let timeElapsed = 0;
let intervalId: ReturnType<typeof setInterval> | null = null;

export type TimerDeclaration = {
	name: string;
	interval: number;
	callback: () => void;
};

const timers: TimerDeclaration[] = [];

const nextFireTime: Map<string, number> = new Map();

export function addTimer(timer: TimerDeclaration): void {
	if (timers.some((t) => t.name === timer.name)) {
		console.warn(`timer with name "${timer.name}" is already registered.`);
		return;
	}

	timers.push(timer);
	nextFireTime.set(timer.name, timeElapsed + timer.interval);
}

export function removeTimer(name: string): void {
	const index = timers.findIndex((t) => t.name === name);
	if (index !== -1) {
		timers.splice(index, 1);
		nextFireTime.delete(name);
	}
}

export function startSystem(): void {
	if (intervalId !== null) {
		console.warn("timer is already running.");
		return;
	}

	intervalId = setInterval(() => {
		timeElapsed++;

		for (const timer of timers) {
			const fireAt = nextFireTime.get(timer.name) ?? 0;
			if (timeElapsed >= fireAt) {
				timer.callback();
				nextFireTime.set(timer.name, timeElapsed + timer.interval);
			}
		}
	}, 1000);
}

export function stopSystem(): void {
	if (intervalId !== null) {
		clearInterval(intervalId);
		intervalId = null;
	}
}

export function getTimeElapsed(): number {
	return timeElapsed;
}

export function resetSystem(): void {
	stopSystem();
	timers.length = 0;
	nextFireTime.clear();
	timeElapsed = 0;
}

startSystem();