mention function '@' fixed

Signal/src/ViewControllers/ConversationView/ConversationInputToolbar.m

@@ -1107,6 +1107,12 @@ const CGFloat kMaxTextViewHeight = 98;
         [self.mentionCandidateSelectionView setPublicChatChannel:publicChat.channel];
     }
     self.mentionCandidateSelectionView.mentionCandidates = mentionCandidates;
+    // Add animation
+//    [UIView animateWithDuration:0.5f animations:^{
+//        self.mentionCandidateSelectionViewSizeConstraint.constant = 6 + MIN(mentionCandidates.count, 4) * 52;
+//        [self setNeedsLayout];
+//        [self layoutIfNeeded];
+//    }];
     self.mentionCandidateSelectionViewSizeConstraint.constant = 6 + MIN(mentionCandidates.count, 4) * 52;
     [self setNeedsLayout];
     [self layoutIfNeeded];
@@ -1115,6 +1121,12 @@ const CGFloat kMaxTextViewHeight = 98;
 
 - (void)hideMentionCandidateSelectionView
 {
+    // Add animation
+//    [UIView animateWithDuration:0.5f animations:^{
+//        self.mentionCandidateSelectionViewSizeConstraint.constant = 0;
+//        [self setNeedsLayout];
+//        [self layoutIfNeeded];
+//    }];
     self.mentionCandidateSelectionViewSizeConstraint.constant = 0;
     [self setNeedsLayout];
     [self layoutIfNeeded];

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -3802,7 +3802,12 @@ typedef enum : NSUInteger {
     if (newText.length > 0) {
         NSUInteger lastCharacterIndex = newText.length - 1;
         unichar lastCharacter = [newText characterAtIndex:lastCharacterIndex];
-        if (lastCharacter == '@') {
+        // Check if there is a whitespace before '@' or the '@' is the first character
+        unichar secondLastCharacter = ' ';
+        if (lastCharacterIndex > 0) {
+            secondLastCharacter = [newText characterAtIndex:lastCharacterIndex - 1];
+        }
+        if (lastCharacter == '@' && [NSCharacterSet.whitespaceAndNewlineCharacterSet characterIsMember:secondLastCharacter]) {
             NSArray<LKMention *> *mentionCandidates = [LKAPI getMentionCandidatesFor:@"" in:self.thread.uniqueId];
             self.currentMentionStartIndex = (NSInteger)lastCharacterIndex;
             [self.inputToolbar showMentionCandidateSelectionViewFor:mentionCandidates in:self.thread];