messenger.js/client.js

const channelSocket = new WebSocket("ws://localhost:9091/connect");
let sessionID = null;
let imTheRoomOwner = false;
let myNickname = "";
/** @section guacamole **/
const ParseCommandString = function(instruction) {
	if(typeof instruction !== "string") {
		return;
	}
	let position = -1;
	let sections = new Array();

	for(;;) {
		let length = instruction.indexOf('.', position + 1);

		if(length === -1) {
			break;
		}

		position = (parseInt(instruction.slice(position + 1, length)) + length) + 1; // todo: not overflow
		sections.push(instruction.slice(length + 1, position)
			.replace(/'/g,	"'")
			.replace(/"/g,	'"')
			.replace(///g,	'/')
			.replace(/&lt;/g,	'<')
			.replace(/&gt;/g,	'>')
			.replace(/&amp;/g,	'&')
		);

		if(instruction.slice(position, position + 1) === ';') {
			break;
		}
	}
	return sections;
}
const EncodeCommandString = function(sections) {
	if(Array.isArray(sections) === false) {
		return;
	}
	let instruction = new String();
	const argv = sections;
	for (let argc = 0; argc < sections.length ; argc++) {
		if(typeof sections[argc] !== "string") {
			argv[argc] = sections[argc].toString();
		}
		argv[argc] = argv[argc]
			.replace(/'/g,	"&#x27;")
			.replace(/"/g,	'&quot;')
			.replace(/\//g,	'&#x2F'	)
			.replace(/</g,	'&lt;'	)
			.replace(/>/g,	'&gt;'	)
			.replace(/&/g,	'&amp;'	)
		;
		instruction = instruction.concat(argv[argc].length.toString(), ".", argv[argc])
		instruction += (argc === sections.length - 1) ? ';' : ',';
	}
	return instruction;
}

/** window.external **/
window.external.CloseApp = function() {
	channelSocket.close(1000, "called CloseApp");
}
// this is important because things expect it
/** window.external.Channel **/
window.external.Channel = {"Data": "", "SendData": null, "Initialize": null}; // "Type" is a defined property
window.external.Channel.SendData = function(d) {channelSocket.send(d)}; // this is dumb but trying to redirect this gives you TypeError's
window.external.Channel.Initialize = function() {
	if(new URL(location.href).searchParams.get("channel") === null) {
		sessionID = Math.random().toString(36).split('.')[1].substring(0,8);
		history.pushState(null, "", `?channel=${sessionID}`);
	} else {
		sessionID = new URL(location.href).searchParams.get("channel");
	}
	createWSEventsNowThatImReady();
};
Object.defineProperty(window.external.Channel, "Type", {
	get: function Type() {
		if(channelSocket.readyState === 1) {
			return 1; // Indirect;
		} else {
			return 2; // Disconnected;
		}
	}
});
/** window.external.Users **/
// This sadly needs to be already configured before an activity tries using it...
// We can't just block execution until we've got the session...
window.external.yellows111_Users = [
	{"Name": "Initiator", "Email": "you@messenger.js", "GlobalIP": "0.0.0.0", "LocalIP": "0.0.0.0", "PUID": "0"},
	{"Name": "Target", "Email": "opponent@messenger.js", "GlobalIP": "0.0.0.0", "LocalIP": "0.0.0.1", "PUID": "1"}
];
window.external.Users = {"Me": null, "me": null, "Inviter": null, "Item": null}; // "Count" is a defined property
window.external.Users.Item = function(which){
	return window.external.yellows111_Users[which];
}
Object.defineProperty(window.external.Users, "Count", {
	get: function Count() {
		return window.external.yellows111_Users.length;
	}
});
if(new URL(location.href).searchParams.get("channel") === null) {
	window.external.Users.Me = window.external.yellows111_Users[0];
	window.external.Users.me = window.external.yellows111_Users[0];
	window.external.Users.Inviter = window.external.yellows111_Users[0];
	document.title = "Initiator: " + document.title;
} else {
	window.external.Users.Me = window.external.yellows111_Users[1];
	window.external.Users.me = window.external.yellows111_Users[1];
	window.external.Users.Inviter = window.external.yellows111_Users[0];
	document.title = "Target: " + document.title;
}

/** websocket stuff **/
channelSocket.binaryType = "arraybuffer"; // what's the point of doing Blob.arrayBuffer every binary call... which is awful because IT'S A PROMISE CALL AND PROMISES SUXX
channelSocket.onmessage = function(event) {
	switch(event.data.constructor.name) {
		case "String": {
			// is a Activity message
			window.external.Channel.Data = event.data;
			Channel_OnDataReceived();
			break;
		}
		case "ArrayBuffer": {
			// is a Command message
			let args = ParseCommandString(new TextDecoder("utf8").decode(event.data));
			switch(args[0]) {
				case "rename": {
					myNickname = args[3];
					break;
				}
				case "connect": {
					switch(args[1]) {
						case 0: {
							console.error("room is full or not avaliable");
							break;
						}
						case 1: {
							console.log("joined room successfully.");
							if(parseInt(args[2])) {
								imTheRoomOwner = false;
							} else {
								imTheRoomOwner = true;
								//window.external.Users.Inviter = window.external.Users.Me;
							}
							break;
						}
						case 2: {
							console.log("disconnecting?");
							break;
						}
					}
					break;
				}
				case "adduser": {
					if(imTheRoomOwner === false) {
						window.external.yellows111_Users[1].Name = myNickname;
					}
					window.external.yellows111_Users[0].Name = args[2];
					Channel_OnRemoteAppLoaded();
					Channel_OnTypeChanged();
					break;
				}
				case "deluser": {
					// todo?
					Channel_OnTypeChanged();
					break;
				}
				case "sync": {
					channelSocket.send(new TextEncoder("utf8").encode(EncodeCommandString(["sync", (new Date).getTime()])));
					break;
				}
				default: {
					console.warn("unknown instruction sequence:", args);
				}
			}
			break;
		}
	}
}
channelSocket.onerror = function() {
	Channel_OnDataError();
}
channelSocket.onclose = function() {
	Channel_OnAppClose();
}
function createWSEventsNowThatImReady() {
	if(channelSocket.readyState === 1) {
		// if we're already there
		channelSocket.send(new TextEncoder("utf8").encode(EncodeCommandString(["rename"])));
		channelSocket.send(new TextEncoder("utf8").encode(EncodeCommandString(["connect", sessionID])));
	}
	channelSocket.onopen = function() {
		channelSocket.send(new TextEncoder("utf8").encode(EncodeCommandString(["rename"])));
		channelSocket.send(new TextEncoder("utf8").encode(EncodeCommandString(["connect", sessionID])));
	}
}