jsOMS/UI/Input/Voice/VoiceManager.js

import { Logger } from '../../../Log/Logger.js';

/**
 * Form manager class.
 *
 * @copyright  Dennis Eichhorn
 * @license    OMS License 1.0
 * @version    1.0.0
 * @since      1.0.0
 */
export class VoiceManager {
    /**
     * @constructor
     *
     * @param {Object} app      Application
     * @param {Object} commands Available commands
     * @param {string} lang     Localization
     *
     * @since 1.0.0
     */
    constructor(app, commands = {}, lang = 'en-US')
    {
        this.app                   = app;
        this.commands              = commands;
        this.lang                  = lang;
        this.recognition           = null;
        this.speechRecognitionList = null;

        if (SpeechRecognition !== null) {
            this.recognition           = new SpeechRecognition();
            this.speechRecognitionList = new SpeechGrammarList();
        }
    };

    /**
     * Setup or re-initialize voice manager.
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    setup()
    {
        if (SpeechRecognition === null) {
            return;
        }

        const self                       = this;
        this.recognition.lang            = this.lang;
        this.recognition.interimResults  = false;
        this.recognition.maxAlternatives = 1;
        this.recognition.continuous      = true;
        this.recognition.lang            = this.lang;

        if (typeof this.commands !== 'undefined') {
            this.speechRecognitionList.addFromString(this.getCommandsString(), 1);
            this.recognition.grammars = this.speechRecognitionList;
        }

        this.recognition.onstart  = function() {};
        this.recognition.onresult = function(event)
        {
            let result = jsOMS.trim(event.results[event.resultIndex][0].transcript);

            if (self.commands.hasOwnProperty(result)) {
                self.commands[result]();
            }
        };

        this.recognition.onspeechend = function()
        {
        };

        this.recognition.onnomatch = function(event)
        {
            Logger.instance.warning('Couldn\'t recognize speech');
        };

        this.recognition.onerror = function(event)
        {
            Logger.instance.warning('Error during speech recognition: ' + event.error);
        };
    };

    /**
     * Create commands/grammar string from commands
     *
     * @return {string}
     *
     * @since 1.0.0
     */
    getCommandsString()
    {
        return '#JSGF V1.0; grammar phrase; public <phrase> = ' + Object.keys(this.commands).join(' | ') + ' ;';
    };

    /**
     * Set language
     *
     * @param {string} lang Language code (e.g. en-US)
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    setLanguage(lang)
    {
        // todo: eventually restart
        this.recognition.lang = lang;
    };

    /**
     * Add command/grammar and callback.
     *
     * @param {string} command Command id
     * @param {callback} callback Callback for command
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    add(command, callback)
    {
        this.commands[command] = callback;
    };

    /**
     * Start voice listener.
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    start()
    {
        if (SpeechRecognition === null) {
            return;
        }

        this.recognition.start();
    };

    /**
     * Stop voice listener.
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    stop()
    {
        if (SpeechRecognition === null) {
            return;
        }

        this.recognition.stop();
    };
};

// todo: remove once obsolete
/** global: webkitSpeechRecognition */
/** global: SpeechRecognition */
var SpeechRecognition = typeof SpeechRecognition !== 'undefined' ? SpeechRecognition : typeof webkitSpeechRecognition !== 'undefined' ? webkitSpeechRecognition : null;

/** global: webkitSpeechGrammarList */
/** global: SpeechGrammarList */
var SpeechGrammarList = typeof SpeechGrammarList !== 'undefined' ? SpeechGrammarList : typeof webkitSpeechGrammarList !== 'undefined' ? webkitSpeechGrammarList : null;

/** global: webkitSpeechRecognitionEvent */
/** global: SpeechRecognitionEvent */
var SpeechRecognitionEvent = typeof SpeechRecognitionEvent !== 'undefined' ? SpeechRecognitionEvent : typeof webkitSpeechRecognitionEvent !== 'undefined' ? webkitSpeechRecognitionEvent : null;