package stream

import (
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"

	"github.com/gin-gonic/gin"
	"github.com/nareix/joy4/av/avutil"
	"github.com/nareix/joy4/av/pubsub"
	"github.com/nareix/joy4/format"
	"github.com/nareix/joy4/format/flv"
	"github.com/nareix/joy4/format/rtmp"

	"hightube/internal/chat"
	"hightube/internal/db"
	"hightube/internal/model"
	"hightube/internal/monitor"
)

func init() {
	// Register all supported audio/video formats
	format.RegisterAll()
}

// RTMPServer manages all active live streams
type RTMPServer struct {
	server   *rtmp.Server
	channels map[string]*pubsub.Queue
	mutex    sync.RWMutex
}

type writeFlusher struct {
	httpFlusher http.Flusher
	io.Writer
}

func (w writeFlusher) Flush() error {
	w.httpFlusher.Flush()
	return nil
}

// NewRTMPServer creates and initializes a new media server
func NewRTMPServer() *RTMPServer {
	s := &RTMPServer{
		channels: make(map[string]*pubsub.Queue),
		server:   &rtmp.Server{},
	}

	// Triggered when a broadcaster (e.g., OBS) starts publishing
	s.server.HandlePublish = func(conn *rtmp.Conn) {
		streamPath := conn.URL.Path // Expected format: /live/{stream_key}
		monitor.Infof("OBS publish attempt: %s", streamPath)

		// Extract stream key from path
		parts := strings.Split(streamPath, "/")
		if len(parts) < 3 || parts[1] != "live" {
			monitor.Warnf("Invalid publish path format: %s", streamPath)
			return
		}
		streamKey := parts[2]

		// Authenticate stream key
		var room model.Room
		if err := db.DB.Where("stream_key = ?", streamKey).First(&room).Error; err != nil {
			monitor.Warnf("Invalid stream key: %s", streamKey)
			return // Reject connection
		}

		monitor.Infof("Stream authenticated for room_id=%d", room.ID)

		// 1. Get audio/video stream metadata
		streams, err := conn.Streams()
		if err != nil {
			monitor.Errorf("Failed to parse stream headers: %v", err)
			return
		}

		// 2. Map the active stream by Room ID so viewers can use /live/{room_id}
		roomLivePath := fmt.Sprintf("/live/%d", room.ID)
		
		s.mutex.Lock()
		q := pubsub.NewQueue()
		q.WriteHeader(streams)
		s.channels[roomLivePath] = q
		s.mutex.Unlock()

		// Mark room as active in DB (using map to ensure true/false is correctly updated)
		db.DB.Model(&room).Updates(map[string]interface{}{"is_active": true})

		// 3. Cleanup on end
		defer func() {
			s.mutex.Lock()
			delete(s.channels, roomLivePath)
			s.mutex.Unlock()
			q.Close()
			// Explicitly set is_active to false using map
			db.DB.Model(&room).Updates(map[string]interface{}{"is_active": false})
			
			// Clear chat history for this room
			chat.MainHub.ClearRoomHistory(fmt.Sprintf("%d", room.ID))
			
			monitor.Infof("Publishing ended for room_id=%d", room.ID)
		}()

		// 4. Continuously copy data packets to our broadcast queue
		avutil.CopyPackets(q, conn)
	}

	// Triggered when a viewer (e.g., VLC) requests playback
	s.server.HandlePlay = func(conn *rtmp.Conn) {
		streamPath := conn.URL.Path // Expected format: /live/{room_id}
		monitor.Infof("RTMP play requested: %s", streamPath)

		// 1. Look for the requested room's data queue
		s.mutex.RLock()
		q, ok := s.channels[streamPath]
		s.mutex.RUnlock()

		if !ok {
			monitor.Warnf("Stream not found or inactive: %s", streamPath)
			return
		}

		// 2. Get the cursor from the latest position and notify client of stream format
		cursor := q.Latest()
		streams, _ := cursor.Streams()
		conn.WriteHeader(streams)

		// 3. Cleanup on end
		defer monitor.Infof("Playback ended: %s", streamPath)

		// 4. Continuously copy data packets to the viewer
		err := avutil.CopyPackets(conn, cursor)
		if err != nil && err != io.EOF {
			// 如果是客户端主动断开连接引起的错误，不将其作为严重错误打印
			errStr := err.Error()
			if strings.Contains(errStr, "broken pipe") || strings.Contains(errStr, "connection reset by peer") {
				monitor.Infof("Viewer disconnected: %s", streamPath)
			} else {
				monitor.Errorf("Playback error on %s: %v", streamPath, err)
			}
		}
	}

	return s
}

// Start launches the RTMP server
func (s *RTMPServer) Start(addr string) error {
	s.server.Addr = addr
	monitor.Infof("RTMP server listening on %s", addr)
	return s.server.ListenAndServe()
}

// HandleHTTPFLV serves browser-compatible HTTP-FLV playback for web clients.
func (s *RTMPServer) HandleHTTPFLV(c *gin.Context) {
	streamPath := fmt.Sprintf("/live/%s", c.Param("room_id"))

	s.mutex.RLock()
	q, ok := s.channels[streamPath]
	s.mutex.RUnlock()

	if !ok {
		c.JSON(http.StatusNotFound, gin.H{"error": "Stream not found or inactive"})
		return
	}

	flusher, ok := c.Writer.(http.Flusher)
	if !ok {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Streaming is not supported by the current server"})
		return
	}

	c.Header("Content-Type", "video/x-flv")
	c.Header("Transfer-Encoding", "chunked")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")
	c.Header("Access-Control-Allow-Origin", "*")
	c.Status(http.StatusOK)
	flusher.Flush()

	muxer := flv.NewMuxerWriteFlusher(writeFlusher{
		httpFlusher: flusher,
		Writer:      c.Writer,
	})
	cursor := q.Latest()

	if err := avutil.CopyFile(muxer, cursor); err != nil && err != io.EOF {
		errStr := err.Error()
		if strings.Contains(errStr, "broken pipe") || strings.Contains(errStr, "connection reset by peer") {
			monitor.Infof("HTTP-FLV viewer disconnected: %s", streamPath)
			return
		}
		monitor.Errorf("HTTP-FLV playback error on %s: %v", streamPath, err)
	}
}

func (s *RTMPServer) ActiveStreamCount() int {
	s.mutex.RLock()
	defer s.mutex.RUnlock()
	return len(s.channels)
}

func (s *RTMPServer) ActiveStreamPaths() []string {
	s.mutex.RLock()
	defer s.mutex.RUnlock()

	paths := make([]string, 0, len(s.channels))
	for path := range s.channels {
		paths = append(paths, path)
	}
	return paths
}