feat(always-on-top): Updates buttons for visitors. (#15369)

* feat(always-on-top): Updates buttons for visitors.

* squash: rename listener.

* squash: Adds visitor to the conference joined event.

* squash: fix comments and lint.

* squash: fix comments.

modules/API/external/external_api.js

         this._participants = {};
         this._myUserID = undefined;
         this._onStageParticipant = undefined;
+        this._iAmvisitor = undefined;
         this._setupListeners();
         id++;
     }
                     email: data.email,
                     avatarURL: data.avatarURL
                 };
+                this._iAmvisitor = data.visitor;
             }
 
             // eslint-disable-next-line no-fallthrough
         });
     }
 
+    /**
+     * Returns whether we have joined as visitor in a meeting.
+     *
+     * @returns {boolean} - Returns true if we have joined as visitor.
+     */
+    isVisitor() {
+        return this._iAmvisitor;
+    }
+
     /**
      * Returns the avatar URL of a participant.
      *

react/features/always-on-top/Toolbar.tsx

 import HangupButton from './HangupButton';
 import VideoMuteButton from './VideoMuteButton';
 
+const { api } = window.alwaysOnTop;
+
 /**
  * The type of the React {@code Component} props of {@link Toolbar}.
  */
     onMouseOver: (e?: React.MouseEvent) => void;
 }
 
+/**
+ * The type of the React {@code Component} state of {@link Toolbar}.
+ */
+interface IState {
+
+    /**
+     * Whether audio button to be shown or not.
+     */
+    showAudioButton: boolean;
+
+    /**
+     * Whether video button to be shown or not.
+     */
+    showVideoButton: boolean;
+}
+
+type Props = Partial<IProps>;
+
 /**
  * Represents the toolbar in the Always On Top window.
  *
  * @augments Component
  */
-export default class Toolbar extends Component<IProps> {
+export default class Toolbar extends Component<Props, IState> {
+    /**
+     * Initializes a new {@code Toolbar} instance.
+     *
+     * @param {IProps} props - The React {@code Component} props to initialize the new {@code Toolbar} instance with.
+     */
+    constructor(props: Props) {
+        super(props);
+
+        this.state = {
+            showAudioButton: true,
+            showVideoButton: true
+        };
+
+        this._videoConferenceJoinedListener = this._videoConferenceJoinedListener.bind(this);
+    }
+
+    /**
+     * Sets listens for changing meetings while showing the toolbar.
+     *
+     * @inheritdoc
+     * @returns {void}
+     */
+    componentDidMount() {
+        api.on('videoConferenceJoined', this._videoConferenceJoinedListener);
+
+        this._videoConferenceJoinedListener();
+    }
+
+    /**
+     * Handles is visitor changes.
+     *
+     * @returns {void}
+     */
+    _videoConferenceJoinedListener() {
+        // for electron clients that embed the api and are not updated
+        if (!api.isVisitor) {
+            console.warn('external API not updated');
+
+            return;
+        }
+
+        const isNotVisitor = !api.isVisitor();
+
+        this.setState({
+            showAudioButton: isNotVisitor,
+            showVideoButton: isNotVisitor
+        });
+    }
+
+    /**
+     * Removes all listeners.
+     *
+     * @inheritdoc
+     * @returns {void}
+     */
+    componentWillUnmount() {
+        api.removeListener('videoConferenceJoined', this._videoConferenceJoinedListener);
+    }
+
     /**
      * Implements React's {@link Component#render()}.
      *
                 className = { `toolbox-content-items always-on-top-toolbox ${className}` }
                 onMouseOut = { onMouseOut }
                 onMouseOver = { onMouseOver }>
-                <AudioMuteButton />
-                <VideoMuteButton />
+                { this.state.showAudioButton && <AudioMuteButton /> }
+                { this.state.showVideoButton && <VideoMuteButton /> }
                 <HangupButton customClass = 'hangup-button' />
             </div>
         );

react/features/external-api/middleware.ts

 import { appendSuffix } from '../display-name/functions';
 import { SUBMIT_FEEDBACK_ERROR, SUBMIT_FEEDBACK_SUCCESS } from '../feedback/actionTypes';
 import { SET_FILMSTRIP_VISIBLE } from '../filmstrip/actionTypes';
+import { iAmVisitor } from '../visitors/functions';
 
 import './subscriber';
 
                 ),
                 avatarURL: loadableAvatarUrl,
                 breakoutRoom,
-                email
+                email,
+                visitor: iAmVisitor(state)
             }
         );
         break;

react/features/toolbox/functions.any.ts

 import { isJwtFeatureEnabledStateless } from '../base/jwt/functions';
 import { IGUMPendingState } from '../base/media/types';
 import { IParticipantFeatures } from '../base/participants/types';
+import { iAmVisitor } from '../visitors/functions';
 
 /**
  * Indicates if the audio mute button is disabled or not.
     const { available, muted, unmuteBlocked, gumPending } = state['features/base/media'].audio;
     const { startSilent } = state['features/base/config'];
 
-    return Boolean(!available || startSilent || (muted && unmuteBlocked) || gumPending !== IGUMPendingState.NONE);
+    return Boolean(!available || startSilent || (muted && unmuteBlocked) || gumPending !== IGUMPendingState.NONE
+        || iAmVisitor(state));
 }
 
 /**