import React, { useState, useEffect } from 'react';
import { Spin, Alert, Tag, Button, Descriptions, Space, Tooltip, Badge } from 'antd';
import {
  CheckCircleOutlined,
  ExclamationCircleOutlined,
  SyncOutlined,
  ClockCircleOutlined,
  FileTextOutlined,
} from '@ant-design/icons';
import { diffLines, ChangeType } from 'diff';
import { Prism as SyntaxHighlighter } from 'react-syntax-highlighter';
import { vscDarkPlus } from 'react-syntax-highlighter/dist/esm/styles/prism';
import api from '../api';

const STATUS_CONFIG = {
  consistent: {
    color: 'success',
    icon: <CheckCircleOutlined />,
    text: '内容一致',
    description: '本地文件与数据库内容完全相同',
  },
  local_newer: {
    color: 'warning',
    icon: <SyncOutlined spin />,
    text: '本地更新',
    description: '本地文件比数据库更新',
  },
  db_newer: {
    color: 'info',
    icon: <SyncOutlined spin />,
    text: '数据库更新',
    description: '数据库文件比本地更新',
  },
  conflict: {
    color: 'error',
    icon: <ExclamationCircleOutlined />,
    text: '存在冲突',
    description: '本地与数据库内容不一致',
  },
};

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: {
          lobster_id,
          file_path: filePath,
          chunked: 'true',
        },
      });

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

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

  const renderDiff = () => {
    if (!diffData) return null;

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

    if (!local_content || !db_content) {
      return (
        <Alert
          message="文件不存在"
          description={local_content ? '数据库中不存在此文件' : '本地不存在此文件'}
          type="info"
          showIcon
        />
      );
    }

    // 使用 diff 库计算行级差异
    const changes = diffLines(db_content || '', local_content || '');

    return (
      <div style={{ maxHeight: '600px', overflowY: 'auto' }}>
        <Descriptions
          bordered
          size="small"
          column={2}
          style={{ marginBottom: 16 }}
        >
          <Descriptions.Item label="状态" span={2}>
            <Badge
              status={STATUS_CONFIG[status]?.color}
              text={
                <Space>
                  {STATUS_CONFIG[status]?.icon}
                  {STATUS_CONFIG[status]?.text}
                </Space>
              }
            />
          </Descriptions.Item>
          {diff.lines_changed !== 0 && (
            <Descriptions.Item label="变动行数" span={2}>
              <Tag color={diff.lines_changed > 0 ? 'green' : 'red'}>
                {diff.lines_changed > 0 ? '+' : ''}{diff.lines_changed}
              </Tag>
              {diff.is_truncated && (
                <Tooltip title="大文件，仅显示头尾差异">
                  <Tag color="orange">已截断</Tag>
                </Tooltip>
              )}
            </Descriptions.Item>
          )}
          <Descriptions.Item label="本地哈希" span={1}>
            <code style={{ fontSize: '12px' }}>
              {diffData.local_hash?.slice(0, 16)}...
            </code>
          </Descriptions.Item>
          <Descriptions.Item label="数据库哈希" span={1}>
            <code style={{ fontSize: '12px' }}>
              {diffData.db_hash?.slice(0, 16)}...
            </code>
          </Descriptions.Item>
        </Descriptions>

        <div className="diff-container">
          {changes.map((change, index) => {
            const lineStyle = {
              paddingLeft: '16px',
              paddingRight: '16px',
              margin: '2px 0',
              fontSize: '13px',
              fontFamily: 'Consolas, Monaco, "Courier New", monospace',
              lineHeight: '1.6',
            };

            if (change.type === ChangeType.Insert) {
              return (
                <div
                  key={index}
                  style={{
                    ...lineStyle,
                    backgroundColor: '#e6fffb',
                    borderLeft: '3px solid #52c41a',
                  }}
                >
                  <span style={{ color: '#52c41a', marginRight: '8px' }}>+</span>
                  {change.value}
                </div>
              );
            } else if (change.type === ChangeType.Delete) {
              return (
                <div
                  key={index}
                  style={{
                    ...lineStyle,
                    backgroundColor: '#fff1f0',
                    borderLeft: '3px solid #ff4d4f',
                    textDecoration: 'line-through',
                    opacity: 0.7,
                  }}
                >
                  <span style={{ color: '#ff4d4f', marginRight: '8px' }}>-</span>
                  {change.value}
                </div>
              );
            } else {
              return (
                <div key={index} style={{ ...lineStyle }}>
                  <span style={{ color: '#d9d9d9', marginRight: '8px' }}> </span>
                  {change.value}
                </div>
              );
            }
          })}
        </div>
      </div>
    );
  };

  if (loading) {
    return (
      <div style={{ textAlign: 'center', padding: '60px 0' }}>
        <Spin size="large" tip="加载中..." />
      </div>
    );
  }

  if (error) {
    return (
      <Alert
        message="加载失败"
        description={error}
        type="error"
        showIcon
        action={
          <Button size="small" onClick={loadDiff}>
            重试
          </Button>
        }
      />
    );
  }

  if (!diffData) {
    return (
      <Alert
        message="请选择文件"
        description="点击左侧文件树中的文件查看差异"
        type="info"
        showIcon
      />
    );
  }

  return (
    <div className="file-diff">
      <div style={{ marginBottom: 16 }}>
        <Space>
          <Button
            size="small"
            icon={<ClockCircleOutlined />}
            onClick={loadDiff}
          >
            刷新
          </Button>
        </Space>
      </div>

      {STATUS_CONFIG[diffData.status] && (
        <Alert
          message={STATUS_CONFIG[diffData.status].text}
          description={STATUS_CONFIG[diffData.status].description}
          type={STATUS_CONFIG[diffData.status].color}
          showIcon
          icon={STATUS_CONFIG[diffData.status].icon}
          style={{ marginBottom: 16 }}
          closable
        />
      )}

      {renderDiff()}
    </div>
  );
}