import 'dart:io';

import 'package:http/http.dart' as http;
import 'package:swagger_generator_flutter/core/config.dart';
import 'package:swagger_generator_flutter/core/exceptions.dart';
import 'package:swagger_generator_flutter/utils/logger.dart';
import 'package:swagger_generator_flutter/utils/path_resolver.dart';

/// Swagger 数据获取器
/// 负责从本地文件或远程 URL 获取 Swagger 文档内容
class SwaggerFetcher {
  /// 获取 Swagger 文档内容
  /// [url] 可以是本地文件路径 (file://) 或远程 URL (http://, https://)
  Future<String> fetch(String url) async {
    appLogger.info('🔄 正在获取Swagger JSON文档: $url');

    if (url.startsWith('http://') || url.startsWith('https://')) {
      return _fetchFromUrl(url);
    } else {
      return _fetchFromFile(url);
    }
  }

  /// 从远程 URL 获取
  Future<String> _fetchFromUrl(String url) async {
    try {
      final response = await http.get(
        Uri.parse(url),
        headers: SwaggerConfig.httpHeaders,
      );

      if (response.statusCode == 200) {
        return response.body;
      } else {
        throw SwaggerParseException(
          'HTTP请求失败',
          url: url,
          statusCode: response.statusCode,
          details: 'HTTP响应状态码: ${response.statusCode}',
        );
      }
    } catch (e) {
      if (e is SwaggerParseException) rethrow;
      throw SwaggerParseException(
        '获取远程Swagger文档失败',
        url: url,
        details: e.toString(),
      );
    }
  }

  /// 从本地文件获取
  Future<String> _fetchFromFile(String url) async {
    try {
      // 移除 file:// 前缀（如果有）
      var filePath = url;
      if (filePath.startsWith('file://')) {
        filePath = filePath.substring(7);
      }

      // 使用 PathResolver 解析路径
      final resolvedPath = PathResolver.resolvePath(filePath);
      final file = File(resolvedPath);

      if (!file.existsSync()) {
        throw SwaggerParseException(
          '本地文件不存在',
          url: url,
          details: '文件路径: $resolvedPath',
        );
      }

      return await file.readAsString();
    } catch (e) {
      if (e is SwaggerParseException) rethrow;
      throw SwaggerParseException(
        '读取本地Swagger文件失败',
        url: url,
        details: e.toString(),
      );
    }
  }
}