RoomDataSource: Handle RoomCreationIntroCell conditional display.

Riot/Modules/Room/DataSources/RoomDataSource.m

@@ -48,6 +48,10 @@
 
 @property(nonatomic, readwrite) RoomEncryptionTrustLevel encryptionTrustLevel;
 
+@property (nonatomic) RoomBubbleCellData *roomCreationCellData;
+
+@property (nonatomic) BOOL showRoomCreationCell;
+
 @end
 
 @implementation RoomDataSource
@@ -205,6 +209,7 @@
     }
     
     [self fetchEncryptionTrustedLevel];
+    [self enableRoomCreationIntroCellDisplayIfNeeded];
 }
 
 - (void)fetchEncryptionTrustedLevel
@@ -213,6 +218,10 @@
     [self.roomDataSourceDelegate roomDataSource:self didUpdateEncryptionTrustLevel:self.encryptionTrustLevel];
 }
 
+- (void)roomDidChange
+{
+    [self enableRoomCreationIntroCellDisplayIfNeeded];
+}
 
 #pragma  mark -
 
@@ -225,6 +234,8 @@
         // Enable the containsLastMessage flag for the cell data which contains the last message.
         @synchronized(bubbles)
         {
+            [self insertRoomCreationIntroCellDataIfNeeded];
+            
             // Reset first all cell data
             for (RoomBubbleCellData *cellData in bubbles)
             {
@@ -963,4 +974,72 @@
     [self.delegate dataSource:self didRecognizeAction:kMXKRoomBubbleCellLongPressOnReactionView inCell:nil userInfo:@{ kMXKRoomBubbleCellEventIdKey: eventId }];
 }
 
+#pragma mark - Room creation intro cell
+
+- (BOOL)canShowRoomCreationIntroCell
+{
+    NSString* userId = self.mxSession.myUser.userId;
+
+    if (!userId || !self.isLive || self.isPeeking)
+    {
+        return NO;
+    }
+    
+    // Room creation cell is only shown for the creator
+    return [self.room.summary.creatorUserId isEqualToString:userId];
+}
+
+- (void)enableRoomCreationIntroCellDisplayIfNeeded
+{
+    self.showRoomCreationCell = [self canShowRoomCreationIntroCell];
+}
+
+// Insert the room creation intro cell at the begining
+- (void)insertRoomCreationIntroCellDataIfNeeded
+{
+    if (self.showRoomCreationCell)
+    {
+        NSUInteger existingRoomCreationCellDataIndex = [self roomBubbleDataIndexWithTag:RoomBubbleCellDataTagRoomCreationIntro];
+        
+        if (existingRoomCreationCellDataIndex != NSNotFound)
+        {
+            [bubbles removeObjectAtIndex:existingRoomCreationCellDataIndex];
+        }
+        
+        NSUInteger roomCreationConfigCellDataIndex = [self roomBubbleDataIndexWithTag:RoomBubbleCellDataTagRoomCreateConfiguration];
+        
+        // Only add room creation intro cell if `bubbles` array contains the room creation event
+        if (roomCreationConfigCellDataIndex != NSNotFound)
+        {
+            MXEvent *event = [MXEvent new];
+            MXRoomState *roomState = [MXRoomState new];
+            RoomBubbleCellData *roomBubbleCellData = [[RoomBubbleCellData alloc] initWithEvent:event andRoomState:roomState andRoomDataSource:self];
+            roomBubbleCellData.tag = RoomBubbleCellDataTagRoomCreationIntro;
+            
+            [bubbles insertObject:roomBubbleCellData atIndex:0];
+                
+            self.roomCreationCellData = roomBubbleCellData;
+        }
+    }
+    else
+    {
+        self.roomCreationCellData = nil;
+    }
+}
+
+- (NSUInteger)roomBubbleDataIndexWithTag:(RoomBubbleCellDataTag)tag
+{
+    return [bubbles indexOfObjectPassingTest:^BOOL(id<MXKRoomBubbleCellDataStoring>  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
+        if ([obj isKindOfClass:RoomBubbleCellData.class])
+        {
+            RoomBubbleCellData *roomBubbleCellData = (RoomBubbleCellData*)obj;
+            if (roomBubbleCellData.tag == tag)
+            {
+                return YES;
+            }
+        }
+        return NO;
+    }];
+}
+
 @end