import React, { useState, useEffect, useCallback } from 'react';
import { Container, Row, Col, Table, Spinner, Alert, Form, Button } from 'react-bootstrap';
import { adminAPI } from '../../services/api';
import { toast } from 'react-toastify';
import { debounce } from '../../utils/debounce';

const OperationLog = () => {
  const [logs, setLogs] = useState([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);
  const [page, setPage] = useState(1);
  const [hasMore, setHasMore] = useState(true);
  const [searchQuery, setSearchQuery] = useState('');
  const [selectedUserId, setSelectedUserId] = useState('');
  const [startDate, setStartDate] = useState('');
  const [endDate, setEndDate] = useState('');
  const [users, setUsers] = useState([]); // 用于用户筛选下拉框

  const fetchLogs = async (pageNumber = page, search = searchQuery, userId = selectedUserId, start = startDate, end = endDate) => {
    try {
      setLoading(true);
      const params = {
        page: pageNumber,
        search: search,
        user_id: userId || undefined,
        start_date: start || undefined,
        end_date: end || undefined,
      };
      const res = await adminAPI.getOperationLogs(params);
      if (pageNumber === 1) {
        setLogs(res.data.logs);
      } else {
        setLogs((prevLogs) => [...prevLogs, ...res.data.logs]);
      }
      setHasMore(res.data.has_more);
      setPage(pageNumber);
    } catch (err) {
      setError('获取操作日志失败');
      toast.error('获取操作日志失败');
      console.error(err);
    } finally {
      setLoading(false);
    }
  };

  const fetchUsersForFilter = async () => {
    try {
      const res = await adminAPI.getUsers({ page: 1, per_page: 9999 }); // 获取所有用户用于筛选
      setUsers(res.data.users);
    } catch (err) {
      console.error('获取用户列表失败', err);
    }
  };

  const loadMore = () => {
    if (hasMore && !loading) {
      fetchLogs(page + 1);
    }
  };

  useEffect(() => {
    fetchUsersForFilter();
  }, []);

  // 防抖搜索函数
  const debouncedSearch = useCallback(
    debounce((search, userId, start, end) => {
      fetchLogs(1, search, userId, start, end);
    }, 500),
    []
  );

  useEffect(() => {
    debouncedSearch(searchQuery, selectedUserId, startDate, endDate);
  }, [searchQuery, selectedUserId, startDate, endDate, debouncedSearch]);

  return (
    <Container fluid className="p-4">
      <Row className="mb-4">
        <Col>
          <h2 className="text-center">操作日志</h2>
        </Col>
      </Row>

      <Row className="mb-4">
        <Col>
          <Form className="d-flex flex-wrap align-items-center">
            <Form.Group controlId="searchQuery" className="me-2 mb-2">
              <Form.Control
                type="text"
                placeholder="搜索操作类型或详情..."
                value={searchQuery}
                onChange={(e) => setSearchQuery(e.target.value)}
              />
            </Form.Group>
            <Form.Group controlId="userFilter" className="me-2 mb-2">
              <Form.Select
                value={selectedUserId}
                onChange={(e) => setSelectedUserId(e.target.value)}
              >
                <option value="">所有用户</option>
                {users.map((user) => (
                  <option key={user.id} value={user.id}>
                    {user.username}
                  </option>
                ))}
              </Form.Select>
            </Form.Group>
            <Form.Group controlId="startDate" className="me-2 mb-2">
              <Form.Control
                type="date"
                value={startDate}
                onChange={(e) => setStartDate(e.target.value)}
              />
            </Form.Group>
            <Form.Group controlId="endDate" className="me-2 mb-2">
              <Form.Control
                type="date"
                value={endDate}
                onChange={(e) => setEndDate(e.target.value)}
              />
            </Form.Group>
          </Form>
        </Col>
      </Row>

      {/* 统一处理加载状态 */}
      {loading && (
        <Row className="justify-content-center">
          <Col xs="auto">
            <Spinner animation="border" role="status">
              <span className="visually-hidden">加载中...</span>
            </Spinner>
          </Col>
        </Row>
      )}

      {error && <Alert variant="danger">{error}</Alert>}

      {/* 无数据状态（仅在非加载且无错误时显示） */}
      {!loading && !error && logs.length === 0 && (
        <Alert variant="info">没有找到操作日志。</Alert>
      )}

      {/* 日志表格（仅在非加载、无错误且有数据时显示） */}
      {!loading && !error && logs.length > 0 && (
        <Row>
          <Col>
            <Table striped bordered hover responsive className="shadow-sm">
              <thead>
                <tr>
                  <th>ID</th>
                  <th>用户</th>
                  <th>操作类型</th>
                  <th>文件ID</th>
                  <th>文件名</th>
                  <th>时间</th>
                  <th>详情</th>
                </tr>
              </thead>
              <tbody>
                {logs.map((log) => (
                  <tr key={log.id}>
                    <td>{log.id}</td>
                    <td>{log.username}</td>
                    <td>{log.operation_type}</td>
                    <td>{log.file_id || 'N/A'}</td>
                    <td>{log.original_filename || 'N/A'}</td>
                    <td>{new Date(log.timestamp).toLocaleString()}</td>
                    <td>{log.details}</td>
                  </tr>
                ))}
              </tbody>
            </Table>
            {hasMore && (
              <div className="d-flex justify-content-center mt-4">
                <Button
                  variant="primary"
                  onClick={loadMore}
                  disabled={loading}
                >
                  {loading ? '加载中...' : '加载更多'}
                </Button>
              </div>
            )}
          </Col>
        </Row>
      )}
    </Container>
  );
};

export default OperationLog;