From f0f5fbf13273d247df0b08c66b8ee58d1941457c Mon Sep 17 00:00:00 2001
From: Robin Ward <robin.ward@gmail.com>
Date: Tue, 20 Dec 2016 13:13:46 -0500
Subject: [PATCH] FIX: Never show the last read marker within 1 post of the
 last

---
 .../discourse/components/topic-progress.js.es6      |  8 +++++---
 .../discourse/widgets/topic-timeline.js.es6         |  1 +
 app/assets/stylesheets/desktop/topic.scss           | 13 +++++++++++++
 app/assets/stylesheets/mobile/topic.scss            | 13 -------------
 4 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/app/assets/javascripts/discourse/components/topic-progress.js.es6 b/app/assets/javascripts/discourse/components/topic-progress.js.es6
index 8321d70148c..f20f47426d7 100644
--- a/app/assets/javascripts/discourse/components/topic-progress.js.es6
+++ b/app/assets/javascripts/discourse/components/topic-progress.js.es6
@@ -39,9 +39,11 @@ export default Ember.Component.extend({
 
   @computed('progressPosition', 'topic.last_read_post_id')
   showBackButton(position, lastReadId) {
-    if (!this.site.mobileView || !lastReadId) { return; }
-    const readPos = this.get('postStream.stream').indexOf(lastReadId) || 0;
-    return readPos > position;
+    if (!lastReadId) { return; }
+
+    const stream = this.get('postStream.stream');
+    const readPos = stream.indexOf(lastReadId) || 0;
+    return (readPos < (stream.length - 1)) && (readPos > position);
   },
 
   @observes('postStream.stream.[]')
diff --git a/app/assets/javascripts/discourse/widgets/topic-timeline.js.es6 b/app/assets/javascripts/discourse/widgets/topic-timeline.js.es6
index 8ef9ad0e2de..8add163c85b 100644
--- a/app/assets/javascripts/discourse/widgets/topic-timeline.js.es6
+++ b/app/assets/javascripts/discourse/widgets/topic-timeline.js.es6
@@ -165,6 +165,7 @@ createWidget('timeline-scrollarea', {
     const hasBackPosition =
       position.lastRead > 3 &&
       Math.abs(position.lastRead - position.current) > 3 &&
+      Math.abs(position.lastRead - position.total) > 1 &&
       (position.lastRead && position.lastRead !== position.total);
 
     if (hasBackPosition) {
diff --git a/app/assets/stylesheets/desktop/topic.scss b/app/assets/stylesheets/desktop/topic.scss
index 571649f60a7..7d56ff403d0 100644
--- a/app/assets/stylesheets/desktop/topic.scss
+++ b/app/assets/stylesheets/desktop/topic.scss
@@ -87,6 +87,19 @@
   width: 757px;
 }
 
+.progress-back-container {
+  position: fixed;
+  width: 0;
+  right: 0;
+  bottom: 40px;
+  z-index: 950;
+  margin-right: 105px;
+
+  .btn {
+    margin: 0;
+  }
+}
+
 #topic-progress-wrapper {
   position: fixed;
   right: 50%;
diff --git a/app/assets/stylesheets/mobile/topic.scss b/app/assets/stylesheets/mobile/topic.scss
index 56eedbf56e2..5e296d889d5 100644
--- a/app/assets/stylesheets/mobile/topic.scss
+++ b/app/assets/stylesheets/mobile/topic.scss
@@ -61,19 +61,6 @@
   margin-right: 148px;
 }
 
-.progress-back-container {
-  position: fixed;
-  width: 0;
-  right: 0;
-  bottom: 40px;
-  z-index: 950;
-  margin-right: 105px;
-
-  .btn {
-    margin: 0;
-  }
-}
-
 #topic-progress-expanded {
   border: 1px solid dark-light-diff($primary, $secondary, 90%, -60%);
   padding: 5px;