/**
 * Performance utilities for optimizing function execution
 */

/**
 * Creates a throttled function that only invokes the provided function at most once
 * per every `wait` milliseconds. The throttled function comes with a `cancel` method
 * to cancel delayed invocations.
 *
 * @param func - The function to throttle
 * @param wait - The number of milliseconds to throttle invocations to
 * @param options - Options object
 * @param options.leading - Specify invoking on the leading edge of the timeout
 * @param options.trailing - Specify invoking on the trailing edge of the timeout
 * @returns The throttled function with a `cancel` method
 */
export function throttle<T extends (...args: any[]) => any>(
	func: T,
	wait: number,
	options: { leading?: boolean; trailing?: boolean } = {}
): T & { cancel: () => void } {
	let timeout: NodeJS.Timeout | null = null;
	let lastCallTime = 0;
	let lastArgs: Parameters<T> | null = null;
	let lastThis: any = null;
	let result: any;

	const { leading = true, trailing = true } = options;

	const invokeFunc = () => {
		if (lastArgs && lastThis) {
			result = func.apply(lastThis, lastArgs);
			lastArgs = null;
			lastThis = null;
		}
	};

	const throttled = function (this: any, ...args: Parameters<T>) {
		const now = Date.now();
		const remaining = wait - (now - lastCallTime);

		lastArgs = args;
		lastThis = this;

		if (remaining <= 0 || remaining > wait) {
			if (timeout) {
				clearTimeout(timeout);
				timeout = null;
			}
			lastCallTime = now;
			if (leading) {
				invokeFunc();
			}
		} else if (!timeout && trailing) {
			timeout = setTimeout(() => {
				lastCallTime = Date.now();
				timeout = null;
				invokeFunc();
			}, remaining);
		}

		return result;
	} as T;

	throttled.cancel = () => {
		if (timeout) {
			clearTimeout(timeout);
			timeout = null;
		}
		lastArgs = null;
		lastThis = null;
	};

	return throttled;
}

/**
 * Creates a debounced function that delays invoking the provided function until
 * after `wait` milliseconds have elapsed since the last time it was invoked.
 *
 * @param func - The function to debounce
 * @param wait - The number of milliseconds to delay
 * @returns The debounced function with a `cancel` method
 */
export function debounce<T extends (...args: any[]) => any>(
	func: T,
	wait: number
): T & { cancel: () => void } {
	let timeout: NodeJS.Timeout | null = null;
	let lastArgs: Parameters<T> | null = null;
	let lastThis: any = null;
	let result: any;

	const debounced = function (this: any, ...args: Parameters<T>) {
		lastArgs = args;
		lastThis = this;

		if (timeout) {
			clearTimeout(timeout);
		}

		timeout = setTimeout(() => {
			if (lastArgs && lastThis) {
				result = func.apply(lastThis, lastArgs);
				lastArgs = null;
				lastThis = null;
			}
			timeout = null;
		}, wait);

		return result;
	} as T;

	debounced.cancel = () => {
		if (timeout) {
			clearTimeout(timeout);
			timeout = null;
		}
		lastArgs = null;
		lastThis = null;
	};

	return debounced;
}