package cmd

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"
	"time"

	"github.com/fatih/color"
	"github.com/spf13/cobra"
	"github.com/torrentclaw/torrentclaw-cli/internal/agent"
	"github.com/torrentclaw/torrentclaw-cli/internal/config"
	"github.com/torrentclaw/torrentclaw-cli/internal/engine"
	"github.com/torrentclaw/torrentclaw-cli/internal/upgrade"
)

// newStartCmd creates the top-level `unarr start` command.
func newStartCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "start",
		Short: "Start the download daemon (foreground)",
		Long: `Start the unarr daemon in the foreground.

Registers with the server, polls for download tasks, and executes them
using the configured download method. Press Ctrl+C to stop gracefully.`,
		Example: `  unarr start
  unarr start --config /path/to/config.toml`,
		RunE: func(cmd *cobra.Command, args []string) error {
			return runDaemonStart()
		},
	}
}

// newStopCmd creates the top-level `unarr stop` placeholder.
func newStopCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "stop",
		Short: "Stop the running daemon",
		RunE: func(cmd *cobra.Command, args []string) error {
			fmt.Println("  Use Ctrl+C in the terminal where the daemon is running.")
			fmt.Println("  (Signal-based stop coming in a future release)")
			return nil
		},
	}
}

// newDaemonCmd creates `unarr daemon` for administrative subcommands.
func newDaemonCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "daemon",
		Short: "Daemon administration (install, uninstall, logs)",
		Long:  "Administrative commands for managing the daemon as a system service.",
	}

	cmd.AddCommand(
		newDaemonInstallCmdReal(),
		newDaemonUninstallCmdReal(),
	)

	return cmd
}


func runDaemonStart() error {
	cfg := loadConfig()
	bold := color.New(color.Bold)

	// Validate config
	if cfg.Auth.APIKey == "" {
		return fmt.Errorf("no API key configured — run 'unarr setup' first")
	}
	if cfg.Agent.ID == "" {
		return fmt.Errorf("no agent ID — run 'unarr setup' first")
	}
	if cfg.Download.Dir == "" {
		return fmt.Errorf("no download directory — run 'unarr setup' first")
	}

	// Validate configured paths are safe
	if err := cfg.ValidatePaths(); err != nil {
		return fmt.Errorf("unsafe configuration: %w", err)
	}

	// Ensure download dir exists
	if err := os.MkdirAll(cfg.Download.Dir, 0o755); err != nil {
		return fmt.Errorf("create download dir: %w", err)
	}

	fmt.Println()
	bold.Println("  unarr Daemon")
	fmt.Println()

	// Parse intervals
	pollInterval, _ := time.ParseDuration(cfg.Daemon.PollInterval)
	if pollInterval == 0 {
		pollInterval = 30 * time.Second
	}
	heartbeatInterval, _ := time.ParseDuration(cfg.Daemon.HeartbeatInterval)
	if heartbeatInterval == 0 {
		heartbeatInterval = 30 * time.Second
	}

	// Create agent client (direct HTTP — always available as fallback)
	ac := agent.NewClient(cfg.Auth.APIURL, cfg.Auth.APIKey, "unarr/"+Version)
	userAgent := "unarr/" + Version

	// Create daemon config
	daemonCfg := agent.DaemonConfig{
		AgentID:           cfg.Agent.ID,
		AgentName:         cfg.Agent.Name,
		Version:           Version,
		DownloadDir:       cfg.Download.Dir,
		PollInterval:      pollInterval,
		HeartbeatInterval: heartbeatInterval,
	}

	// Create transport: Hybrid (WS + HTTP fallback) or HTTP-only
	wsURL := cfg.Auth.WSURL
	if wsURL == "" {
		wsURL = deriveWSURL(cfg.Auth.APIURL, cfg.Agent.ID)
	}

	var transport agent.Transport
	if wsURL != "" {
		httpT := agent.NewHTTPTransport(cfg.Auth.APIURL, cfg.Auth.APIKey, userAgent)
		wsT := agent.NewWSTransport(wsURL, cfg.Auth.APIKey, cfg.Agent.ID, userAgent)
		transport = agent.NewHybridTransport(wsT, httpT)
		log.Printf("Transport: WebSocket (fallback: HTTP) → %s", wsURL)
	}

	// Create daemon
	var d *agent.Daemon
	if transport != nil {
		d = agent.NewDaemonWithTransport(daemonCfg, transport)
	} else {
		d = agent.NewDaemon(daemonCfg, ac)
	}

	// Wire state tracking (connected after manager creation below)
	// Create progress reporter
	var reporter *engine.ProgressReporter
	if transport != nil {
		reporter = engine.NewProgressReporterWithTransport(transport, 3*time.Second)
	} else {
		reporter = engine.NewProgressReporter(ac, 3*time.Second)
	}

	// Parse speed limits
	maxDl, _ := config.ParseSpeed(cfg.Download.MaxDownloadSpeed)
	maxUl, _ := config.ParseSpeed(cfg.Download.MaxUploadSpeed)

