/* ============================================
   UMass Amherst - Main JavaScript
   ============================================ */

document.addEventListener('DOMContentLoaded', () => {

  // ---- Mobile Menu ----
  const menuToggle = document.getElementById('menu-toggle');
  const menuClose = document.getElementById('menu-close');
  const mobileMenu = document.getElementById('mobile-menu');

  if (menuToggle) {
    menuToggle.addEventListener('click', () => {
      mobileMenu.classList.add('active');
      document.body.style.overflow = 'hidden';
    });
  }

  if (menuClose) {
    menuClose.addEventListener('click', () => {
      mobileMenu.classList.remove('active');
      document.body.style.overflow = '';
    });
  }

  document.querySelectorAll('.mobile-menu__link').forEach(link => {
    link.addEventListener('click', () => {
      mobileMenu.classList.remove('active');
      document.body.style.overflow = '';
    });
  });

  document.addEventListener('keydown', (e) => {
    if (e.key === 'Escape' && mobileMenu.classList.contains('active')) {
      mobileMenu.classList.remove('active');
      document.body.style.overflow = '';
    }
  });

  // ---- Hero Slider ----
  const slides = document.querySelectorAll('.hero__slide');
  const dots = document.querySelectorAll('.hero__dot');
  let currentSlide = 0;
  let slideInterval;

  function goToSlide(index) {
    slides.forEach(s => s.classList.remove('active'));
    dots.forEach(d => d.classList.remove('active'));
    slides[index].classList.add('active');
    dots[index].classList.add('active');
    currentSlide = index;
  }

  function nextSlide() {
    const next = (currentSlide + 1) % slides.length;
    goToSlide(next);
  }

  function startAutoSlide() {
    slideInterval = setInterval(nextSlide, 5000);
  }

  function resetAutoSlide() {
    clearInterval(slideInterval);
    startAutoSlide();
  }

  dots.forEach(dot => {
    dot.addEventListener('click', () => {
      const index = parseInt(dot.dataset.slide, 10);
      goToSlide(index);
      resetAutoSlide();
    });
  });

  if (slides.length > 1) {
    startAutoSlide();
  }

  // ---- Scroll Animations ----
  const fadeElements = document.querySelectorAll('.fade-up');

  const observer = new IntersectionObserver((entries) => {
    entries.forEach(entry => {
      if (entry.isIntersecting) {
        entry.target.classList.add('visible');
        observer.unobserve(entry.target);
      }
    });
  }, {
    threshold: 0.1,
    rootMargin: '0px 0px -60px 0px'
  });

  fadeElements.forEach(el => observer.observe(el));

});