Rework unread indicators.

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -741,9 +741,7 @@ typedef enum : NSUInteger {
 {
     NSInteger row = 0;
     for (ConversationViewItem *viewItem in self.viewItems) {
-        OWSInteractionType interactionType
-            = (viewItem ? viewItem.interaction.interactionType : OWSInteractionType_Unknown);
-        if (interactionType == OWSInteractionType_UnreadIndicator) {
+        if (viewItem.unreadIndicator) {
             return [NSIndexPath indexPathForRow:row inSection:0];
         }
         row++;
@@ -4742,7 +4740,6 @@ typedef enum : NSUInteger {
         BOOL canShowDate = NO;
         switch (viewItem.interaction.interactionType) {
             case OWSInteractionType_Unknown:
-            case OWSInteractionType_UnreadIndicator:
             case OWSInteractionType_Offer:
                 canShowDate = NO;
                 break;

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -261,9 +261,6 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
             case OWSInteractionType_Call:
                 measurementCell = [OWSSystemMessageCell new];
                 break;
-            case OWSInteractionType_UnreadIndicator:
-                OWSFail(@"%@ unexpected unread indicator.", self.logTag);
-                return nil;
             case OWSInteractionType_Offer:
                 measurementCell = [OWSContactOffersCell new];
                 break;
@@ -280,11 +277,6 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
 {
     OWSAssert(previousLayoutItem);
 
-    if (self.interaction.interactionType == OWSInteractionType_UnreadIndicator
-        || previousLayoutItem.interaction.interactionType == OWSInteractionType_UnreadIndicator) {
-        return 20.f;
-    }
-
     if (self.hasCellHeader) {
         return OWSMessageHeaderViewDateHeaderVMargin;
     }
@@ -326,9 +318,6 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
         case OWSInteractionType_Call:
             return [collectionView dequeueReusableCellWithReuseIdentifier:[OWSSystemMessageCell cellReuseIdentifier]
                                                              forIndexPath:indexPath];
-        case OWSInteractionType_UnreadIndicator:
-            OWSFail(@"%@ unexpected unread indicator.", self.logTag);
-            return nil;
         case OWSInteractionType_Offer:
             return [collectionView dequeueReusableCellWithReuseIdentifier:[OWSContactOffersCell cellReuseIdentifier]
                                                              forIndexPath:indexPath];

SignalMessaging/Models/TSUnreadIndicatorInteraction.m

@@ -27,7 +27,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (OWSInteractionType)interactionType
 {
-    return OWSInteractionType_UnreadIndicator;
+    return OWSInteractionType_Unknown;
 }
 
 @end

SignalMessaging/utils/ThreadUtil.m

@@ -603,17 +603,10 @@ NS_ASSUME_NONNULL_BEGIN
             = (missingUnseenSafetyNumberChanges.count + nonBlockingSafetyNumberChanges.count);
     }
 
-    // TODO:
     NSInteger unreadIndicatorPosition = visibleUnseenMessageCount;
-    // TODO:
-    //    if (dynamicInteractions.firstUnseenInteractionTimestamp) {
-    //        // The unread indicator is _before_ the last visible unseen message.
-    //        NSInteger unreadIndicatorPosition = visibleUnseenMessageCount + 1;
-    //        if (shouldHaveContactOffers) {
-    //            unreadIndicatorPosition++;
-    //        }
-    //        dynamicInteractions.unreadIndicatorPosition = @(unreadIndicatorPosition);
-    //    }
+    if (shouldHaveContactOffers) {
+        unreadIndicatorPosition++;
+    }
 
     dynamicInteractions.unreadIndicator = [[OWSUnreadIndicator alloc]
             initUnreadIndicatorWithTimestamp:interactionAfterUnreadIndicator.timestampForSorting

SignalServiceKit/src/Messages/Interactions/TSInteraction.h

@@ -15,8 +15,6 @@ typedef NS_ENUM(NSInteger, OWSInteractionType) {
     OWSInteractionType_Error,
     OWSInteractionType_Call,
     OWSInteractionType_Info,
-    // TODO: Obsolete, consider replacing with OWSInteractionType_Unknown.
-    OWSInteractionType_UnreadIndicator,
     OWSInteractionType_Offer,
 };
 

SignalServiceKit/src/Messages/Interactions/TSInteraction.m

@@ -25,8 +25,6 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
             return @"OWSInteractionType_Call";
         case OWSInteractionType_Info:
             return @"OWSInteractionType_Info";
-        case OWSInteractionType_UnreadIndicator:
-            return @"OWSInteractionType_UnreadIndicator";
         case OWSInteractionType_Offer:
             return @"OWSInteractionType_Offer";
     }