PLT-6484 Add /leave command to leave a channel (#6402)

* PLT-6484 Add /leave command to leave a channel

* Text changes requeted on review.

* PLT-6484 Display the right error message when trying to /leave town-square

* PLT-6484 Be able to execute /leave command in direct and group message channels with the same effect as clicking x

* PLT-6484 Refactor to create new leave_private_channel_modal.jsx

* PLT-6484 Remove previous leave private channel logic to use new leave_private_channel_modal.jsx

* Remove dot in command description. Change localized error when leaving Town square.

* disable /leave command in reply threads on the right-hand sidebar, since it is not obvious which channel you should leave

webapp/actions/channel_actions.jsx

@@ -72,6 +72,39 @@ export function executeCommand(message, args, success, error) {
             msg = '/shortcuts';
         }
         break;
+    case '/leave': {
+        // /leave command not supported in reply threads.
+        if (args.channel_id && (args.root_id || args.parent_id)) {
+            GlobalActions.sendEphemeralPost('/leave is not supported in reply threads. Use it in the center channel instead.', args.channel_id, args.parent_id);
+            return;
+        }
+        const channel = ChannelStore.getCurrent();
+        if (channel.type === Constants.PRIVATE_CHANNEL) {
+            GlobalActions.showLeavePrivateChannelModal(channel);
+            return;
+        } else if (
+            channel.type === Constants.DM_CHANNEL ||
+            channel.type === Constants.GM_CHANNEL
+        ) {
+            let name;
+            let category;
+            if (channel.type === Constants.DM_CHANNEL) {
+                name = Utils.getUserIdFromChannelName(channel);
+                category = Constants.Preferences.CATEGORY_DIRECT_CHANNEL_SHOW;
+            } else {
+                name = channel.id;
+                category = Constants.Preferences.CATEGORY_GROUP_CHANNEL_SHOW;
+            }
+            const currentUserId = UserStore.getCurrentId();
+            savePreferences(currentUserId, [{category, name, user_id: currentUserId, value: 'false'}])(dispatch, getState);
+            if (ChannelUtils.isFavoriteChannel(channel)) {
+                unmarkFavorite(channel.id);
+            }
+            browserHistory.push(`${TeamStore.getCurrentTeamRelativeUrl()}/channels/town-square`);
+            return;
+        }
+        break;
+    }
     case '/settings':
         GlobalActions.showAccountSettingsModal();
         return;

webapp/actions/global_actions.jsx

@@ -281,6 +281,13 @@ export function showLeaveTeamModal() {
     });
 }
 
+export function showLeavePrivateChannelModal(channel) {
+    AppDispatcher.handleViewAction({
+        type: ActionTypes.TOGGLE_LEAVE_PRIVATE_CHANNEL_MODAL,
+        value: channel
+    });
+}
+
 export function emitSuggestionPretextChanged(suggestionId, pretext) {
     AppDispatcher.handleViewAction({
         type: ActionTypes.SUGGESTION_PRETEXT_CHANGED,
@@ -351,7 +358,7 @@ export function emitPreferencesDeletedEvent(preferences) {
     });
 }
 
-export function sendEphemeralPost(message, channelId) {
+export function sendEphemeralPost(message, channelId, parentId) {
     const timestamp = Utils.getTimestamp();
     const post = {
         id: Utils.generateId(),
@@ -361,6 +368,8 @@ export function sendEphemeralPost(message, channelId) {
         type: Constants.PostTypes.EPHEMERAL,
         create_at: timestamp,
         update_at: timestamp,
+        root_id: parentId,
+        parent_id: parentId,
         props: {}
     };