refactor analysis of read posts and centralize logic

app/assets/javascripts/discourse/components/eyeline.js

@@ -14,7 +14,91 @@
 **/
 Discourse.Eyeline = function Eyeline(selector) {
   this.selector = selector;
+};
+
+
+/**
+  Call this to analyze the positions of all the nodes in a set 
+
+  returns: a hash with top, bottom and onScreen items 
+          {top: , bottom:, onScreen:}
+ **/
+Discourse.Eyeline.analyze = function(rows) {
+  var current, goingUp, i, increment, offset, 
+      winHeight, winOffset, detected, onScreen,
+      bottom, top, outerHeight;
+  
+  if (rows.length === 0) return;
+  
+  i = parseInt(rows.length / 2, 10);
+  increment = parseInt(rows.length / 4, 10);
+  goingUp = undefined;
+  winOffset = window.pageYOffset || $('html').scrollTop();
+  winHeight = window.innerHeight || $(window).height();
+  
+  while (true) {
+    if (i === 0 || (i >= rows.length - 1)) {
+      break;
     }
+    current = $(rows[i]);
+    offset = current.offset();
+   
+    if (offset.top - winHeight < winOffset) {
+      if (offset.top + current.outerHeight() - window.innerHeight > winOffset) {
+        break;
+      } else {
+        i = i + increment;
+        if (goingUp !== undefined && increment === 1 && !goingUp) {
+          break;
+        }
+        goingUp = true;
+      }
+    } else {
+      i = i - increment;
+      if (goingUp !== undefined && increment === 1 && goingUp) {
+        break;
+      }
+      goingUp = false;
+    }
+    if (increment > 1) {
+      increment = parseInt(increment / 2, 10);
+      goingUp = undefined;
+    }
+    if (increment === 0) {
+      increment = 1;
+      goingUp = undefined;
+    }
+  }
+  
+  onScreen = [];
+  bottom = i;
+  // quick analysis of whats on screen
+  while(true) {
+    if(i < 0) { break;}
+    
+    current = $(rows[i]);
+    offset = current.offset();
+    outerHeight = current.outerHeight();
+    
+    // on screen
+    if(offset.top > winOffset && offset.top + outerHeight < winOffset + winHeight) {
+      onScreen.unshift(i);
+    } else {
+      
+      if(offset.top < winOffset) {
+        top = i;
+        break;
+      } else {
+        // bottom
+      }
+    }
+    i -=1;
+  }
+  
+  return({top: top, bottom: bottom, onScreen: onScreen});
+
+};
+
 
 /**
   Call this whenever you want to consider what is being seen by the browser
@@ -25,9 +109,6 @@ Discourse.Eyeline.prototype.update = function() {
   var $elements, atBottom, bottomOffset, docViewBottom, docViewTop, documentHeight, foundElement, windowHeight,
     _this = this;
 
-  // before anything ... let us not do anything if we have no focus
-  if (!Discourse.get('hasFocus')) { return; }
-
   docViewTop = $(window).scrollTop();
   windowHeight = $(window).height();
   docViewBottom = docViewTop + windowHeight;

app/assets/javascripts/discourse/components/screen_track.js

@@ -138,6 +138,9 @@ Discourse.ScreenTrack = Ember.Object.extend({
     this.topicTime += diff;
     docViewTop = $(window).scrollTop() + $('header').height();
     docViewBottom = docViewTop + $(window).height();
+
+    // TODO: Eyeline has a smarter more accurate function here
+
     return Object.keys(this.timings, function(id) {
       var $element, elemBottom, elemTop, timing;
       $element = $(id);

app/assets/javascripts/discourse/mixins/scrolling.js

@@ -10,16 +10,27 @@
 Discourse.Scrolling = Em.Mixin.create({
 
   /**
-    Begin watching for scroll events. They will be called at max every 100ms.
+    Begin watching for scroll events. By default they will be called at max every 100ms.
+    call with {debounce: N} for a diff time
 
     @method bindScrolling
   */
-  bindScrolling: function() {
+  bindScrolling: function(opts) {
     var onScroll,
       _this = this;
+
+    opts = opts || {debounce: 100};
+
+    if (opts.debounce) {
       onScroll = Discourse.debounce(function() { return _this.scrolled(); }, 100);
+    } else {
+      onScroll = function(){ return _this.scrolled(); };
+    }
+
     $(document).bind('touchmove.discourse', onScroll);
     $(window).bind('scroll.discourse', onScroll);
+
+    // resize is should also fire this cause it causes scrolling of sorts
   },
 
   /**

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

@@ -36,7 +36,7 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     progressWidth = ratio * totalWidth;
     bg = $topicProgress.find('.bg');
     bg.stop(true, true);
-    currentWidth = bg.width()
+    currentWidth = bg.width();
 
     if (currentWidth === totalWidth) {
       bg.width(currentWidth - 1);
@@ -61,13 +61,6 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     if (title) return Discourse.set('title', title);
   }).observes('topic.loaded', 'topic.title'),
 
