export function debounce(
	node: HTMLInputElement,
	{ callback, timeout = 500 }: { callback: () => void; timeout?: number }
) {
	let timer: NodeJS.Timeout;

	function trigger(event: KeyboardEvent) {
		clearTimeout(timer);
		if (event.key !== 'Enter') {
			timer = setTimeout(callback, timeout);
		} else {
			callback();
		}
	}

	node.addEventListener('keyup', trigger);

	return {
		destroy() {
			clearTimeout(timer);
			node.removeEventListener('keyup', trigger);
		}
	};
}

export function clickOutside(
	node: HTMLElement,
	{ handler, ignore }: { handler: () => void; ignore?: HTMLElement }
) {
	const handle = (event: Event) => {
		const target = event.target as HTMLElement;
		if (!target || target === ignore) return;

		if (node && !node.contains(target) && !event.defaultPrevented) {
			handler();
		}
	};

	document.addEventListener('click', handle, true);

	return {
		destroy() {
			document.removeEventListener('click', handle, true);
		}
	};
}

export const focusableElements = [
	'a[href]',
	'area[href]',
	'input:not([disabled]):not([type="hidden"]):not([aria-hidden])',
	'select:not([disabled]):not([aria-hidden])',
	'textarea:not([disabled]):not([aria-hidden])',
	'button:not([disabled]):not([aria-hidden])',
	'iframe',
	'object',
	'embed',
	'[contenteditable]',
	'[tabindex]:not([tabindex^="-"])'
];

let trapped: HTMLElement[] = [];

export function trapFocus(node: HTMLElement) {
	function handler(event: KeyboardEvent) {
		if (event.target === window) return;

		// return if we're not the topmost node to handle
		if (trapped.at(0) !== node) return;

		const focusable = node.querySelectorAll<HTMLElement>(focusableElements.join());

		const first = focusable[0];
		const last = focusable[focusable.length - 1];

		if (event.key === 'Tab') {
			if (!node.contains(document.activeElement)) {
				first.focus();
				event.preventDefault();
			}

			if (event.shiftKey && event.target === first) {
				last.focus();
				event.preventDefault();
			} else if (!event.shiftKey && event.target === last) {
				first.focus();
				event.preventDefault();
			}
		}
	}

	if (document.activeElement instanceof HTMLElement) {
		// if we trap focus, make sure to blur any previously selected external
		// item such that focus does not remain outside of the node
		if (!node.contains(document.activeElement)) {
			document.activeElement.blur();
		}
	}

	document.addEventListener('keydown', handler);
	trapped.unshift(node);

	return {
		destroy() {
			document.removeEventListener('keydown', handler);
			trapped = trapped.filter((i) => i !== node);
		}
	};
}