[FIX] mail: only update timestamps periodically

the messages in a thread were previously rerendered every minutes to
update their timestamps.  This commit only update the timestamps, not
all the message.  This will allow us to keep expanded/folded state in
messages without collapsing them every minutes.

[IMP] mail: add read more/read less support client side

Messages are cleaned up and tagged server sides, with a attribute
data-o-mail-quote.  This commit replace their content with a clickable
read more link, which toggle its display.

addons/mail/static/src/js/thread.js

@@ -12,6 +12,16 @@ var ORDER = {
     DESC: -1,
 };
 
+var read_more = _t('read more');
+var read_less = _t('read less');
+
+function time_from_now(date) {
+    if (moment().diff(date, 'seconds') < 45) {
+        return _t("now");
+    }
+    return date.fromNow();
+}
+
 var Thread = Widget.extend({
     className: 'o_mail_thread',
 
@@ -69,7 +79,6 @@ var Thread = Widget.extend({
     },
 
     render: function (messages, options) {
-        clearTimeout(this.auto_render_timeout);
         var self = this;
         var msgs = _.map(messages, this._preprocess_message.bind(this));
         if (this.options.display_order === ORDER.DESC) {
@@ -100,13 +109,35 @@ var Thread = Widget.extend({
             ORDER: ORDER,
         }));
 
-        this.auto_render_timeout = setTimeout(function () {
-            if (!self.isDestroyed()) {
-                self.render(messages, options);
-            }
-        }, 1000*60); // re-render the thread every minute to update dates
+        _.each(msgs, function(msg) {
+            self.$('[data-message-id="' + msg.id + '"] .o_mail_timestamp')
+                .data('date', msg.date);
+        });
+
+        this.$('[data-o-mail-quote="1"]').each(function () {
+            var $content = $(this);
+            var $read_more = $('<a class="o_mail_read_more" href="#"></a>').text(read_more);
+            var is_read_more = true;
+            $read_more.click(function() {
+                is_read_more = !is_read_more;
+                $content.toggle(!is_read_more);
+                $read_more.text(is_read_more ? read_more : read_less);
+            });
+            $read_more.insertBefore($content);
+        });
+        if (!this.update_timestamps_interval) {
+            this.update_timestamps_interval = setInterval(function() {
+                self.update_timestamps();
+            }, 1000*60);
+        }
     },
 
+    update_timestamps: function () {
+        this.$('.o_mail_timestamp').each(function() {
+            var date = $(this).data('date');
+            $(this).html(time_from_now(date));
+        });
+    },
     on_click_redirect: function (event) {
         var id = $(event.target).data('oe-id');
         if (id) {
@@ -133,21 +164,15 @@ var Thread = Widget.extend({
         var msg = _.extend({}, message);
 
         msg.date = moment.min(msg.date, moment());
-        var date = msg.date.format('YYYY-MM-DD');
+        msg.hour = time_from_now(msg.date);
 
+        var date = msg.date.format('YYYY-MM-DD');
         if (date === moment().format('YYYY-MM-DD')) {
             msg.day = _t("Today");
-            if (moment().diff(msg.date, 'minutes') === 0) {
-                msg.hour = _t("now");
-            } else {
-                msg.hour = msg.date.fromNow();
-            }
         } else if (date === moment().subtract(1, 'days').format('YYYY-MM-DD')) {
-           msg.day = _t("Yesterday");
-           msg.hour = msg.date.format('LT');
+            msg.day = _t("Yesterday");
         } else {
             msg.day = msg.date.format('LL');
-            msg.hour = msg.date.format('LT');
         }
 
         if (_.contains(this.expanded_msg_ids, message.id)) {
@@ -208,6 +233,9 @@ var Thread = Widget.extend({
         this.$('.o_thread_message').removeClass('o_thread_selected_message');
         this.selected_id = null;
     },
+    destroy: function () {
+        clearInterval(this.update_timestamps_interval);
+    },
 });
 
 Thread.ORDER = ORDER;

addons/mail/static/src/less/thread.less

@@ -156,4 +156,11 @@
     .o_mail_no_content {
         .o-webclient-padding();
     }
+
+    [data-o-mail-quote="1"] {
+        display: none;
+    }
+    .o_thread_message .o_thread_message_core .o_mail_read_more {
+        display: block;
+    }
 }

addons/mail/static/src/xml/thread.xml

@@ -87,9 +87,7 @@
                         <t t-esc="message.displayed_author"/>
                     </strong>
 
-                    <small t-att-title="message.date">
-                        - <t t-esc="message.hour"/>
-                    </small>
+                    - <small class="o_mail_timestamp" t-att-title="message.date"><t t-esc="message.hour"/></small>
                     <t t-if="message.model &amp;&amp; (message.model != 'mail.channel') &amp;&amp; options.display_document_link">
                         on <a t-att-href="message.url" t-att-data-oe-model="message.model" t-att-data-oe-id="message.res_id"><t t-esc="message.record_name"/></a>
                     </t>