[IMP] mail: needactions and messages read

Mainly concern the client action:
	- Display needactions per channels
	- For all channels except Inbox, clear needactions when opening the channel
	- Add snackbar to undo needactions clearing
	- Display a separator between read and unread messages in threads
	- Fix active channel (for Inbox and Starred) display in sidebar

Various minor changes in chat_manager:
	- Code refactoring of bus notification handler
	- get_channel() don't fallback anymore on first channel

9 files changed, 352 insertions, 164 deletions

diff --git a/addons/mail/models/mail_channel.py b/addons/mail/models/mail_channel.py
index 4980f295e93..110995e0954 100644
--- a/addons/mail/models/mail_channel.py
+++ b/addons/mail/models/mail_channel.py
@@ -396,6 +396,7 @@ class Channel(models.Model):
         if self.channel_message_ids.ids:
             last_message_id = self.channel_message_ids.ids[0] # zero is the index of the last message
             self.env['mail.channel.partner'].search([('channel_id', 'in', self.ids), ('partner_id', '=', self.env.user.partner_id.id)]).write({'seen_message_id': last_message_id})
+            return last_message_id
 
     @api.multi
     def channel_invite(self, partner_ids):
diff --git a/addons/mail/models/mail_message.py b/addons/mail/models/mail_message.py
index 1dff03cc902..3e93973dd82 100644
--- a/addons/mail/models/mail_message.py
+++ b/addons/mail/models/mail_message.py
@@ -146,52 +146,84 @@ class Message(models.Model):
     # Notification API
     #------------------------------------------------------
 
-    @api.multi
-    def set_message_needaction(self, partner_ids=None):
-        if not partner_ids:
-            partner_ids = [self.env.user.partner_id.id]
-        if set(partner_ids) == set([self.env.user.partner_id.id]):
-            # a user should be able to mark a message as needaction for him
-            self = self.sudo()
-        return self.write({'needaction_partner_ids': [(4, pid) for pid in partner_ids]})
-
-    @api.multi
-    def mark_all_as_read(self):
-        user_id = self.env.user.partner_id.id
-
+    @api.model
+    def mark_all_as_read(self, channel_ids=None):
+        """ Remove all needactions of the current partner. If channel_ids is
+            given, restrict to messages written in one of those channels. """
+        partner_id = self.env.user.partner_id.id
         # possibly horribly inefficient method:
         # it does one db request for the search, and one for each message in
         # the result set to remove the current user from the relation.
-        # unread_messages = self.search([('needaction_partner_ids', 'in', user_id)])
-        # unread_messages.write({'needaction_partner_ids': [(3, user_id)]})
+        # domain = [('needaction_partner_ids', 'in', partner_id)]
+        # if channel_ids:
+        #     domain += [('channel_ids', 'in', channel_ids)]
+        # unread_messages = self.search(domain)
+        # unread_messages.write({'needaction_partner_ids': [(3, partner_id)]})
 
         # a much faster way to do this is in pure sql:
-        self.env.cr.execute("DELETE FROM mail_message_res_partner_needaction_rel WHERE res_partner_id IN %s", [(user_id,)])
+        query = "DELETE FROM mail_message_res_partner_needaction_rel WHERE res_partner_id IN %s"
+        args = [(partner_id,)]
+        if channel_ids:
+            query += """
+                AND mail_message_id in
+                    (SELECT mail_message_id
+                    FROM mail_message_mail_channel_rel
+                    WHERE mail_channel_id in %s)"""
+            args += [tuple(channel_ids)]
+        query += " RETURNING mail_message_id as id"
+        self._cr.execute(query, args)
+        self.invalidate_cache()
+
+        ids = [m['id'] for m in self._cr.dictfetchall()]
+        notification = {'type': 'mark_as_read', 'message_ids': ids, 'channel_ids': channel_ids}
+        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)
+
+        return ids
+
+    @api.multi
+    def mark_as_unread(self, channel_ids=None):
+        """ Add needactions to messages for the current partner. """
+        partner_id = self.env.user.partner_id.id
+        for message in self:
+            message.write({'needaction_partner_ids': [(4, partner_id)]})
+
+        ids = [m.id for m in self]
+        notification = {'type': 'mark_as_unread', 'message_ids': ids, 'channel_ids': channel_ids}
+        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)
 
     @api.multi
     def set_message_done(self, partner_ids=None):
+        """ Remove the needaction from messages for the current partner, or for
+            partners in partner_ids if partner_ids is given. """
         if not partner_ids:
             partner_ids = [self.env.user.partner_id.id]
         if set(partner_ids) == set([self.env.user.partner_id.id]):
             # a user should be able to mark a message as done for him
             self = self.sudo()
-        return self.write({'needaction_partner_ids': [(3, pid) for pid in partner_ids]})
+        self.write({'needaction_partner_ids': [(3, pid) for pid in partner_ids]})
+
+        channel_ids = [c.id for c in self.channel_ids]
+        notification = {'type': 'mark_as_read', 'message_ids': [self.id], 'channel_ids': channel_ids}
+        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)
 
