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

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

function connect(url: string): 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 close(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 on connect to all clients", async () => {
	const s1 = await connect(url);
	const s2 = await connect(url);
	assertEquals(await nextMessage(s1), "2 has joined!");

	const s3 = connect(url);
	Promise.all([nextMessage(s1), nextMessage(s2)]).then((messages) => {
		messages.forEach((message) => {
			assertEquals(message, "3 has joined!");
		});
	});

	await close(s1);
	await close(s2);
	await close(await s3);
});

Deno.test("removes a client from broadcast after it disconnects", async () => {
	const s4 = await connect(url);
	const s5 = await connect(url);
	const s6 = await connect(url);

	await close(s5);

	Promise.all([nextMessage(s4), nextMessage(s6)]).then((messages) => {
		messages.forEach((message) => {
			assertEquals(message, "5 has left!");
		});
	});

	await close(s4);
	await close(s6);
});