[FIX] website_mail_channel: fix discussion group snippet without group

Prevent crash while trying to subscribe to a non existing channel from
a misconfigured snippet.

Also now let the user create the channel linked to the discussion group
directly on snippet drop if no channel is available to select
automatically.

task-2356955

closes odoo/odoo#60608

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

3 files changed, 42 insertions, 7 deletions

diff --git a/addons/website_mail_channel/controllers/main.py b/addons/website_mail_channel/controllers/main.py
index dd7de5fce26..37dd899b3fc 100644
--- a/addons/website_mail_channel/controllers/main.py
+++ b/addons/website_mail_channel/controllers/main.py
@@ -94,6 +94,9 @@ class MailGroup(http.Controller):
         """
         unsubscribe = subscription == 'on'
         channel = request.env['mail.channel'].browse(int(channel_id))
+        if not channel.exists():
+            return False
+
         partner_ids = []
 
         # search partner_id
diff --git a/addons/website_mail_channel/static/src/snippets/s_channel/options.js b/addons/website_mail_channel/static/src/snippets/s_channel/options.js
index b6d89d8928f..5b51bb6afc2 100644
--- a/addons/website_mail_channel/static/src/snippets/s_channel/options.js
+++ b/addons/website_mail_channel/static/src/snippets/s_channel/options.js
@@ -11,9 +11,30 @@ options.registry.Channel = options.Class.extend({
     /**
      * @override
      */
+    async start() {
+        await this._super(...arguments);
+        this.publicChannels = await this._getPublicChannels();
+    },
+    /**
+     * @override
+     */
     cleanForSave: function () {
         this.$target.addClass('d-none');
     },
+    /**
+     * If we have already created channels => select the first one
+     * else => modal prompt (create a new channel)
+     *
+     * @override
+     */
+    onBuilt() {
+        if (this.publicChannels.length) {
+            this.$target[0].dataset.id = this.publicChannels[0][0];
+        } else {
+            const widget = this._requestUserValueWidgets('create_mail_channel_opt')[0];
+            widget.$el.click();
+        }
+    },
 
     //--------------------------------------------------------------------------
     // Options
@@ -56,12 +77,12 @@ options.registry.Channel = options.Class.extend({
     /**
      * @override
      */
-    _renderCustomXML: function (uiFragment) {
-        return this._rpc({
-            model: 'mail.channel',
-            method: 'name_search',
-            args: ['', [['public', '=', 'public']]],
-        }).then(channels => {
+    _renderCustomXML(uiFragment) {
+        // TODO remove this part in master 
+        const createChannelEl = uiFragment.querySelector('we-button[data-create-channel]');
+        createChannelEl.dataset.name = 'create_mail_channel_opt';
+
+        return this._getPublicChannels().then(channels => {
             const menuEl = uiFragment.querySelector('.select_discussion_list');
             for (const channel of channels) {
                 const el = document.createElement('we-button');
@@ -71,5 +92,16 @@ options.registry.Channel = options.Class.extend({
             }
         });
     },
+    /**
+     * @private
+     * @return {Promise}
+     */
+    _getPublicChannels() {
+        return this._rpc({
+            model: 'mail.channel',
+            method: 'name_search',
+            args: ['', [['public', '=', 'public']]],
+        });
+    },
 });
 });
diff --git a/addons/website_mail_channel/views/snippets/s_channel.xml b/addons/website_mail_channel/views/snippets/s_channel.xml
index bd38a8d1aad..78217040d6c 100644
--- a/addons/website_mail_channel/views/snippets/s_channel.xml
+++ b/addons/website_mail_channel/views/snippets/s_channel.xml
@@ -32,7 +32,7 @@
                     <!-- 'we-button' added programmatically with DB data -->
                 </we-select>
                 <we-button class="fa fa-fw fa-plus" title="Create a public discussion group in your backend"
-                           data-create-channel="" data-no-preview="true"/>
+                           data-create-channel="" data-no-preview="true" data-name="create_mail_channel_opt"/>
             </we-row>
         </div>
     </xpath>