import 'dart:async';
import 'dart:io';

import 'package:dio/dio.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_archive/flutter_archive.dart';
import 'package:hadi_hoda_flutter/core/constants/my_api.dart';
import 'package:hadi_hoda_flutter/core/constants/my_constants.dart';
import 'package:hadi_hoda_flutter/core/error_handler/my_exception.dart';
import 'package:hadi_hoda_flutter/core/network/http_request.dart';
import 'package:hadi_hoda_flutter/core/response/base_response.dart';
import 'package:hadi_hoda_flutter/core/utils/local_storage.dart';
import 'package:hadi_hoda_flutter/core/utils/storage_path.dart';
import 'package:hadi_hoda_flutter/features/download/domain/entities/download_entity.dart';
import 'package:hadi_hoda_flutter/features/level/data/model/node_model.dart';
import 'package:hadi_hoda_flutter/features/level/domain/entity/node_entity.dart';
import 'package:hadi_hoda_flutter/features/level/domain/entity/total_data_entity.dart';
import 'package:hive/hive.dart';

abstract class IDownloadDatasource {
  Future<void> saveLevels();

  Future<void> batchDownload(int toLevel);

  Future<int> getLastDownloadedLevel();

  Stream<DownloadEntity> loadingStream();

  void cancelDownload();
}

class DownloadDatasourceImpl implements IDownloadDatasource {
  final IHttpRequest httpRequest;
  final StreamController<DownloadEntity> streamController =
      StreamController<DownloadEntity>.broadcast();
  CancelToken? _audioCancelToken;
  CancelToken? _imageCancelToken;
  bool _isBatchDownloading = false;

  DownloadDatasourceImpl(this.httpRequest);

  @override
  void cancelDownload() {
    _isBatchDownloading = false;
    _cancelAudioDownload();
    _cancelImageDownload();
  }

  void _cancelAudioDownload() {
    _audioCancelToken?.cancel('Download cancelled by user.');
    _audioCancelToken = null;
  }

  void _cancelImageDownload() {
    _imageCancelToken?.cancel('Download cancelled by user.');
    _imageCancelToken = null;
  }

  void _createAudioNewCancelToken() {
    _audioCancelToken = CancelToken();
  }

  void _createImageNewCancelToken() {
    _imageCancelToken = CancelToken();
  }

  int _imageCompleted = 0;
  int _audioCompleted = 0;
  int _targetLevel = 0;

  void _emitProgress() {
    final int totalTasks = _targetLevel * 2;
    final int completedTasks = _imageCompleted + _audioCompleted;

    final double percent = totalTasks == 0
        ? 0
        : (completedTasks / totalTasks) * 100;

    streamController.add(
      DownloadEntity(
        downloadedLevels: completedTasks ~/ 2, // optional
        percent: percent,
      ),
    );
  }

  Future<bool> _isLevelImagesDownloaded(int level) async {
    final String levelPath = '${StoragePath.documentDir.path}/$level/';

    final Directory directory = Directory(levelPath);

    if (!await directory.exists()) {
      return false;
    }

    final List<FileSystemEntity> files = directory.listSync(recursive: false);

    if (files.isEmpty) {
      return false;
    }

    return true;
  }

  Future<void> _getLevelsImages(int toLevel) async {
    for (int level = 1; level <= toLevel; level++) {
      if (!_isBatchDownloading) return;
      final bool isDownloaded = await _isLevelImagesDownloaded(level);

      if (isDownloaded) {
        _imageCompleted++;
        _emitProgress();
        continue;
      }

      await _getLevelImage(level);
    }
  }

  Future<void> _getLevelImage(int level) async {
    if (!_isBatchDownloading) return;
    debugPrint("Started _getLevelImage($level)");
    final String filePath = '${StoragePath.documentDir.path}/images.zip';
    _createImageNewCancelToken();
    try {
      final response = await httpRequest.download(
        urlPath: MyApi.images,
        savePath: filePath,
        queryParameters: {'batch_start': level, 'batch_size': 1},
        cancelToken: _imageCancelToken,
        onReceive: (count, total) {
          debugPrint("Started _getLevelImage($level) : ${(count / total) * 100}");
        },
      );

      if (response is Response && response.statusCode == 204) {
        debugPrint("No image content for level $level (204)");
        _imageCompleted++;
        _emitProgress();
        return;
      }

      final File file = File(filePath);
      if (!await file.exists()) {
        _imageCompleted++;
        _emitProgress();
        return;
      }

      final Directory directory = Directory(
        '${StoragePath.documentDir.path}/$level/',
      );
      await ZipFile.extractToDirectory(
        zipFile: file,
        destinationDir: directory,
        onExtracting: (zipEntry, progress) {
          return ZipFileOperation.includeItem;
        },
      );
      if (await file.exists()) {
        await file.delete(recursive: true);
      }
    } catch (e) {
      if (e is DioException && CancelToken.isCancel(e)) {
        return;
      }
      throw MyException(errorMessage: '$e');
    }
    _imageCompleted++;
    _emitProgress();
  }

