import { useState, useCallback, useEffect } from 'react';
import {
  Button, Descriptions, Form, Input, message, Modal, Popconfirm,
  Result, Select, Space, Spin, Table, Tabs, Tag,
} from 'antd';
import type { ColumnsType } from 'antd/es/table';
import dayjs from 'dayjs';
import { useParams, useNavigate } from 'react-router-dom';

import {
  shiftApi,
  type Shift,
  type PatientAssignment,
  type HandoffLog,
  type CreatePatientAssignmentReq,
  type CreateHandoffReq,
  PERIOD_LABEL,
  SHIFT_STATUS_LABEL,
  SHIFT_STATUS_COLOR,
  CARE_LEVEL_OPTIONS,
  CARE_LEVEL_LABEL,
  CARE_LEVEL_COLOR,
} from '../../api/health/shifts';
import { PageContainer } from '../../components/PageContainer';
import { usePermission } from '../../hooks/usePermission';

export default function ShiftDetail() {
  const { id } = useParams<{ id: string }>();
  const navigate = useNavigate();
  const { hasPermission } = usePermission('health.shifts.manage');

  const [shift, setShift] = useState<Shift | null>(null);
  const [loading, setLoading] = useState(true);

  // Assignments
  const [assignments, setAssignments] = useState<PatientAssignment[]>([]);
  const [assignLoading, setAssignLoading] = useState(false);
  const [assignModalOpen, setAssignModalOpen] = useState(false);
  const [editAssignment, setEditAssignment] = useState<PatientAssignment | null>(null);
  const [assignForm] = Form.useForm();

  // Handoff logs
  const [handoffs, setHandoffs] = useState<HandoffLog[]>([]);
  const [handoffLoading, setHandoffLoading] = useState(false);
  const [handoffModalOpen, setHandoffModalOpen] = useState(false);
  const [handoffForm] = Form.useForm();

  const shiftId = id!;

  const fetchShift = useCallback(async () => {
    setLoading(true);
    try {
      const data = await shiftApi.get(shiftId);
      setShift(data);
    } catch {
      message.error('加载班次详情失败');
    } finally {
      setLoading(false);
    }
  }, [shiftId]);

  const fetchAssignments = useCallback(async () => {
    setAssignLoading(true);
    try {
      const resp = await shiftApi.listAssignments(shiftId, { page: 1, page_size: 200 });
      setAssignments(resp.data);
    } catch {
      message.error('加载患者分配失败');
    } finally {
      setAssignLoading(false);
    }
  }, [shiftId]);

  const fetchHandoffs = useCallback(async () => {
    setHandoffLoading(true);
    try {
      const resp = await shiftApi.listHandoffs({ from_shift_id: shiftId });
      setHandoffs(resp.data);
    } catch {
      message.error('加载交接记录失败');
    } finally {
      setHandoffLoading(false);
    }
  }, [shiftId]);

  useEffect(() => {
    fetchShift();
    fetchAssignments();
    fetchHandoffs();
  }, [fetchShift, fetchAssignments, fetchHandoffs]);

  // --- Assignment CRUD ---

  const handleAddAssignment = () => {
    setEditAssignment(null);
    assignForm.resetFields();
    setAssignModalOpen(true);
  };

  const handleEditAssignment = (record: PatientAssignment) => {
    setEditAssignment(record);
    assignForm.setFieldsValue({
      patient_id: record.patient_id,
      care_level: record.care_level,
      notes: record.notes,
    });
    setAssignModalOpen(true);
  };

  const handleSubmitAssignment = async () => {
    try {
      const values = await assignForm.validateFields();
      if (editAssignment) {
        await shiftApi.updateAssignment(shiftId, editAssignment.id, {
          care_level: values.care_level,
          notes: values.notes,
          version: editAssignment.version,
        });
        message.success('分配已更新');
      } else {
        await shiftApi.createAssignment(shiftId, values as CreatePatientAssignmentReq);
        message.success('患者已分配');
      }
      setAssignModalOpen(false);
      fetchAssignments();
      fetchShift();
    } catch {
      // validation
    }
  };

  const handleRemoveAssignment = async (record: PatientAssignment) => {
    try {
      await shiftApi.deleteAssignment(shiftId, record.id, record.version);
      message.success('已移除分配');
      fetchAssignments();
      fetchShift();
    } catch {
      message.error('移除失败');
    }
  };

  // --- Handoff ---

  const handleCreateHandoff = () => {
    handoffForm.resetFields();
    handoffForm.setFieldsValue({ from_shift_id: shiftId });
    setHandoffModalOpen(true);
  };

  const handleSubmitHandoff = async () => {
    try {
      const values = await handoffForm.validateFields();
      await shiftApi.createHandoff(values as CreateHandoffReq);
      message.success('交接记录已创建');
      setHandoffModalOpen(false);
      fetchHandoffs();
    } catch {
      // validation
    }
  };

