import type { TimerWorkerEvent, TimerWorkerRequest } from "./types";

const timerIdMapping = new Map<number, number>();

self.addEventListener("message", (event: MessageEvent) => {
	const request = event.data as TimerWorkerRequest;

	switch (request.type) {
		case "setTimeout":
		case "setInterval":
			timerIdMapping.set(
				request.id,
				(request.type === "setTimeout" ? setTimeout : setInterval)(() => {
					tick(request.id);

					if (request.type === "setTimeout") {
						timerIdMapping.delete(request.id);
					}
				}, request.timeout),
			);
			break;

		case "clearTimeout":
		case "clearInterval":
			(request.type === "clearTimeout" ? clearTimeout : clearInterval)(
				timerIdMapping.get(request.id),
			);
			timerIdMapping.delete(request.id);
			break;
	}
});

function tick(id: number) {
	const message: TimerWorkerEvent = { type: "tick", id };
	self.postMessage(message);
}