     @api.model
     def unstar_all(self):
+        """ Unstar messages for the current partner. """
         partner_id = self.env.user.partner_id.id
 
         starred_messages = self.search([('starred_partner_ids', 'in', partner_id)])
         starred_messages.write({'starred_partner_ids': [(3, partner_id)]})
 
+        ids = [m.id for m in starred_messages]
+        notification = {'type': 'toggle_star', 'message_ids': ids, 'starred': False}
+        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)
+
     @api.multi
     def set_message_starred(self, starred):
         """ Set messages as (un)starred. Technically, the notifications related
             to uid are set to (un)starred.
 
             :param bool starred: set notification as (un)starred
-            :param bool create_missing: create notifications for missing entries
-                (i.e. when acting on displayed messages not notified)
         """
         # a user should always be able to star a message he can read
         self.check_access_rule('read')
@@ -199,7 +231,9 @@ class Message(models.Model):
             self.sudo().write({'starred_partner_ids': [(4, self.env.user.partner_id.id)]})
         else:
             self.sudo().write({'starred_partner_ids': [(3, self.env.user.partner_id.id)]})
-        return starred
+
+        notification = {'type': 'toggle_star', 'message_ids': [self.id], 'starred': starred}
+        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)
 
     #------------------------------------------------------
     # Message loading for web interface
diff --git a/addons/mail/static/src/js/chat_manager.js b/addons/mail/static/src/js/chat_manager.js
index 6bd96fdc32d..01cc6918264 100644
--- a/addons/mail/static/src/js/chat_manager.js
+++ b/addons/mail/static/src/js/chat_manager.js
@@ -37,7 +37,7 @@ function add_message (data, options) {
         // Keep the array ordered by date when inserting the new message
         messages.splice(_.sortedIndex(messages, msg, 'id'), 0, msg);
         if (options.channel_id) {
-            var channel = _.findWhere(channels, {id: options.channel_id});
+            var channel = chat_manager.get_channel(options.channel_id);
             if (channel.hidden) {
                 channel.hidden = false;
                 chat_manager.bus.trigger('new_channel', channel);
@@ -117,8 +117,8 @@ function make_message (data) {
     }
     var real_channels = _.without(msg.channel_ids, 'channel_inbox', 'channel_starred');
     var origin = real_channels.length ? real_channels[0] : undefined;
-    var channel;
-    if (origin && (channel = _.findWhere(channels, {id: origin}))) {
+    var channel = origin && chat_manager.get_channel(origin);
+    if (channel) {
         msg.origin_id = origin;
         msg.origin_name = channel.name;
     }
@@ -165,7 +165,7 @@ function post_document_message (model_name, res_id, data) {
 
 function add_channel (data, options) {
     options = typeof options === "object" ? options : {};
-    var channel = _.findWhere(channels, {id: data.id});
+    var channel = chat_manager.get_channel(data.id);
     if (channel) {
         if (channel.is_folded !== (data.state === "folded")) {
             channel.is_folded = (data.state === "folded");
@@ -197,6 +197,9 @@ function make_channel (data, options) {
         autoswitch: 'autoswitch' in options ? options.autoswitch : true,
         hidden: options.hidden,
         display_needactions: options.display_needactions,
+        needaction_counter: data.message_needaction_counter || 0,
+        unread_counter: data.message_unread_counter || 0,
+        last_seen_message_id: data.seen_message_id,
         cache: {'[]': {
             all_history_loaded: false,
             loaded: false,
@@ -299,6 +302,126 @@ function fetch_document_messages (ids, options) {
     }
 }
 
