInfo

	// Try numeric index first (1-based, matching /list output)
	if idx, err := strconv.Atoi(prefix); err == nil && idx >= 1 && idx <= len(agentSessions) {
		matched = &agentSessions[idx-1]
	} else {
		for i := range agentSessions {
			if strings.HasPrefix(agentSessions[i].ID, prefix) {
				matched = &agentSessions[i]
				break
			}
		}
	}
	if matched == nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ No session matching %q", prefix))
		return
	}

	slog.Info("cmdSwitch: cleaning up old session", "session_key", msg.SessionKey)
	e.cleanupInteractiveState(msg.SessionKey)
	slog.Info("cmdSwitch: cleanup done", "session_key", msg.SessionKey)

	session := e.sessions.GetOrCreateActive(msg.SessionKey)
	session.AgentSessionID = matched.ID
	session.Name = matched.Summary
	session.ClearHistory()
	e.sessions.Save()

	shortID := matched.ID
	if len(shortID) > 12 {
		shortID = shortID[:12]
	}
	displayName := e.sessions.GetSessionName(matched.ID)
	if displayName == "" {
		displayName = matched.Summary
	}
	e.reply(p, msg.ReplyCtx,
		fmt.Sprintf("✅ Switched to: %s (%s, %d msgs)", displayName, shortID, matched.MessageCount))
}

func (e *Engine) cmdName(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNameUsage))
		return
	}

	// Check if first arg is a number → naming a specific session by list index
	var targetID string
	var name string

	if idx, err := strconv.Atoi(args[0]); err == nil && idx >= 1 {
		// /name <number> <name...>
		if len(args) < 2 {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNameUsage))
			return
		}
		agentSessions, err := e.agent.ListSessions(e.ctx)
		if err != nil {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
			return
		}
		if idx > len(agentSessions) {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ No session #%d", idx))
			return
		}
		targetID = agentSessions[idx-1].ID
		name = strings.Join(args[1:], " ")
	} else {
		// /name <name...> → current session
		session := e.sessions.GetOrCreateActive(msg.SessionKey)
		targetID = session.AgentSessionID
		if targetID == "" {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNameNoSession))
			return
		}
		name = strings.Join(args, " ")
	}

	name = strings.TrimSpace(name)
	if name == "" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNameUsage))
		return
	}

	e.sessions.SetSessionName(targetID, name)

	shortID := targetID
	if len(shortID) > 12 {
		shortID = shortID[:12]
	}
	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgNameSet), name, shortID))
}

func (e *Engine) cmdCurrent(p Platform, msg *Message) {
	s := e.sessions.GetOrCreateActive(msg.SessionKey)
	agentID := s.AgentSessionID
	if agentID == "" {
		agentID = "(new — not yet started)"
	}
	e.reply(p, msg.ReplyCtx, fmt.Sprintf(
		"📌 Current session\nName: %s\nClaude Session: %s\nLocal messages: %d",
		s.Name, agentID, len(s.History)))
}

func (e *Engine) cmdStatus(p Platform, msg *Message) {
	// Platforms
	platNames := make([]string, len(e.platforms))
	for i, pl := range e.platforms {
		platNames[i] = pl.Name()
	}
	platformStr := strings.Join(platNames, ", ")
	if len(platNames) == 0 {
		platformStr = "-"
	}

	// Uptime
	uptimeStr := formatDurationI18n(time.Since(e.startedAt), e.i18n.CurrentLang())

	// Language
	cur := e.i18n.CurrentLang()
	langStr := fmt.Sprintf("%s (%s)", string(cur), langDisplayName(cur))

	// Mode (optional)
	var modeStr string
	if ms, ok := e.agent.(ModeSwitcher); ok {
		mode := ms.GetMode()
		if mode != "" {
			modeStr = e.i18n.Tf(MsgStatusMode, mode)
		}
	}

	// Session info
	s := e.sessions.GetOrCreateActive(msg.SessionKey)
	sessionDisplayName := e.sessions.GetSessionName(s.AgentSessionID)
	if sessionDisplayName == "" {
		sessionDisplayName = s.Name
	}
	sessionStr := e.i18n.Tf(MsgStatusSession, sessionDisplayName, len(s.History))

	// Cron jobs
	var cronStr string
	if e.cronScheduler != nil {
		jobs := e.cronScheduler.Store().ListBySessionKey(msg.SessionKey)
		if len(jobs) > 0 {
			enabledCount := 0
			for _, j := range jobs {
				if j.Enabled {
					enabledCount++
				}
			}
			cronStr = e.i18n.Tf(MsgStatusCron, len(jobs), enabledCount)
		}
	}

	e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgStatusTitle,
		e.name,
		e.agent.Name(),
		platformStr,
		uptimeStr,
		langStr,
		modeStr,
		sessionStr,
		cronStr,
	))
}

func cronTimeFormat(t, now time.Time) string {
	if t.Year() != now.Year() {
		return "2006-01-02 15:04"
	}
	return "01-02 15:04"
}

func formatDurationI18n(d time.Duration, lang Language) string {
	d = d.Round(time.Second)
	days := int(d.Hours()) / 24
	hours := int(d.Hours()) % 24
	minutes := int(d.Minutes()) % 60

	switch lang {
	case LangChinese, LangTraditionalChinese:
		if days > 0 {
			return fmt.Sprintf("%d天 %d小时 %d分钟", days, hours, minutes)
		}
		if hours > 0 {
			return fmt.Sprintf("%d小时 %d分钟", hours, minutes)
		}
		return fmt.Sprintf("%d分钟", minutes)
	case LangJapanese:
		if days > 0 {
			return fmt.Sprintf("%d日 %d時間 %d分", days, hours, minutes)
		}
		if hours > 0 {
			return fmt.Sprintf("%d時間 %d分", hours, minutes)
		}
		return fmt.Sprintf("%d分", minutes)
	case LangSpanish:
		if days > 0 {
			return fmt.Sprintf("%d días %dh %dm", days, hours, minutes)
		}
		if hours > 0 {
			return fmt.Sprintf("%dh %dm", hours, minutes)
		}
		return fmt.Sprintf("%dm", minutes)
	default:
		if days > 0 {
			return fmt.Sprintf("%dd %dh %dm", days, hours, minutes)
		}
		if hours > 0 {
			return fmt.Sprintf("%dh %dm", hours, minutes)
		}
		return fmt.Sprintf("%dm", minutes)
	}
}

func (e *Engine) cmdHistory(p Platform, msg *Message, args []string) {
	s := e.sessions.GetOrCreateActive(msg.SessionKey)
	n := 10
	if len(args) > 0 {
		if v, err := strconv.Atoi(args[0]); err == nil && v > 0 {
			n = v
		}
	}

	entries := s.GetHistory(n)

