package net

import (
	"context"
	"fmt"
	"net/url"
	"sync"
	"time"

	"cellbot/internal/engine"
	"cellbot/internal/protocol"

	"github.com/bytedance/sonic"
	"github.com/fasthttp/websocket"
	"github.com/valyala/fasthttp"
	"go.uber.org/zap"
)

// WebSocketManager WebSocket连接管理器
type WebSocketManager struct {
	connections map[string]*WebSocketConnection
	logger      *zap.Logger
	eventBus    *engine.EventBus
	mu          sync.RWMutex
	upgrader    *websocket.FastHTTPUpgrader
}

// NewWebSocketManager 创建WebSocket管理器
func NewWebSocketManager(logger *zap.Logger, eventBus *engine.EventBus) *WebSocketManager {
	return &WebSocketManager{
		connections: make(map[string]*WebSocketConnection),
		logger:      logger.Named("websocket"),
		eventBus:    eventBus,
		upgrader: &websocket.FastHTTPUpgrader{
			ReadBufferSize:  1024,
			WriteBufferSize: 1024,
			CheckOrigin: func(ctx *fasthttp.RequestCtx) bool {
				return true // 允许所有来源，生产环境应加强检查
			},
		},
	}
}

// ConnectionType 连接类型
type ConnectionType string

const (
	ConnectionTypeReverse ConnectionType = "reverse" // 反向连接（被动接受）
	ConnectionTypeForward ConnectionType = "forward" // 正向连接（主动发起）
)

// WebSocketConnection WebSocket连接
type WebSocketConnection struct {
	ID             string
	Conn           *websocket.Conn
	BotID          string
	Logger         *zap.Logger
	ctx            context.Context
	cancel         context.CancelFunc
	Type           ConnectionType
	RemoteAddr     string
	reconnectURL   string        // 用于正向连接重连
	maxReconnect   int           // 最大重连次数
	reconnectCount int           // 当前重连次数
	heartbeatTick  time.Duration // 心跳间隔
}

// NewWebSocketConnection 创建WebSocket连接
func NewWebSocketConnection(conn *websocket.Conn, botID string, connType ConnectionType, logger *zap.Logger) *WebSocketConnection {
	ctx, cancel := context.WithCancel(context.Background())
	connID := generateConnID()
	return &WebSocketConnection{
		ID:            connID,
		Conn:          conn,
		BotID:         botID,
		Logger:        logger.With(zap.String("conn_id", connID)),
		ctx:           ctx,
		cancel:        cancel,
		Type:          connType,
		RemoteAddr:    conn.RemoteAddr().String(),
		maxReconnect:  5,
		heartbeatTick: 30 * time.Second,
	}
}

// UpgradeWebSocket 升级HTTP连接为WebSocket
func (wsm *WebSocketManager) UpgradeWebSocket(ctx *fasthttp.RequestCtx) (*WebSocketConnection, error) {
	// 获取查询参数
	botID := string(ctx.QueryArgs().Peek("bot_id"))
	if botID == "" {
		return nil, fmt.Errorf("missing bot_id parameter")
	}

	// 创建通道用于传递连接
	connChan := make(chan *websocket.Conn, 1)

	// 升级连接
	err := wsm.upgrader.Upgrade(ctx, func(conn *websocket.Conn) {
		connChan <- conn
	})
	if err != nil {
		return nil, fmt.Errorf("failed to upgrade connection: %w", err)
	}

	// 等待连接在回调中建立
	conn := <-connChan

	// 创建连接对象（反向连接）
	wsConn := NewWebSocketConnection(conn, botID, ConnectionTypeReverse, wsm.logger)

	// 存储连接
	wsm.mu.Lock()
	wsm.connections[wsConn.ID] = wsConn
	wsm.mu.Unlock()

	wsm.logger.Info("WebSocket reverse connection established",
		zap.String("conn_id", wsConn.ID),
		zap.String("bot_id", botID),
		zap.String("remote_addr", wsConn.RemoteAddr))

	// 启动读取循环和心跳
	go wsConn.readLoop(wsm.eventBus)
	go wsConn.heartbeatLoop()

	return wsConn, nil
}

// readLoop 读取循环
func (wsc *WebSocketConnection) readLoop(eventBus *engine.EventBus) {
	defer wsc.close()

	for {
		select {
		case <-wsc.ctx.Done():
			return
		default:
			messageType, message, err := wsc.Conn.ReadMessage()
			if err != nil {
				wsc.Logger.Error("Failed to read message", zap.Error(err))
				return
			}

