Reader: Fix an issue with navigateToCommentID failing to find comments

RELEASE-NOTES.txt

@@ -12,6 +12,7 @@
 * [*] Stats: Fix an issue where tapping on a bar in a bar chart would somtimes select an adjacent bar [#25374]
 * [*] Stats: Improve bar selection. When you tap on a bar, it will now select this subrange without fully navigating it, which makes it much easier to go through multiple subranges. [#25374]
 * [*] Stats: Usability improvements [#25404]
+* [*] Reader: Fix an issue with the "Comments" screen sometimes failing to scroll to the comment selected from the "Notifications" [#25389]
 * [*] Reader: Fix an issue with pan gesture failing to dismiss Lightbox [#25372]
 * [*] Reader: Fix color of links in comments [#25390]
 * [*] Reader: Fix color or links in dark mode on custom themes [#25391]

WordPress/Classes/Services/CommentService.m

@@ -7,7 +7,7 @@
 
 @import WordPressShared;
 
-NSUInteger const WPTopLevelHierarchicalCommentsPerPage = 20;
+NSUInteger const WPTopLevelHierarchicalCommentsPerPage = 40;
 NSInteger const  WPNumberOfCommentsToSync = 100;
 static NSTimeInterval const CommentsRefreshTimeoutInSeconds = 60 * 5; // 5 minutes
 

WordPress/Classes/ViewRelated/Comments/Views/Detail/CommentContentTableViewCell.swift

@@ -205,6 +205,24 @@ final class CommentContentTableViewCell: UITableViewCell, NibReusable {
         containerStackTrailingConstraint.constant = 0
     }
 
+    /// Emphasizes the cell and draws the user's attention with a flash that settles at the target highlight level.
+    func flashHighlight() {
+        isEmphasized = true
+
+        guard let highlightedBackgroundView else {
+            return wpAssertionFailure("background view not configured")
+        }
+
+        let originalBackgroundColor = highlightedBackgroundView.backgroundColor
+        UIView.animate(withDuration: 0.33, delay: 0.5, options: .curveEaseOut) {
+            highlightedBackgroundView.backgroundColor = UIAppColor.blue.withAlphaComponent(0.09)
+        } completion: { _ in
+            UIView.animate(withDuration: 0.33, delay: 1.5, options: .curveEaseOut) {
+                highlightedBackgroundView.backgroundColor = originalBackgroundColor
+            }
+        }
+    }
+
     func hideActions() {
         replyButton.isHidden = true
         likeButton.isHidden = true
@@ -233,7 +251,7 @@ final class CommentContentTableViewCell: UITableViewCell, NibReusable {
         }
         for level in 0..<depth {
             let separatorView = depthSeparators[level] ?? {
-                let separatorView = SeparatorView.vertical()
+                let separatorView = SeparatorView.vertical(width: 1.0)
                 depthSeparators[level] = separatorView
                 contentView.addSubview(separatorView)
                 separatorView.pinEdges([.top, .bottom])

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

@@ -96,6 +96,10 @@ final class ReaderCommentsTableViewController: UIViewController, UITableViewData
     }
 
     @objc func scrollToComment(withID commentID: NSNumber) -> Bool {
+        scrollToComment(withID: commentID, animated: true)
+    }
+
+    func scrollToComment(withID commentID: NSNumber, animated: Bool) -> Bool {
         let comments = fetchResultsController.fetchedObjects ?? []
         guard let comment = comments.first(where: { $0.commentID == commentID.int32Value }) else {
             return false

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

@@ -43,6 +43,11 @@ final class ReaderCommentsViewController: UIViewController, WPContentSyncHelperD
     private var commentModified = false
     private var highlightedIndexPath: IndexPath?
 
+    private var navigationOverlayView: UIView?
+    private var navigationPagesLoaded = 0
+    private var navigationCommentID: Int32?
+    private var onNavigationCommentRendered: (() -> Void)?
+
     private var syncHelper: WPContentSyncHelper?
     private var followCommentsService: FollowCommentsService?
     private var readerCommentsFollowPresenter: ReaderCommentsFollowPresenter?
@@ -362,7 +367,8 @@ final class ReaderCommentsViewController: UIViewController, WPContentSyncHelperD
         let isModerationEnabled = comment.allowsModeration()
         cell.accessoryButton.showsMenuAsPrimaryAction = isModerationEnabled
         cell.accessoryButton.menu = isModerationEnabled ? menu(for: comment, indexPath: indexPath, tableView: tableView, sourceView: cell.accessoryButton) : nil
-        cell.configure(viewModel: viewModel, helper: helper) { [weak tableView] _ in
+        let commentID = comment.commentID
+        cell.configure(viewModel: viewModel, helper: helper) { [weak self, weak tableView] _ in
             guard let tableView else { return }
 