	// Fallback: load from agent backend if in-memory history is empty
	if len(entries) == 0 && s.AgentSessionID != "" {
		if hp, ok := e.agent.(HistoryProvider); ok {
			if agentEntries, err := hp.GetSessionHistory(e.ctx, s.AgentSessionID, n); err == nil {
				entries = agentEntries
			}
		}
	}

	if len(entries) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgHistoryEmpty))
		return
	}

	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("📜 History (last %d):\n\n", len(entries)))
	for _, h := range entries {
		icon := "👤"
		if h.Role == "assistant" {
			icon = "🤖"
		}
		content := h.Content
		if len([]rune(content)) > 200 {
			content = string([]rune(content)[:200]) + "..."
		}
		sb.WriteString(fmt.Sprintf("%s [%s]\n%s\n\n", icon, h.Timestamp.Format("15:04:05"), content))
	}
	e.reply(p, msg.ReplyCtx, sb.String())
}

func (e *Engine) cmdLang(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		cur := e.i18n.CurrentLang()
		name := langDisplayName(cur)
		e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgLangCurrent, name))
		return
	}

	target := strings.ToLower(strings.TrimSpace(args[0]))
	var lang Language
	switch target {
	case "en", "english":
		lang = LangEnglish
	case "zh", "cn", "chinese", "中文":
		lang = LangChinese
	case "zh-tw", "zh_tw", "zhtw", "繁體", "繁体":
		lang = LangTraditionalChinese
	case "ja", "jp", "japanese", "日本語":
		lang = LangJapanese
	case "es", "spanish", "español":
		lang = LangSpanish
	case "auto":
		lang = LangAuto
	default:
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgLangInvalid))
		return
	}

	e.i18n.SetLang(lang)
	name := langDisplayName(lang)
	e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgLangChanged, name))
}

func langDisplayName(lang Language) string {
	switch lang {
	case LangEnglish:
		return "English"
	case LangChinese:
		return "中文"
	case LangTraditionalChinese:
		return "繁體中文"
	case LangJapanese:
		return "日本語"
	case LangSpanish:
		return "Español"
	default:
		return "Auto"
	}
}

func (e *Engine) cmdHelp(p Platform, msg *Message) {
	e.reply(p, msg.ReplyCtx, e.i18n.T(MsgHelp))
}

func (e *Engine) cmdModel(p Platform, msg *Message, args []string) {
	switcher, ok := e.agent.(ModelSwitcher)
	if !ok {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgModelNotSupported))
		return
	}

	fetchCtx, cancel := context.WithTimeout(e.ctx, 10*time.Second)
	defer cancel()
	models := switcher.AvailableModels(fetchCtx)

	if len(args) == 0 {
		var sb strings.Builder
		current := switcher.GetModel()
		if current == "" {
			sb.WriteString(e.i18n.T(MsgModelDefault))
		} else {
			sb.WriteString(e.i18n.Tf(MsgModelCurrent, current))
			sb.WriteString("\n")
		}
		sb.WriteString("\n")
		sb.WriteString(e.i18n.T(MsgModelListTitle))
		for i, m := range models {
			marker := "  "
			if m.Name == current {
				marker = "> "
			}
			desc := m.Desc
			if desc != "" {
				desc = " — " + desc
			}
			sb.WriteString(fmt.Sprintf("%s%d. %s%s\n", marker, i+1, m.Name, desc))
		}
		sb.WriteString("\n")
		sb.WriteString(e.i18n.T(MsgModelUsage))
		e.reply(p, msg.ReplyCtx, sb.String())
		return
	}

	target := args[0]
	if idx, err := strconv.Atoi(target); err == nil && idx >= 1 && idx <= len(models) {
		target = models[idx-1].Name
	}

	switcher.SetModel(target)
	e.cleanupInteractiveState(msg.SessionKey)

	s := e.sessions.GetOrCreateActive(msg.SessionKey)
	s.AgentSessionID = ""
	s.ClearHistory()
	e.sessions.Save()

	e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgModelChanged, target))
}

func (e *Engine) cmdMode(p Platform, msg *Message, args []string) {
	switcher, ok := e.agent.(ModeSwitcher)
	if !ok {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgModeNotSupported))
		return
	}

	if len(args) == 0 {
		current := switcher.GetMode()
		modes := switcher.PermissionModes()
		var sb strings.Builder
		zhLike := e.i18n.IsZhLike()
		for _, m := range modes {
			marker := "  "
			if m.Key == current {
				marker = "▶ "
			}
			if zhLike {
				sb.WriteString(fmt.Sprintf("%s**%s** — %s\n", marker, m.NameZh, m.DescZh))
			} else {
				sb.WriteString(fmt.Sprintf("%s**%s** — %s\n", marker, m.Name, m.Desc))
			}
		}
		sb.WriteString(e.i18n.T(MsgModeUsage))
		e.reply(p, msg.ReplyCtx, sb.String())
		return
	}

	target := strings.ToLower(args[0])
	switcher.SetMode(target)
	newMode := switcher.GetMode()

	e.cleanupInteractiveState(msg.SessionKey)