	// Create torrent downloader
	torrentDl, err := engine.NewTorrentDownloader(engine.TorrentConfig{
		DataDir:         cfg.Download.Dir,
		StallTimeout:    90 * time.Second,
		MaxTimeout:      30 * time.Minute,
		MaxDownloadRate: maxDl,
		MaxUploadRate:   maxUl,
		SeedEnabled:     false,
	})
	if err != nil {
		return fmt.Errorf("create torrent downloader: %w", err)
	}

	if maxDl > 0 || maxUl > 0 {
		dlStr, ulStr := "unlimited", "unlimited"
		if maxDl > 0 {
			dlStr = formatSpeedLog(maxDl)
		}
		if maxUl > 0 {
			ulStr = formatSpeedLog(maxUl)
		}
		log.Printf("Speed limits: download=%s upload=%s", dlStr, ulStr)
	}

	// Create debrid downloader (HTTPS-based, no provider interaction needed)
	debridDl := engine.NewDebridDownloader()

	// Create download manager
	manager := engine.NewManager(engine.ManagerConfig{
		MaxConcurrent: cfg.Download.MaxConcurrent,
		OutputDir:     cfg.Download.Dir,
		Notifications: cfg.Notifications.Enabled,
		Organize: engine.OrganizeConfig{
			Enabled:    cfg.Organize.Enabled,
			MoviesDir:  cfg.Organize.MoviesDir,
			TVShowsDir: cfg.Organize.TVShowsDir,
		},
	}, reporter, torrentDl, debridDl)

	// Wire state tracking
	d.GetActiveCount = manager.ActiveCount

	// Wire: server-side signals -> manager actions + stream tasks
	reporter.SetCancelHandler(func(taskID string) {
		manager.CancelTask(taskID)
		cancelStreamTask(taskID)
	})
	reporter.SetPauseHandler(func(taskID string) {
		manager.PauseTask(taskID)
		cancelStreamTask(taskID)
	})
	reporter.SetDeleteFilesHandler(func(taskID string) {
		manager.CancelAndDeleteFiles(taskID)
		cancelStreamTask(taskID)
	})

	// Wire: stream requested on active download → start HTTP server
	reporter.SetStreamRequestedHandler(func(taskID string) {
		task := manager.GetTask(taskID)
		if task == nil {
			log.Printf("[%s] stream requested but task not found in manager", taskID[:8])
			return
		}
		if task.GetStreamURL() != "" {
			return // already streaming
		}
		srv, err := torrentDl.StartStream(taskID)
		if err != nil {
			log.Printf("[%s] stream failed: %v", taskID[:8], err)
			return
		}
		// Register server before setting URL to avoid TOCTOU race
		streamRegistry.mu.Lock()
		streamRegistry.servers[taskID] = srv
		streamRegistry.mu.Unlock()
		task.SetStreamURL(srv.URL())
	})

	// Wire: daemon claimed tasks -> manager
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	d.OnTasksClaimed = func(tasks []agent.Task) {
		for _, t := range tasks {
			if t.Mode == "stream" {
				go handleStreamTask(ctx, t, reporter, cfg)
			} else if manager.HasCapacity() {
				manager.Submit(ctx, t)
			} else {
				log.Printf("[%s] skipped: no capacity (max %d)", t.ID[:8], cfg.Download.MaxConcurrent)
			}
		}
	}

	// Wire: stream requests for completed downloads → serve file from disk
	d.OnStreamRequested = func(sr agent.StreamRequest) {
		// Check if already streaming this task
		streamRegistry.mu.Lock()
		_, exists := streamRegistry.servers[sr.TaskID]
		streamRegistry.mu.Unlock()
		if exists {
			return
		}

		if _, err := os.Stat(sr.FilePath); err != nil {
			log.Printf("[%s] stream request: file not found: %s", sr.TaskID[:8], sr.FilePath)
			return
		}

		srv := engine.NewStreamServerFromDisk(sr.FilePath, 0)
		streamURL, err := srv.Start(context.Background())
		if err != nil {
			log.Printf("[%s] stream failed: %v", sr.TaskID[:8], err)
			return
		}

		streamRegistry.mu.Lock()
		streamRegistry.servers[sr.TaskID] = srv
		streamRegistry.mu.Unlock()

		log.Printf("[%s] streaming from disk: %s → %s", sr.TaskID[:8], filepath.Base(sr.FilePath), streamURL)

		// Report stream URL back to the server
		go func() {
			if _, err := ac.ReportStatus(ctx, agent.StatusUpdate{
				TaskID:    sr.TaskID,
				StreamURL: streamURL,
			}); err != nil {
				log.Printf("[%s] stream URL report failed: %v", sr.TaskID[:8], err)
			}
		}()
	}

