[FIX] mail, im_livechat: make livechat work properly

- fix traceback on receiving first livechat message due to bad computation of
  correspondent
- fix missing [0] in return of country name_get in channel_info
- fix visitor/correspondent computation to work when chatting with oneself
- reintroduce livechat ordered by last message in discuss sidebar
- improve mock server to make these fixes possible to test
- introduce corresponding tests

PR: #56243
task-2323670

closes odoo/odoo#56414

X-original-commit: f623bfd2c8819604c709bc723153c071dca6e3cc
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

3 files changed, 27 insertions, 9 deletions

diff --git a/addons/mail/static/src/models/message/message.js b/addons/mail/static/src/models/message/message.js
index 582745e28f2..e982df36667 100644
--- a/addons/mail/static/src/models/message/message.js
+++ b/addons/mail/static/src/models/message/message.js
@@ -607,12 +607,13 @@ function factory(dependencies) {
         tracking_value_ids: attr({
             default: [],
         }),
-
         /**
-         * All channels that this message is linked to (from server message
-         * format).
+         * All channels containing this message on the server.
+         * Equivalent of python field `channel_ids`.
          */
-        serverChannels: many2many('mail.thread'),
+        serverChannels: many2many('mail.thread', {
+            inverse: 'messagesAsServerChannel',
+        }),
     };
 
     Message.modelName = 'mail.message';
diff --git a/addons/mail/static/src/models/messaging_notification_handler/messaging_notification_handler.js b/addons/mail/static/src/models/messaging_notification_handler/messaging_notification_handler.js
index 49f07bc5423..d89992d8a4b 100644
--- a/addons/mail/static/src/models/messaging_notification_handler/messaging_notification_handler.js
+++ b/addons/mail/static/src/models/messaging_notification_handler/messaging_notification_handler.js
@@ -56,7 +56,7 @@ function factory(dependencies) {
         /**
          * @private
          * @param {Object[]} notifications
-         * @param {Array} notifications[i][0] meta-data of the notification.
+         * @param {Array|string} notifications[i][0] meta-data of the notification.
          * @param {string} notifications[i][0][0] name of database this
          *   notification comes from.
          * @param {string} notifications[i][0][1] type of notification.
@@ -68,20 +68,25 @@ function factory(dependencies) {
         async _handleNotifications(notifications) {
             const filteredNotifications = this._filterNotificationsOnUnsubscribe(notifications);
             const proms = filteredNotifications.map(notification => {
-                const [[, model, id], data] = notification;
+                const [channel, message] = notification;
+                if (typeof channel === 'string') {
+                    // uuid notification, only for (livechat) public handler
+                    return;
+                }
+                const [, model, id] = channel;
                 switch (model) {
                     case 'ir.needaction':
-                        return this._handleNotificationNeedaction(data);
+                        return this._handleNotificationNeedaction(message);
                     case 'mail.channel':
                         return this._handleNotificationChannel(Object.assign({
                             channelId: id,
-                        }, data));
+                        }, message));
                     case 'res.partner':
                         if (id !== this.env.messaging.currentPartner.id) {
                             // ignore broadcast to other partners
                             return;
                         }
-                        return this._handleNotificationPartner(Object.assign({}, data));
+                        return this._handleNotificationPartner(Object.assign({}, message));
                     default:
                         console.warn(`mail.messaging_notification_handler: Unhandled notification "${model}"`);
                         return;
diff --git a/addons/mail/static/src/models/thread/thread.js b/addons/mail/static/src/models/thread/thread.js
index 74cae5d25ab..e3d48d54e35 100644
--- a/addons/mail/static/src/models/thread/thread.js
+++ b/addons/mail/static/src/models/thread/thread.js
@@ -779,8 +779,13 @@ function factory(dependencies) {
                 partner !== this.env.messaging.currentPartner
             );
             if (correspondents.length === 1) {
+                // 2 members chat
                 return [['link', correspondents[0]]];
             }
+            if (this.members.length === 1) {
+                // chat with oneself
+                return [['link', this.members[0]]];
+            }
             return [['unlink']];
         }
 
@@ -1360,6 +1365,13 @@ function factory(dependencies) {
         messages: many2many('mail.message', {
             inverse: 'threads',
         }),
+        /**
+         * All messages that are contained on this channel on the server.
+         * Equivalent to the inverse of python field `channel_ids`.
+         */
+        messagesAsServerChannel: many2many('mail.message', {
+            inverse: 'serverChannels',
+        }),
         messageSeenIndicators: one2many('mail.message_seen_indicator', {
             inverse: 'thread',
             isCausal: true,