import { Channel } from "rjweb-server";

/**
 * Real-time hub. One RJWEB Channel per human account; the websocket endpoint
 * subscribes each authenticated socket to its owner's channel via
 * `ctr.printChannel(getUserChannel(userId))`. Any server-side event for that
 * user (new notification, request state change) is published to the channel and
 * fanned out to every open socket.
 */
const userChannels = new Map<number, Channel<string>>();

export function getUserChannel(userId: number): Channel<string> {
	let channel = userChannels.get(userId);
	if (!channel) {
		channel = new Channel<string>();
		userChannels.set(userId, channel);
	}
	return channel;
}

export type RealtimeEvent =
	| { kind: "notification"; notification: unknown; unreadCount: number }
	| { kind: "request_event"; event: string; requestPublicId: string }
	| { kind: "ping"; at: string };

export async function publishToUser(userId: number, event: RealtimeEvent): Promise<void> {
	const channel = userChannels.get(userId);
	if (!channel) return; // nobody connected — nothing to push
	await channel.send("text", JSON.stringify(event));
}