Obtainium/lib/app_sources/fdroidRepo.dart

import 'package:easy_localization/easy_localization.dart';
import 'package:html/parser.dart';
import 'package:http/http.dart';
import 'package:obtainium/components/generated_form.dart';
import 'package:obtainium/custom_errors.dart';
import 'package:obtainium/providers/source_provider.dart';

class FDroidRepo extends AppSource {
  FDroidRepo() {
    name = tr('fdroidThirdPartyRepo');

    additionalSourceAppSpecificFormItems = [
      [
        GeneratedFormItem(
            label: tr('appId'),
            hint: tr('reposHaveMultipleApps'),
            required: true,
            key: 'appId')
      ]
    ];
  }

  @override
  String standardizeURL(String url) {
    RegExp standardUrlRegExp =
        RegExp('^https?://.+/fdroid/(repo(/|\\?)|repo\$)');
    RegExpMatch? match = standardUrlRegExp.firstMatch(url.toLowerCase());
    if (match == null) {
      throw InvalidURLError(name);
    }
    return url.substring(0, match.end);
  }

  @override
  String? tryInferringAppId(String standardUrl,
      {List<String> additionalData = const []}) {
    return findGeneratedFormValueByKey(
        additionalSourceAppSpecificFormItems
            .reduce((value, element) => [...value, ...element]),
        additionalData,
        'appId');
  }

  @override
  Future<APKDetails> getLatestAPKDetails(
      String standardUrl, List<String> additionalData,
      {bool trackOnly = false}) async {
    String? appId =
        tryInferringAppId(standardUrl, additionalData: additionalData);
    if (appId == null) {
      throw NoReleasesError();
    }
    var res = await get(Uri.parse('$standardUrl/index.xml'));
    if (res.statusCode == 200) {
      var body = parse(res.body);
      var foundApps = body
          .querySelectorAll('application')
          .where((element) => element.attributes['id'] == appId)
          .toList();
      if (foundApps.isEmpty) {
        throw NoReleasesError();
      }
      var authorName = body.querySelector('repo')?.attributes['name'] ?? name;
      var appName = foundApps[0].querySelector('name')?.innerHtml ?? appId;
      var releases = foundApps[0].querySelectorAll('package');
      String? latestVersion = releases[0].querySelector('version')?.innerHtml;
      if (latestVersion == null) {
        throw NoVersionError();
      }
      List<String> apkUrls = releases
          .where((element) =>
              element.querySelector('version')?.innerHtml == latestVersion &&
              element.querySelector('apkname') != null)
          .map((e) => '$standardUrl/${e.querySelector('apkname')!.innerHtml}')
          .toList();
      return APKDetails(latestVersion, apkUrls, AppNames(authorName, appName));
    } else {
      throw NoReleasesError();
    }
  }
}