Introduce basic audio playback control

src/components/views/audio_messages/AudioPlayer.tsx

@@ -0,0 +1,96 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { Playback, PlaybackState } from "../../../voice/Playback";
+import React, { createRef, ReactNode, RefObject } from "react";
+import { UPDATE_EVENT } from "../../../stores/AsyncStore";
+import PlaybackWaveform from "./PlaybackWaveform";
+import PlayPauseButton from "./PlayPauseButton";
+import { replaceableComponent } from "../../../utils/replaceableComponent";
+import { formatBytes } from "../../../utils/FormattingUtils";
+import DurationClock from "./DurationClock";
+import { Key } from "../../../Keyboard";
+
+interface IProps {
+    // Playback instance to render. Cannot change during component lifecycle: create
+    // an all-new component instead.
+    playback: Playback;
+}
+
+interface IState {
+    playbackPhase: PlaybackState;
+}
+
+@replaceableComponent("views.audio_messages.AudioPlayer")
+export default class AudioPlayer extends React.PureComponent<IProps, IState> {
+    private playPauseRef: RefObject<PlayPauseButton> = createRef();
+
+    constructor(props: IProps) {
+        super(props);
+
+        this.state = {
+            playbackPhase: PlaybackState.Decoding, // default assumption
+        };
+
+        // We don't need to de-register: the class handles this for us internally
+        this.props.playback.on(UPDATE_EVENT, this.onPlaybackUpdate);
+
+        // Don't wait for the promise to complete - it will emit a progress update when it
+        // is done, and it's not meant to take long anyhow.
+        // noinspection JSIgnoredPromiseFromCall
+        this.props.playback.prepare();
+    }
+
+    private onPlaybackUpdate = (ev: PlaybackState) => {
+        this.setState({ playbackPhase: ev });
+    };
+
+    private onKeyPress = (ev: React.KeyboardEvent) => {
+        if (ev.key === Key.SPACE) {
+            ev.stopPropagation();
+            this.playPauseRef.current?.toggle();
+        }
+    };
+
+    protected renderFileSize(): string {
+        const bytes = this.props.playback.sizeBytes;
+        if (!bytes) return null;
+
+        // Not translated as these are units, and therefore universal
+        return `(${formatBytes(bytes)})`;
+    }
+
+    public render(): ReactNode {
+        // tabIndex=0 to ensure that the whole component becomes a tab stop, where we handle keyboard
+        // events for accessibility
+        return <div className='mx_AudioPlayer_container' tabIndex={0} onKeyPress={this.onKeyPress}>
+            <div className='mx_AudioPlayer_primaryContainer'>
+                <PlayPauseButton
+                    playback={this.props.playback}
+                    playbackPhase={this.state.playbackPhase}
+                    tabIndex={-1} // prevent tabbing into the button
+                    ref={this.playPauseRef}
+                />
+                <div className='mx_AudioPlayer_byline'>
+                    <DurationClock playback={this.props.playback} />
+                    &nbsp; {/* easiest way to introduce a gap between the components */}
+                    { this.renderFileSize() }
+                </div>
+            </div>
+            <PlaybackWaveform playback={this.props.playback} />
+        </div>
+    }
+}