import React, { useCallback, useMemo, useRef, useState } from 'react';
import { useImmer } from 'use-immer';
import {
  App,
  Modal,
  Form,
  Select,
  DatePicker,
  InputNumber,
  Input,
  Space,
} from 'antd';
import { PlusOutlined } from '@ant-design/icons';
import dayjs, { Dayjs } from 'dayjs';
import api from '../../api';
import { downloadBlob } from '../../utils/download';
import PermissionButton from '../../components/PermissionButton';
import { message } from '../../ui/app-message';
import { usePermission } from '../../hooks/usePermission';
import { useQuery } from '@tanstack/react-query';
import { useApiMutation } from '../../hooks/useApiMutation';
import { getErrorMessage } from '../../utils/error';
import { validateResponse } from '../../utils/validate';
import { classroomsSchema, organizationsSchema, rentalsSchema } from '../../api/schemas';
import { RentalTable } from './RentalTable';

interface UnavailableDatesResponse {
  dates: string[];
}

export const unavailableDatesCacheKey = (classroomId: number, date: Dayjs) =>
  `${classroomId}:${date.format('YYYY-MM')}`;

const ClassroomRentalsPage: React.FC = () => {
  const { modal } = App.useApp();
  const { hasPermission, hasAnyPermission } = usePermission();
  const canPurgeRental = hasPermission('rental:purge');
  const [modalOpen, setModalOpen] = useState(false);
  const [editing, setEditing] = useState<any>(null);
  const [form] = Form.useForm();
  const [filterMonth, setFilterMonth] = useState<Dayjs | null>(null);
  const [filterStatus, setFilterStatus] = useState<string | undefined>();
  const [searchText, setSearchText] = useState('');
  const [saving, setSaving] = useState(false);
  const [unavailableDates, setUnavailableDates] = useImmer<Set<string>>(new Set());
  const loadedUnavailableMonths = useRef<Set<string>>(new Set());
  const unavailableRequestVersion = useRef(0);
  const [unavailableDatesLoading, setUnavailableDatesLoading] = useState(false);
  const selectedClassroomId = Form.useWatch('classroomId', form);

  const {
    data = [],
    isLoading,
    isFetching,
  } = useQuery<any[]>({
    queryKey: ['classroom-rentals', filterMonth],
    queryFn: async () => {
      try {
        const params: any = {};
        if (filterMonth) params.month = filterMonth.format('YYYY-MM');
        params.includeEnded = true;
        return validateResponse<any[]>(
          rentalsSchema,
          await api.get('/classroom-rentals', { params }),
        );
      } catch (e: any) {
        message.error(e?.message || '加载失败，请稍后重试');
        return [];
      }
    },
  });
  const {
    data: meta = { classrooms: [], organizations: [] },
  } = useQuery<{ classrooms: any[]; organizations: any[] }>({
    queryKey: ['classroom-rentals', 'meta'],
    enabled: hasAnyPermission('rental:create', 'rental:edit'),
    queryFn: async () => {
      try {
        const [cr, tn]: any = await Promise.all([
          api.get('/classrooms'),
          api.get('/organizations', { params: { scope: 'all' } }),
        ]);
        return {
          classrooms: validateResponse<any[]>(classroomsSchema, cr),
          organizations: validateResponse<any[]>(organizationsSchema, tn),
        };
      } catch (e: any) {
        message.error(e?.message || '加载教室列表失败');
        return { classrooms: [], organizations: [] };
      }
    },
  });
  const classrooms = meta.classrooms;
  const organizations = meta.organizations;
  const loading = isLoading || isFetching;

