GSoC - Adding / Removing || Adding comment

lib/locator.dart

@@ -1,5 +1,6 @@
 import 'package:get_it/get_it.dart';
 import 'package:talawa/main.dart';
+import 'package:talawa/services/comment_service.dart';
 import 'package:talawa/services/database_mutation_functions.dart';
 import 'package:talawa/services/event_service.dart';
 import 'package:talawa/services/graphql_config.dart';
@@ -19,6 +20,7 @@ import 'package:talawa/view_model/pre_auth_view_models/select_organization_view_
 import 'package:talawa/view_model/pre_auth_view_models/set_url_view_model.dart';
 import 'package:talawa/view_model/pre_auth_view_models/signup_details_view_model.dart';
 import 'package:talawa/view_model/pre_auth_view_models/waiting_view_model.dart';
+import 'package:talawa/view_model/widgets_view_models/comments_view_model.dart';
 import 'package:talawa/view_model/widgets_view_models/custom_drawer_view_model.dart';
 import 'package:talawa/view_model/widgets_view_models/like_button_view_model.dart';
 import 'package:talawa/view_model/widgets_view_models/progress_dialog_view_model.dart';
@@ -41,9 +43,10 @@ void setupLocator() {
   //userConfig
   locator.registerSingleton(UserConfig());
 
+  //Services
   locator.registerLazySingleton(() => PostService());
-
   locator.registerLazySingleton(() => EventService());
+  locator.registerLazySingleton(() => CommentService());
 
   //graphql
   locator.registerSingleton(GraphqlConfig());
@@ -74,4 +77,5 @@ void setupLocator() {
   locator.registerFactory(() => ProgressDialogViewModel());
   locator.registerFactory(() => CustomDrawerViewModel());
   locator.registerFactory(() => LikeButtonViewModel());
+  locator.registerFactory(() => CommentsViewModel());
 }

lib/services/comment_service.dart

@@ -0,0 +1,32 @@
+import 'package:talawa/locator.dart';
+import 'package:talawa/services/database_mutation_functions.dart';
+import 'package:talawa/utils/comment_queries.dart';
+
+class CommentService {
+  CommentService() {
+    _dbFunctions = locator<DataBaseMutationFunctions>();
+  }
+  late DataBaseMutationFunctions _dbFunctions;
+
+  Future<void> createComments(String postId, String text) async {
+    print("comment service called");
+    final String _createCommentQuery = CommentQueries().createComment();
+    final result =
+        await _dbFunctions.gqlAuthMutation(_createCommentQuery, variables: {
+      'postId': postId, //Add your variables here
+      'text': text
+    });
+    print("comment added");
+    print(result);
+    return result;
+  }
+
+  Future getCommentsForPost(String postId) async {
+    final String _getCommmentQuery = CommentQueries().getPostsComments(postId);
+    final result = await _dbFunctions.gqlAuthMutation(_getCommmentQuery);
+    if (result.data != null) {
+      return result.data["commentsByPost"] as List;
+    }
+    return [];
+  }
+}

lib/services/post_service.dart

@@ -11,22 +11,36 @@ import 'package:talawa/utils/post_queries.dart';
 class PostService {
   PostService() {
     _postStream = _postStreamController.stream.asBroadcastStream();
+    _updatedPostStream =
+        _updatedPostStreamController.stream.asBroadcastStream();
     _currentOrg = _userConfig.currentOrg;
     setOrgStreamSubscription();
   }
+  // Stream for entire posts
+  final StreamController<List<Post>> _postStreamController =
+      StreamController<List<Post>>();
+  late Stream<List<Post>> _postStream;
+
+  //Stream for individul post update
+  final StreamController<Post> _updatedPostStreamController =
+      StreamController<Post>();
+  late Stream<Post> _updatedPostStream;
 
-  final StreamController<Post> _postStreamController = StreamController<Post>();
-  late Stream<Post> _postStream;
   final _userConfig = locator<UserConfig>();
   final _dbFunctions = locator<DataBaseMutationFunctions>();
   late OrgInfo _currentOrg;
+  final Set<String> _renderedPostID = {};
+  // ignore: prefer_final_fields
+  List<Post> _posts = [];
 
   //Getters
-  Stream<Post> get postStream => _postStream;
+  Stream<List<Post>> get postStream => _postStream;
+  Stream<Post> get updatedPostStream => _updatedPostStream;
 
