import { isBrowser, isHTMLElement } from './is.js';
import { sleep } from './sleep.js';
/**
 * Manage roving focus between elements. Sets the current active element to
 * tabindex -1 and the next element to tabindex 0.
 *
 * @param nextElement The element to focus on
 */
export function handleRovingFocus(nextElement) {
    if (!isBrowser)
        return;
    sleep(1).then(() => {
        const currentFocusedElement = document.activeElement;
        if (!isHTMLElement(currentFocusedElement) || currentFocusedElement === nextElement)
            return;
        currentFocusedElement.tabIndex = -1;
        if (nextElement) {
            nextElement.tabIndex = 0;
            nextElement.focus();
        }
    });
}
function getFocusableElements() {
    return Array.from(document.querySelectorAll('a[href]:not([tabindex="-1"]), button:not([disabled]):not([tabindex="-1"]), input:not([disabled]):not([tabindex="-1"]), select:not([disabled]):not([tabindex="-1"]), textarea:not([disabled]):not([tabindex="-1"]), [tabindex]:not([tabindex="-1"])'));
}
export function getNextFocusable(currentElement) {
    const focusableElements = getFocusableElements();
    const currentIndex = focusableElements.indexOf(currentElement);
    const nextIndex = currentIndex + 1;
    const nextElement = focusableElements[nextIndex];
    if (nextIndex < focusableElements.length && isHTMLElement(nextElement)) {
        return nextElement;
    }
    return null;
}
export function getPreviousFocusable(currentElement) {
    const focusableElements = getFocusableElements();
    const currentIndex = focusableElements.indexOf(currentElement);
    const previousIndex = currentIndex - 1;
    const prevElement = focusableElements[previousIndex];
    if (previousIndex >= 0 && isHTMLElement(prevElement)) {
        return prevElement;
    }
    return null;
}