             if tableView.alpha == 0 {
@@ -373,6 +379,7 @@ final class ReaderCommentsViewController: UIViewController, WPContentSyncHelperD
             UIView.setAnimationsEnabled(false)
             tableView.performBatchUpdates({})
             UIView.setAnimationsEnabled(true)
+            self?.commentRenderedIfNeeded(commentID: commentID)
         }
 
         cell.isEmphasized = indexPath == highlightedIndexPath
@@ -427,15 +434,89 @@ final class ReaderCommentsViewController: UIViewController, WPContentSyncHelperD
         self.highlightedIndexPath = indexPath
     }
 
+    // Shows an overlay while searching for the target comment across pages (up to 5).
+    // Once found, waits for the cell's WebKit content to finish rendering, then
+    // fades the overlay out and flashes the cell to draw the user's attention.
     private func navigateToCommentIDIfNeeded() {
-        guard let navigateToCommentID, let tableVC else {
-            return
+        guard let navigateToCommentID, let tableVC else { return }
+
+        showNavigationOverlay()
+
+        if tableVC.scrollToComment(withID: navigateToCommentID, animated: false) {
+            let commentID = navigateToCommentID.int32Value
+            self.navigateToCommentID = nil
+            self.navigationPagesLoaded = 0
+            setupNavigationReveal(commentID: commentID, in: tableVC)
+        } else if navigationPagesLoaded < 5, let syncHelper, syncHelper.hasMoreContent {
+            navigationPagesLoaded += 1
+            syncHelper.syncMoreContent()
+        } else {
+            self.navigateToCommentID = nil
+            self.navigationPagesLoaded = 0
+            hideNavigationOverlay(completion: nil)
         }
-        DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(500)) {
-            if tableVC.scrollToComment(withID: navigateToCommentID) {
-                self.navigateToCommentID = nil
+    }
+
+    private func setupNavigationReveal(commentID: Int32, in tableVC: ReaderCommentsTableViewController) {
+        navigationCommentID = commentID
+
+        let reveal: () -> Void = { [weak self, weak tableVC] in
+            guard let self, let tableVC, self.navigationCommentID == commentID else { return }
+            self.navigationCommentID = nil
+            self.onNavigationCommentRendered = nil
+
+            guard let indexPath = self.highlightedIndexPath else { return }
+            tableVC.tableView.scrollToRow(at: indexPath, at: .top, animated: false)
+
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.33) { [weak self, weak tableVC] in
+                guard let self, let tableVC else { return }
+                // The initial scroll occasionally fails due to the async rendering
+                tableVC.tableView.scrollToRow(at: indexPath, at: .top, animated: false)
+                self.hideNavigationOverlay {
+                    (tableVC.tableView.cellForRow(at: indexPath) as? CommentContentTableViewCell)?.flashHighlight()
+                }
             }
         }
+
+        onNavigationCommentRendered = reveal
+
+        // Safety timeout in case the render callback never fires
+        DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) { [weak self] in
+            guard self?.navigationCommentID == commentID else { return }
+            reveal()
+        }
+    }
+
+    func commentRenderedIfNeeded(commentID: Int32) {
+        guard commentID == navigationCommentID else { return }
+        onNavigationCommentRendered?()
+    }
+
+    private func showNavigationOverlay() {
+        guard navigationOverlayView == nil else { return }
+        let overlay = UIView()
+        overlay.backgroundColor = .systemBackground
+        let spinner = UIActivityIndicatorView(style: .medium)
+        spinner.startAnimating()
+        overlay.addSubview(spinner)
+        spinner.pinCenter()
+        view.addSubview(overlay)
+        overlay.pinEdges()
+        navigationOverlayView = overlay
+    }
+
+    private func hideNavigationOverlay(completion: (() -> Void)?) {
+        guard let overlay = navigationOverlayView else {
+            completion?()
+            return
+        }
+        navigationOverlayView = nil
+        UIView.animate(withDuration: 0.33) {
+            overlay.alpha = 0
+        } completion: { _ in
+            overlay.removeFromSuperview()
+            completion?()
+        }
     }
 
     // MARK: - Tracking