-  newPostsPresent: (function() {
-    if (this.get('topic.highest_post_number')) {
-      this.updateBar();
-      this.examineRead();
-    }
-  }).observes('topic.highest_post_number'),
-
   currentPostChanged: (function() {
     var current = this.get('controller.currentPost');
 
@@ -112,6 +105,7 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
   willDestroyElement: function() {
     var screenTrack, controller;
     this.unbindScrolling();
+    $(window).unbind('resize.discourse-on-scroll');
 
     controller = this.get('controller');
     controller.unsubscribe();
@@ -123,22 +117,13 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     }
 
     this.set('screenTrack', null);
-
-    $(window).unbind('scroll.discourse-on-scroll');
-    $(document).unbind('touchmove.discourse-on-scroll');
-    $(window).unbind('resize.discourse-on-scroll');
-
     this.resetExamineDockCache();
   },
 
   didInsertElement: function(e) {
     var topicView = this;
-    var onScroll = Discourse.debounce(function() { return topicView.onScroll(); }, 10);
-
-    $(window).bind('scroll.discourse-on-scroll', onScroll);
-    $(document).bind('touchmove.discourse-on-scroll', onScroll);
-    $(window).bind('resize.discourse-on-scroll', onScroll);
-    this.bindScrolling();
+    this.bindScrolling({debounce: 0});
+    $(window).bind('resize.discourse-on-scroll', function() { scrolled(false); });
 
     var controller = this.get('controller');
     controller.subscribe();
@@ -151,44 +136,19 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     screenTrack.start();
     this.set('screenTrack', screenTrack);
 
-    // Track the user's eyeline
-    var eyeline = new Discourse.Eyeline('.topic-post');
-    eyeline.on('saw', function(e) {
-      topicView.postSeen(e.detail);
-    });
-
-    eyeline.on('sawBottom', function(e) {
-      topicView.postSeen(e.detail);
-      topicView.nextPage(e.detail);
-    });
-
-    eyeline.on('sawTop', function(e) {
-      topicView.postSeen(e.detail);
-      topicView.prevPage(e.detail);
-    });
-
-    this.set('eyeline', eyeline);
     this.$().on('mouseup.discourse-redirect', '.cooked a, a.track-link', function(e) {
       return Discourse.ClickTrack.trackClick(e);
     });
 
-    this.onScroll();
+    this.scrolled();
   },
 
   // Triggered whenever any posts are rendered, debounced to save over calling
   postsRendered: Discourse.debounce(function() {
     var $window = $(window);
     var $lastPost = $('.row:last');
-
-    // we consider stuff at the end of the list as read, right away (if it is visible)
-    if ($window.height() + $window.scrollTop() >= $lastPost.offset().top + $lastPost.height()) {
-      this.examineRead();
-    } else {
-      // last is not in view, so only examine in 2 seconds
-      var topicView = this;
-      Em.run.later(function() { topicView.examineRead(); }, 2000);
-    }
-  }, 100),
+    this.scrolled(false);
+  }, 50),
 
   resetRead: function(e) {
     this.get('screenTrack').cancel();
@@ -204,18 +164,16 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
 
   gotFocus: function(){
     if (Discourse.get('hasFocus')){
-      this.examineRead();
+      this.scrolled();
     }
   }.observes("Discourse.hasFocus"),
 
-  // Called for every post seen
+  // Called for every post seen, returns the post number
   postSeen: function($post) {
     var post, postView, _ref;
-    this.set('postNumberSeen', null);
     postView = Ember.View.views[$post.prop('id')];
     if (postView) {
       post = postView.get('post');
-      this.set('postNumberSeen', post.get('post_number'));
       if (post.get('post_number') > (this.get('topic.last_read_post_number') || 0)) {
         this.set('topic.last_read_post_number', post.get('post_number'));
       }
@@ -224,6 +182,7 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
         _ref = this.get('screenTrack');
         if (_ref) { _ref.guessedSeen(post.get('post_number')); }
       }
+      return post.get('post_number');
     }
   },
 
@@ -309,22 +268,12 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
   }).observes('topic.highest_post_number'),
 
   loadMore: function(post) {
-    if (this.get('controller.loading') || this.get('controller.seenBottom')) return;
+    if (this.get('controller.loading')) { return; }
 
     // Don't load if we know we're at the bottom
-    if (this.get('topic.highest_post_number') === post.get('post_number')) {
-      var eyeline = this.get('eyeline');
-      if (eyeline) {
-        eyeline.flushRest();
-      }
+    if (this.get('topic.highest_post_number') === post.get('post_number')) { return; }
 
-      // Update our current post to the last number we saw
-      var postNumberSeen = this.get('postNumberSeen');
-      if (postNumberSeen) {
-        this.set('controller.currentPost', postNumberSeen);
-      }
-      return;
-    }
+    if (this.get('controller.seenBottom')) { return; }
 
