Default avatar support

Fixes #264

Implement the equivalent of java's String.hashCode on the conversation model.
Change avatar template and attributes. Use css classes for colors.

js/models/conversations.js

@@ -237,11 +237,22 @@
         }
     },
 
-    getAvatarUrl: function() {
+    getAvatar: function() {
         if (this.avatarUrl === undefined) {
             this.updateAvatarUrl(true);
         }
-        return this.avatarUrl || '/images/default.png';
+        if (this.avatarUrl) {
+            return { url: this.avatarUrl };
+        } else if (this.isPrivate()) {
+            var title = this.getTitle() || '';
+            var initials = title.trim()[0];
+            return {
+                color: Math.abs(this.hashCode()) % 17,
+                content: initials
+            };
+        } else {
+            return { url: '/images/default.png' };
+        }
     },
 
     resolveConflicts: function(number) {
@@ -262,6 +273,22 @@
                 }
             });
         }.bind(this));
+    },
+    hashCode: function() {
+        if (this.hash === undefined) {
+            var string = this.getTitle() || '';
+            if (string.length === 0) {
+                return 0;
+            }
+            var hash = 0;
+            for (var i = 0; i < string.length; i++) {
+                hash = ((hash<<5)-hash) + string.charCodeAt(i);
+                hash = hash & hash; // Convert to 32bit integer
+            }
+
+            this.hash = hash;
+        }
+        return this.hash;
     }
   });
 

js/views/conversation_list_item_view.js

@@ -45,7 +45,7 @@
                     last_message: this.model.get('lastMessage'),
                     last_message_timestamp: moment(this.model.get('timestamp')).format('MMM D'),
                     number: this.model.getNumber(),
-                    avatar_url: this.model.getAvatarUrl()
+                    avatar: this.model.getAvatar()
                 }, this.render_partials())
             );
 

js/views/message_detail_view.js

@@ -31,9 +31,9 @@
         },
         render_attributes: function() {
             return {
-                name       : this.model.getTitle(),
-                avatar_url : this.model.getAvatarUrl(),
-                conflict   : this.conflict
+                name     : this.model.getTitle(),
+                avatar   : this.model.getAvatar(),
+                conflict : this.conflict
             };
         }
     });

js/views/message_view.js

@@ -62,7 +62,7 @@
                     message: this.model.get('body'),
                     timestamp: moment(this.model.get('sent_at')).fromNow(),
                     sender: (contact && contact.getTitle()) || '',
-                    avatar_url: (contact && contact.getAvatarUrl())
+                    avatar: (contact && contact.getAvatar())
                 }, this.render_partials())
             );
 

js/views/new_group_update_view.js

@@ -67,7 +67,7 @@
         render_attributes: function() {
             return {
                 name: this.model.getTitle(),
-                avatar_url: this.model.getAvatarUrl()
+                avatar: {url: this.model.getAvatar()}
             };
         },
         send: function() {