Simplify like update code

lib/helpers/posts_helper.dart

@@ -85,7 +85,7 @@ class PostsHelper {
       linkDescription: map["link_description"],
       linkImage: map["link_image"],
       likes: map["likes"],
-      userLikes: map["userlike"],
+      userLike: map["userlike"],
       access: _APIUserAccessMap[map["user_access"]],
       comments: comments,
     );

lib/models/comment.dart

@@ -1,3 +1,4 @@
+import 'package:comunic/models/like_element.dart';
 import 'package:meta/meta.dart';
 
 /// Comments
@@ -6,7 +7,7 @@ import 'package:meta/meta.dart';
 ///
 /// @author Pierre HUBERT
 
-class Comment {
+class Comment implements LikeElement {
   final int id;
   final int userID;
   final int postID;

lib/models/like_element.dart

@@ -0,0 +1,11 @@
+/// Element that can be liked by the user
+///
+/// @author Pierre HUBERT
+
+abstract class LikeElement {
+
+  int get id;
+  bool userLike;
+  int likes;
+
+}

lib/models/post.dart

@@ -2,13 +2,14 @@ import 'package:comunic/enums/post_kind.dart';
 import 'package:comunic/enums/post_visibility_level.dart';
 import 'package:comunic/enums/user_access_levels.dart';
 import 'package:comunic/lists/comments_list.dart';
+import 'package:comunic/models/like_element.dart';
 import 'package:meta/meta.dart';
 
 /// Single post information
 ///
 /// @author Pierre HUBERT
 
-class Post {
+class Post implements LikeElement {
   final int id;
   final int userID;
   final int userPageID;
@@ -27,7 +28,7 @@ class Post {
   final String linkDescription;
   final String linkImage;
   int likes;
-  bool userLikes;
+  bool userLike;
   final UserAccessLevels access;
   final CommentsList comments;
 
@@ -50,7 +51,7 @@ class Post {
     @required this.linkDescription,
     @required this.linkImage,
     @required this.likes,
-    @required this.userLikes,
+    @required this.userLike,
     @required this.access,
     @required this.comments
   })  : assert(id != null),
@@ -62,7 +63,7 @@ class Post {
         assert(kind != null),
         assert(kind != PostKind.COUNTDOWN || timeEnd != null),
         assert(likes != null),
-        assert(userLikes != null),
+        assert(userLike != null),
         assert(access != null);
 
   bool get hasContent => content != null;

lib/ui/tiles/post_tile.dart

@@ -6,6 +6,7 @@ import 'package:comunic/helpers/comments_helper.dart';
 import 'package:comunic/helpers/likes_helper.dart';
 import 'package:comunic/lists/users_list.dart';
 import 'package:comunic/models/comment.dart';
+import 'package:comunic/models/like_element.dart';
 import 'package:comunic/models/new_comment.dart';
 import 'package:comunic/models/post.dart';
 import 'package:comunic/models/user.dart';
@@ -126,7 +127,7 @@ class _PostTileState extends State<PostTile> {
           // Like button
           Center(
             child: InkWell(
-              onTap: () => _updateLike(),
+              onTap: () => _updatePostLike(),
               child: Row(
                 crossAxisAlignment: CrossAxisAlignment.center,
                 mainAxisAlignment: MainAxisAlignment.center,
@@ -135,7 +136,7 @@ class _PostTileState extends State<PostTile> {
                     padding: const EdgeInsets.only(left: 8.0, right: 8.0),
                     child: Icon(
                       Icons.thumb_up,
-                      color: widget.post.userLikes ? Colors.blue : null,
+                      color: widget.post.userLike ? Colors.blue : null,
                     ),
                   ),
                   Text(widget.post.likes < 2
@@ -339,34 +340,28 @@ class _PostTileState extends State<PostTile> {
   }
 
   /// Update like status
-  Future<void> _updateLike() async {
+  Future<void> _updatePostLike() async {
-    // Update liking status
+    _updateElementLike(LikesType.POST, widget.post);
-    _likesHelper.setLiking(
-      type: LikesType.POST,
-      like: !widget.post.userLikes,
-      id: widget.post.id,
-    );
-
-    // Save new like status
-    setState(() {
-      widget.post.userLikes = !widget.post.userLikes;
-      widget.post.userLikes ? widget.post.likes++ : widget.post.likes--;
-    });
   }
 
   /// Invert comment like status
   Future<void> _updateCommentLike(Comment comment) async {
+    _updateElementLike(LikesType.COMMENT, comment);
+  }
+
+  /// Invert element like status
+  Future<void> _updateElementLike(LikesType type, LikeElement element) async {
     // Update liking status
     _likesHelper.setLiking(
-      type: LikesType.COMMENT,
+      type: type,
-      like: !comment.userLike,
+      like: !element.userLike,
-      id: comment.id,
+      id: element.id,
     );
 
     // Save new like status
     setState(() {
-      comment.userLike = !comment.userLike;
+      element.userLike = !element.userLike;
-      comment.userLike ? comment.likes++ : comment.likes--;
+      element.userLike ? element.likes++ : element.likes--;
     });
   }
 }