import { useState, useRef } from 'react';
import { View, Text } from '@tarojs/components';
import Taro, { useDidShow, useReachBottom } from '@tarojs/taro';
import { listConsultations, ConsultationSession } from '../../services/consultation';
import { notificationService } from '../../services/notification';
import Loading from '../../components/Loading';
import GuestGuard from '../../components/GuestGuard';
import { useAuthStore } from '../../stores/auth';
import './index.scss';

type MsgTab = 'consultation' | 'notification';

interface NotificationItem {
  id: string;
  title: string;
  desc: string;
  time: string;
  type: string;
  read?: boolean;
}

const NOTIFY_ICONS: Record<string, { icon: string; bg: string; color: string }> = {
  appointment: { icon: '约', bg: '#F0DDD4', color: '#C4623A' },
  alert: { icon: '警', bg: '#FFF3E0', color: '#C4873A' },
  followup: { icon: '随', bg: '#E8F0E8', color: '#5B7A5E' },
  points: { icon: '分', bg: '#F0DDD4', color: '#C4623A' },
  report: { icon: '报', bg: '#E8F0E8', color: '#5B7A5E' },
};

export default function Messages() {
  const user = useAuthStore((s) => s.user);
  const [activeTab, setActiveTab] = useState<MsgTab>('consultation');
  const [sessions, setSessions] = useState<ConsultationSession[]>([]);
  const [notifications, setNotifications] = useState<NotificationItem[]>([]);
  const [loading, setLoading] = useState(false);
  const [page, setPage] = useState(1);
  const [total, setTotal] = useState(0);
  const loadingRef = useRef(false);

  const loadData = async (tab: MsgTab, pageNum: number = 1, isRefresh = false) => {
    if (loadingRef.current) return;
    loadingRef.current = true;
    setLoading(true);
    try {
      if (tab === 'consultation') {
        const res = await listConsultations({ page: pageNum, page_size: 20 });
        const list = res.data || [];
        if (isRefresh) {
          setSessions(list);
        } else {
          setSessions((prev) => [...prev, ...list]);
        }
        setTotal(res.total || 0);
      } else {
        const res = await notificationService.list<{ data: unknown[]; total?: number }>({ page: pageNum, page_size: 20 });
        const list = (res as { data?: unknown[] })?.data || [];
        if (isRefresh) {
          setNotifications(list as NotificationItem[]);
        } else {
          setNotifications((prev) => [...prev, ...(list as NotificationItem[])]);
        }
        setTotal((res as { total?: number })?.total || 0);
      }
      setPage(pageNum);
    } catch {
      if (isRefresh) {
        if (tab === 'consultation') setSessions([]);
        else setNotifications([]);
      }
    } finally {
      setLoading(false);
      loadingRef.current = false;
    }
  };

  useDidShow(() => {
    if (user) loadData(activeTab, 1, true);
  });

  const handleTabChange = (tab: MsgTab) => {
    setActiveTab(tab);
    loadData(tab, 1, true);
  };

  useReachBottom(() => {
    const currentList = activeTab === 'consultation' ? sessions : notifications;
    if (!loading && currentList.length < total) {
      loadData(activeTab, page + 1);
    }
  });

  const formatTime = (dateStr: string | null) => {
    if (!dateStr) return '';
    const d = new Date(dateStr);
    const now = new Date();
    const diffMs = now.getTime() - d.getTime();
    const diffMin = Math.floor(diffMs / 60000);
    if (diffMin < 60) return `${diffMin} 分钟前`;
    const diffHour = Math.floor(diffMin / 60);
    if (diffHour < 24) return `${diffHour} 小时前`;
    return dateStr.slice(0, 10);
  };

  if (!user) {
    return <GuestGuard title='请先登录' desc='登录后即可查看消息和通知' />;
  }

  const unreadConsultCount = sessions.filter((s) => s.unread_count_patient > 0).length;

  return (
    <View className='messages-page'>
      {/* 页头 */}
      <View className='messages-header'>
        <Text className='messages-title'>消息</Text>
      </View>