  const saveMutation = useApiMutation(
    async (payload: Record<string, unknown>) =>
      editing
        ? api.put(`/classroom-rentals/${editing.id}`, payload)
        : api.post('/classroom-rentals', payload),
    {
      invalidate: [['classroom-rentals']],
      onError: (error: unknown) => {
        const e = error as {
          conflicts?: Array<{ organizationName?: string; startDate?: string; endDate?: string }>;
        };
        if (e?.conflicts?.length) {
          const list = e.conflicts
            .map((c) => `${c.organizationName}(${c.startDate}~${c.endDate})`)
            .join('、');
          message.error(`时间段冲突：${list}`);
        } else {
          message.error(getErrorMessage(error, '操作失败'));
        }
      },
    },
  );
  const saveCellMutation = useApiMutation(
    async ({ record, field, value }: { record: any; field: string; value: unknown }) =>
      api.put(`/classroom-rentals/${record.id}`, { [field]: value }),
    { invalidate: [['classroom-rentals']] },
  );
  const deleteMutation = useApiMutation(
    async (id: number) => api.delete(`/classroom-rentals/${id}`),
    { invalidate: [['classroom-rentals']] },
  );
  const purgeMutation = useApiMutation(
    async (id: number) => api.delete(`/classroom-rentals/${id}/permanent`),
    { invalidate: [['classroom-rentals']] },
  );
  const actionMutation = useApiMutation(
    async ({ id, action }: { id: number; action: 'cancel' | 'end' }) =>
      api.put(`/classroom-rentals/${id}/${action}`),
    { invalidate: [['classroom-rentals']] },
  );
  const deleteContractMutation = useApiMutation(
    async (id: number) => api.delete(`/classroom-rentals/${id}/contract`),
    { invalidate: [['classroom-rentals']] },
  );
  const uploadContractMutation = useApiMutation(
    async ({ id, formData }: { id: number; formData: FormData }) =>
      api.post(`/classroom-rentals/${id}/contract`, formData),
    { invalidate: [['classroom-rentals']] },
  );

  const filteredData = useMemo(() => {
    return data.filter((r: any) => {
      if (filterStatus && r.effectiveStatus !== filterStatus) return false;
      if (!searchText) return true;
      const s = searchText.toLowerCase();
      const matchClassroom = r.classroom?.name?.toLowerCase().includes(s);
      const matchOrganization = r.lesseeOrganization?.name?.toLowerCase().includes(s);
      return matchClassroom || matchOrganization;
    });
  }, [data, searchText, filterStatus]);

  const resetUnavailableDates = () => {
    unavailableRequestVersion.current += 1;
    loadedUnavailableMonths.current.clear();
    setUnavailableDates(new Set());
  };

  const loadUnavailableDates = useCallback(
    async (classroomId: number, date: Dayjs, excludeId?: number) => {
      const key = unavailableDatesCacheKey(classroomId, date);
      if (loadedUnavailableMonths.current.has(key)) return;
      loadedUnavailableMonths.current.add(key);
      const requestVersion = unavailableRequestVersion.current;

      setUnavailableDatesLoading(true);
      try {
        const response = await api.get<UnavailableDatesResponse>(
          '/classroom-rentals/unavailable-dates',
          {
            params: {
              classroomId,
              year: date.year(),
              month: date.month() + 1,
              excludeId,
            },
          },
        );
        if (requestVersion !== unavailableRequestVersion.current) return;
        setUnavailableDates((draft) => {
          response.dates.forEach((item) => draft.add(item));
        });
      } catch (e: any) {
        loadedUnavailableMonths.current.delete(key);
        if (requestVersion === unavailableRequestVersion.current) {
          message.error(e?.message || '加载教室占用日期失败');
        }
      } finally {
        if (requestVersion === unavailableRequestVersion.current) {
          setUnavailableDatesLoading(false);
        }
      }
    },
    [setUnavailableDates],
  );

  const handleClassroomChange = (classroomId: number) => {
    form.setFieldValue('dateRange', undefined);
    resetUnavailableDates();
    void loadUnavailableDates(classroomId, dayjs(), editing?.id);
    void loadUnavailableDates(classroomId, dayjs().add(1, 'month'), editing?.id);
  };

  const handleCalendarChange = (date: Dayjs) => {
    const classroomId = form.getFieldValue('classroomId');
    if (classroomId) void loadUnavailableDates(classroomId, date, editing?.id);
  };

  const isDateUnavailable = (date: Dayjs) => unavailableDates.has(date.format('YYYY-MM-DD'));

  const rangeIncludesUnavailableDate = (range?: [Dayjs, Dayjs]) => {
    if (!range) return false;
    for (
      let date = range[0].startOf('day');
      !date.isAfter(range[1], 'day');
      date = date.add(1, 'day')
    ) {
      if (isDateUnavailable(date)) return true;
    }
    return false;
  };

