Scope subject autocomplete to the stream

(imported from commit 6e9972c93d5f56f29db37b522e20768b8fb641df)

tools/jslint/check-all.js

@@ -38,7 +38,7 @@ var globals =
 
     // zephyr.js
     + ' message_array message_dict'
-    + ' status_classes clear_table add_to_table subject_list'
+    + ' status_classes clear_table add_to_table subject_dict'
     + ' keep_pointer_in_view move_pointer_at_page_top_and_bottom'
     + ' respond_to_message'
     + ' select_message select_message_by_id'

zephyr/static/js/ui.js

@@ -112,7 +112,6 @@ var autocomplete_needs_update = false;
 
 function update_autocomplete() {
     stream_list.sort();
-    subject_list.sort();
     people_list.sort();
 
     var huddle_typeahead_list = $.map(people_list, function (person) {
@@ -125,7 +124,13 @@ function update_autocomplete() {
         items: 3
     });
     $( "#subject" ).typeahead({
-        source: subject_list,
+        source: function (query, process) {
+            var stream_name = $("#stream").val();
+            if (subject_dict.hasOwnProperty(stream_name)) {
+                return subject_dict[stream_name];
+            }
+            return [];
+        },
         items: 2
     });
     $( "#huddle_recipient" ).typeahead({

zephyr/static/js/zephyr.js

@@ -1,6 +1,6 @@
 var message_array = [];
 var message_dict = {};
-var subject_list = [];
+var subject_dict = {};
 
 $(function () {
     var i;
@@ -368,9 +368,14 @@ function add_message_metadata(dummy, message) {
     switch (message.type) {
     case 'stream':
         message.is_stream = true;
-        if ($.inArray(message.subject, subject_list) === -1) {
-            subject_list.push(message.subject);
-            autocomplete_needs_update = true;
+        if (! subject_dict.hasOwnProperty(message.display_recipient)) {
+            subject_dict[message.display_recipient] = [];
+        }
+        if ($.inArray(message.subject, subject_dict[message.display_recipient]) === -1) {
+            subject_dict[message.display_recipient].push(message.subject);
+            subject_dict[message.display_recipient].sort();
+            // We don't need to update the autocomplete after this because
+            // the subject box's source is a function
         }
         message.reply_to = message.sender_email;