FIX: Small bugs with progress indicator

app/assets/javascripts/discourse/controllers/topic_controller.js

@@ -19,7 +19,7 @@ Discourse.TopicController = Discourse.ObjectController.extend(Discourse.Selected
   }.property('postStream.filteredPostsCount', 'progressPosition'),
 
   jumpBottomDisabled: function() {
-    return this.get('progressPosition') === this.get('postStream.filteredPostsCount');
+    return this.get('progressPosition') >= this.get('postStream.filteredPostsCount');
   }.property('postStream.filteredPostsCount', 'progressPosition'),
 
   canMergeTopic: function() {
@@ -60,6 +60,12 @@ Discourse.TopicController = Discourse.ObjectController.extend(Discourse.Selected
     return canDelete;
   }.property('selectedPostsCount'),
 
+  streamPercentage: function() {
+    if (!this.get('postStream.loaded')) { return 0; }
+    if (this.get('postStream.filteredPostsCount') === 0) { return 0; }
+    return this.get('progressPosition') / this.get('postStream.filteredPostsCount');
+  }.property('postStream.loaded', 'progressPosition', 'postStream.filteredPostsCount'),
+
   multiSelectChanged: function() {
     // Deselect all posts when multi select is turned off
     if (!this.get('multiSelect')) {

app/assets/javascripts/discourse/models/post_stream.js

@@ -430,6 +430,30 @@ Discourse.PostStream = Em.Object.extend({
     }
   },
 
+  /**
+    Returns the closest post number given a postNumber that may not exist in the stream.
+    For example, if the user asks for a post that's deleted or otherwise outside the range.
+    This allows us to set the progress bar with the correct number.
+
+    @method closestPostNumberFor
+    @param {Integer} postNumber the post number we're looking for
+  **/
+  closestPostNumberFor: function(postNumber) {
+    if (!this.get('hasPosts')) { return; }
+
+    var closest = null;
+    this.get('posts').forEach(function (p) {
+      if (closest === postNumber) { return; }
+      if (!closest) { closest = p.get('post_number'); }
+
+      if (Math.abs(postNumber - p.get('post_number')) < Math.abs(closest - postNumber)) {
+        closest = p.get('post_number');
+      }
+    });
+
+    return closest;
+  },
+
   /**
     @private
 

app/assets/javascripts/discourse/routes/topic_from_params_route.js

@@ -32,9 +32,13 @@ Discourse.TopicFromParamsRoute = Discourse.Route.extend({
 
     var topicController = this.controllerFor('topic');
     postStream.refresh(params).then(function () {
+
+      // The post we requested might not exist. Let's find the closest post
+      var closest = postStream.closestPostNumberFor(params.nearPost) || 1;
+
       topicController.setProperties({
-        currentPost: params.nearPost || 1,
-        progressPosition: params.nearPost || 1
+        currentPost: closest,
+        progressPosition: closest
       });
 
       if (topic.present('draft')) {
@@ -46,7 +50,6 @@ Discourse.TopicFromParamsRoute = Discourse.Route.extend({
           ignoreIfChanged: true
         });
       }
-
     });
 
 

app/assets/javascripts/discourse/views/topic_view.js

@@ -17,22 +17,19 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
 
   postStream: Em.computed.alias('controller.postStream'),
 
-  updateBar: function() {
-    if (!this.get('postStream.loaded')) return;
 
+  updateBar: function() {
     var $topicProgress = $('#topic-progress');
     if (!$topicProgress.length) return;
 
-    var ratio = this.get('controller.progressPosition') / this.get('postStream.filteredPostsCount');
     var totalWidth = $topicProgress.width();
-    var progressWidth = ratio * totalWidth;
-    var bg = $topicProgress.find('.bg');
-    var currentWidth = bg.width();
+    var progressWidth = this.get('controller.streamPercentage') * totalWidth;
 
-    bg.css("border-right-width", (progressWidth === totalWidth) ? "0px" : "1px")
+    $topicProgress.find('.bg')
+                  .css("border-right-width", (progressWidth === totalWidth) ? "0px" : "1px")
                   .width(progressWidth);
 
-  }.observes('controller.progressPosition', 'postStream.filteredPostsCount', 'topic.loaded'),
+  }.observes('controller.streamPercentage'),
 
   updateTitle: function() {
     var title = this.get('topic.title');
@@ -86,6 +83,9 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     });
 
     this.updatePosition();
+
+    // We want to make sure the progress bar is updated after it's rendered
+    this.updateBar();
   },
 
   debounceLoadSuggested: Discourse.debounce(function(){
@@ -169,6 +169,7 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     if (!postView) return;
     var post = postView.get('post');
     if (!post) return;
+
     this.set('controller.progressPosition', this.get('postStream').indexOf(post) + 1);
   },
 
@@ -184,9 +185,14 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     this.updatePosition();
   },
 
-  updatePosition: function() {
-    var topic = this.get('controller.model');
 
+  /**
+    Process the posts the current user has seen in the topic.
+
+    @private
+    @method processSeenPosts
+  **/
+  processSeenPosts: function() {
     var rows = $('.topic-post.ready');
     if (!rows || rows.length === 0) { return; }
 
@@ -235,6 +241,16 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     } else {
       console.error("can't update position ");
     }
+  },
+
+  /**
+    The user has scrolled the window, or it is finished rendering and ready for processing.
+
+    @method updatePosition
+  **/
+  updatePosition: function() {
+
+    this.processSeenPosts();
 
     var offset = window.pageYOffset || $('html').scrollTop();
     if (!this.get('docAt')) {
@@ -244,7 +260,8 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
       }
     }
 
-    var headerController = this.get('controller.controllers.header');
+    var headerController = this.get('controller.controllers.header'),
+        topic = this.get('controller.model');
     if (this.get('docAt')) {
       headerController.set('showExtraInfo', offset >= this.get('docAt') || topic.get('postStream.firstPostNotLoaded'));
     } else {

test/javascripts/models/post_stream_test.js

@@ -54,6 +54,19 @@ test('appending posts', function() {
   ok(postStream.get('lastPostLoaded'), "the last post is still the last post in the new stream");
 });
 
+test('closestPostNumberFor', function() {
+  var postStream = buildStream(1231);
+
+  blank(postStream.closestPostNumberFor(1), "there is no closest post when nothing is loaded");
+
+  postStream.appendPost(Discourse.Post.create({id: 1, post_number: 2}));
+  postStream.appendPost(Discourse.Post.create({id: 2, post_number: 3}));
+
+  equal(postStream.closestPostNumberFor(2), 2, "If a post is in the stream it returns its post number");
+  equal(postStream.closestPostNumberFor(3), 3, "If a post is in the stream it returns its post number");
+  equal(postStream.closestPostNumberFor(10), 3, "it clips to the upper bound of the stream");
+  equal(postStream.closestPostNumberFor(0), 2, "it clips to the lower bound of the stream");
+});
 
 test('updateFromJson', function() {
   var postStream = buildStream(1231);