package server

import (
	"context"
	"log"
	"net/http"
	"sync"

	"ky-go-kratos/app/websocket/internal/conf"
	"ky-go-kratos/app/websocket/internal/service"

	"github.com/gorilla/websocket"
)

type WebSocketServer struct {
	conf       *conf.Server
	svc        *service.WebSocketService
	upgrader   websocket.Upgrader
	clients    map[*websocket.Conn]bool
	broadcast  chan []byte
	register   chan *websocket.Conn
	unregister chan *websocket.Conn
	mu         sync.RWMutex
	server     *http.Server
	done       chan struct{} // 添加 done 通道用于优雅关闭
}

// NewWebSocketServer 创建 WebSocket 服务器
func NewWebSocketServer(c *conf.Server, svc *service.WebSocketService) *WebSocketServer {
	return &WebSocketServer{
		conf: c,
		svc:  svc,
		upgrader: websocket.Upgrader{
			CheckOrigin: func(r *http.Request) bool {
				return true // 允许所有来源的连接
			},
		},
		clients:    make(map[*websocket.Conn]bool),
		broadcast:  make(chan []byte),
		register:   make(chan *websocket.Conn),
		unregister: make(chan *websocket.Conn),
		done:       make(chan struct{}),
	}
}

// Start 启动 WebSocket 服务器
func (s *WebSocketServer) Start(ctx context.Context) error {
	mux := http.NewServeMux()
	mux.HandleFunc(s.conf.Websocket.Path, s.handleWebSocket)

	s.server = &http.Server{
		Addr:    s.conf.Websocket.Addr,
		Handler: mux,
	}

	go s.run()

	log.Printf("Starting WebSocket server on %s%s", s.conf.Websocket.Addr, s.conf.Websocket.Path)

	go func() {
		if err := s.server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Printf("Failed to start WebSocket server: %v", err)
		}
	}()

	return nil
}

// Stop 停止 WebSocket 服务器
func (s *WebSocketServer) Stop(ctx context.Context) error {
	// 关闭所有 WebSocket 连接
	s.mu.Lock()
	for client := range s.clients {
		client.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseGoingAway, "Server is shutting down"))
		client.Close()
		delete(s.clients, client)
	}
	s.mu.Unlock()

	// 关闭通道
	close(s.done)
	close(s.broadcast)
	close(s.register)
	close(s.unregister)

	// 关闭 HTTP 服务器
	if s.server != nil {
		return s.server.Shutdown(ctx)
	}
	return nil
}

// handleWebSocket 处理 WebSocket 连接请求
func (s *WebSocketServer) handleWebSocket(w http.ResponseWriter, r *http.Request) {
	log.Printf("Received WebSocket connection request from %s", r.RemoteAddr)

	conn, err := s.upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Printf("Failed to upgrade connection: %v", err)
		return
	}

	log.Printf("WebSocket connection established with %s", r.RemoteAddr)
	s.register <- conn
	go s.readPump(conn)
}

// readPump 读取 WebSocket 消息
func (s *WebSocketServer) readPump(conn *websocket.Conn) {
	defer func() {
		s.unregister <- conn
		conn.Close()
	}()

	for {
		select {
		case <-s.done:
			return
		default:
			_, message, err := conn.ReadMessage()
			if err != nil {
				if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
					log.Printf("error: %v", err)
				}
				return
			}

			log.Printf("Received message: %v", string(message))

			// 处理接收到的消息
			if err := s.svc.HandleMessage(context.Background(), message); err != nil {
				log.Printf("Error handling message: %v", err)
				continue
			}

			// 广播消息给所有客户端
			select {
			case s.broadcast <- message:
			case <-s.done:
				return
			}
		}
	}
}

// run 运行 WebSocket 服务器
func (s *WebSocketServer) run() {
	for {
		select {
		case <-s.done: // 如果 done 通道被关闭，则退出循环
			return
		case client := <-s.register: // 如果 register 通道有新的连接，则将连接添加到 clients 中
			s.mu.Lock()
			s.clients[client] = true
			s.mu.Unlock()
			log.Printf("New client connected. Total clients: %d", len(s.clients))
		case client := <-s.unregister: // 如果 unregister 通道有连接关闭，则将连接从 clients 中删除
			s.mu.Lock()
			if _, ok := s.clients[client]; ok {
				delete(s.clients, client)
				client.Close()
			}
			s.mu.Unlock()
			log.Printf("Client disconnected. Total clients: %d", len(s.clients))
		case message := <-s.broadcast: // 如果 broadcast 通道有消息，则广播消息给所有客户端
			s.mu.Lock()
			for client := range s.clients {
				err := client.WriteMessage(websocket.TextMessage, message)
				if err != nil {
					log.Printf("Error broadcasting message: %v", err)
					client.Close()
					delete(s.clients, client)
				}
			}
			s.mu.Unlock()
		}
	}
}