	modes := switcher.PermissionModes()
	displayName := newMode
	zhLike := e.i18n.IsZhLike()
	for _, m := range modes {
		if m.Key == newMode {
			if zhLike {
				displayName = m.NameZh
			} else {
				displayName = m.Name
			}
			break
		}
	}
	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgModeChanged), displayName))
}

func (e *Engine) cmdQuiet(p Platform, msg *Message) {
	e.interactiveMu.Lock()
	state, ok := e.interactiveStates[msg.SessionKey]
	e.interactiveMu.Unlock()

	if !ok || state == nil {
		// No state yet, create one so the flag persists
		state = &interactiveState{platform: p, replyCtx: msg.ReplyCtx, quiet: true}
		e.interactiveMu.Lock()
		e.interactiveStates[msg.SessionKey] = state
		e.interactiveMu.Unlock()
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgQuietOn))
		return
	}

	state.mu.Lock()
	state.quiet = !state.quiet
	quiet := state.quiet
	state.mu.Unlock()

	if quiet {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgQuietOn))
	} else {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgQuietOff))
	}
}

func (e *Engine) cmdStop(p Platform, msg *Message) {
	e.interactiveMu.Lock()
	state, ok := e.interactiveStates[msg.SessionKey]
	e.interactiveMu.Unlock()

	if !ok || state == nil {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNoExecution))
		return
	}

	// Cancel pending permission if any
	state.mu.Lock()
	pending := state.pending
	if pending != nil {
		state.pending = nil
	}
	state.mu.Unlock()
	if pending != nil {
		pending.resolve()
	}

	e.cleanupInteractiveState(msg.SessionKey)
	e.reply(p, msg.ReplyCtx, e.i18n.T(MsgExecutionStopped))
}

func (e *Engine) cmdCompress(p Platform, msg *Message) {
	compressor, ok := e.agent.(ContextCompressor)
	if !ok || compressor.CompressCommand() == "" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCompressNotSupported))
		return
	}

	// Check for an active interactive session
	e.interactiveMu.Lock()
	state, hasState := e.interactiveStates[msg.SessionKey]
	e.interactiveMu.Unlock()

	if !hasState || state == nil || state.agentSession == nil || !state.agentSession.Alive() {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCompressNoSession))
		return
	}

	session := e.sessions.GetOrCreateActive(msg.SessionKey)
	if !session.TryLock() {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPreviousProcessing))
		return
	}

	e.send(p, msg.ReplyCtx, e.i18n.T(MsgCompressing))

	msg.Content = compressor.CompressCommand()
	go e.processInteractiveMessage(p, msg, session)
}

func (e *Engine) cmdAllow(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		if auth, ok := e.agent.(ToolAuthorizer); ok {
			tools := auth.GetAllowedTools()
			if len(tools) == 0 {
				e.reply(p, msg.ReplyCtx, e.i18n.T(MsgNoToolsAllowed))
			} else {
				e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCurrentTools), strings.Join(tools, ", ")))
			}
		} else {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgToolAuthNotSupported))
		}
		return
	}

	toolName := strings.TrimSpace(args[0])
	if auth, ok := e.agent.(ToolAuthorizer); ok {
		if err := auth.AddAllowedTools(toolName); err != nil {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgToolAllowFailed), err))
			return
		}
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgToolAllowedNew), toolName))
	} else {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgToolAuthNotSupported))
	}
}

func (e *Engine) cmdProvider(p Platform, msg *Message, args []string) {
	switcher, ok := e.agent.(ProviderSwitcher)
	if !ok {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderNotSupported))
		return
	}

	if len(args) == 0 {
		current := switcher.GetActiveProvider()
		providers := switcher.ListProviders()
		if current == nil && len(providers) == 0 {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderNone))
			return
		}
		if current != nil {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderCurrent), current.Name))
			return
		}
		// Has providers but no active one — show the list
		var sb strings.Builder
		sb.WriteString(e.i18n.T(MsgProviderListTitle))
		for _, prov := range providers {
			marker := "  "
			if current != nil && prov.Name == current.Name {
				marker = "▶ "
			}
			detail := prov.Name
			if prov.BaseURL != "" {
				detail += " (" + prov.BaseURL + ")"
			}
			if prov.Model != "" {
				detail += " [" + prov.Model + "]"
			}
			sb.WriteString(fmt.Sprintf("%s%s\n", marker, detail))
		}
		sb.WriteString("\n" + e.i18n.T(MsgProviderSwitchHint))
		e.reply(p, msg.ReplyCtx, sb.String())
		return
	}

	sub := matchSubCommand(strings.ToLower(args[0]), []string{
		"list", "add", "remove", "switch", "current", "clear", "reset", "none",
	})
	switch sub {
	case "list":
		providers := switcher.ListProviders()
		if len(providers) == 0 {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderListEmpty))
			return
		}
		current := switcher.GetActiveProvider()
		var sb strings.Builder
		sb.WriteString(e.i18n.T(MsgProviderListTitle))
		for _, prov := range providers {
			marker := "  "
			if current != nil && prov.Name == current.Name {
				marker = "▶ "
			}
			detail := prov.Name
			if prov.BaseURL != "" {
				detail += " (" + prov.BaseURL + ")"
			}
			if prov.Model != "" {
				detail += " [" + prov.Model + "]"
			}
			sb.WriteString(fmt.Sprintf("%s%s\n", marker, detail))
		}
		sb.WriteString("\n" + e.i18n.T(MsgProviderSwitchHint))
		e.reply(p, msg.ReplyCtx, sb.String())

	case "add":
		e.cmdProviderAdd(p, msg, switcher, args[1:])

	case "remove", "rm", "delete":
		e.cmdProviderRemove(p, msg, switcher, args[1:])

	case "switch":
		if len(args) < 2 {
			e.reply(p, msg.ReplyCtx, "Usage: /provider switch <name>")
			return
		}
		e.switchProvider(p, msg, switcher, args[1])

	case "current":
		current := switcher.GetActiveProvider()
		if current == nil {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderNone))
			return
		}
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderCurrent), current.Name))