+var channel_seen = _.throttle(function (channel) {
+    return ChannelModel.call('channel_seen', [[channel.id]]).then(function (last_seen_message_id) {
+        channel.last_seen_message_id = last_seen_message_id;
+    });
+}, 3000);
+
+// Notification handlers
+// ---------------------------------------------------------------------------------
+function on_notification (notification) {
+    var model = notification[0][1];
+    if (model === 'ir.needaction') {
+        // new message in the inbox
+        on_needaction_notification(notification[1]);
+    } else if (model === 'mail.channel') {
+        // new message in a channel
+        on_channel_notification(notification[1]);
+    } else if (model === 'res.partner') {
+        // channel joined/left, message marked as read/(un)starred, chat open/closed
+        on_partner_notification(notification[1]);
+    }
+}
+
+function on_needaction_notification (message) {
+    message = add_message(message, { channel_id: 'channel_inbox', show_notification: true} );
+    needaction_counter++;
+    var channel = chat_manager.get_channel(message.channel_ids[0]);
+    if (channel) {
+        channel.needaction_counter++;
+    }
+    chat_manager.bus.trigger('update_needaction', needaction_counter);
+}
+
+function on_channel_notification (message) {
+    var channel = chat_manager.get_channel(message.channel_ids[0]);
+    if (channel) {
+        channel.unread_counter++;
+        add_message(message, { channel_id: channel.id, show_notification: true });
+    }
+}
+
+function on_partner_notification (data) {
+    if (data.info === "unsubscribe") {
+        channels = _.without(channels, chat_manager.get_channel(data.id));
+        chat_manager.bus.trigger("unsubscribe_from_channel", data.id);
+    } else if (data.type === 'toggle_star') {
+        on_toggle_star_notification(data);
+    } else if (data.type === 'mark_as_read') {
+        on_mark_as_read_notification(data);
+    } else if (data.type === 'mark_as_unread') {
+        on_mark_as_unread_notification(data);
+    } else {
+        on_chat_session_notification(data);
+    }
+}
+
+function on_toggle_star_notification (data) {
+    _.each(data.message_ids, function (msg_id) {
+        var message = _.findWhere(messages, { id: msg_id });
+        if (message) {
+            message.is_starred = data.starred;
+            if (!message.is_starred) {
+                remove_message_from_channel("channel_starred", message);
+            }
+            chat_manager.bus.trigger('update_message', message);
+        }
+    });
+}
+
+function on_mark_as_read_notification (data) {
+    _.each(data.message_ids, function (msg_id) {
+        var message = _.findWhere(messages, { id: msg_id });
+        if (message) {
+            remove_message_from_channel("channel_inbox", message);
+            chat_manager.bus.trigger('update_message', message);
+        }
+    });
+    if (data.channel_ids.length) {
+        _.each(data.channel_ids, function (channel_id) {
+            var channel = chat_manager.get_channel(channel_id);
+            if (channel) {
+                channel.needaction_counter -= data.message_ids.length;
+            }
+        });
+    } else {
+        _.each(channels, function (channel) {
+            channel.needaction_counter = 0;
+        });
+    }
+    needaction_counter -= data.message_ids.length;
+    chat_manager.bus.trigger('update_needaction', needaction_counter);
+}
+
+function on_mark_as_unread_notification (data) {
+    _.each(data.channel_ids, function (channel_id) {
+        var channel = chat_manager.get_channel(channel_id);
+        if (channel) {
+            channel.needaction_counter += data.message_ids.length;
+        }
+    });
+    needaction_counter += data.message_ids.length;
+    chat_manager.bus.trigger('update_needaction', needaction_counter);
+}
+
+function on_chat_session_notification (chat_session) {
+    if ((chat_session.channel_type === "channel") && (chat_session.public === "private") && (chat_session.state === "open")) {
+        add_channel(chat_session, {autoswitch: false});
+        if (!chat_session.is_minimized) {
+            web_client.do_notify(_t("Private Channel"), _t("You have been invited to: ") + chat_session.name);
+        }
+    }
+    // partner specific change (open a detached window for example)
+    if ((chat_session.state === "open") || (chat_session.state === "folded")) {
+        add_channel(chat_session, {autoswitch: false});
+        if (chat_session.is_minimized) {
+            chat_manager.bus.trigger("open_chat", chat_session);
+        }
+    } else if (chat_session.state === "closed") {
+        chat_manager.bus.trigger("close_chat", chat_session);
+    }
+}
 
 // Public interface
 //----------------------------------------------------------------------------------
@@ -335,42 +458,28 @@ var chat_manager = {
     toggle_star_status: function (message_id) {
         var msg = _.findWhere(messages, { id: message_id });
 