   //Setters
   void setOrgStreamSubscription() {
     _userConfig.currentOrfInfoStream.listen((updatedOrganization) {
+      _renderedPostID.clear();
       _currentOrg = updatedOrganization;
     });
   }
@@ -42,16 +56,64 @@ class PostService {
     if (result.data!['postsByOrganization'] == null) return;
 
     final List postsJson = result.data!['postsByOrganization'] as List;
+
+    final List<Post> _newPosts = [];
     postsJson.forEach((postJson) {
       final Post post = Post.fromJson(postJson as Map<String, dynamic>);
-      _postStreamController.add(post);
+      if (!_renderedPostID.contains(post.sId)) {
+        _newPosts.add(post);
+        _renderedPostID.add(post.sId);
+      }
     });
+    _postStreamController.add(_newPosts);
+    _posts = _newPosts;
   }
 
-  Future<void> addLike(String postID) {
+  // --- Functions related to Likes --- //
+  Future<void> addLike(String postID) async {
+    _localAddLike(postID);
     final String mutation = PostQueries().addLike();
-    final result =
-        _dbFunctions.gqlAuthMutation(mutation, variables: {"postID": postID});
+    final result = await _dbFunctions
+        .gqlAuthMutation(mutation, variables: {"postID": postID});
+    print(result);
     return result;
   }
+
+  void _localAddLike(String postID) {
+    _posts.forEach((post) {
+      if (post.sId == postID) {
+        post.likedBy!.add(LikedBy(sId: _userConfig.currentUser.id));
+        _updatedPostStreamController.add(post);
+      }
+    });
+  }
+
+  Future<void> removeLike(String postID) async {
+    _removeLocal(postID);
+    final String mutation = PostQueries().removeLike();
+    final result = await _dbFunctions
+        .gqlAuthMutation(mutation, variables: {"postID": postID});
+    print(result);
+    return result;
+  }
+
+  void _removeLocal(String postID) {
+    _posts.forEach((post) {
+      if (post.sId == postID) {
+        post.likedBy!.removeWhere(
+            (likeUser) => likeUser.sId == _userConfig.currentUser.id);
+        _updatedPostStreamController.add(post);
+      }
+    });
+  }
+
+  // --- Functions related to comments --- //
+  void addCommentLocally(String postID) {
+    for (int i = 0; i < _posts.length; i++) {
+      if (_posts[i].sId == postID) {
+        _posts[i].comments!.add(Comments(sId: postID));
+        _updatedPostStreamController.add(_posts[i]);
+      }
+    }
+  }
 }

lib/utils/comment_queries.dart

@@ -0,0 +1,31 @@
+class CommentQueries {
+  String createComment() {
+    return """
+     mutation createComment(\$postId: ID!, \$text: String!) { 
+      createComment(postId: \$postId, 
+        data:{
+          text: \$text,
+        }
+      ){
+        _id
+      }
+    }
+  """;
+  }
+
+  String getPostsComments(String postId) {
+    return """
+    query{
+      commentsByPost(id: "$postId"){
+        _id
+        text
+        createdAt
+        creator{
+          firstName
+          lastName
+        }
+      }
+    }
+    """;
+  }
+}

lib/utils/post_queries.dart

@@ -42,4 +42,18 @@ class PostQueries {
     }
   """;
   }
+
+  String removeLike() {
+    return """
+     mutation unlikePost(\$postID: ID!) { 
+      unlikePost( id: \$postID,)
+      {
+        _id
+        likedBy{
+        _id
+        }
+      }
+    }
+  """;
+  }
 }

lib/view_model/after_auth_view_models/feed_view_models/organization_feed_view_model.dart

@@ -10,7 +10,8 @@ import 'package:talawa/view_model/base_view_model.dart';
 
 class OrganizationFeedViewModel extends BaseModel {
   // Local caching variables for a session.
-  final List<Post> _posts = [], _pinnedPosts = [];
+  // ignore: prefer_final_fields
+  List<Post> _posts = [], _pinnedPosts = [];
   final Set<String> _renderedPostID = {};
   late String _currentOrgname = "";
 
@@ -22,6 +23,7 @@ class OrganizationFeedViewModel extends BaseModel {
   // Stream variables
   late StreamSubscription _currentOrganizationStreamSubscription;
   late StreamSubscription _postsSubscription;
+  late StreamSubscription _updatePostSubscription;
 