	case "clear", "reset", "none":
		switcher.SetActiveProvider("")
		e.cleanupInteractiveState(msg.SessionKey)
		if e.providerSaveFunc != nil {
			if err := e.providerSaveFunc(""); err != nil {
				slog.Error("failed to save provider", "error", err)
			}
		}
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderCleared))

	default:
		e.switchProvider(p, msg, switcher, args[0])
	}
}

func (e *Engine) cmdProviderAdd(p Platform, msg *Message, switcher ProviderSwitcher, args []string) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderAddUsage))
		return
	}

	var prov ProviderConfig

	// Join args back; detect JSON (starts with '{') vs positional
	raw := strings.Join(args, " ")
	raw = strings.TrimSpace(raw)

	if strings.HasPrefix(raw, "{") {
		// JSON format: /provider add {"name":"relay","api_key":"sk-xxx",...}
		var jp struct {
			Name    string            `json:"name"`
			APIKey  string            `json:"api_key"`
			BaseURL string            `json:"base_url"`
			Model   string            `json:"model"`
			Env     map[string]string `json:"env"`
		}
		if err := json.Unmarshal([]byte(raw), &jp); err != nil {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderAddFailed), "invalid JSON: "+err.Error()))
			return
		}
		if jp.Name == "" {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderAddFailed), "\"name\" is required"))
			return
		}
		prov = ProviderConfig{Name: jp.Name, APIKey: jp.APIKey, BaseURL: jp.BaseURL, Model: jp.Model, Env: jp.Env}
	} else {
		// Positional: /provider add <name> <api_key> [base_url] [model]
		if len(args) < 2 {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgProviderAddUsage))
			return
		}
		prov.Name = args[0]
		prov.APIKey = args[1]
		if len(args) > 2 {
			prov.BaseURL = args[2]
		}
		if len(args) > 3 {
			prov.Model = args[3]
		}
	}

	// Check for duplicates
	for _, existing := range switcher.ListProviders() {
		if existing.Name == prov.Name {
			e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderAddFailed), fmt.Sprintf("provider %q already exists", prov.Name)))
			return
		}
	}

	// Add to runtime
	updated := append(switcher.ListProviders(), prov)
	switcher.SetProviders(updated)

	// Persist to config
	if e.providerAddSaveFunc != nil {
		if err := e.providerAddSaveFunc(prov); err != nil {
			slog.Error("failed to persist provider", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderAdded), prov.Name, prov.Name))
}

func (e *Engine) cmdProviderRemove(p Platform, msg *Message, switcher ProviderSwitcher, args []string) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, "Usage: /provider remove <name>")
		return
	}
	name := args[0]

	providers := switcher.ListProviders()
	found := false
	var remaining []ProviderConfig
	for _, prov := range providers {
		if prov.Name == name {
			found = true
		} else {
			remaining = append(remaining, prov)
		}
	}

	if !found {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderNotFound), name))
		return
	}

	// If removing the active provider, clear it
	active := switcher.GetActiveProvider()
	switcher.SetProviders(remaining)
	if active != nil && active.Name == name {
		// No active provider after removal
		slog.Info("removed active provider, clearing selection", "name", name)
	}

	// Persist
	if e.providerRemoveSaveFunc != nil {
		if err := e.providerRemoveSaveFunc(name); err != nil {
			slog.Error("failed to persist provider removal", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderRemoved), name))
}

func (e *Engine) switchProvider(p Platform, msg *Message, switcher ProviderSwitcher, name string) {
	if !switcher.SetActiveProvider(name) {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderNotFound), name))
		return
	}
	e.cleanupInteractiveState(msg.SessionKey)

	if e.providerSaveFunc != nil {
		if err := e.providerSaveFunc(name); err != nil {
			slog.Error("failed to save provider", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgProviderSwitched), name))
}

// ──────────────────────────────────────────────────────────────
// Helpers
// ──────────────────────────────────────────────────────────────

// SendToSession sends a message to an active session from an external caller (API/CLI).
// If sessionKey is empty, it picks the first active session.
func (e *Engine) SendToSession(sessionKey, message string) error {
	e.interactiveMu.Lock()
	defer e.interactiveMu.Unlock()

	var state *interactiveState
	if sessionKey != "" {
		state = e.interactiveStates[sessionKey]
	} else {
		// Pick the first active session
		for _, s := range e.interactiveStates {
			state = s
			break
		}
	}

	if state == nil {
		return fmt.Errorf("no active session found (key=%q)", sessionKey)
	}

	state.mu.Lock()
	p := state.platform
	replyCtx := state.replyCtx
	state.mu.Unlock()

	if p == nil {
		return fmt.Errorf("no active session found (key=%q)", sessionKey)
	}

	return p.Send(e.ctx, replyCtx, message)
}

// sendPermissionPrompt sends a permission prompt, using inline buttons when the platform supports them.
func (e *Engine) sendPermissionPrompt(p Platform, replyCtx any, prompt string) {
	if bs, ok := p.(InlineButtonSender); ok {
		buttons := [][]ButtonOption{
			{
				{Text: e.i18n.T(MsgPermBtnAllow), Data: "perm:allow"},
				{Text: e.i18n.T(MsgPermBtnDeny), Data: "perm:deny"},
			},
			{
				{Text: e.i18n.T(MsgPermBtnAllowAll), Data: "perm:allow_all"},
			},
		}
		if err := bs.SendWithButtons(e.ctx, replyCtx, prompt, buttons); err == nil {
			return
		}
		slog.Warn("sendPermissionPrompt: inline buttons failed, falling back to text")
	}
	e.send(p, replyCtx, prompt)
}

// send wraps p.Send with error logging and slow-operation warnings.
func (e *Engine) send(p Platform, replyCtx any, content string) {
	start := time.Now()
	if err := p.Send(e.ctx, replyCtx, content); err != nil {
		slog.Error("platform send failed", "platform", p.Name(), "error", err, "content_len", len(content))
	}
	if elapsed := time.Since(start); elapsed >= slowPlatformSend {
		slog.Warn("slow platform send", "platform", p.Name(), "elapsed", elapsed, "content_len", len(content))
	}
}

