/// <reference lib="deno.ns" />
import { assertEquals } from "jsr:@std/assert";

const url = "ws://0.0.0.0:6969";

function connect(): Promise<WebSocket> {
	return new Promise((resolve, reject) => {
		const socket = new WebSocket(url);
		socket.onopen = () => resolve(socket);
		socket.onerror = (e) => reject(e);
	});
}

function nextMessage(socket: WebSocket): Promise<unknown> {
	return new Promise((resolve, reject) => {
		const onMessage = (e: MessageEvent) => {
			socket.removeEventListener("message", onMessage);
			try {
				resolve(JSON.parse(e.data));
			} catch {
				resolve(e.data);
			}
		};
		socket.addEventListener("message", onMessage);
		socket.addEventListener("error", reject, { once: true });
	});
}

function closeAndWait(socket: WebSocket): Promise<void> {
	return new Promise((resolve) => {
		if (socket.readyState === WebSocket.CLOSED) return resolve();
		socket.onclose = () => resolve();
		socket.close();
	});
}

Deno.test("broadcasts a message from one client to another", async () => {
	const a = await connect(); // 1
	const b = await connect(); // 2

	const received = await nextMessage(b);
	assertEquals(received, "2 has joined!");

	await closeAndWait(a);
	await closeAndWait(b);
});

Deno.test("removes a client from broadcast after it disconnects", async () => {
	// test are executed in a row so the ID will just increment
	const a = await connect(); // 3
	const b = await connect(); // 4

	await closeAndWait(b);

	const msg = await nextMessage(a);
	assertEquals(msg, "4 has left!");

	await closeAndWait(a);
});