-        return MessageModel.call('set_message_starred', [[message_id], !msg.is_starred]).then(function () {
-            msg.is_starred = !msg.is_starred;
-            if (!msg.is_starred) {
-                remove_message_from_channel("channel_starred", msg);
-            }
-            chat_manager.bus.trigger('update_message', msg);
-        });
+        return MessageModel.call('set_message_starred', [[message_id], !msg.is_starred]);
+    },
+    unstar_all: function () {
+        return MessageModel.call('unstar_all', [[]], {});
     },
     mark_as_read: function (message_id) {
-        return MessageModel.call('set_message_done', [[message_id]]).then(function () {
-            var message = _.findWhere(messages, { id: message_id });
-            remove_message_from_channel("channel_inbox", message);
-            chat_manager.bus.trigger('update_message', message);
-            needaction_counter = needaction_counter - 1;
-            chat_manager.bus.trigger('update_needaction', needaction_counter);
-        });
+        return MessageModel.call('set_message_done', [[message_id]]);
     },
-
-    mark_all_as_read: function () {
-        MessageModel.call('mark_all_as_read', [[]], {}).then(function (ids) {
-            _.each(messages, function (msg) {
-                remove_message_from_channel("channel_inbox", msg);
-                chat_manager.bus.trigger('update_message', msg);
-            });
-            needaction_counter = 0;
-            chat_manager.bus.trigger('update_needaction', needaction_counter);
-        });
+    mark_all_as_read: function (channel) {
+        if ((!channel && needaction_counter) || (channel && channel.needaction_counter)) {
+            return MessageModel.call('mark_all_as_read', channel ? [[channel.id]] : [[]]);
+        }
+        return $.when();
     },
-
-    unstar_all: function () {
-        MessageModel.call('unstar_all', [[]], {}).then(function (ids) {
-            _.each(messages, function (msg) {
-                remove_message_from_channel("channel_starred", msg);
-                chat_manager.bus.trigger('update_message', msg);
-            });
-        });
+    undo_mark_as_read: function (message_ids, channel) {
+        return MessageModel.call('mark_as_unread', [message_ids, [channel.id]]);
+    },
+    mark_channel_as_seen: function (channel) {
+        if (channel.unread_counter > 0) {
+            channel.unread_counter = 0;
+            channel_seen(channel);
+        }
     },
 
     get_channels: function () {
@@ -378,7 +487,7 @@ var chat_manager = {
     },
 
     get_channel: function (id) {
-        return _.findWhere(channels, {id: id}) || channels[0];
+        return _.findWhere(channels, {id: id});
     },
 
     all_history_loaded: function (channel, domain) {
@@ -435,11 +544,11 @@ var chat_manager = {
         });
     },
     close_chat_session: function (channel_id) {
-        var channel = _.findWhere(channels, {id: channel_id});
+        var channel = this.get_channel(channel_id);
         ChannelModel.call("channel_fold", [], {uuid : channel.uuid, state : "closed"});
     },
     fold_channel: function (channel_id) {
-        var channel = _.findWhere(channels, {id: channel_id});
+        var channel = this.get_channel(channel_id);
         return ChannelModel.call("channel_fold", [], {uuid : channel.uuid}).then(function () {
             channel.is_folded = !channel.is_folded;
         });
@@ -479,52 +588,7 @@ function init () {
     var load_menu_id = ir_model.call("xmlid_to_res_id", ["mail.mail_channel_menu_root_chat"]);
     var load_action_id = ir_model.call("xmlid_to_res_id", ["mail.mail_channel_action_client_chat"]);
 
-    bus.on('notification', null, function (notification) {
-        var model = notification[0][1];
-        if (model === 'ir.needaction') {
-            // new message in the inbox
-            var message = notification[1];
-            message = add_message(message, { channel_id: 'channel_inbox', show_notification: true} );
-            needaction_counter = needaction_counter + 1;
-            chat_manager.bus.trigger('update_needaction', needaction_counter);
-        }
-        if (model === 'mail.channel') {
-            // new message in a channel
-            var message = notification[1];
-            var channel_id = message.channel_ids[0];
-            var channel = _.findWhere(channels, {id: channel_id});
-            if (channel) {
-                add_message(message, { channel_id: channel_id, show_notification: true });
-            }
-        }
-        if (model === 'res.partner') {
-            var chat_session = notification[1];
-            if (chat_session.info === "unsubscribe") {
-                var channel = _.findWhere(channels, {id: chat_session.id});
-                if (channel) {
-                    channels = _.without(channels, channel);
-                }
-                chat_manager.bus.trigger("unsubscribe_from_channel", chat_session.id);
-                return;
-            }
-            if ((chat_session.channel_type === "channel") && (chat_session.public === "private") && (chat_session.state === "open")) {
-                add_channel(chat_session, {autoswitch: false});
-                if (!chat_session.is_minimized) {
-                    web_client.do_notify(_t("Private Channel"), _t("You have been invited to: ") + chat_session.name);
-                }
-            }
-            // partner specific change (open a detached window for example)
-            if ((chat_session.state === "open") || (chat_session.state === "folded")) {
-                add_channel(chat_session, {autoswitch: false});
-                if (chat_session.is_minimized) {
-                    chat_manager.bus.trigger("open_chat", chat_session);
-                }
-            }
-            if (chat_session.state === "closed") {
-                chat_manager.bus.trigger("close_chat", chat_session);
-            }
-        }
-    });
+    bus.on('notification', null, on_notification);
 
