import 'dart:io';

import 'package:dio/dio.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_cache_manager/flutter_cache_manager.dart';
import 'package:http/http.dart';
import 'package:path/path.dart' as path;
import 'package:path_provider/path_provider.dart';

import '../../config/address.dart';
import '../../extension/extensions.dart';
import '../debug_log.dart';
import '../image/image_data_handle/image_crypto.dart';
import '../net/load_apk/dio_cli.dart';

class ImageCacheManager extends CacheManager {
  static const image_key = "customCache";

// 工厂模式
  factory ImageCacheManager() => _getInstance();

  static ImageCacheManager get instance => _getInstance();
  static ImageCacheManager? _instance;

  static ImageCacheManager _getInstance() {
    _instance ??= ImageCacheManager._internal();
    return _instance!;
  }

  ImageCacheManager._internal()
      : super(Config(image_key, maxNrOfCacheObjects: 400, stalePeriod: const Duration(days: 7), fileService: CustomFileRespons()));

  Future<String> getFilePath() async {
    var directory = await getTemporaryDirectory();
    return path.join(directory.path, image_key);
  }
}

class CustomFileRespons extends HttpFileService {
  DioCli client = DioCli(
      options: BaseOptions(
          connectTimeout: const Duration(milliseconds: 30000),
          receiveTimeout: const Duration(milliseconds: 30000),
          sendTimeout: const Duration(milliseconds: 30000),
          validateStatus: (int? status) {
            if (status != null) return status < 600;
            return false;
          }));

  @override
  Future<FileServiceResponse> get(String url, {Map<String, String>? headers = const {}}) async {
    if (!url.startsWith("http") && !url.startsWith("https")) {
      url = path.join(Address.baseImagePath ?? '', url);
    }

    if (kDebugMode) {
      debugLog("image_request", "get()...begin...ulr:$url...");
    }

    headers?['cache-control'] = 'max-age=31104000';

    final resp = await client.getBytes(url, headers: headers);
    final statusCode = resp.data?.statusCode ?? HttpStatus.badRequest;

    // 失败 / 非 2xx：直接抛。避免错误响应(空内容、CDN 错误页)被落盘缓存成坏图，
    // 让 CachedNetworkImage 走 errorWidget；下次能重新请求，而不是一直命中坏缓存。
    if (resp.err != null || statusCode < 200 || statusCode >= 300) {
      if (kDebugMode) {
        debugLog("image_request", "get()...failed...$url...code:($statusCode): ${resp.err}");
      }
      throw HttpException("image fetch failed ($statusCode): ${resp.err}", uri: Uri.tryParse(url));
    }

    // 解密(Dio 不同版本 bytes 返回 List<int> 或 Uint8List)。解密失败 / 空字节同样抛出，不缓存坏图。
    Uint8List bytes;
    try {
      final raw = resp.data?.data;
      final decrypted = raw == null ? null : ImageCrypto.decryptImage(raw is Uint8List ? raw : Uint8List.fromList(raw));
      if (decrypted == null || decrypted.isEmpty) {
        throw const FormatException("empty image bytes");
      }
      //部分 CDN 返回的加密 JPEG 缺末尾 EOI(FF D9)，Skia 严格 decoder 会拒；补 EOI 让标准 decoder 也能解
      bytes = _repairJpegEoiIfNeeded(decrypted);
    } catch (e) {
      if (kDebugMode) debugLog("ImageCacheManager", "decrypt failed: $url -> $e");
      throw HttpException("image decrypt failed: $e", uri: Uri.tryParse(url));
    }

    final respHeaders = <String, String>{};
    resp.data?.headers.forEach((key, arrayValue) {
      if (arrayValue.notEmpty()) respHeaders[key] = arrayValue[0];
    });

    if (kDebugMode) {
      debugLog("image_request", "get()...success...$url...code:($statusCode): contentLength:${bytes.length}");
    }

    return HttpGetResponse(StreamedResponse(
      Stream.value(bytes),
      statusCode,
      contentLength: bytes.length, // 补 EOI 后用真实长度
      headers: respHeaders,
    ));
  }
}

//判断是 jpeg 头但无 FF D9 结尾时补 EOI；其他格式 / 已完整 jpeg 原样返回
Uint8List _repairJpegEoiIfNeeded(Uint8List bytes) {
  if (bytes.length < 4) return bytes;
  final isJpeg = bytes[0] == 0xFF && bytes[1] == 0xD8 && bytes[2] == 0xFF;
  if (!isJpeg) return bytes;
  final hasEoi = bytes[bytes.length - 2] == 0xFF && bytes[bytes.length - 1] == 0xD9;
  if (hasEoi) return bytes;
  final fixed = Uint8List(bytes.length + 2)
    ..setRange(0, bytes.length, bytes)
    ..[bytes.length] = 0xFF
    ..[bytes.length + 1] = 0xD9;
  return fixed;
}