// reply wraps p.Reply with error logging and slow-operation warnings.
func (e *Engine) reply(p Platform, replyCtx any, content string) {
	start := time.Now()
	if err := p.Reply(e.ctx, replyCtx, content); err != nil {
		slog.Error("platform reply failed", "platform", p.Name(), "error", err, "content_len", len(content))
	}
	if elapsed := time.Since(start); elapsed >= slowPlatformSend {
		slog.Warn("slow platform reply", "platform", p.Name(), "elapsed", elapsed, "content_len", len(content))
	}
}

// ──────────────────────────────────────────────────────────────
// /memory command
// ──────────────────────────────────────────────────────────────

func (e *Engine) cmdMemory(p Platform, msg *Message, args []string) {
	mp, ok := e.agent.(MemoryFileProvider)
	if !ok {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryNotSupported))
		return
	}

	if len(args) == 0 {
		// /memory — show project memory
		e.showMemoryFile(p, msg, mp.ProjectMemoryFile(), false)
		return
	}

	sub := matchSubCommand(strings.ToLower(args[0]), []string{"add", "global", "show", "help"})
	switch sub {
	case "add":
		text := strings.TrimSpace(strings.Join(args[1:], " "))
		if text == "" {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryAddUsage))
			return
		}
		e.appendMemoryFile(p, msg, mp.ProjectMemoryFile(), text)

	case "global":
		if len(args) == 1 {
			// /memory global — show global memory
			e.showMemoryFile(p, msg, mp.GlobalMemoryFile(), true)
			return
		}
		if strings.ToLower(args[1]) == "add" {
			text := strings.TrimSpace(strings.Join(args[2:], " "))
			if text == "" {
				e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryAddUsage))
				return
			}
			e.appendMemoryFile(p, msg, mp.GlobalMemoryFile(), text)
		} else {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryAddUsage))
		}

	case "show":
		e.showMemoryFile(p, msg, mp.ProjectMemoryFile(), false)

	case "help", "--help", "-h":
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryAddUsage))

	default:
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryAddUsage))
	}
}

func (e *Engine) showMemoryFile(p Platform, msg *Message, filePath string, isGlobal bool) {
	if filePath == "" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryNotSupported))
		return
	}

	data, err := os.ReadFile(filePath)
	if err != nil || len(strings.TrimSpace(string(data))) == 0 {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryEmpty), filePath))
		return
	}

	content := string(data)
	if len([]rune(content)) > 2000 {
		content = string([]rune(content)[:2000]) + "\n\n... (truncated)"
	}

	if isGlobal {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryShowGlobal), filePath, content))
	} else {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryShowProject), filePath, content))
	}
}

func (e *Engine) appendMemoryFile(p Platform, msg *Message, filePath, text string) {
	if filePath == "" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgMemoryNotSupported))
		return
	}

	dir := filepath.Dir(filePath)
	if err := os.MkdirAll(dir, 0o755); err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryAddFailed), err))
		return
	}

	f, err := os.OpenFile(filePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryAddFailed), err))
		return
	}
	defer f.Close()

	entry := "\n- " + text + "\n"
	if _, err := f.WriteString(entry); err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryAddFailed), err))
		return
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgMemoryAdded), filePath))
}

// ──────────────────────────────────────────────────────────────
// /cron command
// ──────────────────────────────────────────────────────────────

func (e *Engine) cmdCron(p Platform, msg *Message, args []string) {
	if e.cronScheduler == nil {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCronNotAvailable))
		return
	}

	if len(args) == 0 {
		e.cmdCronList(p, msg)
		return
	}

	sub := matchSubCommand(strings.ToLower(args[0]), []string{
		"add", "list", "del", "delete", "rm", "remove", "enable", "disable",
	})
	switch sub {
	case "add":
		e.cmdCronAdd(p, msg, args[1:])
	case "list":
		e.cmdCronList(p, msg)
	case "del", "delete", "rm", "remove":
		e.cmdCronDel(p, msg, args[1:])
	case "enable":
		e.cmdCronToggle(p, msg, args[1:], true)
	case "disable":
		e.cmdCronToggle(p, msg, args[1:], false)
	default:
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCronUsage))
	}
}

func (e *Engine) cmdCronAdd(p Platform, msg *Message, args []string) {
	// /cron add <min> <hour> <day> <month> <weekday> <prompt...>
	if len(args) < 6 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCronAddUsage))
		return
	}

	cronExpr := strings.Join(args[:5], " ")
	prompt := strings.Join(args[5:], " ")

	job := &CronJob{
		ID:         GenerateCronID(),
		Project:    e.name,
		SessionKey: msg.SessionKey,
		CronExpr:   cronExpr,
		Prompt:     prompt,
		Enabled:    true,
		CreatedAt:  time.Now(),
	}

	if err := e.cronScheduler.AddJob(job); err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
		return
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCronAdded), job.ID, cronExpr, truncateStr(prompt, 60)))
}

func (e *Engine) cmdCronList(p Platform, msg *Message) {
	jobs := e.cronScheduler.Store().ListBySessionKey(msg.SessionKey)
	if len(jobs) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCronEmpty))
		return
	}

	lang := e.i18n.CurrentLang()
	now := time.Now()
	var sb strings.Builder
	sb.WriteString(fmt.Sprintf(e.i18n.T(MsgCronListTitle), len(jobs)))
	sb.WriteString("\n")
	sb.WriteString("\n")

	for i, j := range jobs {
		if i > 0 {
			sb.WriteString("\n")
		}

		status := "✅"
		if !j.Enabled {
			status = "⏸"
		}
		desc := j.Description
		if desc == "" {
			desc = truncateStr(j.Prompt, 60)
		}
		sb.WriteString(fmt.Sprintf("%s %s\n", status, desc))