	// Wire: WS control actions (pause/cancel/stream pushed from server)
	d.OnControlAction = func(action, taskID string) {
		switch action {
		case "cancel":
			manager.CancelTask(taskID)
			cancelStreamTask(taskID)
		case "pause":
			manager.PauseTask(taskID)
			cancelStreamTask(taskID)
		case "resume":
			log.Printf("[%s] resume requested via WebSocket", taskID[:8])
		case "stream":
			task := manager.GetTask(taskID)
			if task == nil {
				return
			}
			if task.GetStreamURL() != "" {
				return
			}
			srv, err := torrentDl.StartStream(taskID)
			if err != nil {
				log.Printf("[%s] stream failed: %v", taskID[:8], err)
				return
			}
			streamRegistry.mu.Lock()
			streamRegistry.servers[taskID] = srv
			streamRegistry.mu.Unlock()
			task.SetStreamURL(srv.URL())
		}
	}

	// Wire: server-requested upgrade
	d.OnUpgradeRequested = func(targetVersion string) {

		// Wait for active downloads to finish
		if active := manager.ActiveCount(); active > 0 {
			log.Printf("Waiting for %d active download(s) to finish before upgrading...", active)
			manager.Wait()
		}

		upgrader := &upgrade.Upgrader{CurrentVersion: Version}
		result := upgrader.Execute(ctx, targetVersion)

		// Report result to server
		reportCtx, reportCancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer reportCancel()
		errMsg := ""
		if result.Error != nil {
			errMsg = result.Error.Error()
		}
		upgradeResult := agent.UpgradeResult{
			AgentID: cfg.Agent.ID,
			Success: result.Success,
			Version: result.NewVersion,
			Error:   errMsg,
		}
		if transport != nil {
			_ = transport.ReportUpgradeResult(reportCtx, upgradeResult)
		} else {
			_ = ac.ReportUpgradeResult(reportCtx, upgradeResult)
		}

		if !result.Success {
			log.Printf("Upgrade failed: %v", result.Error)
			d.ClearUpgradeInProgress()
			return
		}

		// Restart: replace current process with the new binary
		log.Printf("Upgrade successful (%s → %s), restarting...", result.OldVersion, result.NewVersion)

		// Deregister first so the server knows we're restarting
		deregCtx, deregCancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer deregCancel()
		_ = ac.Deregister(deregCtx, cfg.Agent.ID)

		// Flush progress reporter
		cancel()

		// Re-exec with the same args — the new binary takes over
		binPath, err := os.Executable()
		if err != nil {
			log.Printf("Could not determine executable path: %v", err)
			os.Exit(75) // EX_TEMPFAIL
		}
		// syscall.Exec replaces the current process (Unix)
		execErr := syscall.Exec(binPath, os.Args, os.Environ())
		// If we get here, exec failed (e.g. Windows)
		log.Printf("Exec failed: %v — exiting for service manager restart", execErr)
		os.Exit(75)
	}

	// Config hot-reload (SIGUSR1 on Unix, no-op on Windows)
	// Tickers are initialized inside d.Run(), so we pass the daemon
	// and the reload goroutine reads them when the signal arrives.
	startReloadWatcher(&ReloadableConfig{Daemon: d})

	// Signal handling
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	// Start progress reporter in background
	go reporter.Run(ctx)

	// Start daemon (blocks)
	errCh := make(chan error, 1)
	go func() {
		errCh <- d.Run(ctx)
	}()

	// Wait for signal or error
	select {
	case sig := <-sigCh:
		fmt.Printf("\n  Received %s, shutting down...\n", sig)
		cancel()

		// Give active downloads 30s to finish
		shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 30*time.Second)
		defer shutdownCancel()
		manager.Shutdown(shutdownCtx)

		fmt.Println("  Daemon stopped.")
		return nil

	case err := <-errCh:
		cancel()
		return err
	}
}

// deriveWSURL derives a WebSocket URL from the API URL.
// https://torrentclaw.com → wss://unarr.torrentclaw.com/ws/{agentId}
func deriveWSURL(apiURL, agentID string) string {
	if apiURL == "" || agentID == "" {
		return ""
	}
	// Parse domain from API URL
	domain := apiURL
	for _, prefix := range []string{"https://", "http://"} {
		if len(domain) > len(prefix) && domain[:len(prefix)] == prefix {
			domain = domain[len(prefix):]
			break
		}
	}
	// Strip trailing slash/path
	for i := 0; i < len(domain); i++ {
		if domain[i] == '/' {
			domain = domain[:i]
			break
		}
	}

	return "wss://unarr." + domain + "/ws/" + agentID
}

func formatSpeedLog(bps int64) string {
	switch {
	case bps >= 1024*1024*1024:
		return fmt.Sprintf("%.1f GB/s", float64(bps)/(1024*1024*1024))
	case bps >= 1024*1024:
		return fmt.Sprintf("%.1f MB/s", float64(bps)/(1024*1024))
	case bps >= 1024:
		return fmt.Sprintf("%.0f KB/s", float64(bps)/1024)
	default:
		return fmt.Sprintf("%d B/s", bps)
	}
}