  const handleSave = async () => {
    const values = await form.validateFields();
    if (rangeIncludesUnavailableDate(values.dateRange)) {
      message.error('所选日期范围包含已排课或已租赁日期，请重新选择');
      return;
    }
    setSaving(true);
    const payload = {
      classroomId: values.classroomId,
      lessorOrganizationId: values.lessorOrganizationId,
      lesseeOrganizationId: values.lesseeOrganizationId,
      startDate: values.dateRange[0].format('YYYY-MM-DD'),
      endDate: values.dateRange[1].format('YYYY-MM-DD'),
      dailyRate: values.dailyRate,
      totalAmount: values.totalAmount,
      notes: values.notes,
    };
    try {
      await saveMutation.mutateAsync(payload);
      message.success(editing ? '更新成功' : '创建成功');
      setModalOpen(false);
      form.resetFields();
      setEditing(null);
    } catch {
      // 错误提示由 useApiMutation 统一处理
    } finally {
      setSaving(false);
    }
  };

  const saveCell = async (record: any, field: string, value: unknown) => {
    try {
      await saveCellMutation.mutateAsync({ record, field, value });
      message.success('已保存');
    } catch {
      // 错误提示由 useApiMutation 统一处理
    }
  };

  const handleDelete = async (id: number) => {
    try {
      await deleteMutation.mutateAsync(id);
      message.success('已归档');
    } catch {
      // 错误提示由 useApiMutation 统一处理
    }
  };

  const handlePurge = (id: number, name: string) => {
    modal.confirm({
      title: `永久删除租赁订单（${name}）？`,
      content: '删除后不可恢复，排课与合同文件将被清除（存在考勤记录时将无法删除）。确定继续？',
      okText: '永久删除',
      okButtonProps: { danger: true },
      cancelText: '取消',
      onOk: async () => {
        try {
          await purgeMutation.mutateAsync(id);
          message.success('已永久删除（不可恢复）');
        } catch {
          // 错误提示由 useApiMutation 统一处理
        }
      },
    });
  };

  const handleRentalAction = async (id: number, action: 'cancel' | 'end') => {
    try {
      await actionMutation.mutateAsync({ id, action });
      message.success(action === 'cancel' ? '租赁已取消' : '租赁已结束');
    } catch {
      // 错误提示由 useApiMutation 统一处理
    }
  };

  const handleDownloadContract = async (id: number, filename?: string) => {
    try {
      await downloadBlob(`/classroom-rentals/${id}/contract`, filename || `contract-${id}.pdf`);
    } catch (e) {
      console.error('下载合同失败', e);
      message.error('下载失败（可能文件已丢失）');
    }
  };

  const handleDeleteContract = async (id: number) => {
    try {
      await deleteContractMutation.mutateAsync(id);
      message.success('合同已移除');
    } catch {
      // 错误提示由 useApiMutation 统一处理
    }
  };

  const handleUploadContract = async (id: number, formData: FormData) => {
    return uploadContractMutation.mutateAsync({ id, formData });
  };

  const openEdit = (record: any) => {
    setEditing(record);
    resetUnavailableDates();
    form.setFieldsValue({
      classroomId: record.classroomId,
      lessorOrganizationId: record.lessorOrganizationId,
      lesseeOrganizationId: record.lesseeOrganizationId,
      dateRange: [dayjs(record.startDate), dayjs(record.endDate)],
      dailyRate: record.dailyRate ? Number(record.dailyRate) : undefined,
      totalAmount: record.totalAmount ? Number(record.totalAmount) : undefined,
      notes: record.notes,
    });
    setModalOpen(true);
    void loadUnavailableDates(record.classroomId, dayjs(record.startDate), record.id);
    void loadUnavailableDates(
      record.classroomId,
      dayjs(record.startDate).add(1, 'month'),
      record.id,
    );
  };