		sb.WriteString(fmt.Sprintf("ID: %s\n", j.ID))

		human := CronExprToHuman(j.CronExpr, lang)
		sb.WriteString(e.i18n.Tf(MsgCronScheduleLabel, human, j.CronExpr))

		nextRun := e.cronScheduler.NextRun(j.ID)
		if !nextRun.IsZero() {
			fmtStr := cronTimeFormat(nextRun, now)
			sb.WriteString(e.i18n.Tf(MsgCronNextRunLabel, nextRun.Format(fmtStr)))
		}

		if !j.LastRun.IsZero() {
			fmtStr := cronTimeFormat(j.LastRun, now)
			sb.WriteString(e.i18n.Tf(MsgCronLastRunLabel, j.LastRun.Format(fmtStr)))
			if j.LastError != "" {
				sb.WriteString(fmt.Sprintf(" (failed: %s)", truncateStr(j.LastError, 40)))
			}
			sb.WriteString("\n")
		}
	}

	sb.WriteString(fmt.Sprintf("\n%s", e.i18n.T(MsgCronListFooter)))
	e.reply(p, msg.ReplyCtx, sb.String())
}

func (e *Engine) cmdCronDel(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCronDelUsage))
		return
	}
	id := args[0]
	if e.cronScheduler.RemoveJob(id) {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCronDeleted), id))
	} else {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCronNotFound), id))
	}
}

func (e *Engine) cmdCronToggle(p Platform, msg *Message, args []string, enable bool) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCronDelUsage))
		return
	}
	id := args[0]
	var err error
	if enable {
		err = e.cronScheduler.EnableJob(id)
	} else {
		err = e.cronScheduler.DisableJob(id)
	}
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
		return
	}
	if enable {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCronEnabled), id))
	} else {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCronDisabled), id))
	}
}

// ──────────────────────────────────────────────────────────────
// Custom command execution & management
// ──────────────────────────────────────────────────────────────

func (e *Engine) executeCustomCommand(p Platform, msg *Message, cmd *CustomCommand, args []string) {
	prompt := ExpandPrompt(cmd.Prompt, args)

	session := e.sessions.GetOrCreateActive(msg.SessionKey)
	if !session.TryLock() {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPreviousProcessing))
		return
	}

	slog.Info("executing custom command",
		"command", cmd.Name,
		"source", cmd.Source,
		"user", msg.UserName,
	)

	msg.Content = prompt
	go e.processInteractiveMessage(p, msg, session)
}

func (e *Engine) cmdCommands(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		e.cmdCommandsList(p, msg)
		return
	}

	sub := matchSubCommand(strings.ToLower(args[0]), []string{
		"list", "add", "del", "delete", "rm", "remove",
	})
	switch sub {
	case "list":
		e.cmdCommandsList(p, msg)
	case "add":
		e.cmdCommandsAdd(p, msg, args[1:])
	case "del", "delete", "rm", "remove":
		e.cmdCommandsDel(p, msg, args[1:])
	default:
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCommandsUsage))
	}
}

func (e *Engine) cmdCommandsList(p Platform, msg *Message) {
	cmds := e.commands.ListAll()
	if len(cmds) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCommandsEmpty))
		return
	}

	var sb strings.Builder
	sb.WriteString(e.i18n.Tf(MsgCommandsTitle, len(cmds)))

	for _, c := range cmds {
		desc := c.Description
		if desc == "" {
			desc = truncateStr(c.Prompt, 50)
		}
		tag := ""
		if c.Source == "agent" {
			tag = " [agent]"
		}
		sb.WriteString(fmt.Sprintf("  /%s — %s%s\n", c.Name, desc, tag))
	}

	sb.WriteString("\n" + e.i18n.T(MsgCommandsHint))
	e.reply(p, msg.ReplyCtx, sb.String())
}

func (e *Engine) cmdCommandsAdd(p Platform, msg *Message, args []string) {
	// /commands add <name> <prompt...>
	if len(args) < 2 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCommandsAddUsage))
		return
	}
	name := strings.ToLower(args[0])
	prompt := strings.Join(args[1:], " ")

	if _, exists := e.commands.Resolve(name); exists {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCommandsAddExists), name, name))
		return
	}

	e.commands.Add(name, "", prompt, "config")

	if e.commandSaveAddFunc != nil {
		if err := e.commandSaveAddFunc(name, "", prompt); err != nil {
			slog.Error("failed to persist command", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCommandsAdded), name, truncateStr(prompt, 80)))
}

func (e *Engine) cmdCommandsDel(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgCommandsDelUsage))
		return
	}
	name := strings.ToLower(args[0])

	if !e.commands.Remove(name) {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCommandsNotFound), name))
		return
	}

	if e.commandSaveDelFunc != nil {
		if err := e.commandSaveDelFunc(name); err != nil {
			slog.Error("failed to persist command removal", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgCommandsDeleted), name))
}

// ──────────────────────────────────────────────────────────────
// Skill discovery & execution
// ──────────────────────────────────────────────────────────────

func (e *Engine) executeSkill(p Platform, msg *Message, skill *Skill, args []string) {
	prompt := BuildSkillInvocationPrompt(skill, args)

	session := e.sessions.GetOrCreateActive(msg.SessionKey)
	if !session.TryLock() {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgPreviousProcessing))
		return
	}

	slog.Info("executing skill",
		"skill", skill.Name,
		"source", skill.Source,
		"user", msg.UserName,
	)

	msg.Content = prompt
	go e.processInteractiveMessage(p, msg, session)
}

func (e *Engine) cmdSkills(p Platform, msg *Message) {
	skills := e.skills.ListAll()
	if len(skills) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgSkillsEmpty))
		return
	}

	var sb strings.Builder
	sb.WriteString(e.i18n.Tf(MsgSkillsTitle, e.agent.Name(), len(skills)))

	for _, s := range skills {
		desc := s.Description
		name := s.Name
		sb.WriteString(fmt.Sprintf("  /%s — %s\n", name, desc))
	}

	sb.WriteString("\n" + e.i18n.T(MsgSkillsHint))
	e.reply(p, msg.ReplyCtx, sb.String())
}