   // Getters
   List<Post> get posts => _posts;
@@ -44,15 +46,18 @@ class OrganizationFeedViewModel extends BaseModel {
   void initialise() {
     // For caching/initalizing the current organization after the stream subsciption has canceled and the stream is updated
     _currentOrgname = _userConfig.currentOrg.name!;
-
+    _postService.getPosts();
     // ------
     // Attasching the stream subscription to rebuild the widgets automatically
     _currentOrganizationStreamSubscription = _userConfig.currentOrfInfoStream
         .listen((updatedOrganization) =>
             setCurrentOrganizationName(updatedOrganization.name!));
 
-    _postsSubscription = _postService.postStream
-        .listen((newPost) => checkIfExistsAndAddNewPost(newPost));
+    _postsSubscription =
+        _postService.postStream.listen((newPosts) => buildNewPosts(newPosts));
+
+    _updatePostSubscription =
+        _postService.updatedPostStream.listen((post) => updatedPost(post));
   }
 
   void initializeWithDemoData() {
@@ -69,13 +74,9 @@ class OrganizationFeedViewModel extends BaseModel {
     // });
   }
 
-  void checkIfExistsAndAddNewPost(Post newPost) {
-    if (!_renderedPostID.contains(newPost.sId)) {
-      // print(newPost.sId);
-      _renderedPostID.add(newPost.sId);
-      _posts.add(newPost);
-      notifyListeners();
-    }
+  void buildNewPosts(List<Post> newPosts) {
+    _posts = newPosts;
+    notifyListeners();
   }
 
   void navigateToIndividualPage(Post post) {
@@ -92,11 +93,22 @@ class OrganizationFeedViewModel extends BaseModel {
     // Canceling the subscription so that there will be no rebuild after the widget is disposed.
     _currentOrganizationStreamSubscription.cancel();
     _postsSubscription.cancel();
+    _updatePostSubscription.cancel();
     super.dispose();
   }
 
   addNewPost(Post newPost) {
     _posts.insert(0, newPost);
     notifyListeners();
   }
+
+  updatedPost(Post post) {
+    for (int i = 0; i < _posts.length; i++) {
+      if (_posts[i].sId == post.sId) {
+        _posts[i] = post;
+        notifyListeners();
+        break;
+      }
+    }
+  }
 }

lib/view_model/widgets_view_models/comments_view_model.dart

@@ -0,0 +1,54 @@
+import 'package:talawa/enums/enums.dart';
+import 'package:talawa/locator.dart';
+import 'package:talawa/models/comment/comment_model.dart';
+import 'package:talawa/services/comment_service.dart';
+import 'package:talawa/services/post_service.dart';
+import 'package:talawa/services/user_config.dart';
+import 'package:talawa/view_model/base_view_model.dart';
+
+class CommentsViewModel extends BaseModel {
+  late CommentService _commentService;
+  late PostService _postService;
+  late String _postID;
+  late List<Comment> _commentlist;
+  late UserConfig _userConfig;
+
+  // Getters
+  List<Comment> get commentList => _commentlist;
+
+  void initialise(String postID) {
+    _commentlist = [];
+    _postID = postID;
+    _commentService = locator<CommentService>();
+    _userConfig = locator<UserConfig>();
+    _postService = locator<PostService>();
+    notifyListeners();
+    getComments();
+  }
+
+  Future getComments() async {
+    setState(ViewState.busy);
+    final List _commentsJSON =
+        await _commentService.getCommentsForPost(_postID) as List;
+    print(_commentsJSON);
+    _commentsJSON.forEach((commentJson) {
+      _commentlist.add(Comment.fromJson(commentJson as Map<String, dynamic>));
+    });
+    setState(ViewState.idle);
+  }
+
+  Future createComment(String msg) async {
+    print("comment viewModel called");
+    await _commentService.createComments(_postID, msg);
+    addCommentLocally(msg);
+  }
+
+  void addCommentLocally(String msg) {
+    _postService.addCommentLocally(_postID);
+    final _creator = _userConfig.currentUser;
+    final Comment _localComment = Comment(
+        text: msg, createdAt: DateTime.now().toString(), creator: _creator);
+    _commentlist.insert(0, _localComment);
+    notifyListeners();
+  }
+}