import 'dart:typed_data';

import 'package:dio/dio.dart';

/// 预签名直传失败。
///
/// - [statusCode] 为 null 表示网络层失败（断连/超时），可原凭据重试；
/// - 403 为存储侧拒绝签名（凭据过期/被改动），须重新 createUpload 换新凭据；
/// - 其余状态码按可重试处理（重试走完整重传）。
class MediaDirectUploadException implements Exception {
  const MediaDirectUploadException({this.statusCode, required this.message});

  final int? statusCode;
  final String message;

  /// 存储侧拒绝了凭据（签名过期/不符），重试前必须换新凭据。
  bool get isCredentialRejected => statusCode == 403;

  @override
  String toString() => 'MediaDirectUploadException($statusCode): $message';
}

/// 预签名 PUT 直传抽象（两步上传第二步的传输层）。
///
/// 不走业务信封、不带 Bearer 鉴权——鉴权就是 URL 里的签名本身;
/// [headers] 即 createUpload 返回的 requiredHeaders，必须原样携带
/// （Content-Type 已签进签名，改动即 403）。
abstract class MediaDirectUploadClient {
  Future<void> put({
    required String url,
    required Map<String, String> headers,
    required Uint8List bytes,
    void Function(int sent, int total)? onProgress,
  });
}

/// 基于裸 Dio 的实现：独立实例，无 AuthInterceptor（预签名 URL 携带
/// Authorization 头会破坏 SigV4 校验），sendTimeout 按 10 MiB 弱网上限放宽。
class DioMediaDirectUploadClient implements MediaDirectUploadClient {
  DioMediaDirectUploadClient({Dio? dio})
    : _dio =
          dio ??
          Dio(
            BaseOptions(
              connectTimeout: const Duration(seconds: 5),
              sendTimeout: const Duration(seconds: 120),
              receiveTimeout: const Duration(seconds: 30),
              validateStatus: (_) => true,
            ),
          );

  final Dio _dio;

  @override
  Future<void> put({
    required String url,
    required Map<String, String> headers,
    required Uint8List bytes,
    void Function(int sent, int total)? onProgress,
  }) async {
    final Response<Object?> response;
    try {
      response = await _dio.put<Object?>(
        url,
        data: Stream<Uint8List>.value(bytes),
        options: Options(
          headers: {...headers, Headers.contentLengthHeader: bytes.length},
        ),
        onSendProgress: onProgress,
      );
    } on DioException catch (error) {
      throw MediaDirectUploadException(message: '直传网络失败：${error.type.name}');
    }
    final status = response.statusCode ?? 0;
    if (status < 200 || status >= 300) {
      throw MediaDirectUploadException(
        statusCode: status,
        message: '存储侧拒绝直传：HTTP $status',
      );
    }
  }
}