import { useEffect, useRef, useState } from 'react';
import { useParams } from 'react-router-dom';
import { api } from '../../services/api-client';
import { getConnection, startConnection } from '../../services/signalr';
import type { ConsultationMessage } from '../../types';

export default function ChatPage() {
  const { id } = useParams<{ id: string }>();
  const [messages, setMessages] = useState<ConsultationMessage[]>([]);
  const [status, setStatus] = useState('');
  const [text, setText] = useState('');
  const [connected, setConnected] = useState(false);
  const bottomRef = useRef<HTMLDivElement>(null);

  // 加载历史消息
  useEffect(() => {
    if (!id) return;
    api.get<{ status: string; messages: ConsultationMessage[] }>(`/api/doctor/consultations/${id}/messages`)
      .then(data => {
        setMessages(data.messages);
        setStatus(data.status);
      })
      .catch(() => {});
  }, [id]);

  // 建立 SignalR 连接
  useEffect(() => {
    if (!id) return;
    let disposed = false;

    (async () => {
      try {
        const conn = getConnection();
        await startConnection();
        if (disposed) return;

        // 加入问诊房间
        await conn.invoke('JoinConsultation', id);
        setConnected(true);

        // 注册消息接收
        const handler = (msg: ConsultationMessage & { consultationId: string }) => {
          if (msg.consultationId !== id) return;
          setMessages(prev => {
            if (prev.some(m => m.id === msg.id)) return prev; // 去重
            return [...prev, msg];
          });
        };
        conn.on('ReceiveMessage', handler);

        // 重连时重新加入房间
        conn.onreconnected(() => {
          conn.invoke('JoinConsultation', id);
        });
      } catch { /* ignore */ }
    })();

    return () => {
      disposed = true;
      const conn = getConnection();
      if (conn.state === 'Connected') {
        conn.invoke('LeaveConsultation', id).catch(() => {});
        conn.off('ReceiveMessage');
      }
    };
  }, [id]);

  // 自动滚到底部
  useEffect(() => {
    bottomRef.current?.scrollIntoView({ behavior: 'smooth' });
  }, [messages]);

  async function sendMessage() {
    if (!text.trim() || !id) return;
    const content = text.trim();
    setText('');

    // 通过 HTTP 发送（后端会通过 SignalR 广播）
    try {
      await api.post(`/api/doctor/consultations/${id}/messages`, { content });
    } catch {
      // fallback: 直接通过 SignalR 发送
      try {
        await getConnection().invoke('SendMessage', id, 'Doctor', '医生 · 王建国', content);
      } catch { /* ignore */ }
    }
  }

  return (
    <div style={{ display: 'flex', flexDirection: 'column', height: '100vh' }}>
      {/* 顶栏 */}
      <div style={{ background: '#FFF', padding: '16px 24px', borderBottom: '1px solid #EDF0F7', display: 'flex', alignItems: 'center', justifyContent: 'space-between' }}>
        <div>
          <div style={{ fontSize: 16, fontWeight: 600 }}>问诊对话</div>
          <div style={{ fontSize: 12, color: '#9BA0B4', marginTop: 2 }}>
            {status === 'AiTalking' ? 'AI 分身对话中' : status === 'WaitingDoctor' ? '等待医生回复' : status === 'DoctorReplied' ? '医生已回复' : status === 'Closed' ? '已结束' : status}
          </div>
        </div>
        <div style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
          <div style={{ width: 8, height: 8, borderRadius: 4, background: connected ? '#20C997' : '#EF4444' }} />
          <span style={{ fontSize: 12, color: '#9BA0B4' }}>{connected ? '已连接' : '未连接'}</span>
        </div>
      </div>

      {/* 消息列表 */}
      <div style={{ flex: 1, overflow: 'auto', padding: '20px 24px' }}>
        {messages.map((msg, i) => {
          const isDoctor = msg.senderType === 'Doctor';
          const isAi = msg.senderType === 'Ai';
          return (
            <div key={msg.id || i} style={{ display: 'flex', flexDirection: 'column', alignItems: isDoctor ? 'flex-end' : 'flex-start', marginBottom: 16 }}>
              {/* 发送者名称 */}
              {!isDoctor && msg.senderName && (
                <div style={{ fontSize: 11, color: '#9BA0B4', marginBottom: 4, marginLeft: 8 }}>{msg.senderName}</div>
              )}
              {/* 气泡 */}
              <div style={{
                maxWidth: '70%',
                padding: '12px 18px',
                borderRadius: isDoctor ? '18px 4px 18px 18px' : '4px 18px 18px 18px',
                background: isDoctor ? '#4F6EF7' : isAi ? '#F5F5F5' : '#FFF',
                color: isDoctor ? '#FFF' : '#1A1D28',
                border: isDoctor ? 'none' : '1px solid #EDF0F7',
                fontSize: 15,
                lineHeight: 1.6,
                whiteSpace: 'pre-wrap',
                wordBreak: 'break-word',
              }}>
                {msg.content}
              </div>
              {/* AI 标记 */}
              {isAi && (
                <div style={{ fontSize: 10, color: '#F9A825', marginTop: 4, marginLeft: 8, background: '#FFF8E1', padding: '2px 8px', borderRadius: 6 }}>
                  AI 分析，仅供参考
                </div>
              )}
              {/* 时间 */}
              <div style={{ fontSize: 11, color: '#CCC', marginTop: 4, marginLeft: 8, marginRight: 8 }}>
                {new Date(msg.createdAt).toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' })}
              </div>
            </div>
          );
        })}
        <div ref={bottomRef} />
      </div>

      {/* 输入栏 */}
      <div style={{ background: '#FFF', padding: '14px 24px', borderTop: '1px solid #EDF0F7' }}>
        <div style={{ display: 'flex', gap: 12 }}>
          <input
            value={text}
            onChange={e => setText(e.target.value)}
            onKeyDown={e => e.key === 'Enter' && sendMessage()}
            placeholder="输入回复..."
            style={{ flex: 1, padding: '12px 18px', border: '1px solid #E1E5ED', borderRadius: 12, fontSize: 15, outline: 'none' }}
          />
          <button
            onClick={sendMessage}
            disabled={!text.trim()}
            style={{ padding: '12px 24px', background: text.trim() ? '#4F6EF7' : '#E1E5ED', color: text.trim() ? '#FFF' : '#9BA0B4', border: 'none', borderRadius: 12, fontSize: 15, fontWeight: 600 }}>
            发送
          </button>
        </div>
      </div>
    </div>
  );
}