From 28b17896cc65a20f90f0279bca04f0bb14c5337a Mon Sep 17 00:00:00 2001
From: Sean Conrad <toblerpwn@gmail.com>
Date: Tue, 25 Nov 2014 15:08:37 -0800
Subject: [PATCH 1/2] scrollToBottomAnimated: fix long message handling

fixes #480
---
 .../Controllers/JSQMessagesViewController.m                     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/JSQMessagesViewController/Controllers/JSQMessagesViewController.m b/JSQMessagesViewController/Controllers/JSQMessagesViewController.m
index 5ae0856b6..9cbbc9e25 100644
--- a/JSQMessagesViewController/Controllers/JSQMessagesViewController.m
+++ b/JSQMessagesViewController/Controllers/JSQMessagesViewController.m
@@ -366,7 +366,7 @@ - (void)scrollToBottomAnimated:(BOOL)animated
     }
     
     [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:items - 1 inSection:0]
-                                atScrollPosition:UICollectionViewScrollPositionTop
+                                atScrollPosition:UICollectionViewScrollPositionBottom
                                         animated:animated];
 }
 

From 6a04d7585d6920ba87287d29870e0a39cd24f089 Mon Sep 17 00:00:00 2001
From: Sean Conrad <toblerpwn@gmail.com>
Date: Tue, 25 Nov 2014 16:02:44 -0800
Subject: [PATCH 2/2] improve layout for smaller cells

in some cases, `Top` alignment is best - this commit handles those cases
---
 .../Controllers/JSQMessagesViewController.m        | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/JSQMessagesViewController/Controllers/JSQMessagesViewController.m b/JSQMessagesViewController/Controllers/JSQMessagesViewController.m
index 9cbbc9e25..c2540b437 100644
--- a/JSQMessagesViewController/Controllers/JSQMessagesViewController.m
+++ b/JSQMessagesViewController/Controllers/JSQMessagesViewController.m
@@ -365,8 +365,20 @@ - (void)scrollToBottomAnimated:(BOOL)animated
         return;
     }
     
+    // if last object is huge, use UICollectionViewScrollPositionBottom for better appearance
+    // else use Top
+    NSInteger finalRow = MAX(0, [self.collectionView numberOfItemsInSection:0] - 1);
+    NSIndexPath *finalIndexPath = [NSIndexPath indexPathForItem:finalRow
+                                                      inSection:0];
+    CGSize finalCellSize = [self.collectionView.collectionViewLayout sizeForItemAtIndexPath:finalIndexPath];
+    
+    CGFloat maxHeight = CGRectGetHeight(self.collectionView.bounds) - self.collectionView.contentInset.top - CGRectGetHeight(self.inputToolbar.bounds);
+    
+    BOOL hugeCell = (maxHeight < finalCellSize.height);
+    UICollectionViewScrollPosition position = (hugeCell) ? UICollectionViewScrollPositionBottom : UICollectionViewScrollPositionTop;
+    
     [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:items - 1 inSection:0]
-                                atScrollPosition:UICollectionViewScrollPositionBottom
+                                atScrollPosition:position
                                         animated:animated];
 }