From 312b7eaa0c7c075ab042bbe755a3d977f8b5064d Mon Sep 17 00:00:00 2001
From: Maxime Poulin <maxpoulin64@gmail.com>
Date: Wed, 25 May 2016 03:41:41 -0400
Subject: [PATCH] Keep chat stickied to the bottom on resize

Fixes the chat not staying at the bottom when opening the on-screen keyboard on mobile.
---
 client/js/libs/jquery/stickyscroll.js | 33 +++++++++++++++++++++------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/client/js/libs/jquery/stickyscroll.js b/client/js/libs/jquery/stickyscroll.js
index d86740b3..e50b748f 100644
--- a/client/js/libs/jquery/stickyscroll.js
+++ b/client/js/libs/jquery/stickyscroll.js
@@ -1,29 +1,48 @@
 (function($) {
 	$.fn.unsticky = function() {
-		return this.unbind(".sticky");
+		return this.trigger("unstick.sticky").unbind(".sticky");
 	};
 
 	$.fn.sticky = function() {
 		var self = this;
 		var stuckToBottom = true;
+		var lastStick = 0;
 
+		var keepToBottom = function() {
+			if (stuckToBottom) {
+				self.scrollBottom();
+			}
+		};
+
+		$(window).on("resize.sticky", keepToBottom);
 		self
-			.on("scroll.sticky", function(e) {
-				stuckToBottom = self.isScrollBottom();
+			.on("unstick.sticky", function() {
+				$(window).off("resize.sticky", keepToBottom);
 			})
-			.on("msg.sticky", function() {
-				if (stuckToBottom) {
+			.on("scroll.sticky", function() {
+				// When resizing, sometimes the browser sends a bunch of extra scroll events due to content
+				// reflow, so if we resized within 250ms we can assume it's one of those. The order of said
+				// events is not predictable, and scroll can happen last, so not setting stuckToBottom is
+				// not enough, we have to force the scroll still.
+				if (stuckToBottom && Date.now() - lastStick < 250) {
 					self.scrollBottom();
+				} else {
+					stuckToBottom = self.isScrollBottom();
 				}
 			})
+			.on("scrollBottom.sticky", function() {
+				stuckToBottom = true;
+				lastStick = Date.now();
+				this.scrollTop = this.scrollHeight;
+			})
+			.on("msg.sticky", keepToBottom)
 			.scrollBottom();
 
 		return self;
 	};
 
 	$.fn.scrollBottom = function() {
-		var el = this[0];
-		this.scrollTop(el.scrollHeight);
+		this.trigger("scrollBottom.sticky");
 		return this;
 	};