Infer GitHub App ID where possible

lib/app_sources/apkcombo.dart

@@ -19,8 +19,8 @@ class APKCombo extends AppSource {
   }
 
   @override
-  String? tryInferringAppId(String standardUrl,
+  Future<String?> tryInferringAppId(String standardUrl,
-      {Map<String, dynamic> additionalSettings = const {}}) {
+      {Map<String, dynamic> additionalSettings = const {}}) async {
     return Uri.parse(standardUrl).pathSegments.last;
   }
 
@@ -83,7 +83,7 @@ class APKCombo extends AppSource {
     String standardUrl,
     Map<String, dynamic> additionalSettings,
   ) async {
-    String appId = tryInferringAppId(standardUrl)!;
+    String appId = (await tryInferringAppId(standardUrl))!;
     var preres = await sourceRequest(standardUrl);
     if (preres.statusCode != 200) {
       throw getObtainiumHttpError(preres);

lib/app_sources/apkpure.dart

@@ -24,8 +24,8 @@ class APKPure extends AppSource {
   }
 
   @override
-  String? tryInferringAppId(String standardUrl,
+  Future<String?> tryInferringAppId(String standardUrl,
-      {Map<String, dynamic> additionalSettings = const {}}) {
+      {Map<String, dynamic> additionalSettings = const {}}) async {
     return Uri.parse(standardUrl).pathSegments.last;
   }
 
@@ -34,7 +34,7 @@ class APKPure extends AppSource {
     String standardUrl,
     Map<String, dynamic> additionalSettings,
   ) async {
-    String appId = tryInferringAppId(standardUrl)!;
+    String appId = (await tryInferringAppId(standardUrl))!;
     String host = Uri.parse(standardUrl).host;
     var res = await sourceRequest('$standardUrl/download');
     if (res.statusCode == 200) {

lib/app_sources/fdroid.dart

@@ -31,8 +31,8 @@ class FDroid extends AppSource {
   }
 
   @override
-  String? tryInferringAppId(String standardUrl,
+  Future<String?> tryInferringAppId(String standardUrl,
-      {Map<String, dynamic> additionalSettings = const {}}) {
+      {Map<String, dynamic> additionalSettings = const {}}) async {
     return Uri.parse(standardUrl).pathSegments.last;
   }
 
@@ -63,7 +63,7 @@ class FDroid extends AppSource {
     String standardUrl,
     Map<String, dynamic> additionalSettings,
   ) async {
-    String? appId = tryInferringAppId(standardUrl);
+    String? appId = await tryInferringAppId(standardUrl);
     String host = Uri.parse(standardUrl).host;
     return getAPKUrlsFromFDroidPackagesAPIResponse(
         await sourceRequest('https://$host/api/v1/packages/$appId'),

lib/app_sources/github.dart

@@ -6,6 +6,7 @@ import 'package:obtainium/app_sources/html.dart';
 import 'package:obtainium/components/generated_form.dart';
 import 'package:obtainium/custom_errors.dart';
 import 'package:obtainium/providers/apps_provider.dart';
+import 'package:obtainium/providers/logs_provider.dart';
 import 'package:obtainium/providers/settings_provider.dart';
 import 'package:obtainium/providers/source_provider.dart';
 import 'package:url_launcher/url_launcher_string.dart';
@@ -79,6 +80,44 @@ class GitHub extends AppSource {
     canSearch = true;
   }
 
