/**
 * Svelte action for smooth anchor scrolling
 *
 * Intercepts anchor link clicks to smoothly scroll to the target element
 * instead of jumping instantly. Updates URL hash without causing scroll.
 *
 * @example
 * ```svelte
 * <a href="#section" use:smoothScroll>Go to Section</a>
 * <div id="section">Section Content</div>
 * ```
 *
 * @param node - The anchor element to attach to
 * @returns Action object with destroy method
 */
export function smoothScroll(node: HTMLAnchorElement) {
    const handleClick = (event: MouseEvent) => {
        event.preventDefault();

        const hash = node.getAttribute('href');
        if (!hash || hash === '#') return;

        const targetElement = document.querySelector(hash);

        if (targetElement) {
            targetElement.scrollIntoView({
                behavior: 'smooth',
                block: 'start',
            });

            // Update URL hash without triggering scroll
            history.pushState(null, '', hash);
        }
    };

    node.addEventListener('click', handleClick);

    return {
        destroy() {
            node.removeEventListener('click', handleClick);
        },
    };
}