      {/* 分段控件 Tab */}
      <View className='msg-segment'>
        <View
          className={`msg-segment-tab ${activeTab === 'consultation' ? 'msg-segment-active' : ''}`}
          onClick={() => handleTabChange('consultation')}
        >
          <Text className='msg-segment-text'>咨询</Text>
          {unreadConsultCount > 0 && (
            <View className='msg-segment-badge'>
              <Text className='msg-segment-badge-text'>{unreadConsultCount}</Text>
            </View>
          )}
        </View>
        <View
          className={`msg-segment-tab ${activeTab === 'notification' ? 'msg-segment-active' : ''}`}
          onClick={() => handleTabChange('notification')}
        >
          <Text className='msg-segment-text'>通知</Text>
        </View>
      </View>

      <View className='msg-content'>
        {/* 咨询列表 */}
        {activeTab === 'consultation' && (
          loading ? (
            <Loading />
          ) : sessions.length === 0 ? (
            <View className='msg-empty'>
              <Text className='msg-empty-text'>暂无咨询消息</Text>
            </View>
          ) : (
            <View className='msg-list'>
              {sessions.map((session) => {
                const doctorName = session.last_message?.slice(0, 1) || '医';
                const hasUnread = session.unread_count_patient > 0;
                return (
                  <View
                    key={session.id}
                    className={`consult-card ${hasUnread ? '' : 'consult-card-muted'}`}
                    onClick={() => Taro.navigateTo({ url: `/pages/consultation/detail/index?id=${session.id}` })}
                  >
                    <View className={`consult-avatar ${hasUnread ? 'consult-avatar-active' : ''}`}>
                      <Text className='consult-avatar-char'>{doctorName}</Text>
                    </View>
                    <View className='consult-body'>
                      <View className='consult-row'>
                        <Text className='consult-doctor'>
                          {session.consultation_type === 'online' ? '在线咨询' : '门诊咨询'}
                        </Text>
                        <Text className='consult-time'>{formatTime(session.last_message_at)}</Text>
                      </View>
                      <View className='consult-row'>
                        <Text className='consult-preview'>
                          {session.last_message || session.subject || '暂无消息'}
                        </Text>
                        {hasUnread && (
                          <View className='consult-badge'>
                            <Text className='consult-badge-text'>
                              {session.unread_count_patient > 99 ? '99+' : session.unread_count_patient}
                            </Text>
                          </View>
                        )}
                      </View>
                    </View>
                  </View>
                );
              })}
            </View>
          )
        )}

        {/* 通知列表 */}
        {activeTab === 'notification' && (
          loading ? (
            <Loading />
          ) : notifications.length === 0 ? (
            <View className='msg-empty'>
              <Text className='msg-empty-text'>暂无新通知</Text>
            </View>
          ) : (
            <View className='msg-list'>
              {notifications.map((n) => {
                const cfg = NOTIFY_ICONS[n.type] || NOTIFY_ICONS.report;
                const isUnread = !n.read;
                return (
                  <View key={n.id} className={`notify-card ${isUnread ? '' : 'notify-card-muted'}`}>
                    <View className='notify-icon' style={`background:${cfg.bg};`}>
                      <Text className='notify-icon-char' style={`color:${cfg.color};`}>{cfg.icon}</Text>
                    </View>
                    <View className='notify-body'>
                      <View className='notify-row'>
                        <Text className={`notify-title ${isUnread ? 'notify-title-bold' : ''}`}>{n.title}</Text>
                        <Text className='notify-time'>{n.time}</Text>
                      </View>
                      <Text className='notify-desc'>{n.desc}</Text>
                    </View>
                    {isUnread && <View className='notify-dot' />}
                  </View>
                );
              })}
            </View>
          )
        )}
      </View>
    </View>
  );
}