Reader: Fix comments being misplaced after parent comment is moderated

MIGRATIONS.md

@@ -3,6 +3,12 @@
 This file documents changes in the data model. Please explain any changes to the
 data model as well as any custom migrations.
 
+## WordPress 138
+
+@dvdchr 2022-03-07
+
+- `Comment`: added `visibleOnReader` attribute. (required, default `true`, `Boolean`)
+
 ## WordPress 137
 
 @dvdchr 2021-11-26

WordPress/Classes/Models/Comment+CoreDataProperties.swift

@@ -28,6 +28,12 @@ extension Comment {
     @NSManaged public var hierarchy: String
     @NSManaged public var replyID: Int32
 
+    /// Determines if the comment should be displayed in the Reader comment thread.
+    ///
+    /// Note that this property is only updated and guaranteed to be correct within the comment thread.
+    /// The value may be outdated when accessed from other places (e.g. My Sites, Notifications).
+    @NSManaged public var visibleOnReader: Bool
+
     /*
      // Hierarchy is a string representation of a comments ancestors. Each ancestor's
      // is denoted by a ten character zero padded representation of its ID

WordPress/Classes/Services/CommentService+Replies.swift

@@ -35,6 +35,45 @@ extension CommentService {
             failure(error)
         }
     }
+
+    /// Update the visibility of the comment's replies on the comment thread.
+    /// Note that this only applies to comments fetched from the Reader Comments section (i.e. has a reference to the `ReaderPost`).
+    ///
+    /// - Parameters:
+    ///   - ancestorComment: The ancestor comment that will have its reply comments iterated.
+    ///   - completion: The block executed after the replies are updated.
+    func updateRepliesVisibility(for ancestorComment: Comment, completion: (() -> Void)? = nil) {
+        guard let context = ancestorComment.managedObjectContext,
+              let post = ancestorComment.post as? ReaderPost,
+              let comments = post.comments as? Set<Comment> else {
+                  completion?()
+                  return
+              }
+
+        let isVisible = (ancestorComment.status == CommentStatusType.approved.description)
+
+        // iterate over the ancestor comment's descendants and update their visibility for the comment thread.
+        //
+        // the hierarchy property stores ancestral info by storing a string version of its comment ID hierarchy,
+        // e.g.: "0000000012.0000000025.00000000035". The idea is to check if the ancestor comment's ID exists in the hierarchy.
+        // as an optimization, skip checking the hierarchy when the comment is the direct child of the ancestor comment.
+        context.perform {
+            comments.filter { comment in
+                comment.parentID == ancestorComment.commentID
+                || comment.hierarchy
+                    .split(separator: ".")
+                    .compactMap({ Int32($0) })
+                    .contains(ancestorComment.commentID)
+            }.forEach { childComment in
+                childComment.visibleOnReader = isVisible
+            }
+
+            ContextManager.shared.save(context)
+            DispatchQueue.main.async {
+                completion?()
+            }
+        }
+    }
 }
 
 private extension CommentService {

WordPress/Classes/Services/CommentService.m

@@ -1169,6 +1169,7 @@ - (void)mergeHierarchicalComments:(NSArray *)comments forPage:(NSUInteger)page f
         return;
     }
 
+    NSMutableSet<NSNumber *> *visibleCommentIds = [NSMutableSet new];
     NSMutableArray *ancestors = [NSMutableArray array];
     NSMutableArray *commentsToKeep = [NSMutableArray array];
     NSString *entityName = NSStringFromClass([Comment class]);
@@ -1186,7 +1187,18 @@ - (void)mergeHierarchicalComments:(NSArray *)comments forPage:(NSUInteger)page f
         // Calculate hierarchy and depth.
         ancestors = [self ancestorsForCommentWithParentID:[NSNumber numberWithInt:comment.parentID] andCurrentAncestors:ancestors];
         comment.hierarchy = [self hierarchyFromAncestors:ancestors andCommentID:[NSNumber numberWithInt:comment.commentID]];
-        comment.depth = [ancestors count];
+
+        // Comments are shown on the thread when (1) it is approved, and (2) its ancestors are approved.
+        // Having the comments sorted hierarchically ascending ensures that each comment's predecessors will be visited first.
+        // Therefore, we only need to check if the comment and its direct parent are approved.
+        // Ref: https://github.com/wordpress-mobile/WordPress-iOS/issues/18081
+        BOOL hasValidParent = comment.parentID > 0 && [visibleCommentIds containsObject:@(comment.parentID)];
+        if ([comment isApproved] && ([comment isTopLevelComment] || hasValidParent)) {
+            [visibleCommentIds addObject:@(comment.commentID)];
+        }
+        comment.visibleOnReader = [visibleCommentIds containsObject:@(comment.commentID)];
+
+        comment.depth = ancestors.count;
         comment.post = post;
         comment.content = [self sanitizeCommentContent:comment.content isPrivateSite:post.isPrivate];
         [commentsToKeep addObject:comment];

WordPress/Classes/ViewRelated/Reader/Comments/ReaderCommentsViewController.m

@@ -1215,7 +1215,7 @@ - (NSFetchRequest *)fetchRequest
     NSString *approvedStatus = [Comment descriptionFor:CommentStatusTypeApproved];
 
     NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:NSStringFromClass([Comment class])];
-    fetchRequest.predicate = [NSPredicate predicateWithFormat:@"post = %@ AND status = %@", self.post, approvedStatus];
+    fetchRequest.predicate = [NSPredicate predicateWithFormat:@"post = %@ AND status = %@ AND visibleOnReader = %@", self.post, approvedStatus, @YES];
     NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"hierarchy" ascending:YES];
     [fetchRequest setSortDescriptors:@[sortDescriptor]];
 

WordPress/Classes/ViewRelated/Reader/Comments/ReaderCommentsViewController.swift

@@ -245,16 +245,23 @@ private extension ReaderCommentsViewController {
 
     func moderateComment(_ comment: Comment, status: CommentStatusType) {
         let successBlock: (String) -> Void = { [weak self] noticeText in
-            self?.commentModified = true
-            self?.refreshAfterCommentModeration()
+            guard let self = self else {
+                return
+            }
 
-            // Dismiss any old notices to avoid stacked Undo notices.
-            self?.dismissNotice()
+            // when a comment is unapproved/spammed/trashed, ensure that all of the replies are hidden.
+            self.commentService.updateRepliesVisibility(for: comment) {
+                self.commentModified = true
+                self.refreshAfterCommentModeration()
 
-            // If the status is Approved, the user has undone a comment moderation.
-            // So don't show the Undo option in this case.
-            (status == .approved) ? self?.displayNotice(title: noticeText) :
-                                    self?.showActionableNotice(title: noticeText, comment: comment)
+                // Dismiss any old notices to avoid stacked Undo notices.
+                self.dismissNotice()
+
+                // If the status is Approved, the user has undone a comment moderation.
+                // So don't show the Undo option in this case.
+                (status == .approved) ? self.displayNotice(title: noticeText) :
+                                        self.showActionableNotice(title: noticeText, comment: comment)
+            }
         }
 
         switch status {

WordPress/Classes/WordPress.xcdatamodeld/.xccurrentversion

@@ -3,6 +3,6 @@
 <plist version="1.0">
 <dict>
 	<key>_XCCurrentVersionName</key>
-	<string>WordPress 137.xcdatamodel</string>
+	<string>WordPress 138.xcdatamodel</string>
 </dict>
 </plist>