Handle notifications for open conversations.

Signal/src/ViewControllers/ConversationView/ConversationViewController.h

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import <SignalMessaging/OWSViewController.h>
@@ -25,6 +25,8 @@ typedef NS_ENUM(NSUInteger, ConversationViewAction) {
 
 - (void)popKeyBoard;
 
+- (void)scrollToFirstUnreadMessage:(BOOL)isAnimated;
+
 #pragma mark 3D Touch Methods
 
 - (void)peekSetup;

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -752,7 +752,7 @@ typedef enum : NSUInteger {
 
     // We want to set the initial scroll state the first time we enter the view.
     if (!self.viewHasEverAppeared) {
-        [self scrollToDefaultPosition];
+        [self scrollToDefaultPosition:NO];
     } else if (self.menuActionsViewController != nil) {
         [self scrollToMenuActionInteraction:NO];
     }
@@ -807,7 +807,7 @@ typedef enum : NSUInteger {
     return [NSIndexPath indexPathForRow:row inSection:0];
 }
 
-- (void)scrollToDefaultPosition
+- (void)scrollToDefaultPosition:(BOOL)isAnimated
 {
     if (self.isUserScrolling) {
         return;
@@ -824,14 +824,14 @@ typedef enum : NSUInteger {
 
     if (indexPath) {
         if (indexPath.section == 0 && indexPath.row == 0) {
-            [self.collectionView setContentOffset:CGPointZero animated:NO];
+            [self.collectionView setContentOffset:CGPointZero animated:isAnimated];
         } else {
             [self.collectionView scrollToItemAtIndexPath:indexPath
                                         atScrollPosition:UICollectionViewScrollPositionTop
-                                                animated:NO];
+                                                animated:isAnimated];
         }
     } else {
-        [self scrollToBottomAnimated:NO];
+        [self scrollToBottomAnimated:isAnimated];
     }
 }
 
@@ -3899,7 +3899,7 @@ typedef enum : NSUInteger {
 
         // Adjust content offset to prevent the presented keyboard from obscuring content.
         if (!self.viewHasEverAppeared) {
-            [self scrollToDefaultPosition];
+            [self scrollToDefaultPosition:NO];
         } else if (wasScrolledToBottom) {
             // If we were scrolled to the bottom, don't do any fancy math. Just stay at the bottom.
             [self scrollToBottomAnimated:NO];
@@ -4026,6 +4026,11 @@ typedef enum : NSUInteger {
     [self didScrollToBottom];
 }
 
+- (void)scrollToFirstUnreadMessage:(BOOL)isAnimated
+{
+    [self scrollToDefaultPosition:isAnimated];
+}
+
 #pragma mark - UIScrollViewDelegate
 
 - (void)updateLastKnownDistanceFromBottom

Signal/src/environment/SignalApp.h

@@ -46,6 +46,8 @@ NS_ASSUME_NONNULL_BEGIN
                       focusMessageId:(nullable NSString *)focusMessageId
                             animated:(BOOL)isAnimated;
 
+- (void)presentConversationForThreadAndShowFirstUnreadMessage:(TSThread *)thread animated:(BOOL)isAnimated;
+
 #pragma mark - Methods
 
 + (void)resetAppData;

Signal/src/environment/SignalApp.m

@@ -122,6 +122,35 @@ NS_ASSUME_NONNULL_BEGIN
     });
 }
 
+- (void)presentConversationForThreadAndShowFirstUnreadMessage:(TSThread *)thread animated:(BOOL)isAnimated
+{
+    OWSAssertIsOnMainThread();
+
+    OWSLogInfo(@"");
+
+    if (!thread) {
+        OWSFailDebug(@"Can't present nil thread.");
+        return;
+    }
+
+    DispatchMainThreadSafe(^{
+        UIViewController *frontmostVC = [[UIApplication sharedApplication] frontmostViewController];
+
+        if ([frontmostVC isKindOfClass:[ConversationViewController class]]) {
+            ConversationViewController *conversationVC = (ConversationViewController *)frontmostVC;
+            if ([conversationVC.thread.uniqueId isEqualToString:thread.uniqueId]) {
+                [conversationVC scrollToFirstUnreadMessage:isAnimated];
+                return;
+            }
+        }
+
+        [self.homeViewController presentThread:thread
+                                        action:ConversationViewActionNone
+                                focusMessageId:nil
+                                      animated:isAnimated];
+    });
+}
+
 - (void)didChangeCallLoggingPreference:(NSNotification *)notitication
 {
     [AppEnvironment.shared.callService createCallUIAdapter];