// ── /config command ──────────────────────────────────────────

// configItem describes a configurable runtime parameter.
type configItem struct {
	key     string
	desc    string // en description
	descZh  string // zh description
	getFunc func() string
	setFunc func(string) error
}

func (ci configItem) description(isZh bool) string {
	if isZh && ci.descZh != "" {
		return ci.descZh
	}
	return ci.desc
}

func (e *Engine) configItems() []configItem {
	return []configItem{
		{
			key:    "thinking_max_len",
			desc:   "Max chars for thinking messages (0=no truncation)",
			descZh: "思考消息最大长度 (0=不截断)",
			getFunc: func() string {
				return fmt.Sprintf("%d", e.display.ThinkingMaxLen)
			},
			setFunc: func(v string) error {
				n, err := strconv.Atoi(v)
				if err != nil {
					return fmt.Errorf("invalid integer: %s", v)
				}
				if n < 0 {
					return fmt.Errorf("value must be >= 0")
				}
				e.display.ThinkingMaxLen = n
				if e.displaySaveFunc != nil {
					return e.displaySaveFunc(&n, nil)
				}
				return nil
			},
		},
		{
			key:    "tool_max_len",
			desc:   "Max chars for tool use messages (0=no truncation)",
			descZh: "工具消息最大长度 (0=不截断)",
			getFunc: func() string {
				return fmt.Sprintf("%d", e.display.ToolMaxLen)
			},
			setFunc: func(v string) error {
				n, err := strconv.Atoi(v)
				if err != nil {
					return fmt.Errorf("invalid integer: %s", v)
				}
				if n < 0 {
					return fmt.Errorf("value must be >= 0")
				}
				e.display.ToolMaxLen = n
				if e.displaySaveFunc != nil {
					return e.displaySaveFunc(nil, &n)
				}
				return nil
			},
		},
	}
}

func (e *Engine) cmdConfig(p Platform, msg *Message, args []string) {
	items := e.configItems()
	isZh := e.i18n.IsZhLike()

	if len(args) == 0 {
		var sb strings.Builder
		sb.WriteString(e.i18n.T(MsgConfigTitle))
		for _, item := range items {
			sb.WriteString(fmt.Sprintf("`%s` = `%s`\n  %s\n\n", item.key, item.getFunc(), item.description(isZh)))
		}
		sb.WriteString(e.i18n.T(MsgConfigHint))
		e.reply(p, msg.ReplyCtx, sb.String())
		return
	}

	sub := matchSubCommand(strings.ToLower(args[0]), []string{"get", "set", "reload"})

	switch sub {
	case "reload":
		e.cmdConfigReload(p, msg)
		return
	case "get":
		if len(args) < 2 {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgConfigGetUsage))
			return
		}
		key := strings.ToLower(args[1])
		for _, item := range items {
			if item.key == key {
				e.reply(p, msg.ReplyCtx, fmt.Sprintf("`%s` = `%s`\n  %s", key, item.getFunc(), item.description(isZh)))
				return
			}
		}
		e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgConfigKeyNotFound, key))

	case "set":
		if len(args) < 3 {
			e.reply(p, msg.ReplyCtx, e.i18n.T(MsgConfigSetUsage))
			return
		}
		key := strings.ToLower(args[1])
		value := args[2]
		for _, item := range items {
			if item.key == key {
				if err := item.setFunc(value); err != nil {
					e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
					return
				}
				e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgConfigUpdated, key, item.getFunc()))
				return
			}
		}
		e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgConfigKeyNotFound, key))

	default:
		key := strings.ToLower(sub)
		for _, item := range items {
			if item.key == key {
				if len(args) >= 2 {
					if err := item.setFunc(args[1]); err != nil {
						e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
						return
					}
					e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgConfigUpdated, key, item.getFunc()))
				} else {
					e.reply(p, msg.ReplyCtx, fmt.Sprintf("`%s` = `%s`\n  %s", key, item.getFunc(), item.description(isZh)))
				}
				return
			}
		}
		e.reply(p, msg.ReplyCtx, e.i18n.Tf(MsgConfigKeyNotFound, key))
	}
}

// ── /doctor command ─────────────────────────────────────────

func (e *Engine) cmdDoctor(p Platform, msg *Message) {
	results := RunDoctorChecks(e.ctx, e.agent, e.platforms)
	report := FormatDoctorResults(results, e.i18n)
	e.reply(p, msg.ReplyCtx, report)
}

func (e *Engine) cmdUpgrade(p Platform, msg *Message, args []string) {
	subCmd := ""
	if len(args) > 0 {
		subCmd = matchSubCommand(args[0], []string{"confirm", "check"})
	}

	if subCmd == "confirm" {
		e.cmdUpgradeConfirm(p, msg)
		return
	}

	// Default: check for updates
	e.reply(p, msg.ReplyCtx, e.i18n.T(MsgUpgradeChecking))

	cur := CurrentVersion
	if cur == "" || cur == "dev" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgUpgradeDevBuild))
		return
	}

	release, err := CheckForUpdate(cur)
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %s", err))
		return
	}
	if release == nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgUpgradeUpToDate), cur))
		return
	}

	body := release.Body
	if len([]rune(body)) > 300 {
		body = string([]rune(body)[:300]) + "…"
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgUpgradeAvailable), cur, release.TagName, body))
}

func (e *Engine) cmdUpgradeConfirm(p Platform, msg *Message) {
	cur := CurrentVersion
	if cur == "" || cur == "dev" {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgUpgradeDevBuild))
		return
	}

	release, err := CheckForUpdate(cur)
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %s", err))
		return
	}
	if release == nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgUpgradeUpToDate), cur))
		return
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgUpgradeDownloading), release.TagName))

