import React, { useState, useEffect } from 'react';
import { Spin, Alert, Tabs } from 'antd';
import ReactDiffViewer from 'react-diff-viewer-continued';
import api from '../api';

export default function FileDiff({ filePath, lobsterId }) {
  const [loading, setLoading] = useState(false);
  const [diffData, setDiffData] = useState(null);
  const [error, setError] = useState(null);

  const loadDiff = async () => {
    setLoading(true);
    setError(null);

    try {
      const response = await api.get('/diff/', {
        params: { file_path: filePath, lobster_id: lobsterId }
      });

      if (response.success) {
        setDiffData(response.data);
      } else {
        setError(response.error || '加载失败');
      }
    } catch (err) {
      setError(err.message || '网络错误');
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    if (filePath) {
      loadDiff();
    }
  }, [filePath]);

  if (loading) {
    return <Spin tip="加载中..." />;
  }

  if (error) {
    return <Alert message={error} type="error" />;
  }

  if (!diffData) {
    return <Alert message="请选择文件" type="info" />;
  }

  const { local_content, db_content, status, diff } = diffData;

  // 文件不存在的情况
  if (!local_content && !db_content) {
    return <Alert message="文件不存在" type="warning" />;
  }

  if (!local_content) {
    return (
      <Alert
        message="文件仅存在于数据库"
        description="点击「同步到本地」将文件恢复到本地"
        type="info"
        showIcon
      />
    );
  }

  if (!db_content) {
    return (
      <Alert
        message="文件仅存在于本地"
        description="点击「同步到数据库」将文件备份到数据库"
        type="warning"
        showIcon
      />
    );
  }

  const STATUS_MESSAGES = {
    consistent: '文件内容一致',
    local_newer: '本地文件有更新',
    db_newer: '数据库版本更新',
    conflict: '文件内容冲突',
  };

  return (
    <div>
      <Alert
        message={STATUS_MESSAGES[status] || '未知状态'}
        type={status === 'consistent' ? 'success' : 'warning'}
        style={{ marginBottom: 16 }}
        showIcon
      />

      <Tabs
        defaultActiveKey="diff"
        items={[
          {
            key: 'diff',
            label: '差异对比',
            children: (
              <div style={{ overflowX: 'auto' }}>
                <ReactDiffViewer
                  oldValue={db_content || ''}
                  newValue={local_content || ''}
                  splitView={true}
                  useDarkTheme={false}
                  leftTitle="数据库版本"
                  rightTitle="本地版本"
                />
              </div>
            ),
          },
          {
            key: 'local',
            label: '本地内容',
            children: (
              <pre style={{
                padding: '16px',
                background: '#f5f5f5',
                borderRadius: '4px',
                maxHeight: '500px',
                overflow: 'auto',
                whiteSpace: 'pre-wrap',
                wordBreak: 'break-word'
              }}>
                {local_content}
              </pre>
            ),
          },
          {
            key: 'db',
            label: '数据库内容',
            children: (
              <pre style={{
                padding: '16px',
                background: '#f5f5f5',
                borderRadius: '4px',
                maxHeight: '500px',
                overflow: 'auto',
                whiteSpace: 'pre-wrap',
                wordBreak: 'break-word'
              }}>
                {db_content}
              </pre>
            ),
          },
        ]}
      />
    </div>
  );
}