Add trailing bookend with current subscribed status in some narrows.

This is basically just the logical extension of the previous commit
for the case where the last thing we did was subscribe or unsubscribe.

This even magically updates when you subscribe or unsubscribe from
another window :).

(imported from commit 2399329d11bf66aa0b614a21d2b3cf4035452279)

zephyr/static/js/message_list.js

@@ -76,6 +76,7 @@ MessageList.prototype = {
     _clear_rendering_state: function MessageList__clear_rendering_state() {
         this._message_groups = [];
         this._clear_table();
+        this.last_message_historical = false;
     },
 
     clear: function  MessageList_clear(opts) {
@@ -245,6 +246,11 @@ MessageList.prototype = {
         var current_group = [];
         var new_message_groups = [];
 
+        if (where === "bottom") {
+            // Remove the trailing bookend; it'll be re-added after we do our rendering
+            this.clear_trailing_bookend();
+        }
+
         if (where === 'top' && this.collapse_messages && this._message_groups.length > 0) {
             // Delete the current top message group, and add it back in with these
             // messages, in order to collapse properly.
@@ -319,6 +325,7 @@ MessageList.prototype = {
 
             messages_to_render.push(message);
             prev = message;
+            self.last_message_historical = message.historical;
         });
 
         if (messages_to_render.length === 0) {
@@ -371,6 +378,8 @@ MessageList.prototype = {
         } else {
             table.append(rendered_elems);
 
+            this.update_trailing_bookend();
+
             // XXX: This is absolutely awful.  There is a firefox bug
             // where when table rows as DOM elements are appended (as
             // opposed to as a string) a border is sometimes added to the
@@ -430,6 +439,43 @@ MessageList.prototype = {
         }
     },
 
+    clear_trailing_bookend: function MessageList_clear_trailing_bookend() {
+        var trailing_bookend = rows.get_table(this.table_name).find('#trailing_bookend');
+        trailing_bookend.remove();
+    },
+
+    // Maintains a trailing bookend element explaining any changes in
+    // your subscribed/unsubscribed status at the bottom of the
+    // message list.
+    update_trailing_bookend: function MessageList_update_trailing_bookend() {
+        this.clear_trailing_bookend();
+        if (!this.narrowed) {
+            return;
+        }
+        var stream = narrow.stream();
+        if (stream === undefined) {
+            return;
+        }
+        var trailing_bookend_content, subscribed = subs.have(stream);
+        if (subscribed) {
+            if (this.last_message_historical) {
+                trailing_bookend_content = "--- Subscribed to stream " + stream + " ---";
+            }
+        } else {
+            if (!this.last_message_historical) {
+                trailing_bookend_content = "--- Unsubscribed from stream " + stream + " ---";
+            } else {
+                trailing_bookend_content = "--- Not subscribed to stream " + stream + " ---";
+            }
+        }
+        if (trailing_bookend_content !== undefined) {
+            var rendered_trailing_bookend = $(templates.render('trailing_bookend', {
+                trailing_bookend: trailing_bookend_content
+            }));
+            rows.get_table(this.table_name).append(rendered_trailing_bookend);
+        }
+    },
+
     append: function MessageList_append(messages) {
         this._items = this._items.concat(messages);
         this._add_to_hash(messages);

zephyr/static/js/narrow.js

@@ -276,6 +276,16 @@ function build_filter(operators_mixed_case) {
     };
 }
 
+exports.stream = function () {
+    var j;
+    for (j = 0; j < current_operators.length; j++) {
+        if (current_operators[j][0] === "stream") {
+            return current_operators[j][1];
+        }
+    }
+    return undefined;
+};
+
 exports.activate = function (operators, opts) {
     opts = $.extend({}, {
         then_select_id: home_msg_list.selected_id(),

zephyr/static/js/subs.js

@@ -301,6 +301,10 @@ function mark_subscribed(stream_name, attrs) {
         return;
     }
 
+    if (current_msg_list.narrowed) {
+        current_msg_list.update_trailing_bookend();
+    }
+
     // Update unread counts as the new stream in sidebar might
     // need its unread counts re-calculated
     process_loaded_for_unread(all_msg_list.all());
@@ -338,6 +342,11 @@ function mark_unsubscribed(stream_name) {
         // Already unsubscribed
         return;
     }
+
+    if (current_msg_list.narrowed) {
+        current_msg_list.update_trailing_bookend();
+    }
+
     typeahead_helper.update_autocomplete();
 }
 

zephyr/static/templates/message.handlebars

@@ -88,3 +88,11 @@
 </tr>
 {{/with}}
 {{/each}}
+
+{{#if trailing_bookend}}
+<tr id="trailing_bookend" class="bookend_tr"><td/>
+<td /><td class="bookend">
+<center>{{trailing_bookend}}</center>
+<span class="tiny"><p></p></span></td>
+</tr>
+{{/if}}

zephyr/static/templates/trailing_bookend.handlebars

@@ -0,0 +1,9 @@
+{{! Client-side Mustache template for rendering the trailing bookend.}}
+
+{{#if trailing_bookend}}
+<tr id="trailing_bookend" class="bookend_tr"><td/>
+<td /><td class="bookend">
+<center>{{trailing_bookend}}</center>
+<span class="tiny"><p></p></span></td>
+</tr>
+{{/if}}