			// 只处理文本消息，忽略其他类型
			if messageType != websocket.TextMessage {
				wsc.Logger.Warn("Received non-text message, ignoring",
					zap.Int("message_type", messageType))
				continue
			}

			// 处理消息
			wsc.handleMessage(message, eventBus)
		}
	}
}

// handleMessage 处理消息
func (wsc *WebSocketConnection) handleMessage(data []byte, eventBus *engine.EventBus) {
	wsc.Logger.Debug("Received message", zap.ByteString("data", data))

	// 解析JSON消息为BaseEvent
	var event protocol.BaseEvent
	if err := sonic.Unmarshal(data, &event); err != nil {
		wsc.Logger.Error("Failed to parse message", zap.Error(err), zap.ByteString("data", data))
		return
	}

	// 验证必需字段
	if event.Type == "" {
		wsc.Logger.Warn("Event type is empty", zap.ByteString("data", data))
		return
	}

	// 如果没有时间戳，使用当前时间
	if event.Timestamp == 0 {
		event.Timestamp = time.Now().Unix()
	}

	// 如果没有SelfID，使用连接的BotID
	if event.SelfID == "" {
		event.SelfID = wsc.BotID
	}

	// 确保Data字段不为nil
	if event.Data == nil {
		event.Data = make(map[string]interface{})
	}

	wsc.Logger.Info("Event received",
		zap.String("type", string(event.Type)),
		zap.String("detail_type", event.DetailType),
		zap.String("self_id", event.SelfID))

	// 发布到事件总线
	eventBus.Publish(&event)
}

// SendMessage 发送消息
func (wsc *WebSocketConnection) SendMessage(data []byte) error {
	wsc.Logger.Debug("Sending message", zap.ByteString("data", data))

	err := wsc.Conn.WriteMessage(websocket.TextMessage, data)
	if err != nil {
		return fmt.Errorf("failed to send message: %w", err)
	}
	return nil
}

// heartbeatLoop 心跳循环
func (wsc *WebSocketConnection) heartbeatLoop() {
	ticker := time.NewTicker(wsc.heartbeatTick)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			// 发送ping消息
			if err := wsc.Conn.WriteControl(websocket.PingMessage, []byte{}, time.Now().Add(10*time.Second)); err != nil {
				wsc.Logger.Warn("Failed to send ping", zap.Error(err))
				return
			}
			wsc.Logger.Debug("Heartbeat ping sent")

		case <-wsc.ctx.Done():
			return
		}
	}
}

// reconnectLoop 重连循环（仅用于正向连接）
func (wsc *WebSocketConnection) reconnectLoop(wsm *WebSocketManager) {
	<-wsc.ctx.Done() // 等待连接断开

	if wsc.Type != ConnectionTypeForward || wsc.reconnectURL == "" {
		return
	}

	wsc.Logger.Info("Connection closed, attempting to reconnect",
		zap.Int("max_reconnect", wsc.maxReconnect))

	for wsc.reconnectCount < wsc.maxReconnect {
		wsc.reconnectCount++
		backoff := time.Duration(wsc.reconnectCount) * 5 * time.Second

		wsc.Logger.Info("Reconnecting",
			zap.Int("attempt", wsc.reconnectCount),
			zap.Int("max", wsc.maxReconnect),
			zap.Duration("backoff", backoff))

		time.Sleep(backoff)

		// 尝试重新连接
		conn, _, err := websocket.DefaultDialer.Dial(wsc.reconnectURL, nil)
		if err != nil {
			wsc.Logger.Error("Reconnect failed", zap.Error(err))
			continue
		}

		// 更新连接
		wsc.Conn = conn
		wsc.RemoteAddr = conn.RemoteAddr().String()
		wsc.ctx, wsc.cancel = context.WithCancel(context.Background())
		wsc.reconnectCount = 0 // 重置重连计数

		wsc.Logger.Info("Reconnected successfully",
			zap.String("remote_addr", wsc.RemoteAddr))

		// 重新启动读取循环和心跳
		go wsc.readLoop(wsm.eventBus)
		go wsc.heartbeatLoop()
		go wsc.reconnectLoop(wsm)

		return
	}

	wsc.Logger.Error("Max reconnect attempts reached, giving up",
		zap.Int("attempts", wsc.reconnectCount))