     // Don't double load ever
     if (this.topic.posts.last().post_number !== post.post_number) return;
@@ -353,26 +302,6 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     });
   },
 
-  // Examine which posts are on the screen and mark them as read. Also figure out if we
-  // need to load more posts.
-  examineRead: function() {
-    // Track posts time on screen
-    var postNumberSeen, _ref, _ref1;
-    if (_ref = this.get('screenTrack')) {
-      _ref.scrolled();
-    }
-
-    // Update what we can see
-    if (_ref1 = this.get('eyeline')) {
-      _ref1.update();
-    }
-
-    // Update our current post to the last number we saw
-    if (postNumberSeen = this.get('postNumberSeen')) {
-      this.set('controller.currentPost', postNumberSeen);
-    }
-  },
-
   cancelEdit: function() {
     // close editing mode
     this.set('editingTopic', false);
@@ -415,63 +344,51 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     this.dockedCounter = false;
   },
 
-  detectDockPosition: function() {
-    var current, goingUp, i, increment, offset, post, postView, rows, winHeight, winOffset;
-    rows = $(".topic-post");
-    if (rows.length === 0) return;
-    i = parseInt(rows.length / 2, 10);
-    increment = parseInt(rows.length / 4, 10);
-    goingUp = undefined;
-    winOffset = window.pageYOffset || $('html').scrollTop();
-    winHeight = window.innerHeight || $(window).height();
-    while (true) {
-      if (i === 0 || (i >= rows.length - 1)) {
-        break;
-      }
-      current = $(rows[i]);
-      offset = current.offset();
-      if (offset.top - winHeight < winOffset) {
-        if (offset.top + current.outerHeight() - window.innerHeight > winOffset) {
-          break;
-        } else {
-          i = i + increment;
-          if (goingUp !== undefined && increment === 1 && !goingUp) {
-            break;
-          }
-          goingUp = true;
-        }
-      } else {
-        i = i - increment;
-        if (goingUp !== undefined && increment === 1 && goingUp) {
-          break;
-        }
-        goingUp = false;
-      }
-      if (increment > 1) {
-        increment = parseInt(increment / 2, 10);
-        goingUp = undefined;
-      }
-      if (increment === 0) {
-        increment = 1;
-        goingUp = undefined;
-      }
-    }
-    postView = Ember.View.views[rows[i].id];
+  updateDock: function(postView) {
     if (!postView) return;
     post = postView.get('post');
     if (!post) return;
     this.set('progressPosition', post.get('post_number'));
   },
 
-  ensureDockIsTestedOnChange: (function() {
-    // this is subtle, firstPostLoaded will trigger ember to render the view containing #topic-title
-    //  onScroll needs do know about it to be able to make a decision about the dock
-    Em.run.next(this, this.onScroll);
-  }).observes('firstPostLoaded'),
+  nonUrgentScrolled: Discourse.debounce(function(opts){
+      var screenTrack = this.get('screenTrack');
+      if(opts.track && screenTrack) {
+        screenTrack.scrolled();
+      }
+      this.set('controller.currentPost', opts.currentPost);
+  },500),
+
+  scrolled: function(track) {
+    var $lastPost, firstLoaded, lastPostOffset, offset, 
+        title, info, rows, screenTrack, _this, currentPost;
+
+    _this = this;
+    rows = $('.topic-post');
+    info = Discourse.Eyeline.analyze(rows);
+
+    // top on screen 
+    if(info.top === 0 || info.onScreen[0] === 0 || info.bottom === 0) {
+      this.prevPage($(rows[0]));
+    }
+
+    // bottom of screen
+    if(info.bottom === rows.length-1) {
+      currentPost = _this.postSeen($(rows[info.bottom]));
+      this.nextPage($(rows[info.bottom]));
+    }
+
+    // update dock 
+    this.updateDock(Ember.View.views[rows[info.bottom].id]);
+
+    // mark everything on screen read
+    $.each(info.onScreen,function(){
+      var seen = _this.postSeen($(rows[this]));
+      currentPost = currentPost || seen;
+    });
+
+    this.nonUrgentScrolled({track: track!==false, currentPost: currentPost});
     
-  onScroll: function() {
-    var $lastPost, firstLoaded, lastPostOffset, offset, title;
-    this.detectDockPosition();
     offset = window.pageYOffset || $('html').scrollTop();
     firstLoaded = this.get('firstPostLoaded');
     if (!this.docAt) {
@@ -518,12 +435,8 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
       opts.catLink = "<a href=\"" + Discourse.getURL("/categories") + "\">" + (Em.String.i18n("topic.browse_all_categories")) + "</a>";
       return Ember.String.i18n("topic.read_more", opts);
     }
-  }).property(),
+  }).property()
 
-  // The window has been scrolled
-  scrolled: function(e) {
-    return this.examineRead();
-  }
 });
 
 Discourse.TopicView.reopenClass({