     return $.when(load_menu_id, load_action_id, load_channels, load_emojis).then(function (menu_id, action_id) {
         discuss_ids = {
diff --git a/addons/mail/static/src/js/chatter.js b/addons/mail/static/src/js/chatter.js
index 5b98786ccdc..fae9e294e57 100644
--- a/addons/mail/static/src/js/chatter.js
+++ b/addons/mail/static/src/js/chatter.js
@@ -776,7 +776,7 @@ var Chatter = form_common.AbstractField.extend({
         var def;
         var channel = chat_manager.get_channel(channel_id);
         // If not registered to 'channel' yet, do it
-        if (channel.id !== channel_id) {
+        if (!channel) {
             def = chat_manager.join_channel(channel_id);
         }
         $.when(def).then(function () {
diff --git a/addons/mail/static/src/js/client_action.js b/addons/mail/static/src/js/client_action.js
index 6c5b4ecba5b..7974203abe4 100644
--- a/addons/mail/static/src/js/client_action.js
+++ b/addons/mail/static/src/js/client_action.js
@@ -109,6 +109,14 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
             var channel_id = $(event.target).data("channel-id");
             this.unsubscribe_from_channel(chat_manager.get_channel(channel_id));
         },
+        "click .o_snackbar_undo": function (event) {
+            event.preventDefault();
+            var channel = this.channel;
+            this.$snackbar.remove();
+            this.clear_needactions_def.then(function (msgs_ids) {
+                chat_manager.undo_mark_as_read(msgs_ids, channel);
+            });
+        },
     },
 
     on_attach_callback: function () {
@@ -146,6 +154,9 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
                                  this.action.context.active_id ||
                                  this.action.params.default_active_id ||
                                  'channel_inbox';
+        var default_channel = chat_manager.get_channel(default_channel_id) ||
+                              chat_manager.get_channel('channel_inbox');
+
         this.searchview = new SearchView(this, dataset, view_id, {}, options);
         this.searchview.on('search_data', this, this.on_search);
 
@@ -167,14 +178,15 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
         this.$buttons.on('click', '.o_mail_toggle_channels', function () {
             self.$('.o_mail_chat_sidebar').slideToggle(200);
         });
-        this.$buttons.on('click', '.o_mail_chat_button_mark_read', chat_manager.mark_all_as_read);
+        this.$buttons.on('click', '.o_mail_chat_button_mark_read', function () {
+            chat_manager.mark_all_as_read();
+        });
         this.$buttons.on('click', '.o_mail_chat_button_unstar_all', chat_manager.unstar_all);
 
-
         this.thread.on('redirect', this, this.on_redirect);
         this.thread.on('redirect_to_channel', this, function (channel_id) {
             var channel = chat_manager.get_channel(channel_id);
-            if (channel.id === channel_id) {
+            if (channel) {
                 this.set_channel(channel);
             } else {
                 chat_manager.join_channel(channel_id);
@@ -196,7 +208,7 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
         this.render_sidebar();
 
         return $.when(def1, def2, def3)
-            .then(this.set_channel.bind(this, chat_manager.get_channel(default_channel_id)))
+            .then(this.set_channel.bind(this, default_channel))
             .then(function () {
                 chat_manager.bus.on('new_message', self, self.on_new_message);
                 chat_manager.bus.on('update_message', self, self.on_update_message);
@@ -204,7 +216,7 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
                 chat_manager.bus.on('anyone_listening', self, function (channel, query) {
                     query.is_displayed = query.is_displayed || channel.id === self.channel.id;
                 });
-                chat_manager.bus.on('update_needaction', self, self.on_update_needaction);
+                chat_manager.bus.on('update_needaction', self, self.render_sidebar);
                 chat_manager.bus.on('unsubscribe_from_channel', self, self.render_sidebar);
             });
     },
@@ -212,8 +224,9 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
     render_sidebar: function () {
         var self = this;
         var $sidebar = QWeb.render("mail.chat.Sidebar", {
+            active_channel_id: this.channel ? this.channel.id: undefined,
             channels: chat_manager.get_channels(),
-            needaction_counter: chat_manager.get_needaction_counter()
+            needaction_counter: chat_manager.get_needaction_counter(),
         });
         this.$(".o_mail_chat_sidebar").replaceWith($sidebar);
 
@@ -303,41 +316,59 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
             this.channels_scrolltop[this.channel.id] = this.thread.get_scrolltop();
         }
         var new_channel_scrolltop = this.channels_scrolltop[channel.id];
-        this.channel = channel;
-
-        // Update control panel
-        this.set("title", channel.name);
-        // Hide 'detach' button in static channels
-        this.$buttons
-            .find('.o_mail_chat_button_detach')
-            .toggle(channel.type !== "static");
-        // Hide 'invite', 'unsubscribe' and 'settings' buttons in static channels and DM
-        this.$buttons
-            .find('.o_mail_chat_button_invite, .o_mail_chat_button_unsubscribe, .o_mail_chat_button_settings')
-            .toggle(channel.type !== "dm" && channel.type !== 'static');
 