+  @override
+  Future<String?> tryInferringAppId(String standardUrl,
+      {Map<String, dynamic> additionalSettings = const {}}) async {
+    const possibleBuildGradleLocations = [
+      '/app/build.gradle',
+      'android/app/build.gradle',
+      'src/app/build.gradle'
+    ];
+    for (var path in possibleBuildGradleLocations) {
+      try {
+        var res = await sourceRequest(
+            '${await convertStandardUrlToAPIUrl(standardUrl)}/contents/$path');
+        if (res.statusCode == 200) {
+          try {
+            var body = jsonDecode(res.body);
+            var appId = utf8
+                .decode(base64
+                    .decode(body['content'].toString().split('\n').join('')))
+                .split('\n')
+                .map((e) => e.trim())
+                .where((l) => l.startsWith('applicationId "'))
+                .first
+                .split('"')[1];
+            if (appId.isNotEmpty) {
+              return appId;
+            }
+          } catch (err) {
+            LogsProvider().add(
+                'Error parsing build.gradle from ${res.request!.url.toString()}: ${err.toString()}');
+          }
+        }
+      } catch (err) {
+        // Ignore - ID will be extracted from the APK
+      }
+    }
+    return null;
+  }
+
   @override
   String sourceSpecificStandardizeURL(String url) {
     RegExp standardUrlRegEx = RegExp('^https?://$host/[^/]+/[^/]+');
@@ -97,6 +136,12 @@ class GitHub extends AppSource {
     return creds != null && creds.isNotEmpty ? '$creds@' : '';
   }
 
+  Future<String> getAPIHost() async =>
+      'https://${await getCredentialPrefixIfAny()}api.$host';
+
+  Future<String> convertStandardUrlToAPIUrl(String standardUrl) async =>
+      '${await getAPIHost()}/repos${standardUrl.substring('https://$host'.length)}';
+
   @override
   String? changeLogPageFromStandardUrl(String standardUrl) =>
       '$standardUrl/releases';
@@ -239,7 +284,7 @@ class GitHub extends AppSource {
   ) async {
     return await getLatestAPKDetailsCommon2(standardUrl, additionalSettings,
         (bool useTagUrl) async {
-      return 'https://${await getCredentialPrefixIfAny()}api.$host/repos${standardUrl.substring('https://$host'.length)}/${useTagUrl ? 'tags' : 'releases'}?per_page=100';
+      return '${await convertStandardUrlToAPIUrl(standardUrl)}/${useTagUrl ? 'tags' : 'releases'}?per_page=100';
     }, (Response res) {
       rateLimitErrorCheck(res);
     });
@@ -281,7 +326,7 @@ class GitHub extends AppSource {
   Future<Map<String, List<String>>> search(String query) async {
     return searchCommon(
         query,
-        'https://${await getCredentialPrefixIfAny()}api.$host/search/repositories?q=${Uri.encodeQueryComponent(query)}&per_page=100',
+        '${await getAPIHost()}/search/repositories?q=${Uri.encodeQueryComponent(query)}&per_page=100',
         'items', onHttpErrorCode: (Response res) {
       rateLimitErrorCheck(res);
     });

lib/app_sources/izzyondroid.dart

@@ -18,8 +18,8 @@ class IzzyOnDroid extends AppSource {
   }
 
   @override
-  String? tryInferringAppId(String standardUrl,
+  Future<String?> tryInferringAppId(String standardUrl,
-      {Map<String, dynamic> additionalSettings = const {}}) {
+      {Map<String, dynamic> additionalSettings = const {}}) async {
     return FDroid().tryInferringAppId(standardUrl);
   }
 
@@ -28,7 +28,7 @@ class IzzyOnDroid extends AppSource {
     String standardUrl,
     Map<String, dynamic> additionalSettings,
   ) async {
-    String? appId = tryInferringAppId(standardUrl);
+    String? appId = await tryInferringAppId(standardUrl);
     return FDroid().getAPKUrlsFromFDroidPackagesAPIResponse(
         await sourceRequest(
             'https://apt.izzysoft.de/fdroid/api/v1/packages/$appId'),

lib/providers/source_provider.dart

@@ -434,8 +434,8 @@ abstract class AppSource {
     throw NotImplementedError();
   }
 
-  String? tryInferringAppId(String standardUrl,
+  Future<String?> tryInferringAppId(String standardUrl,
-      {Map<String, dynamic> additionalSettings = const {}}) {
+      {Map<String, dynamic> additionalSettings = const {}}) async {
     return null;
   }
 }
@@ -592,7 +592,7 @@ class SourceProvider {
         : apk.names.name[0].toUpperCase() + apk.names.name.substring(1);
     return App(
         currentApp?.id ??
-            source.tryInferringAppId(standardUrl,
+            await source.tryInferringAppId(standardUrl,
                 additionalSettings: additionalSettings) ??
             generateTempID(standardUrl, additionalSettings),
         standardUrl,