	if err := SelfUpdate(release.TagName); err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %s", err))
		return
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgUpgradeSuccess), release.TagName))
}

func (e *Engine) cmdConfigReload(p Platform, msg *Message) {
	if e.configReloadFunc == nil {
		e.reply(p, msg.ReplyCtx, "❌ Config reload not available")
		return
	}
	result, err := e.configReloadFunc()
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
		return
	}
	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgConfigReloaded),
		result.DisplayUpdated, result.ProvidersUpdated, result.CommandsUpdated))
}

func (e *Engine) cmdRestart(p Platform, msg *Message) {
	e.reply(p, msg.ReplyCtx, e.i18n.T(MsgRestarting))
	select {
	case RestartCh <- RestartRequest{
		SessionKey: msg.SessionKey,
		Platform:   p.Name(),
	}:
	default:
	}
}

func (e *Engine) cmdAlias(p Platform, msg *Message, args []string) {
	if len(args) == 0 {
		e.cmdAliasList(p, msg)
		return
	}

	sub := matchSubCommand(strings.ToLower(args[0]), []string{"list", "add", "del", "delete", "remove"})
	switch sub {
	case "list":
		e.cmdAliasList(p, msg)
	case "add":
		e.cmdAliasAdd(p, msg, args[1:])
	case "del", "delete", "remove":
		e.cmdAliasDel(p, msg, args[1:])
	default:
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgAliasUsage))
	}
}

func (e *Engine) cmdAliasList(p Platform, msg *Message) {
	e.aliasMu.RLock()
	defer e.aliasMu.RUnlock()

	if len(e.aliases) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgAliasEmpty))
		return
	}

	var sb strings.Builder
	sb.WriteString(fmt.Sprintf(e.i18n.T(MsgAliasListHeader), len(e.aliases)))
	sb.WriteString("\n")

	names := make([]string, 0, len(e.aliases))
	for n := range e.aliases {
		names = append(names, n)
	}
	sort.Strings(names)

	for _, n := range names {
		sb.WriteString(fmt.Sprintf("  %s → %s\n", n, e.aliases[n]))
	}
	e.reply(p, msg.ReplyCtx, strings.TrimRight(sb.String(), "\n"))
}

func (e *Engine) cmdAliasAdd(p Platform, msg *Message, args []string) {
	if len(args) < 2 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgAliasUsage))
		return
	}
	name := args[0]
	command := strings.Join(args[1:], " ")
	if !strings.HasPrefix(command, "/") {
		command = "/" + command
	}

	e.aliasMu.Lock()
	e.aliases[name] = command
	e.aliasMu.Unlock()

	if e.aliasSaveAddFunc != nil {
		if err := e.aliasSaveAddFunc(name, command); err != nil {
			slog.Error("alias: save failed", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgAliasAdded), name, command))
}

func (e *Engine) cmdAliasDel(p Platform, msg *Message, args []string) {
	if len(args) < 1 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgAliasUsage))
		return
	}
	name := args[0]

	e.aliasMu.Lock()
	_, exists := e.aliases[name]
	if exists {
		delete(e.aliases, name)
	}
	e.aliasMu.Unlock()

	if !exists {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgAliasNotFound), name))
		return
	}

	if e.aliasSaveDelFunc != nil {
		if err := e.aliasSaveDelFunc(name); err != nil {
			slog.Error("alias: save failed", "error", err)
		}
	}

	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgAliasDeleted), name))
}

func (e *Engine) cmdDelete(p Platform, msg *Message, args []string) {
	deleter, ok := e.agent.(SessionDeleter)
	if !ok {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgDeleteNotSupported))
		return
	}

	if len(args) == 0 {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgDeleteUsage))
		return
	}

	agentSessions, err := e.agent.ListSessions(e.ctx)
	if err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
		return
	}

	prefix := strings.TrimSpace(args[0])
	var matched *AgentSessionInfo

	if idx, err := strconv.Atoi(prefix); err == nil && idx >= 1 && idx <= len(agentSessions) {
		matched = &agentSessions[idx-1]
	} else {
		for i := range agentSessions {
			if strings.HasPrefix(agentSessions[i].ID, prefix) {
				matched = &agentSessions[i]
				break
			}
		}
	}

	if matched == nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ No session matching %q", prefix))
		return
	}

	// Prevent deleting the currently active session
	activeSession := e.sessions.GetOrCreateActive(msg.SessionKey)
	if activeSession.AgentSessionID == matched.ID {
		e.reply(p, msg.ReplyCtx, e.i18n.T(MsgDeleteActiveDenied))
		return
	}

	displayName := e.sessions.GetSessionName(matched.ID)
	if displayName == "" {
		displayName = matched.Summary
	}
	if displayName == "" {
		shortID := matched.ID
		if len(shortID) > 12 {
			shortID = shortID[:12]
		}
		displayName = shortID
	}

	if err := deleter.DeleteSession(e.ctx, matched.ID); err != nil {
		e.reply(p, msg.ReplyCtx, fmt.Sprintf("❌ %v", err))
		return
	}

	e.sessions.SetSessionName(matched.ID, "")
	e.reply(p, msg.ReplyCtx, fmt.Sprintf(e.i18n.T(MsgDeleteSuccess), displayName))
}

// truncateIf truncates s to maxLen runes. 0 means no truncation.
func truncateIf(s string, maxLen int) string {
	if maxLen <= 0 {
		return s
	}
	if utf8.RuneCountInString(s) <= maxLen {
		return s
	}
	return string([]rune(s)[:maxLen]) + "..."
}

func splitMessage(text string, maxLen int) []string {
	if len(text) <= maxLen {
		return []string{text}
	}
	var chunks []string
	for len(text) > 0 {
		end := maxLen
		if end > len(text) {
			end = len(text)
		}
		if end < len(text) {
			if idx := strings.LastIndex(text[:end], "\n"); idx > 0 {
				end = idx + 1
			}
		}
		chunks = append(chunks, text[:end])
		text = text[end:]
	}
	return chunks
}