  Future<bool> _isLevelAudiosDownloaded(int level) async {
    final lang =
        LocalStorage.readData(key: MyConstants.selectLanguage) ??
        MyConstants.defaultLanguage;
    final String levelPath = '${StoragePath.documentDir.path}/$lang/$level/';

    final Directory directory = Directory(levelPath);

    if (!await directory.exists()) {
      return false;
    }

    final List<FileSystemEntity> files = directory.listSync(recursive: false);

    if (files.isEmpty) {
      return false;
    }

    return true;
  }

  Future<void> _getLevelsAudios(int toLevel) async {
    for (int level = 1; level <= toLevel; level++) {
      if (!_isBatchDownloading) return;
      final bool isDownloaded = await _isLevelAudiosDownloaded(level);

      if (isDownloaded) {
        _audioCompleted++;
        _emitProgress();
        continue;
      }

      await _getLevelAudio(level);
    }
  }

  Future<void> _getLevelAudio(int level) async {
    if (!_isBatchDownloading) return;
    debugPrint("Started _getLevelAudio($level)");

    final String filePath = '${StoragePath.documentDir.path}/audios.zip';
    _createAudioNewCancelToken();
    final lang =
        LocalStorage.readData(key: MyConstants.selectLanguage) ??
        MyConstants.defaultLanguage;
    try {
      final response = await httpRequest.download(
        urlPath: MyApi.audios,
        savePath: filePath,
        queryParameters: {
          'batch_start': level,
          'batch_size': 1,
          'lang': lang,
        },
        cancelToken: _audioCancelToken,
        onReceive: (count, total) {
          debugPrint("Started _getLevelAudio($level) : ${(count / total) * 100}");
        },
      );

      if (response is Response && response.statusCode == 204) {
        debugPrint("No audio content for level $level (204)");
        _audioCompleted++;
        _emitProgress();
        return;
      }

      final File file = File(filePath);
      if (!await file.exists()) {
        _audioCompleted++;
        _emitProgress();
        return;
      }

      final Directory directory = Directory(
        '${StoragePath.documentDir.path}/$lang/$level/',
      );
      await ZipFile.extractToDirectory(
        zipFile: file,
        destinationDir: directory,
        onExtracting: (zipEntry, progress) {
          return ZipFileOperation.includeItem;
        },
      );
      if (await file.exists()) {
        await file.delete(recursive: true);
      }
    } catch (e) {
      if (e is DioException && CancelToken.isCancel(e)) {
        return;
      }
      throw MyException(errorMessage: '$e');
    }
    _audioCompleted++;
    _emitProgress();
  }

  @override
  Future<int> getLastDownloadedLevel() async {
    int lastCompleteLevel = 0;

    for (int level = 1; level <= 50; level++) {
      final bool imageExists = await _isLevelImagesDownloaded(level);

      final bool audioExists = await _isLevelAudiosDownloaded(level);

      if (imageExists && audioExists) {
        lastCompleteLevel = level;
      } else {
        break; // stop at first incomplete level
      }
    }

    return lastCompleteLevel;
  }

  @override
  Future<void> saveLevels() async {
    final String selectedLanguage =
        LocalStorage.readData(key: MyConstants.selectLanguage) ??
        MyConstants.defaultLanguage;
    final Box<TotalDataEntity> data = Hive.box(MyConstants.levelBox);

    // Check if data already exists for this language
    bool dataExists = false;
    try {
      data.values.firstWhere((e) => e.code == selectedLanguage);
      dataExists = true;
    } catch (_) {
      dataExists = false;
    }

    if (!dataExists) {
      final response = await httpRequest.get(
        path: MyApi.levels,
        queryParameters: {'lang': selectedLanguage},
      );
      final List<NodeEntity> levels = BaseResponse.getDataList<NodeEntity>(
        response?['path'],
        (json) => NodeModel.fromJson(json),
      );
      LocalStorage.saveData(key: MyConstants.maxLevelCount, value: '${levels.length}');
      await data.add(TotalDataEntity(code: selectedLanguage, nodes: levels));
    }
  }

  @override
  Future<void> batchDownload(int toLevel) async {
    debugPrint("Started batchDownload($toLevel)");
    
    // Cancel any existing batch download before starting a new one
    cancelDownload();
    
    _isBatchDownloading = true;
    _targetLevel = toLevel;
    _imageCompleted = 0;
    _audioCompleted = 0;

    try {
      await Future.wait([_getLevelsImages(toLevel), _getLevelsAudios(toLevel)]);
    } finally {
      _isBatchDownloading = false;
    }
  }

  @override
  Stream<DownloadEntity> loadingStream() => streamController.stream;
}