import React, { useCallback, useMemo, useState } from 'react';
import { useQuery } from '@tanstack/react-query';
import { Button, Card, Col, Empty, Row, Spin, Tag, Tooltip } from 'antd';
import {
  ArrowRightOutlined,
  CheckCircleFilled,
  ClockCircleOutlined,
  ReloadOutlined,
  ScheduleOutlined,
  TeamOutlined,
} from '@ant-design/icons';
import dayjs from 'dayjs';
import api from '../../api';
import { QueryErrorState } from '../../components/QueryState';
import {
  canPullAttendance,
  getSchedulePhase,
  type SchedulePhase,
} from './attendance-workspace';
import LessonAttendanceDetail from './LessonAttendanceDetail';
import type { LessonAttendanceSchedule } from './types';

type TodaySchedule = LessonAttendanceSchedule;

interface AssignedClass {
  classId: number;
  className: string;
  classCode: string;
  roleType: string;
  subject: string;
}

interface TeacherWorkspaceData {
  assignedClasses: AssignedClass[];
  todaySchedules: TodaySchedule[];
}

export const TeacherAttendanceWorkspace: React.FC<{ canCreate: boolean }> = ({ canCreate }) => {
  const [selectedSchedule, setSelectedSchedule] = useState<TodaySchedule | null>(null);

  const {
    data: workspace,
    isFetching,
    isPending,
    isError,
    refetch,
  } = useQuery<TeacherWorkspaceData | null>({
    queryKey: ['attendance', 'workspace'],
    queryFn: async () => {
      return await api.get<TeacherWorkspaceData>('/rbac/teacher-workspace');
    },
  });
  // isPending 覆盖自动重试的退避窗口，避免「加载失败/重试中」短暂闪现为空态
  const loading = isPending || isFetching;
  const loadWorkspace = useCallback(() => refetch(), [refetch]);

  const classNameById = useMemo(
    () => new Map(workspace?.assignedClasses.map((item) => [item.classId, item.className]) ?? []),
    [workspace],
  );

  const openAttendance = useCallback((schedule: TodaySchedule) => {
    setSelectedSchedule(schedule);
  }, []);

  const now = new Date();
  const schedules = workspace?.todaySchedules ?? [];
  const startedCount = schedules.filter((item) =>
    canPullAttendance(getSchedulePhase(item.startTime, item.endTime, now)),
  ).length;
  const nextSchedule = schedules.find(
    (item) => getSchedulePhase(item.startTime, item.endTime, now) !== 'ended',
  );

  return (
    <div className="attendance-page teacher-attendance">
      <section className="attendance-hero attendance-hero--teacher">
        <div>
          <h1>今天，从课程开始</h1>
          <p>
            {dayjs().format('MM月DD日 dddd')} · 课程开始后可查看最新打卡结果；课程截止时系统自动拉取并结算缺勤。
          </p>
        </div>
        <Button icon={<ReloadOutlined />} onClick={() => void loadWorkspace()}>
          刷新
        </Button>
      </section>

      <Row gutter={[16, 16]} className="teacher-overview">
        <Col xs={24} md={8}>
          <div className="teacher-kpi">
            <span>今日课程</span>
            <strong>{schedules.length}</strong>
            <small>节</small>
          </div>
        </Col>
        <Col xs={24} md={8}>
          <div className="teacher-kpi">
            <span>已开始</span>
            <strong>{startedCount}</strong>
            <small>节，可查看考勤</small>
          </div>
        </Col>
        <Col xs={24} md={8}>
          <div className="teacher-kpi teacher-kpi--next">
            <span>下一节</span>
            <strong>{nextSchedule ? nextSchedule.startTime : '—'}</strong>
            <small>{nextSchedule?.subject || '今天没有更多课程'}</small>
          </div>
        </Col>
      </Row>

      <div className="attendance-section-heading">
        <div>
          <span>今日教学节奏</span>
          <h2>我的课程</h2>
        </div>
        <span className="attendance-section-note">课程开始后可拉取钉钉考勤记录</span>
      </div>

      <Spin spinning={loading}>
        {isError ? (
          <Card className="attendance-empty-card">
            <QueryErrorState
              title="课程数据加载失败"
              description="请检查网络后点击重试；若持续失败请联系管理员。"
              onRetry={() => void loadWorkspace()}
            />
          </Card>
        ) : schedules.length === 0 ? (
          <Card className="attendance-empty-card">
            <Empty
              image={Empty.PRESENTED_IMAGE_SIMPLE}
              description={
                <div>
                  <strong>今天还没有课程</strong>
                  <p>请联系教务管理员安排课程。</p>
                </div>
              }
            />
          </Card>
        ) : (
          <div className="lesson-timeline">
            {schedules.map((schedule, index) => {
              const phase = getSchedulePhase(schedule.startTime, schedule.endTime, now);
              return (
                <LessonCard
                  key={schedule.id}
                  schedule={schedule}
                  phase={phase}
                  className={classNameById.get(schedule.classId) || `班级 ${schedule.classId}`}
                  index={index + 1}
                  onOpen={canCreate ? () => openAttendance(schedule) : undefined}
                />
              );
            })}
          </div>
        )}
      </Spin>

      {canCreate ? (
        <LessonAttendanceDetail
          key={selectedSchedule?.id ?? 'closed'}
          schedule={selectedSchedule}
          className={
            selectedSchedule
              ? classNameById.get(selectedSchedule.classId) || `班级 ${selectedSchedule.classId}`
              : ''
          }
          onClose={() => setSelectedSchedule(null)}
        />
      ) : null}
    </div>
  );
};

export const LessonCard: React.FC<{
  schedule: TodaySchedule;
  phase: SchedulePhase;
  className: string;
  index: number;
  onOpen?: () => void;
}> = ({ schedule, phase, className, index, onOpen }) => {
  const phaseMeta = {
    upcoming: { label: '待上课', icon: <ClockCircleOutlined />, tone: 'upcoming' },
    ongoing: { label: '进行中', icon: <ScheduleOutlined />, tone: 'ongoing' },
    ended: { label: '已结束', icon: <CheckCircleFilled />, tone: 'ended' },
  }[phase];

  return (
    <article className={`lesson-card lesson-card--${phaseMeta.tone}`}>
      <div className="lesson-sequence">{String(index).padStart(2, '0')}</div>
      <div className="lesson-time">
        <strong>{schedule.startTime}</strong>
        <span />
        <strong>{schedule.endTime}</strong>
      </div>
      <div className="lesson-main">
        <div className="lesson-title-row">
          <h3>{schedule.subject}</h3>
          <Tag icon={phaseMeta.icon}>{phaseMeta.label}</Tag>
        </div>
        <p>
          <TeamOutlined /> {className}
          <span>教室 {schedule.classroomId}</span>
        </p>
      </div>
      <div className="lesson-action">
        {phase === 'upcoming' ? (
          <Tooltip title="课程尚未开始">
            <Button disabled>等待上课</Button>
          </Tooltip>
        ) : onOpen ? (
          <Button type="primary" onClick={onOpen}>
            {phase === 'ongoing' ? '查看当前考勤' : '拉取 / 查看考勤'} <ArrowRightOutlined />
          </Button>
        ) : null}
      </div>
    </article>
  );
};