-        this.$buttons
-            .find('.o_mail_chat_button_mark_read')
-            .toggle(channel.id === "channel_inbox");
-
-        this.$buttons
-            .find('.o_mail_chat_button_unstar_all')
-            .toggle(channel.id === "channel_starred");
-
-        this.update_cp();
+        this.channel = channel;
+        this.messages_separator_position = undefined; // reset value on channel change
+        this.unread_counter = this.channel.unread_counter;
+        this.last_seen_message_id = this.channel.last_seen_message_id;
+        this.clear_needactions_def = $.Deferred();
+        if (this.$snackbar) {
+            this.$snackbar.remove();
+        }
 
         this.action.context.active_id = channel.id;
         this.action.context.active_ids = [channel.id];
 
-        this.$('.o_mail_chat_channel_item')
-            .removeClass('o_active')
-            .filter('[data-channel-id=' + channel.id + ']')
-            .removeClass('o_unread_message')
-            .addClass('o_active');
+        return this.fetch_and_render_thread().then(function () {
+            // Mark channel's messages as read and clear needactions
+            if (channel.type !== 'static') {
+                // Display snackbar if needactions have been cleared
+                if (channel.needaction_counter > 0) {
+                    self.$snackbar = $(QWeb.render('mail.chat.UndoSnackbar', {
+                        nb_needactions: channel.needaction_counter,
+                    }));
+                    self.$('.o_mail_chat_content').append(self.$snackbar);
+                }
+                chat_manager.mark_channel_as_seen(channel);
+                self.clear_needactions_def = chat_manager.mark_all_as_read(channel);
+            }
 
-        this.$('.o_chat_composer').toggle(channel.type !== 'static');
+            // Update control panel
+            self.set("title", channel.name);
+            // Hide 'detach' button in static channels
+            self.$buttons
+                .find('.o_mail_chat_button_detach')
+                .toggle(channel.type !== "static");
+            // Hide 'invite', 'unsubscribe' and 'settings' buttons in static channels and DM
+            self.$buttons
+                .find('.o_mail_chat_button_invite, .o_mail_chat_button_unsubscribe, .o_mail_chat_button_settings')
+                .toggle(channel.type !== "dm" && channel.type !== 'static');
+            self.$buttons
+                .find('.o_mail_chat_button_mark_read')
+                .toggle(channel.id === "channel_inbox");
+            self.$buttons
+                .find('.o_mail_chat_button_unstar_all')
+                .toggle(channel.id === "channel_starred");
+            self.update_cp();
+
+            self.$('.o_chat_composer').toggle(channel.type !== 'static');
+
+            self.$('.o_mail_chat_channel_item')
+                .removeClass('o_active')
+                .filter('[data-channel-id=' + channel.id + ']')
+                .removeClass('o_unread_message')
+                .addClass('o_active');
 
-        return this.fetch_and_render_thread().then(function () {
             self.thread.scroll_to({offset: new_channel_scrolltop});
             if (!config.device.touch) {
                 self.composer.focus();
@@ -367,11 +398,24 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
             });
     },
 
