refactor: repositories screen constructor

lib/screens/organization.dart

@@ -123,7 +123,7 @@ class OrganizationScreen extends StatelessWidget {
                 count: payload['pinnableItems']['totalCount'],
                 text: 'Repositories',
                 screenBuilder: (context) =>
-                    RepositoriesScreen(login, org: true),
+                    RepositoriesScreen.ofOrganization(login),
               ),
               EntryItem(
                 count: payload['membersWithRole']['totalCount'],

lib/screens/repositories.dart

@@ -6,43 +6,51 @@ import 'package:provider/provider.dart';
 import '../utils/utils.dart';
 import 'package:git_touch/widgets/repository_item.dart';
 
-// TODO: refactor
 class RepositoriesScreen extends StatelessWidget {
   final String login;
-  final bool star;
-  final bool org;
+  final String title;
+  final String scope;
+  final String resource;
+  final String extra0;
+  final String extra1;
+  final String extra2;
 
-  RepositoriesScreen(this.login, {this.star = false, this.org = false});
-
-  String get scope => org ? 'organization' : 'user';
-  String get resource =>
-      org ? 'pinnableItems' : star ? 'starredRepositories' : 'repositories';
-  String get fieldOrderBy {
-    if (star) {
-      return 'STARRED_AT';
-    }
-    if (org) {
-      return 'PUSHED_AT';
-    }
-    return 'UPDATED_AT';
-  }
+  RepositoriesScreen(this.login)
+      : title = 'Repositories',
+        scope = 'user',
+        resource = 'repositories',
+        extra0 = 'orderBy: {field: UPDATED_AT, direction: DESC}',
+        extra1 = '',
+        extra2 = '';
+  RepositoriesScreen.stars(this.login)
+      : title = 'Stars',
+        scope = 'user',
+        resource = 'starredRepositories',
+        extra0 = 'orderBy: {field: STARRED_AT, direction: DESC}',
+        extra1 = '',
+        extra2 = '';
+  RepositoriesScreen.ofOrganization(this.login)
+      : title = 'Repositories',
+        scope = 'organization',
+        resource = 'pinnableItems',
+        extra0 = 'types: [REPOSITORY]',
+        extra1 = '... on Repository {',
+        extra2 = '}';
 
   Future<ListPayload> _queryRepos(BuildContext context, [String cursor]) async {
-    var filterChunk = org
-        ? ', types: [REPOSITORY],'
-        : ', orderBy: {field: $fieldOrderBy, direction: DESC}';
     var cursorChunk = cursor == null ? '' : ', after: "$cursor"';
-    var contentChunk = org ? '''... on Repository { $repoChunk }''' : repoChunk;
     var data = await Provider.of<SettingsModel>(context).query('''
 {
   $scope(login: "$login") {
-    $resource(first: $pageSize$cursorChunk$filterChunk) {
+    $resource(first: $pageSize$cursorChunk, $extra0) {
       pageInfo {
         hasNextPage
         endCursor
       }
       nodes {
-        $contentChunk
+        $extra1
+        $repoChunk
+        $extra2
       }
     }
   }
@@ -60,7 +68,7 @@ class RepositoriesScreen extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return ListScaffold(
-      title: AppBarTitle(star ? 'Stars' : 'Repositories'),
+      title: AppBarTitle(title),
       onRefresh: () => _queryRepos(context),
       onLoadMore: (cursor) => _queryRepos(context, cursor),
       itemBuilder: (payload) => RepositoryItem(payload),

lib/screens/user.dart

@@ -209,8 +209,7 @@ class UserScreen extends StatelessWidget {
               EntryItem(
                 count: payload['starredRepositories']['totalCount'],
                 text: 'Stars',
-                screenBuilder: (context) =>
-                    RepositoriesScreen(login, star: true),
+                screenBuilder: (context) => RepositoriesScreen.stars(login),
               ),
               EntryItem(
                 count: payload['followers']['totalCount'],