(() => {
    const reduceMotion = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    const selectors = [
        ".section__head",
        ".info-card",
        ".feature-card",
        ".object-card",
        ".service-card",
        ".gallery__item",
        ".review-card",
        ".stats article",
        ".booking__form",
        ".contacts-card",
        ".hours-card",
    ];

    const elements = Array.from(document.querySelectorAll(selectors.join(",")));
    if (!elements.length) return;

    const siblingCounters = new WeakMap();

    elements.forEach((element) => {
        element.classList.add("scroll-reveal");
        const parent = element.parentElement;
        let offsetIndex = 0;

        if (parent) {
            offsetIndex = siblingCounters.get(parent) ?? 0;
            siblingCounters.set(parent, offsetIndex + 1);
        }

        element.style.setProperty("--reveal-delay", `${(offsetIndex % 4) * 80}ms`);
    });

    if (reduceMotion || !("IntersectionObserver" in window)) {
        elements.forEach((element) => element.classList.add("is-visible"));
        return;
    }

    const observer = new IntersectionObserver(
        (entries, currentObserver) => {
            entries.forEach((entry) => {
                if (!entry.isIntersecting) return;
                entry.target.classList.add("is-visible");
                currentObserver.unobserve(entry.target);
            });
        },
        {
            threshold: 0.18,
            rootMargin: "0px 0px -12% 0px"
        }
    );

    elements.forEach((element) => observer.observe(element));
})();