-    get_thread_rendering_options: function () {
+    get_thread_rendering_options: function (messages) {
+        // Compute position of the 'New messages' separator, only once when joining
+        // a channel to keep it in the thread when new messages arrive
+        if (_.isUndefined(this.messages_separator_position)) {
+            var msg_id = this.last_seen_message_id;
+            if (!this.unread_counter) {
+                this.messages_separator_position = false; // no unread message -> don't display separator
+            } else if ((msg_id === false) || !_.findWhere(messages, {id: msg_id})) {
+                this.messages_separator_position = 'top'; // all displayed messages are unread
+            } else {
+                this.messages_separator_position = msg_id; // last read message is msg_id
+            }
+        }
         return {
+            channel_id: this.channel.id,
             display_load_more: !chat_manager.all_history_loaded(this.channel, this.domain),
             display_needactions: this.channel.display_needactions,
-            channel_id: this.channel.id,
+            messages_separator_position: this.messages_separator_position,
             squash_close_messages: this.channel.type !== 'static',
         };
     },
@@ -379,7 +423,7 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
     fetch_and_render_thread: function () {
         var self = this;
         return chat_manager.get_messages({channel_id: this.channel.id, domain: this.domain}).then(function(result) {
-            self.thread.render(result, self.get_thread_rendering_options());
+            self.thread.render(result, self.get_thread_rendering_options(result));
             self.update_button_status(result.length === 0);
         });
     },
@@ -405,7 +449,10 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
         return chat_manager
             .fetch_more(this.channel, this.domain)
             .then(function(result) {
-                self.thread.render(result, self.get_thread_rendering_options());
+                if (self.messages_separator_position === 'top') {
+                    self.messages_separator_position = undefined; // reset value to re-compute separator position
+                }
+                self.thread.render(result, self.get_thread_rendering_options(result));
                 offset += framework.getPosition(document.querySelector(oldest_msg_selector)).top;
                 self.thread.scroll_to({offset: offset});
             });
@@ -493,16 +540,15 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
     on_new_message: function (message) {
         var self = this;
         if (_.contains(message.channel_ids, this.channel.id)) {
+            if (this.channel.type !== 'static') {
+                chat_manager.mark_channel_as_seen(this.channel);
+            }
             this.fetch_and_render_thread().then(function () {
                 self.thread.scroll_to({id: message.id});
             });
         }
-        // Indicate in the sidebar that there is a new message in the corresponding channels
-        _.each(_.without(message.channel_ids, this.channel.id), function (channel_id) {
-                self.$('.o_mail_chat_channel_item')
-                    .filter('[data-channel-id=' + channel_id + ']')
-                    .addClass('o_unread_message');
-        });
+        // Re-render sidebar to indicate that there is a new message in the corresponding channels
+        this.render_sidebar();
         // Dump scroll position of channels in which the new message arrived
         this.channels_scrolltop = _.omit(this.channels_scrolltop, message.channel_ids);
     },
@@ -512,7 +558,7 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
         if ((current_channel_id === "channel_starred" && !message.is_starred) ||
             (current_channel_id === "channel_inbox" && !message.is_needaction)) {
             chat_manager.get_messages({channel_id: this.channel.id, domain: this.domain}).then(function (messages) {
-                var options = self.get_thread_rendering_options();
+                var options = self.get_thread_rendering_options(messages);
                 self.thread.remove_message_and_render(message.id, messages, options).then(function () {
                     self.update_button_status(messages.length === 0);
                 });
@@ -527,12 +573,6 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
             this.set_channel(channel);
         }
     },
-    on_update_needaction: function () {
-        var $needaction_badge = QWeb.render("mail.chat.SidebarNeedaction", {
-            needaction_counter: chat_manager.get_needaction_counter()
-        });
-        this.$('.o_mail_sidebar_needaction').replaceWith($needaction_badge);
-    },
 
     on_click_button_invite: function () {
         var title = _.str.sprintf(_t('Invite people to %s'), this.channel.name);
diff --git a/addons/mail/static/src/less/client_action.less b/addons/mail/static/src/less/client_action.less
index 9f8d501c3a2..f6194bfc973 100644
--- a/addons/mail/static/src/less/client_action.less
+++ b/addons/mail/static/src/less/client_action.less
@@ -67,9 +67,10 @@
 
     .o_mail_chat_content {
         .o-flex(1, 1, 100%);
-        height: 100%;
         .o-flex-display();
         .o-flex-flow(column, nowrap);
+        height: 100%;
+        position: relative;
 
         .o_mail_thread {
             .o-flex(1, 0, 0);
@@ -100,6 +101,14 @@
                 }
             }
         }
+        .o_mail_snackbar {
+            .o-position-absolute(15px, 15px);
+            padding-top: 10px;
+            padding-bottom: 10px;
+            background-color: lighten(@odoo-brand-optional, 50%);
+            border-color: lighten(@odoo-brand-optional, 40%);
+            color: @odoo-brand-optional;
+        }
     }
 }
 
diff --git a/addons/mail/static/src/less/thread.less b/addons/mail/static/src/less/thread.less
index bcb73d4dd7c..df865d14a4f 100644
--- a/addons/mail/static/src/less/thread.less
+++ b/addons/mail/static/src/less/thread.less
@@ -22,6 +22,19 @@
         }
     }
 