  return (
    <div>
      <div
        style={{
          marginBottom: 16,
          display: 'flex',
          justifyContent: 'space-between',
          flexWrap: 'wrap',
          gap: 8,
        }}
      >
        <Space wrap>
          <Input.Search
            placeholder="搜索教室/承租机构"
            allowClear
            style={{ width: 180 }}
            onSearch={(v) => setSearchText(v)}
            onChange={(e) => {
              if (!e.target.value) setSearchText('');
            }}
          />
          <DatePicker
            picker="month"
            placeholder="按月筛选"
            value={filterMonth}
            onChange={setFilterMonth}
            allowClear
            format="YYYY-MM"
          />
          <Select
            placeholder="状态"
            allowClear
            style={{ width: 110 }}
            value={filterStatus}
            onChange={setFilterStatus}
            options={[
              { value: 'active', label: '进行中' },
              { value: 'ended', label: '已结束' },
              { value: 'cancelled', label: '已取消' },
            ]}
          />
        </Space>
        <PermissionButton
          permission="rental:create"
          type="primary"
          icon={<PlusOutlined />}
          onClick={() => {
            setEditing(null);
            form.resetFields();
            resetUnavailableDates();
            setModalOpen(true);
          }}
        >
          新增租赁
        </PermissionButton>
      </div>
      <RentalTable
        data={filteredData}
        loading={loading}
        classrooms={classrooms}
        organizations={organizations}
        canPurgeRental={canPurgeRental}
        hasPermission={hasPermission}
        onSaveCell={saveCell}
        onEdit={openEdit}
        onAction={handleRentalAction}
        onArchive={handleDelete}
        onPurge={handlePurge}
        onDownloadContract={handleDownloadContract}
        onDeleteContract={handleDeleteContract}
        onUploadContract={handleUploadContract}
      />
      <Modal
        title={editing ? '编辑租赁' : '新增租赁'}
        open={modalOpen}
        onOk={handleSave}
        onCancel={() => {
          setModalOpen(false);
          setEditing(null);
          resetUnavailableDates();
        }}
        confirmLoading={saving}
        okText="保存"
        width={600}
      >
        <Form form={form} layout="vertical">
          <Form.Item name="classroomId" label="教室" rules={[{ required: true }]}>
            <Select
              showSearch
              optionFilterProp="label"
              placeholder="选择教室"
              onChange={handleClassroomChange}
              options={classrooms
                .filter((c) => c.status === 'available')
                .map((c) => ({
                  value: c.id,
                  label: `${c.building ? c.building + ' · ' : ''}${c.name}（${c.roomType}）`,
                }))}
            />
          </Form.Item>
          <Form.Item name="lessorOrganizationId" label="出租机构" tooltip="默认由本机构出租">
            <Select
              showSearch
              optionFilterProp="label"
              placeholder="默认本机构"
              allowClear
              options={organizations
                .filter((organization) => organization.isHost)
                .map((organization) => ({
                  value: organization.id,
                  label: `${organization.name}（本机构）`,
                }))}
            />
          </Form.Item>
          <Form.Item
            name="lesseeOrganizationId"
            label="承租机构"
            rules={[{ required: true, message: '请选择承租机构' }]}
          >
            <Select
              showSearch
              optionFilterProp="label"
              placeholder="选择外部承租机构"
              options={organizations
                .filter((organization) => !organization.isHost && organization.status === 'active')
                .map((organization) => ({
                  value: organization.id,
                  label: organization.name,
                }))}
            />
          </Form.Item>
          <Form.Item name="dateRange" label="租赁起止日期" rules={[{ required: true }]}>
            <DatePicker.RangePicker
              style={{ width: '100%' }}
              placeholder={['开始日期', '结束日期']}
              format="YYYY-MM-DD"
              disabled={!selectedClassroomId}
              disabledDate={(date) => unavailableDatesLoading || isDateUnavailable(date)}
              onPanelChange={(dates) => dates.forEach((date) => date && handleCalendarChange(date))}
            />
          </Form.Item>
          <Form.Item name="dailyRate" label="日租金（可选）">
            <InputNumber min={0.01} precision={2} style={{ width: '100%' }} prefix="¥" />
          </Form.Item>
          <Form.Item name="totalAmount" label="合同总额（可选）">
            <InputNumber min={0.01} precision={2} style={{ width: '100%' }} prefix="¥" />
          </Form.Item>
          <Form.Item name="notes" label="备注">
            <Input.TextArea rows={2} />
          </Form.Item>
        </Form>
      </Modal>
    </div>
  );
};

export default ClassroomRentalsPage;
