import 'dart:io';
import 'package:path_provider/path_provider.dart';
import 'package:path/path.dart' as path;

/// Manages the persistent downloads directory structure
class DownloadStorageService {
  /// Get the root downloads directory
  Future<Directory> getDownloadsDir() async {
    final appDir = await getApplicationDocumentsDirectory();
    final downloadsDir = Directory(path.join(appDir.path, 'downloads'));
    if (!await downloadsDir.exists()) {
      await downloadsDir.create(recursive: true);
    }
    return downloadsDir;
  }

  /// Get the directory for a specific series
  Future<Directory> getSeriesDir(String seriesId) async {
    final downloadsDir = await getDownloadsDir();
    final seriesDir = Directory(path.join(downloadsDir.path, seriesId));
    if (!await seriesDir.exists()) {
      await seriesDir.create(recursive: true);
    }
    return seriesDir;
  }

  /// Get the directory for an image stream chapter
  Future<Directory> getChapterDir(String seriesId, String chapterId) async {
    final seriesDir = await getSeriesDir(seriesId);
    final chapterDir = Directory(path.join(seriesDir.path, chapterId));
    if (!await chapterDir.exists()) {
      await chapterDir.create(recursive: true);
    }
    return chapterDir;
  }

  /// Get the file path for an EPUB chapter
  Future<String> getEpubPath(String seriesId, String chapterId) async {
    final seriesDir = await getSeriesDir(seriesId);
    return path.join(seriesDir.path, '$chapterId.epub');
  }

  /// Delete all files for a series
  Future<void> deleteSeriesFiles(String seriesId) async {
    final downloadsDir = await getDownloadsDir();
    final seriesDir = Directory(path.join(downloadsDir.path, seriesId));
    if (await seriesDir.exists()) {
      await seriesDir.delete(recursive: true);
    }
  }

  /// Delete files for a single chapter
  Future<void> deleteChapterFiles(
      String seriesId, String chapterId, bool isEpub) async {
    if (isEpub) {
      final epubPath = await getEpubPath(seriesId, chapterId);
      final file = File(epubPath);
      if (await file.exists()) {
        await file.delete();
      }
    } else {
      final downloadsDir = await getDownloadsDir();
      final chapterDir =
          Directory(path.join(downloadsDir.path, seriesId, chapterId));
      if (await chapterDir.exists()) {
        await chapterDir.delete(recursive: true);
      }
    }
  }

  /// Get total disk usage for all downloads
  Future<int> getTotalDownloadSize() async {
    final downloadsDir = await getDownloadsDir();
    if (!await downloadsDir.exists()) return 0;

    int totalSize = 0;
    await for (final entity
        in downloadsDir.list(recursive: true, followLinks: false)) {
      if (entity is File) {
        totalSize += await entity.length();
      }
    }
    return totalSize;
  }
}