livetrax/share/web_surfaces/shared/channel.js

/*
 * Copyright © 2020 Luciano Iam <lucianito@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

export const JSON_INF = 1.0e+128;

export const Node = Object.freeze({
	TEMPO: "tempo",
	STRIP_DESC: "strip_desc",
	STRIP_METER: "strip_meter",
	STRIP_GAIN: "strip_gain",
	STRIP_PAN: "strip_pan",
	STRIP_MUTE: "strip_mute",
	STRIP_PLUGIN_DESC: "strip_plugin_desc",
	STRIP_PLUGIN_ENABLE: "strip_plugin_enable",
	STRUP_PLUGIN_PARAM_DESC: "strip_plugin_param_desc",
	STRIP_PLUGIN_PARAM_VALUE: "strip_plugin_param_value"
});


export function nodeAddressHash(node, addr) {
	return [node].concat(addr || []).join('_');
}


export class MessageChannel {

	constructor (host) {
		// https://developer.mozilla.org/en-US/docs/Web/API/URL/host
		this.host = host;
	}

	async open () {
		return new Promise((resolve, reject) => {
			this.socket = new WebSocket(`ws://${this.host}`);

			this.socket.onclose = () => this.closeCallback();

			this.socket.onerror = (error) => this.errorCallback(error);

			this.socket.onmessage = (event) => {
				this.messageCallback (Message.fromJsonText(event.data));
			};

			this.socket.onopen = resolve;
		});
	}

	send (msg) {
		this.socket.send(msg.toJsonText());
	}

	closeCallback () {
		// empty
	}
	
	errorCallback (error) {
		// empty
	}

	messageCallback (msg) {
		// empty
	}

}


export class Message {

	constructor (node, addr, val) {
		this.node = node;
		this.addr = addr;
		this.val = [];

		for (const i in val) {
			if (val[i] >= JSON_INF) {
				this.val.push(Infinity);
			} else if (val[i] <= -JSON_INF) {
				this.val.push(-Infinity);
			} else {
				this.val.push(val[i]);
			}
		}
	}

	static fromJsonText (jsonText) {
		let rawMsg = JSON.parse(jsonText);
		return new Message(rawMsg.node, rawMsg.addr || [], rawMsg.val);
	}

	toJsonText () {
		let val = [];

		for (const i in this.val) {
			if (this.val[i] == Infinity) {
				val.push(JSON_INF);
			} else if (this.val[i] == -Infinity) {
				val.push(-JSON_INF);
			} else {
				val.push(this.val[i]);
			}
		}
		
		return JSON.stringify({node: this.node, addr: this.addr, val: val});
	}

	get hash () {
		return nodeAddressHash(this.node, this.addr);
	}

	toString () {
		return `${this.node} (${this.addr}) = ${this.val}`;
	}

}