	// 从管理器中移除连接
	wsm.RemoveConnection(wsc.ID)
}

// close 关闭连接
func (wsc *WebSocketConnection) close() {
	wsc.cancel()
	if err := wsc.Conn.Close(); err != nil {
		wsc.Logger.Error("Failed to close connection", zap.Error(err))
	}
}

// RemoveConnection 移除连接
func (wsm *WebSocketManager) RemoveConnection(connID string) {
	wsm.mu.Lock()
	defer wsm.mu.Unlock()

	if conn, ok := wsm.connections[connID]; ok {
		conn.close()
		delete(wsm.connections, connID)
		wsm.logger.Info("WebSocket connection removed", zap.String("conn_id", connID))
	}
}

// GetConnection 获取连接
func (wsm *WebSocketManager) GetConnection(connID string) (*WebSocketConnection, bool) {
	wsm.mu.RLock()
	defer wsm.mu.RUnlock()
	conn, ok := wsm.connections[connID]
	return conn, ok
}

// GetConnectionByBotID 根据BotID获取连接
func (wsm *WebSocketManager) GetConnectionByBotID(botID string) []*WebSocketConnection {
	wsm.mu.RLock()
	defer wsm.mu.RUnlock()

	connections := make([]*WebSocketConnection, 0)
	for _, conn := range wsm.connections {
		if conn.BotID == botID {
			connections = append(connections, conn)
		}
	}
	return connections
}

// BroadcastToBot 向指定Bot的所有连接广播消息
func (wsm *WebSocketManager) BroadcastToBot(botID string, data []byte) {
	connections := wsm.GetConnectionByBotID(botID)
	for _, conn := range connections {
		if err := conn.SendMessage(data); err != nil {
			wsm.logger.Error("Failed to send message to connection",
				zap.String("conn_id", conn.ID),
				zap.Error(err))
		}
	}
}

// DialConfig WebSocket客户端连接配置
type DialConfig struct {
	URL           string
	BotID         string
	MaxReconnect  int
	HeartbeatTick time.Duration
}

// Dial 建立WebSocket客户端连接（正向连接）
func (wsm *WebSocketManager) Dial(addr string, botID string) (*WebSocketConnection, error) {
	return wsm.DialWithConfig(DialConfig{
		URL:           addr,
		BotID:         botID,
		MaxReconnect:  5,
		HeartbeatTick: 30 * time.Second,
	})
}

// DialWithConfig 使用配置建立WebSocket客户端连接
func (wsm *WebSocketManager) DialWithConfig(config DialConfig) (*WebSocketConnection, error) {
	u, err := url.Parse(config.URL)
	if err != nil {
		return nil, fmt.Errorf("invalid URL: %w", err)
	}

	// 验证URL scheme必须是ws或wss
	if u.Scheme != "ws" && u.Scheme != "wss" {
		return nil, fmt.Errorf("invalid URL scheme: %s, expected ws or wss", u.Scheme)
	}

	conn, _, err := websocket.DefaultDialer.Dial(config.URL, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to dial: %w", err)
	}

	wsConn := NewWebSocketConnection(conn, config.BotID, ConnectionTypeForward, wsm.logger)
	wsConn.reconnectURL = config.URL
	wsConn.maxReconnect = config.MaxReconnect
	wsConn.heartbeatTick = config.HeartbeatTick

	wsm.mu.Lock()
	wsm.connections[wsConn.ID] = wsConn
	wsm.mu.Unlock()

	wsm.logger.Info("WebSocket forward connection established",
		zap.String("conn_id", wsConn.ID),
		zap.String("bot_id", config.BotID),
		zap.String("addr", config.URL),
		zap.String("remote_addr", wsConn.RemoteAddr))

	// 启动读取循环和心跳
	go wsConn.readLoop(wsm.eventBus)
	go wsConn.heartbeatLoop()

	// 如果是正向连接，启动重连监控
	if wsConn.Type == ConnectionTypeForward {
		go wsConn.reconnectLoop(wsm)
	}

	return wsConn, nil
}

// generateConnID 生成连接ID
func generateConnID() string {
	return fmt.Sprintf("conn-%d", time.Now().UnixNano())
}