dart_pkpass/lib/src/pass_file.dart

import 'dart:convert';
import 'dart:typed_data';

import 'package:archive/archive.dart';
import 'package:crypto/crypto.dart';
import 'package:intl/locale.dart';

import 'package:pkpass/pkpass.dart';
import 'package:pkpass/src/file_matcher.dart';

final _utf8codec = Utf8Codec();
final _jsonCodec = JsonCodec();

class PassFile {
  PassFile(this.metadata, this._folder);

  static Future<PassFile> parse(Uint8List pass) async {
    final codec = ZipDecoder();
    Archive archive;
    try {
      archive = codec.decodeBytes(pass);
    } catch (e) {
      throw InvalidEncodingError();
    }

    Map<String, String> manifest;

    try {
      final file = archive.files
          .singleWhere((element) => element.name == 'manifest.json');
      manifest = (_jsonCodec.decode(
        _utf8codec.decode(
          file.rawContent?.toUint8List() ?? (file.content as Uint8List),
        ),
      ) as Map)
          .cast<String, String>();
    } catch (e) {
      throw ManifestNotFoundError();
    }

    final folder = <ArchiveFile>[];

    await Future.wait(
      manifest.entries.map(
        (manifestEntry) async {
          final file = archive.files
              .singleWhere((element) => element.name == manifestEntry.key);

          final content =
              file.rawContent?.toUint8List() ?? file.content as Uint8List;

          String hash = sha1.convert(content).toString();

          final checksum = manifestEntry.value;

          if (hash != checksum) {
            throw ManifestChecksumError(expected: checksum, actual: hash);
          }

          folder.add(file);
        },
      ),
    );

    final passFile =
        archive.singleWhere((element) => element.name == 'pass.json');

    final PassMetadata metadata = PassMetadata.fromJson(
      _jsonCodec.decode(passFile.stringContent) as Map<String, Object?>,
    );

    return PassFile(metadata, folder);
  }

  final PassMetadata metadata;

  final List<ArchiveFile> _folder;

  Uint8List? _matchUtf8List({
    required String name,
    required Locale? locale,
    required int scale,
  }) {
    final files = _folder.map((e) => e.name).toList();
    final path = FileMatcher.matchFile(
      files: files,
      name: name,
      scale: scale,
      locale: locale,
    );
    if (path == null) return null;
    final file = _folder.singleWhere((element) => element.name == path);
    final content = file.rawContent?.toUint8List() ?? file.content as Uint8List;
    return content;
  }

  Uint8List? getBackground({Locale? locale, int scale = 1}) =>
      _matchUtf8List(name: 'background', locale: locale, scale: scale);
  Uint8List? getFooter({Locale? locale, int scale = 1}) =>
      _matchUtf8List(name: 'footer', locale: locale, scale: scale);
  Uint8List? getIcon({Locale? locale, int scale = 1}) =>
      _matchUtf8List(name: 'icon', locale: locale, scale: scale);
  Uint8List? getLogo({Locale? locale, int scale = 1}) =>
      _matchUtf8List(name: 'logo', locale: locale, scale: scale);
  Uint8List? getStrip({Locale? locale, int scale = 1}) =>
      _matchUtf8List(name: 'strip', locale: locale, scale: scale);
  Uint8List? getThumbnail({Locale? locale, int scale = 1}) =>
      _matchUtf8List(name: 'thumbnail', locale: locale, scale: scale);
}

extension on ArchiveFile {
  String get stringContent =>
      _utf8codec.decode(rawContent?.toUint8List() ?? (content as Uint8List));
}