import 'dart:io';

import 'package:dio/dio.dart';
import 'package:flutter_cache_manager/flutter_cache_manager.dart';
import 'package:hgdj/tools_base/debug_log.dart';
import 'package:http/http.dart' hide Response;

import '../../extension/extensions.dart';
import '../../hj_utils/file_util.dart';
import '../net/load_apk/dio_cli.dart';
import 'cancel_token_manager.dart';

/// dio 文件下载器（视频流缓存的 FileService）
class DioFileService extends FileService {
  /// 真正请求的 dio
  final _dio = createDio();

  @override
  Future<FileServiceResponse> get(String url,
      {Map<String, String>? headers = const {}}) async {
    // cancelToken 用文件名注册、下载结束后按同一 key 移除
    //（原来 createToken 用 name 而 remove 用 url，key 不一致：既移不掉导致泄漏，又会 firstWhere 抛 StateError）
    final name = FileUtil.getName(url);
    final token = CancelTokenManager().createToken(name);

    // 每次请求用独立 Options：本类随 VideoCacheManager 单例，共享一份 Options 会被并发请求互相覆盖 headers
    final options = Options(
      method: 'GET',
      sendTimeout: const Duration(milliseconds: 5000),
      receiveTimeout: const Duration(milliseconds: 10000),
      headers: {...?headers, 'cache-control': 'max-age=31104000'},
      contentType: ContentType.binary.toString(),
      responseType: ResponseType.stream,
    );

    Response<ResponseBody>? resp;
    try {
      debugLog("DioFileService get: $url");
      resp = await _dio.get<ResponseBody>(url,
          cancelToken: token, options: options);
    } catch (e) {
      debugLog("DioFileService get error: $url -> $e");
    } finally {
      CancelTokenManager().remove(name);
    }

    // 只认 200/206；其余（含请求异常 resp==null）直接抛：避免返回空流挂起、坏响应被缓存
    final statusCode = resp?.statusCode ?? HttpStatus.badRequest;
    if (resp?.data == null || (statusCode != 200 && statusCode != 206)) {
      throw HttpException("video chunk fetch failed ($statusCode): $url");
    }

    final respHeaders = <String, String>{};
    resp!.headers.forEach((key, values) {
      if (values.notEmpty()) respHeaders[key] = values.first;
    });
    // Content-Length 可能缺失/非数字，安全解析（原 contentLengthS[0] 在空串时会 RangeError）；缺失传 null 表示长度未知
    final contentLength =
        int.tryParse(respHeaders[Headers.contentLengthHeader] ?? '');

    debugLog(
        "DioFileService resp($statusCode): $url contentLength:$contentLength");

    return HttpGetResponse(StreamedResponse(
      resp.data!.stream,
      statusCode,
      headers: respHeaders,
      contentLength: contentLength,
    ));
  }
}