From 189e765315f0e327b97b5a5226be481d0345c770 Mon Sep 17 00:00:00 2001
From: Gabriel Cebrian <gabceb@gmail.com>
Date: Wed, 20 Mar 2013 18:27:08 -0700
Subject: [PATCH] Fixes to deal with empty channels

---
 .../backbone/helpers/channels.js.coffee         | 17 +++++++++++++----
 .../backbone/views/channel_pane.js.coffee       |  6 ++++--
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/app/assets/javascripts/backbone/helpers/channels.js.coffee b/app/assets/javascripts/backbone/helpers/channels.js.coffee
index c7923cf9..45357e5b 100644
--- a/app/assets/javascripts/backbone/helpers/channels.js.coffee
+++ b/app/assets/javascripts/backbone/helpers/channels.js.coffee
@@ -20,7 +20,7 @@ class Kandan.Helpers.Channels
 
   @scrollToLatestMessage: (channelId)->
     if channelId
-      theScrollArea = $('#channels-'+channelId)
+      theScrollArea = @channelPane(channelId)
       theScrollArea.scrollTop(theScrollArea.prop('scrollHeight'))
     else
       $('.channels-pane').scrollTop($('.channels-pane').prop('scrollHeight'))
@@ -28,6 +28,9 @@ class Kandan.Helpers.Channels
   @currentScrollPosition: (channelId)->
     $('channels-pane').scrollTop()
 
+  @channelPane: (channelId)->
+    $("#channels-#{channelId}")
+
   @channelActivitiesEl: (channelId)->
     $("#channel-activities-#{channelId}")
 
@@ -92,12 +95,12 @@ class Kandan.Helpers.Channels
 
 
   @channelExists: (channelId)->
-    return true if $("#channels-#{channelId}").length > 0
+    return true if @channelPane(channelId).length > 0
     false
 
 
   @createChannelArea: (channel)->
-    channelArea = "#channels-#{channel.get('id')}"
+    channelArea = @channelPane(channel.get('id'))
     totalTabs = $("#kandan").tabs("length")
     $createTab = $("#create_channel").parents("li").detach()
     $("#kandan").tabs("add", channelArea, "#{channel.get("name")}", totalTabs)
@@ -161,12 +164,18 @@ class Kandan.Helpers.Channels
 
 
   @setPaginationState: (channelId, moreActivities, oldest)->
-    @channelPaginationEl(channelId).data("oldest", oldest)
     console.log "pagination element", moreActivities, @channelPaginationEl(channelId)
     if moreActivities == true
+      # Only set pagination data if there are more activities. Otherwise is useless
+      @channelPaginationEl(channelId).data("oldest", oldest.get("id"))
+
       @channelPaginationEl(channelId).show()
     else
       @channelPaginationEl(channelId).hide()
+      
+      # If there are no more messages we will unbind the scroll event
+      @channelPane(channelId).unbind("scroll")
+
 
 
   @setPaginationData: (channelId)->
diff --git a/app/assets/javascripts/backbone/views/channel_pane.js.coffee b/app/assets/javascripts/backbone/views/channel_pane.js.coffee
index dde9420a..613735af 100644
--- a/app/assets/javascripts/backbone/views/channel_pane.js.coffee
+++ b/app/assets/javascripts/backbone/views/channel_pane.js.coffee
@@ -55,12 +55,14 @@ class Kandan.Views.ChannelPane extends Backbone.View
           activityView = new Kandan.Views.ShowActivity({activity: activity, silence_mentions: true})
           $container.find(".channel-activities").prepend(activityView.render().el)
 
-        $container.scrollTop($current_top_element.offset().top)
+        if $current_top_element.length != 0
+          $container.scrollTop($current_top_element.offset().top)
 
         Kandan.Helpers.Channels.setPaginationState(
           collection.channelId,
           collection.moreActivities,
-          _.last(collection.models).get("id")
+          _.last(collection.models),
+          $container
         )
 
         @loading_new_messages = false