feat: redesign match play and add broadcast tooling

streamer/obs.ts

@@ -0,0 +1,87 @@
+/**
+ * Just enough of obs-websocket 5 (built into OBS 28+) to switch scenes and
+ * set up sources: https://github.com/obsproject/obs-websocket/blob/master/docs/generated/protocol.md
+ */
+import { createHash, randomUUID } from 'node:crypto';
+
+const sha256 = (text: string) => createHash('sha256').update(text).digest('base64');
+
+/** The challenge-response from the protocol's Authentication section. */
+export function obsAuthentication(password: string, salt: string, challenge: string) {
+	return sha256(sha256(password + salt) + challenge);
+}
+
+export class Obs {
+	private socket: WebSocket | null = null;
+	private pending = new Map<string, { resolve(data: unknown): void; reject(err: Error): void }>();
+
+	constructor(
+		private url: string,
+		private password: string
+	) {}
+
+	get connected() {
+		return this.socket?.readyState === WebSocket.OPEN;
+	}
+
+	connect(): Promise<void> {
+		return new Promise((resolve, reject) => {
+			const socket = new WebSocket(this.url);
+			this.socket = socket;
+			socket.onerror = () =>
+				reject(
+					new Error(
+						`Could not reach OBS at ${this.url}. Is Tools → WebSocket Server Settings enabled?`
+					)
+				);
+			socket.onclose = () => {
+				for (const waiter of this.pending.values()) waiter.reject(new Error('OBS disconnected'));
+				this.pending.clear();
+			};
+			socket.onmessage = (event) => {
+				const { op, d } = JSON.parse(String(event.data));
+				if (op === 0) {
+					const auth = d.authentication as { salt: string; challenge: string } | undefined;
+					socket.send(
+						JSON.stringify({
+							op: 1,
+							d: {
+								rpcVersion: 1,
+								eventSubscriptions: 0,
+								...(auth
+									? { authentication: obsAuthentication(this.password, auth.salt, auth.challenge) }
+									: {})
+							}
+						})
+					);
+				} else if (op === 2) resolve();
+				else if (op === 7) {
+					const waiter = this.pending.get(d.requestId);
+					this.pending.delete(d.requestId);
+					if (d.requestStatus?.result) waiter?.resolve(d.responseData);
+					else
+						waiter?.reject(
+							new Error(
+								`OBS ${d.requestType}: ${d.requestStatus?.comment ?? d.requestStatus?.code}`
+							)
+						);
+				}
+			};
+		});
+	}
+
+	request<T = unknown>(requestType: string, requestData: Record<string, unknown> = {}): Promise<T> {
+		const socket = this.socket;
+		if (!socket || socket.readyState !== WebSocket.OPEN)
+			return Promise.reject(new Error('OBS is not connected'));
+		const requestId = randomUUID();
+		return new Promise<T>((resolve, reject) => {
+			this.pending.set(requestId, { resolve: resolve as (data: unknown) => void, reject });
+			socket.send(JSON.stringify({ op: 6, d: { requestType, requestId, requestData } }));
+		});
+	}
+
+	close() {
+		this.socket?.close();
+	}
+}