/* @flow */

import React, { Component } from 'react';

import { translate } from '../../base/i18n/functions';
import Audio from '../../base/media/components/Audio';

const TEST_SOUND_PATH = 'sounds/ring.wav';

/**
 * The type of the React {@code Component} props of {@link AudioOutputPreview}.
 */
type Props = {

    /**
     * The device id of the audio output device to use.
     */
    deviceId: string,

    /**
     * Invoked to obtain translated strings.
     */
    t: Function
};

/**
 * React component for playing a test sound through a specified audio device.
 *
 * @augments Component
 */
class AudioOutputPreview extends Component<Props> {
    _audioElement: ?Object;

    /**
     * Initializes a new AudioOutputPreview instance.
     *
     * @param {Object} props - The read-only React Component props with which
     * the new instance is to be initialized.
     */
    constructor(props: Props) {
        super(props);

        this._audioElement = null;

        this._audioElementReady = this._audioElementReady.bind(this);
        this._onClick = this._onClick.bind(this);
        this._onKeyPress = this._onKeyPress.bind(this);
    }

    /**
     * Updates the audio element when the target output device changes and the
     * audio element has re-rendered.
     *
     * @inheritdoc
     * @returns {void}
     */
    componentDidUpdate() {
        this._setAudioSink();
    }

    /**
     * Implements React's {@link Component#render()}.
     *
     * @inheritdoc
     * @returns {ReactElement}
     */
    render() {
        return (
            <div className = 'audio-output-preview'>
                <a
                    aria-label = { this.props.t('deviceSelection.testAudio') }
                    onClick = { this._onClick }
                    onKeyPress = { this._onKeyPress }
                    role = 'button'
                    tabIndex = { 0 }>
                    { this.props.t('deviceSelection.testAudio') }
                </a>
                <Audio
                    setRef = { this._audioElementReady }
                    src = { TEST_SOUND_PATH } />
            </div>
        );
    }

    _audioElementReady: (Object) => void;

    /**
     * Sets the instance variable for the component's audio element so it can be
     * accessed directly.
     *
     * @param {Object} element - The DOM element for the component's audio.
     * @private
     * @returns {void}
     */
    _audioElementReady(element: Object) {
        this._audioElement = element;

        this._setAudioSink();
    }

    _onClick: () => void;

    /**
     * Plays a test sound.
     *
     * @private
     * @returns {void}
     */
    _onClick() {
        this._audioElement
            && this._audioElement.play();
    }

    _onKeyPress: (Object) => void;

    /**
     * KeyPress handler for accessibility.
     *
     * @param {Object} e - The key event to handle.
     *
     * @returns {void}
     */
    _onKeyPress(e) {
        if (e.key === ' ' || e.key === 'Enter') {
            e.preventDefault();
            this._onClick();
        }
    }

    /**
     * Updates the target output device for playing the test sound.
     *
     * @private
     * @returns {void}
     */
    _setAudioSink() {
        this._audioElement
            && this.props.deviceId
            && this._audioElement.setSinkId(this.props.deviceId);
    }
}

export default translate(AudioOutputPreview);