// WebSocket实时通信工具
// 专为小程序设计的WebSocket封装，模拟Socket.IO功能

// 导入配置
const API = require('./api.js');

// WebSocket连接实例
let socket = null;
let isConnecting = false;
let reconnectAttempts = 0;
const maxReconnectAttempts = 5;
const reconnectDelay = 3000; // 重连延迟时间（毫秒）

// 事件监听器存储
const eventListeners = {};

// 存储当前连接的用户信息
let currentUserPhone = null;
let currentChatId = null;

// 获取WebSocket服务器URL
function getSocketUrl() {
  // 从API的BASE_URL获取服务器地址
  // 注意：小程序中无法直接获取API的BASE_URL，需要根据环境设置
  const baseUrl = API.isTestMode() ? API.SERVER_CONFIG.DEFAULT_LOCAL_IP : API.SERVER_CONFIG.PRODUCTION;
  // 替换http为ws，https为wss
  return baseUrl.replace(/^http/, 'ws');
}

// 初始化WebSocket连接
function initSocket(userPhone, chatId) {
  return new Promise((resolve, reject) => {
    // 存储当前用户信息
    currentUserPhone = userPhone;
    currentChatId = chatId;

    // 如果已经连接，直接返回
    if (socket && socket.connected) {
      console.log('WebSocket已经连接');
      resolve(socket);
      return;
    }

    // 如果正在连接中，等待连接完成
    if (isConnecting) {
      console.log('WebSocket正在连接中...');
      // 等待连接完成
      const checkConnection = setInterval(() => {
        if (socket && socket.connected) {
          clearInterval(checkConnection);
          resolve(socket);
        } else if (!isConnecting) {
          clearInterval(checkConnection);
          reject(new Error('WebSocket连接失败'));
        }
      }, 100);
      return;
    }

    isConnecting = true;
    reconnectAttempts = 0;

    try {
      const socketUrl = getSocketUrl();
      const fullUrl = `${socketUrl}?user_phone=${userPhone}&chat_id=${chatId}`;
      console.log('正在连接WebSocket服务器:', fullUrl);

      // 创建WebSocket连接
      socket = wx.connectSocket({
        url: fullUrl,
        header: {
          'content-type': 'application/json'
        },
        protocols: ['chat'],
        success: () => {
          console.log('WebSocket连接创建请求发送成功');
        },
        fail: (error) => {
          console.error('WebSocket连接创建失败:', error);
          isConnecting = false;
          reject(error);
        }
      });

      // 连接成功事件
      socket.onOpen(() => {
        console.log('WebSocket连接成功');
        socket.connected = true;
        isConnecting = false;
        reconnectAttempts = 0;
        resolve(socket);
      });

      // 连接错误事件
      socket.onError((error) => {
        console.error('WebSocket连接错误:', error);
        socket.connected = false;
        isConnecting = false;
        reject(error);
      });

      // 断开连接事件
      socket.onClose((res) => {
        console.log('WebSocket断开连接:', res);
        socket.connected = false;
        isConnecting = false;
        // 如果不是手动断开（code !== 1000），尝试重连
        if (res.code !== 1000) {
          reconnect();
        }
      });

      // 接收消息事件
      socket.onMessage((res) => {
        console.log('收到WebSocket消息:', res);
        try {
          const message = JSON.parse(res.data);
          // 触发对应类型的事件
          if (message.type) {
            emitEvent(message.type, message.data);
          } else {
            // 兼容旧格式消息
            emitEvent('message', message);
          }
        } catch (error) {
          console.error('消息解析失败:', error);
        }
      });

    } catch (error) {
      console.error('初始化WebSocket失败:', error);
      isConnecting = false;
      reject(error);
    }
  });
}

// 重连函数
function reconnect() {
  if (reconnectAttempts >= maxReconnectAttempts) {
    console.error('WebSocket重连次数超过限制，停止重连');
    return;
  }

  reconnectAttempts++;
  console.log(`WebSocket正在重连，尝试次数: ${reconnectAttempts}/${maxReconnectAttempts}`);

  // 延迟重连
  setTimeout(() => {
    if (currentUserPhone && currentChatId) {
      initSocket(currentUserPhone, currentChatId)
        .then(() => {
          console.log('WebSocket重连成功');
        })
        .catch((error) => {
          console.error('WebSocket重连失败:', error);
        });
    }
  }, reconnectDelay);
}

// 发送消息
function sendMessage(messageData) {
  return new Promise((resolve, reject) => {
    if (!socket || !socket.connected) {
      reject(new Error('WebSocket未连接'));
      return;
    }

    try {
      // 构造消息格式，模拟Socket.IO的事件机制
      const message = {
        type: 'chat message',
        data: messageData
      };

      socket.send({
        data: JSON.stringify(message),
        success: () => {
          console.log('WebSocket消息发送成功');
          resolve({ success: true });
        },
        fail: (error) => {
          console.error('WebSocket消息发送失败:', error);
          reject(error);
        }
      });
    } catch (error) {
      console.error('发送WebSocket消息失败:', error);
      reject(error);
    }
  });
}

// 断开连接
function disconnect() {
  if (socket) {
    console.log('手动断开WebSocket连接');
    socket.close(1000, 'normal closure');
    socket = null;
  }
  isConnecting = false;
  reconnectAttempts = 0;
}

// 注册事件监听器
function on(eventName, callback) {
  if (!eventListeners[eventName]) {
    eventListeners[eventName] = [];
  }
  eventListeners[eventName].push(callback);
}

// 移除事件监听器
function off(eventName, callback) {
  if (eventListeners[eventName]) {
    if (callback) {
      eventListeners[eventName] = eventListeners[eventName].filter(cb => cb !== callback);
    } else {
      delete eventListeners[eventName];
    }
  }
}

// 触发事件
function emitEvent(eventName, data) {
  if (eventListeners[eventName]) {
    eventListeners[eventName].forEach(callback => {
      try {
        callback(data);
      } catch (error) {
        console.error('事件监听器执行错误:', error);
      }
    });
  }
}

// 导出WebSocket工具
module.exports = {
  initSocket,
  sendMessage,
  disconnect,
  on,
  off,
  isConnected: () => socket && socket.connected
};