Refactor read state tracking

Adds support for handling early arriving read receipts.

// FREEBIE

background.html

@@ -395,6 +395,7 @@
 
   <script type='text/javascript' src='js/notifications.js'></script>
   <script type='text/javascript' src='js/delivery_receipts.js'></script>
+  <script type='text/javascript' src='js/read_receipts.js'></script>
   <script type='text/javascript' src='js/libphonenumber-util.js'></script>
   <script type='text/javascript' src='js/models/messages.js'></script>
   <script type='text/javascript' src='js/models/conversations.js'></script>

js/background.js

@@ -245,31 +245,8 @@
     function onReadReceipt(ev) {
         var timestamp = ev.timestamp.toNumber();
         var sender    = ev.sender;
-        var messages  = new Whisper.MessageCollection();
-        var groups    = new Whisper.ConversationCollection();
         console.log('read receipt ', sender, timestamp);
-        groups.fetchGroups(sender).then(function() {
+        Whisper.ReadReceipts.add({sender: sender, timestamp: timestamp});
-            messages.fetchSentAt(timestamp).then(function() {
-                var ids = groups.pluck('id');
-                ids.push(sender);
-                var message = messages.find(function(message) {
-                    return (message.isIncoming() && message.isUnread() &&
-                            _.contains(ids, message.get('conversationId')));
-                });
-                if (message) {
-                    message.markRead().then(function() {
-                        var conversation = ConversationController.get({
-                            id: message.get('conversationId')
-                        });
-
-                        if (conversation) {
-                            // notify frontend listeners
-                            conversation.trigger('read', message);
-                        }
-                    });
-                }
-            });
-        });
     }
 
     // lazy hack

js/models/messages.js

@@ -326,7 +326,12 @@
                         }
                         attributes.active_at = now;
                         if (type === 'incoming') {
-                            attributes.unreadCount = conversation.get('unreadCount') + 1;
+                            // experimental
+                            if (Whisper.ReadReceipts.forMessage(message)) {
+                                message.unset('unread');
+                            } else {
+                                attributes.unreadCount = conversation.get('unreadCount') + 1;
+                            }
                         }
                         conversation.set(attributes);
 

js/read_receipts.js

@@ -0,0 +1,47 @@
+/*
+ * vim: ts=4:sw=4:expandtab
+ */
+;(function() {
+    'use strict';
+    window.Whisper = window.Whisper || {};
+    Whisper.ReadReceipts = new (Backbone.Collection.extend({
+        initialize: function() {
+            this.on('add', this.onReceipt);
+        },
+        forMessage: function(message) {
+            var receipt = this.findWhere({
+                sender: message.get('source'),
+                timestamp: message.get('sent_at')
+            });
+            if (receipt) {
+                console.log('Found early read receipt for message');
+                this.remove(receipt);
+                return receipt;
+            }
+        },
+        onReceipt: function(receipt) {
+            var messages  = new Whisper.MessageCollection();
+            messages.fetchSentAt(receipt.get('timestamp')).then(function() {
+                var message = messages.find(function(message) {
+                    return (message.isIncoming() && message.isUnread() &&
+                            message.get('source') === receipt.get('sender'));
+                });
+                if (message) {
+                    this.remove(receipt);
+                    message.markRead().then(function() {
+                        var conversation = ConversationController.get({
+                            id: message.get('conversationId')
+                        });
+
+                        if (conversation) {
+                            // notify frontend listeners
+                            conversation.trigger('read', message);
+                        }
+                    });
+                } else {
+                    console.log('No message for read receipt');
+                }
+            }.bind(this));
+        }
+    }))();
+})();