package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"tuner/api"
	"tuner/m3u"
	"tuner/process"
)

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

func main() {
	playlistPath := getEnv("PLAYLIST_PATH", "/data/playlist.m3u")
	mediamtxBin := getEnv("MEDIAMTX_PATH", "mediamtx")
	mediamtxCfg := getEnv("MEDIAMTX_CONFIG", "mediamtx.yml")
	port := getEnv("RESTREAMER_PORT", "8080")

	// Initialize process managers
	mtxManager := process.NewMediaMTXManager(mediamtxBin, mediamtxCfg)
	ffmpegManager := process.NewFFmpegManager()

	// Build shared app state
	app := &api.App{
		PlaylistPath: playlistPath,
		MediaMTX:     mtxManager,
		FFmpeg:       ffmpegManager,
	}

	// Load playlist (warn but don't crash if missing)
	channels, err := m3u.ParseFile(playlistPath)
	if err != nil {
		log.Printf("[startup] warning: could not load playlist %s: %v", playlistPath, err)
	} else {
		app.Channels = channels
		log.Printf("[startup] loaded %d channels from %s", len(channels), playlistPath)
	}

	// Start MediaMTX (warn but don't crash if binary not found)
	if err := mtxManager.Start(); err != nil {
		log.Printf("[startup] warning: could not start mediamtx: %v", err)
	}

	// Register routes
	mux := http.NewServeMux()

	// API routes
	mux.HandleFunc("/api/status", app.HandleStatus)
	mux.HandleFunc("/api/admin/channels", app.HandleChannels)
	mux.HandleFunc("/api/admin/groups", app.HandleGroups)
	mux.HandleFunc("/api/admin/source", app.HandleSetSource)
	mux.HandleFunc("/api/admin/channel", app.HandleSetChannel)
	mux.HandleFunc("/api/admin/playlist/reload", app.HandleReloadPlaylist)
	mux.HandleFunc("/api/admin/process/status", app.HandleProcessStatus)

	// Serve frontend static files (falls back to index.html for SPA routing)
	frontendDir := getEnv("FRONTEND_DIR", "frontend/dist")
	if info, err := os.Stat(frontendDir); err == nil && info.IsDir() {
		fs := http.FileServer(http.Dir(frontendDir))
		mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			// Try to serve the file; if it doesn't exist, serve index.html (SPA fallback)
			path := frontendDir + r.URL.Path
			if _, err := os.Stat(path); os.IsNotExist(err) && r.URL.Path != "/" {
				http.ServeFile(w, r, frontendDir+"/index.html")
				return
			}
			fs.ServeHTTP(w, r)
		}))
		log.Printf("[startup] serving frontend from %s", frontendDir)
	} else {
		mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "text/plain")
			w.Write([]byte("Tuner backend running. Frontend not found."))
		})
		log.Printf("[startup] frontend dir %s not found, serving placeholder", frontendDir)
	}

	// Wrap with middleware
	handler := api.Logging(api.CORS(mux))

	server := &http.Server{
		Addr:    ":" + port,
		Handler: handler,
	}

	// Graceful shutdown
	go func() {
		sigCh := make(chan os.Signal, 1)
		signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
		sig := <-sigCh
		log.Printf("[shutdown] received %v, shutting down...", sig)

		// Stop child processes
		if err := ffmpegManager.Stop(); err != nil {
			log.Printf("[shutdown] error stopping ffmpeg: %v", err)
		}
		if err := mtxManager.Stop(); err != nil {
			log.Printf("[shutdown] error stopping mediamtx: %v", err)
		}

		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		if err := server.Shutdown(ctx); err != nil {
			log.Printf("[shutdown] http server shutdown error: %v", err)
		}
	}()

	log.Printf("[startup] listening on :%s", port)
	if err := server.ListenAndServe(); err != http.ErrServerClosed {
		log.Fatalf("[fatal] server error: %v", err)
	}
	log.Println("[shutdown] complete")
}