add @ symbol when there is mention in unread messages

Session/Shared/ConversationCell.swift

@@ -1,4 +1,5 @@
 import UIKit
+import SessionUIKit
 
 final class ConversationCell : UITableViewCell {
     var threadViewModel: ThreadViewModel! { didSet { update() } }
@@ -37,6 +38,26 @@ final class ConversationCell : UITableViewCell {
         return result
     }()
     
+    private lazy var hasMentionView: UIView = {
+        let result = UIView()
+        result.backgroundColor = Colors.accent
+        let size = ConversationCell.unreadCountViewSize
+        result.set(.width, to: size)
+        result.set(.height, to: size)
+        result.layer.masksToBounds = true
+        result.layer.cornerRadius = size / 2
+        return result
+    }()
+    
+    private lazy var hasMentionLabel: UILabel = {
+        let result = UILabel()
+        result.font = .boldSystemFont(ofSize: Values.verySmallFontSize)
+        result.textColor = Colors.text
+        result.text = "@"
+        result.textAlignment = .center
+        return result
+    }()
+    
     private lazy var timestampLabel: UILabel = {
         let result = UILabel()
         result.font = .systemFont(ofSize: Values.smallFontSize)
@@ -98,9 +119,12 @@ final class ConversationCell : UITableViewCell {
         // Unread count view
         unreadCountView.addSubview(unreadCountLabel)
         unreadCountLabel.pin(to: unreadCountView)
+        // Has mention view
+        hasMentionView.addSubview(hasMentionLabel)
+        hasMentionLabel.pin(to: hasMentionView)
         // Label stack view
         let topLabelSpacer = UIView.hStretchingSpacer()
-        let topLabelStackView = UIStackView(arrangedSubviews: [ displayNameLabel, unreadCountView, topLabelSpacer, timestampLabel ])
+        let topLabelStackView = UIStackView(arrangedSubviews: [ displayNameLabel, unreadCountView, hasMentionView, topLabelSpacer, timestampLabel ])
         topLabelStackView.axis = .horizontal
         topLabelStackView.alignment = .center
         topLabelStackView.spacing = Values.smallSpacing / 2 // Effectively Values.smallSpacing because there'll be spacing before and after the invisible spacer
@@ -176,6 +200,7 @@ final class ConversationCell : UITableViewCell {
         unreadCountLabel.text = unreadCount < 100 ? "\(unreadCount)" : "99+"
         let fontSize = (unreadCount < 100) ? Values.verySmallFontSize : 8
         unreadCountLabel.font = .boldSystemFont(ofSize: fontSize)
+        hasMentionView.isHidden = !threadViewModel.hasUnreadMentions
         profilePictureView.update(for: thread)
         displayNameLabel.text = getDisplayName()
         timestampLabel.text = DateUtil.formatDate(forDisplay: threadViewModel.lastMessageDate)

SessionMessagingKit/Threads/TSThread.h

@@ -57,6 +57,9 @@ BOOL IsNoteToSelfEnabled(void);
 - (NSUInteger)unreadMessageCountWithTransaction:(YapDatabaseReadTransaction *)transaction
     NS_SWIFT_NAME(unreadMessageCount(transaction:));
 
+- (BOOL)hasUnreadMentionMessageWithTransaction:(YapDatabaseReadTransaction *)transaction
+    NS_SWIFT_NAME(hasUnreadMentionMessage(transaction:));
+
 - (void)markAllAsReadWithTransaction:(YapDatabaseReadWriteTransaction *)transaction;
 
 /**

SessionMessagingKit/Threads/TSThread.m

@@ -264,6 +264,32 @@ BOOL IsNoteToSelfEnabled(void)
     return count;
 }
 
+- (BOOL)hasUnreadMentionMessageWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
+    __block BOOL hasUnreadMention = false;
+    
+    YapDatabaseViewTransaction *unreadMessages = [transaction ext:TSUnreadDatabaseViewExtensionName];
+    [unreadMessages enumerateKeysAndObjectsInGroup:self.uniqueId
+                                        usingBlock:^(NSString *collection, NSString *key, id object, NSUInteger index, BOOL *stop) {
+        if (![object isKindOfClass:[TSIncomingMessage class]]) {
+            return;
+        }
+        TSIncomingMessage* unreadMessage = (TSIncomingMessage*)object;
+        if (unreadMessage.read) {
+            NSLog(@"Found an already read message in the * unread * messages list.");
+            return;
+        }
+        
+        if (unreadMessage.isUserMentioned) {
+            hasUnreadMention = true;
+            *stop = YES;
+        }
+    }];
+
+    return hasUnreadMention;
+    
+}
+
 - (void)markAllAsReadWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     for (id<OWSReadTracking> message in [self unseenMessagesWithTransaction:transaction]) {

SignalUtilitiesKit/Messaging/ThreadViewModel.swift

@@ -15,6 +15,7 @@ public class ThreadViewModel: NSObject {
     @objc public let name: String
     @objc public let isMuted: Bool
     @objc public let isOnlyNotifyingForMentions: Bool
+    @objc public let hasUnreadMentions: Bool
 
     var isContactThread: Bool {
         return !isGroupThread
@@ -49,6 +50,7 @@ public class ThreadViewModel: NSObject {
 
         self.unreadCount = thread.unreadMessageCount(transaction: transaction)
         self.hasUnreadMessages = unreadCount > 0
+        self.hasUnreadMentions = thread.hasUnreadMentionMessage(transaction: transaction)
     }
 
     @objc