feat: lobby related notifications

lang/main.json

         "knockButton": "Ask to Join",
         "knockTitle": "Someone wants to join the meeting",
         "nameField": "Enter your name",
+        "notificationLobbyAccessDenied": "{{targetParticipantName}} has been rejected to join by {{originParticipantName}}",
+        "notificationLobbyAccessGranted": "{{targetParticipantName}} has been allowed to join by {{originParticipantName}}",
+        "notificationLobbyDisabled": "Lobby has been disabled by {{originParticipantName}}",
+        "notificationLobbyEnabled": "Lobby has been enabled by {{originParticipantName}}",
+        "notificationTitle": "Lobby",
         "passwordField": "Enter meeting password",
         "passwordJoinButton": "Join",
         "reject": "Reject",

react/features/lobby/functions.js

 // @flow
 
 import { getCurrentConference } from '../base/conference';
+import { toState } from '../base/redux';
+
+const JID_PATTERN = '[^@]+@[^/]+/(.+)';
+
+/**
+ * Returns a knocking participant by ID or JID.
+ *
+ * @param {Function | Object} stateful - The Redux state or a function that resolves to the Redux state.
+ * @param {string} id - The ID or JID of the participant.
+ * @returns {Object}
+ */
+export function getKnockingParticipantById(stateful: Function | Object, id: string): Object {
+    const { knockingParticipants } = toState(stateful)['features/lobby'];
+    const idToFind = getIdFromJid(id) || id;
+
+    return knockingParticipants.find(p => p.id === idToFind);
+}
 
 /**
  * Approves (lets in) or rejects a knocking participant.
         }
     }
 }
+
+/**
+ * Parses an ID from a JID, if a JID is provided, undefined otherwise.
+ *
+ * @param {string} jid - The JID to get the ID from.
+ * @returns {?string}
+ */
+function getIdFromJid(jid: string): ?string {
+    const match = new RegExp(JID_PATTERN, 'g').exec(jid) || [];
+
+    return match[1];
+}

react/features/lobby/middleware.js

 
 import { CONFERENCE_FAILED, CONFERENCE_JOINED } from '../base/conference';
 import { JitsiConferenceErrors, JitsiConferenceEvents } from '../base/lib-jitsi-meet';
-import { getFirstLoadableAvatarUrl } from '../base/participants';
+import { getFirstLoadableAvatarUrl, getParticipantDisplayName } from '../base/participants';
 import { MiddlewareRegistry, StateListenerRegistry } from '../base/redux';
 import { NOTIFICATION_TYPE, showNotification } from '../notifications';
 import { isPrejoinPageEnabled } from '../prejoin/functions';
     startKnocking,
     setPasswordJoinFailed
 } from './actions';
+import { getKnockingParticipantById } from './functions';
 
 MiddlewareRegistry.register(store => next => action => {
     switch (action.type) {
  */
 StateListenerRegistry.register(
     state => state['features/base/conference'].conference,
-    (conference, { dispatch }, previousConference) => {
+    (conference, { dispatch, getState }, previousConference) => {
         if (conference && !previousConference) {
             conference.on(JitsiConferenceEvents.MEMBERS_ONLY_CHANGED, enabled => {
                 dispatch(setLobbyModeEnabled(enabled));
             conference.on(JitsiConferenceEvents.LOBBY_USER_LEFT, id => {
                 dispatch(knockingParticipantLeft(id));
             });
+
+            conference.on(JitsiConferenceEvents.ENDPOINT_MESSAGE_RECEIVED, (origin, sender) =>
+                _maybeSendLobbyNotification(origin, sender, {
+                    dispatch,
+                    getState
+                })
+            );
         }
     });
 
         });
     }
 }
+
+/**
+ * Check the endpoint message that arrived through the conference and
+ * sends a lobby notification, if the message belongs to the feature.
+ *
+ * @param {Object} origin - The origin (initiator) of the message.
+ * @param {Object} message - The actual message.
+ * @param {Object} store - The Redux store.
+ * @returns {void}
+ */
+function _maybeSendLobbyNotification(origin, message, { dispatch, getState }) {
+    if (!origin?._id || message?.type !== 'lobby-notify') {
+        return;
+    }
+
+    const notificationProps: any = {
+        descriptionArguments: {
+            originParticipantName: getParticipantDisplayName(getState, origin._id)
+        },
+        titleKey: 'lobby.notificationTitle'
+    };
+
+    switch (message.event) {
+    case 'LOBBY-ENABLED':
+        notificationProps.descriptionKey = `lobby.notificationLobby${message.value ? 'En' : 'Dis'}abled`;
+        break;
+    case 'LOBBY-ACCESS-GRANTED':
+        notificationProps.descriptionKey = 'lobby.notificationLobbyAccessGranted';
+        notificationProps.descriptionArguments.targetParticipantName
+            = getKnockingParticipantById(getState, message.value)?.name;
+        break;
+    case 'LOBBY-ACCESS-DENIED':
+        notificationProps.descriptionKey = 'lobby.notificationLobbyAccessDenied';
+        notificationProps.descriptionArguments.targetParticipantName
+            = getKnockingParticipantById(getState, message.value)?.name;
+        break;
+    }
+
+    dispatch(showNotification(notificationProps, 5000));
+}