  // --- Columns ---

  const assignColumns: ColumnsType<PatientAssignment> = [
    { title: '患者 ID', dataIndex: 'patient_id', width: 280, ellipsis: true },
    {
      title: '护理等级',
      dataIndex: 'care_level',
      width: 120,
      render: (v: string) => <Tag color={CARE_LEVEL_COLOR[v] ?? 'default'}>{CARE_LEVEL_LABEL[v] ?? v}</Tag>,
    },
    { title: '备注', dataIndex: 'notes', width: 200, ellipsis: true, render: (v: string) => v ?? '-' },
    {
      title: '操作', width: 140, render: (_, record) => hasPermission ? (
        <Space>
          <Button size="small" onClick={() => handleEditAssignment(record)}>编辑</Button>
          <Popconfirm title="确定移除此患者？" onConfirm={() => handleRemoveAssignment(record)}>
            <Button size="small" danger>移除</Button>
          </Popconfirm>
        </Space>
      ) : null,
    },
  ];

  const handoffColumns: ColumnsType<HandoffLog> = [
    { title: '患者 ID', dataIndex: 'patient_id', width: 280, ellipsis: true },
    { title: '目标班次', dataIndex: 'to_shift_id', width: 280, ellipsis: true },
    { title: '交接备注', dataIndex: 'notes', width: 200, ellipsis: true, render: (v: string) => v ?? '-' },
    {
      title: '交接时间',
      dataIndex: 'created_at',
      width: 170,
      render: (v: string) => dayjs(v).format('YYYY-MM-DD HH:mm'),
    },
  ];

  if (loading) return <Spin size="large" style={{ display: 'block', margin: '80px auto' }} />;
  if (!shift) return <Result status="404" title="班次不存在" />;
  if (!hasPermission) return <Result status="403" title="权限不足" />;

  return (
    <PageContainer
      title={`${dayjs(shift.shift_date).format('YYYY-MM-DD')} ${PERIOD_LABEL[shift.period] ?? shift.period}`}
      onBack={() => navigate('/health/shifts')}
    >
      <Descriptions bordered size="small" column={3} style={{ marginBottom: 24 }}>
        <Descriptions.Item label="状态">
          <Tag color={SHIFT_STATUS_COLOR[shift.status] ?? 'default'}>{SHIFT_STATUS_LABEL[shift.status] ?? shift.status}</Tag>
        </Descriptions.Item>
        <Descriptions.Item label="患者数">{shift.patient_count ?? assignments.length}</Descriptions.Item>
        <Descriptions.Item label="责任护士">{shift.nurse_id ?? '-'}</Descriptions.Item>
        {shift.notes && <Descriptions.Item label="备注" span={3}>{shift.notes}</Descriptions.Item>}
      </Descriptions>

      <Tabs
        defaultActiveKey="assignments"
        items={[
          {
            key: 'assignments',
            label: `患者分配 (${assignments.length})`,
            children: (
              <>
                <Space style={{ marginBottom: 12 }}>
                  <Button type="primary" size="small" onClick={handleAddAssignment}>分配患者</Button>
                </Space>
                <Table<PatientAssignment>
                  rowKey="id"
                  columns={assignColumns}
                  dataSource={assignments}
                  loading={assignLoading}
                  pagination={false}
                  size="small"
                />
              </>
            ),
          },
          {
            key: 'handoffs',
            label: `交接记录 (${handoffs.length})`,
            children: (
              <>
                <Button type="primary" size="small" style={{ marginBottom: 12 }} onClick={handleCreateHandoff}>
                  新建交接
                </Button>
                <Table<HandoffLog>
                  rowKey="id"
                  columns={handoffColumns}
                  dataSource={handoffs}
                  loading={handoffLoading}
                  pagination={false}
                  size="small"
                />
              </>
            ),
          },
        ]}
      />

      {/* Assignment Modal */}
      <Modal
        title={editAssignment ? '编辑分配' : '分配患者'}
        open={assignModalOpen}
        onOk={handleSubmitAssignment}
        onCancel={() => setAssignModalOpen(false)}
        width={480}
      >
        <Form form={assignForm} layout="vertical">
          <Form.Item name="patient_id" label="患者 ID" rules={[{ required: true, message: '请输入患者 ID' }]}>
            <Input placeholder="患者 UUID" disabled={!!editAssignment} />
          </Form.Item>
          <Form.Item name="care_level" label="护理等级">
            <Select options={CARE_LEVEL_OPTIONS} placeholder="选择等级" allowClear />
          </Form.Item>
          <Form.Item name="notes" label="备注">
            <Input.TextArea rows={2} />
          </Form.Item>
        </Form>
      </Modal>

      {/* Handoff Modal */}
      <Modal
        title="新建交接记录"
        open={handoffModalOpen}
        onOk={handleSubmitHandoff}
        onCancel={() => setHandoffModalOpen(false)}
        width={520}
      >
        <Form form={handoffForm} layout="vertical">
          <Form.Item name="from_shift_id" label="来源班次" rules={[{ required: true }]}>
            <Input disabled />
          </Form.Item>
          <Form.Item name="to_shift_id" label="目标班次 ID" rules={[{ required: true, message: '请输入目标班次 ID' }]}>
            <Input placeholder="目标班次 UUID" />
          </Form.Item>
          <Form.Item name="patient_id" label="患者 ID" rules={[{ required: true, message: '请输入患者 ID' }]}>
            <Input placeholder="患者 UUID" />
          </Form.Item>
          <Form.Item name="notes" label="交接备注">
            <Input.TextArea rows={3} placeholder="需要交代的特殊事项" />
          </Form.Item>
        </Form>
      </Modal>
    </PageContainer>
  );
}