import React, { useState, useEffect, useRef } from 'react';
import { Send, LogOut, Users, MessageCircle } from 'lucide-react';
import { User, Message, OnlineUser } from '../types';
import { messageAPI } from '../utils/api';
import { socketService } from '../utils/socket';

interface ChatProps {
  user: User;
  onLogout: () => void;
}

const Chat: React.FC<ChatProps> = ({ user, onLogout }) => {
  const [messages, setMessages] = useState<Message[]>([]);
  const [newMessage, setNewMessage] = useState('');
  const [onlineUsers, setOnlineUsers] = useState<OnlineUser[]>([]);
  const [loading, setLoading] = useState(true);
  const messagesEndRef = useRef<HTMLDivElement>(null);

  const scrollToBottom = () => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
  };

  useEffect(() => {
    scrollToBottom();
  }, [messages]);

  useEffect(() => {
    const initializeChat = async () => {
      try {
        // 获取历史消息
        const historyMessages = await messageAPI.getMessages();
        setMessages(historyMessages);

        // 连接Socket
        const token = localStorage.getItem('token');
        if (token) {
          const socket = socketService.connect(token);

          // 监听新消息
          socketService.onNewMessage((message: Message) => {
            setMessages(prev => [...prev, message]);
          });

          // 监听用户上线
          socketService.onUserJoined((userData) => {
            console.log(`${userData.username} 加入了聊天室`);
          });

          // 监听用户下线
          socketService.onUserLeft((userData) => {
            console.log(`${userData.username} 离开了聊天室`);
          });

          // 监听在线用户列表
          socketService.onOnlineUsers((users: OnlineUser[]) => {
            setOnlineUsers(users);
          });
        }
      } catch (error) {
        console.error('初始化聊天失败:', error);
      } finally {
        setLoading(false);
      }
    };

    initializeChat();

    // 清理函数
    return () => {
      socketService.offAllListeners();
      socketService.disconnect();
    };
  }, []);

  const handleSendMessage = (e: React.FormEvent) => {
    e.preventDefault();
    if (newMessage.trim()) {
      socketService.sendMessage(newMessage.trim());
      setNewMessage('');
    }
  };

  const handleLogout = () => {
    socketService.disconnect();
    onLogout();
  };

  const formatTime = (timestamp: Date) => {
    return new Date(timestamp).toLocaleTimeString('zh-CN', {
      hour: '2-digit',
      minute: '2-digit',
    });
  };

  if (loading) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gray-50">
        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary-600"></div>
      </div>
    );
  }

  return (
    <div className="flex h-screen bg-gray-50">
      {/* 侧边栏 */}
      <div className="w-64 bg-white border-r border-gray-200 flex flex-col">
        {/* 用户信息 */}
        <div className="p-4 border-b border-gray-200">
          <div className="flex items-center space-x-3">
            <div className="w-10 h-10 bg-primary-600 rounded-full flex items-center justify-center">
              <span className="text-white font-medium">
                {user.username.charAt(0).toUpperCase()}
              </span>
            </div>
            <div className="flex-1">
              <h3 className="font-medium text-gray-900">{user.username}</h3>
              <p className="text-sm text-gray-500">{user.email}</p>
            </div>
            <button
              onClick={handleLogout}
              className="p-2 text-gray-400 hover:text-gray-600 rounded-lg hover:bg-gray-100"
              title="退出登录"
            >
              <LogOut className="h-5 w-5" />
            </button>
          </div>
        </div>

        {/* 在线用户 */}
        <div className="flex-1 p-4">
          <div className="flex items-center space-x-2 mb-4">
            <Users className="h-5 w-5 text-gray-500" />
            <h4 className="font-medium text-gray-900">
              在线用户 ({onlineUsers.length})
            </h4>
          </div>
          <div className="space-y-2">
            {onlineUsers.map((onlineUser) => (
              <div key={onlineUser.userId} className="flex items-center space-x-3">
                <div className="w-8 h-8 bg-green-500 rounded-full flex items-center justify-center">
                  <span className="text-white text-sm font-medium">
                    {onlineUser.username.charAt(0).toUpperCase()}
                  </span>
                </div>
                <span className="text-sm text-gray-700">{onlineUser.username}</span>
                {onlineUser.userId === user.id && (
                  <span className="text-xs text-gray-500">(你)</span>
                )}
              </div>
            ))}
          </div>
        </div>
      </div>

      {/* 主聊天区域 */}
      <div className="flex-1 flex flex-col">
        {/* 聊天头部 */}
        <div className="bg-white border-b border-gray-200 p-4">
          <div className="flex items-center space-x-2">
            <MessageCircle className="h-6 w-6 text-primary-600" />
            <h2 className="text-lg font-semibold text-gray-900">聊天室</h2>
          </div>
        </div>

        {/* 消息列表 */}
        <div className="flex-1 overflow-y-auto p-4 space-y-4 custom-scrollbar">
          {messages.map((message) => (
            <div
              key={message.id}
              className={`flex ${
                message.sender.id === user.id ? 'justify-end' : 'justify-start'
              }`}
            >
              <div
                className={`message-bubble ${
                  message.sender.id === user.id ? 'message-own' : 'message-other'
                }`}
              >
                {message.sender.id !== user.id && (
                  <div className="text-xs font-medium mb-1 text-gray-600">
                    {message.sender.username}
                  </div>
                )}
                <div className="text-sm">{message.content}</div>
                <div
                  className={`text-xs mt-1 ${
                    message.sender.id === user.id
                      ? 'text-primary-200'
                      : 'text-gray-500'
                  }`}
                >
                  {formatTime(message.timestamp)}
                </div>
              </div>
            </div>
          ))}
          <div ref={messagesEndRef} />
        </div>

        {/* 消息输入 */}
        <div className="bg-white border-t border-gray-200 p-4">
          <form onSubmit={handleSendMessage} className="flex space-x-4">
            <input
              type="text"
              value={newMessage}
              onChange={(e) => setNewMessage(e.target.value)}
              placeholder="输入消息..."
              className="flex-1 input-field"
            />
            <button
              type="submit"
              disabled={!newMessage.trim()}
              className="btn-primary disabled:opacity-50 disabled:cursor-not-allowed flex items-center space-x-2"
            >
              <Send className="h-4 w-4" />
              <span>发送</span>
            </button>
          </form>
        </div>
      </div>
    </div>
  );
};

export default Chat;