+    .o_thread_new_messages_separator {
+        border-bottom: solid lighten(@odoo-brand-primary, 15%) 1px;
+        text-align: right;
+        .o_thread_separator_label {
+            position: relative;
+            top: 8px;
+            padding: 0 10px;
+            background: white;
+            color: lighten(@odoo-brand-primary, 15%);
+            font-size: smaller;
+        }
+    }
+
     .o_thread_message {
         .o-flex-display();
         padding: 4px 0;
diff --git a/addons/mail/static/src/xml/client_action.xml b/addons/mail/static/src/xml/client_action.xml
index aa6a9bad802..b6dcbb7e18a 100644
--- a/addons/mail/static/src/xml/client_action.xml
+++ b/addons/mail/static/src/xml/client_action.xml
@@ -10,11 +10,14 @@
     </t>
     <t t-name="mail.chat.Sidebar">
         <div class="o_mail_chat_sidebar">
-            <div class="o_mail_chat_channel_item" data-channel-id="channel_inbox">
+            <div t-attf-class="o_mail_chat_channel_item #{(active_channel_id == 'channel_inbox') ? 'o_active': ''}"
+                 data-channel-id="channel_inbox">
                 @ Inbox
+                <t t-set="counter" t-value="needaction_counter"/>
                 <t t-call="mail.chat.SidebarNeedaction"/>
             </div>
-            <div class="o_mail_chat_channel_item" data-channel-id="channel_starred">
+            <div t-attf-class="o_mail_chat_channel_item #{(active_channel_id == 'channel_starred') ? 'o_active': ''}"
+                 data-channel-id="channel_starred">
                 <span class="fa fa-star-o"/> Starred
             </div>
 
@@ -47,8 +50,8 @@
         </div>
     </t>
     <t t-name="mail.chat.SidebarNeedaction">
-        <span t-attf-class="o_mail_sidebar_needaction badge pull-right #{(!needaction_counter ? 'hide' : '')}">
-            <t t-esc="needaction_counter"/>
+        <span t-attf-class="o_mail_sidebar_needaction badge pull-right #{(!counter ? 'hide' : '')}">
+            <t t-esc="counter"/>
         </span>
     </t>
     <t t-name="mail.chat.SidebarTitle">
@@ -71,10 +74,14 @@
     </t>
     <t t-name="mail.chat.SidebarItems">
         <t t-foreach="channels" t-as="channel">
-            <div t-if="channel.type === channel_type" class="o_mail_chat_channel_item" t-att-data-channel-id="channel.id">
+            <t t-set="counter" t-value="channel.needaction_counter"/>
+            <div t-if="channel.type === channel_type" t-att-data-channel-id="channel.id"
+                 t-attf-class="o_mail_chat_channel_item #{channel.unread_counter ? ' o_unread_message' : ''} #{(active_channel_id == channel.id) ? 'o_active': ''}">
                 <span><i t-if="display_status" t-att-class="'o_user_status fa ' + (channel.status == 'online' ? 'fa-circle' : 'fa-circle-o')"/></span>
                 <span t-if="display_hash" class="o_mail_hash">#</span> <t t-esc="channel.name"/>
-                <span class="fa fa-times pull-right o_mail_partner_unpin" t-att-title="_t('Close')" t-att-data-channel-id="channel.id"/>
+                <t t-call="mail.chat.SidebarNeedaction"/>
+                <span t-attf-class="fa fa-times pull-right o_mail_partner_unpin #{counter ? 'hide' : ''}"
+                      t-att-title="_t('Close')" t-att-data-channel-id="channel.id"/>
             </div>
         </t>
         <div t-if="!disable_add_channel" class="o_mail_add_channel" t-attf-data-type="#{channel_type}">
@@ -83,6 +90,16 @@
         </div>
     </t>
 
+    <t t-name="mail.chat.UndoSnackbar">
+        <div class="alert alert-dismissible o_mail_snackbar" role="alert">
+            <button type="button" class="close" data-dismiss="alert" aria-label="Close">
+                <span aria-hidden="true">&amp;times;</span>
+            </button>
+            <t t-esc="nb_needactions"/> message(s) marked as read.
+            <a href="#" class="alert-link o_snackbar_undo">Undo</a>
+        </div>
+    </t>
+
     <!-- Buttons of the Control Panel -->
     <t t-name="mail.chat.ControlButtons">
         <div>
diff --git a/addons/mail/static/src/xml/thread.xml b/addons/mail/static/src/xml/thread.xml
index 94719437441..7d1c28e964a 100644
--- a/addons/mail/static/src/xml/thread.xml
+++ b/addons/mail/static/src/xml/thread.xml
@@ -17,6 +17,7 @@
     </t>
 
     <t t-name="mail.ChatThread.Content">
+        <t t-if="options.messages_separator_position == 'top'" t-call="mail.MessagesSeparator"/>
         <t t-set="current_day" t-value="0"/>
         <t t-foreach="messages" t-as="message">
             <div t-if="current_day != message.date.split(' ')[0]" class="o_thread_date_separator">
@@ -102,6 +103,15 @@
                 </t>
             </div>
         </div>
+        <t t-if="options.messages_separator_position == message.id">
+            <t t-call="mail.MessagesSeparator"/>
+        </t>
+    </t>
+
+    <t t-name="mail.MessagesSeparator">
+        <div class="o_thread_new_messages_separator">
+            <span class="o_thread_separator_label">New messages</span>
+        </div>
     </t>
 
     <t t-name="mail.ChatThread.MessageTracking">