// ─── Scroll reveal ─────────────────────────────────────────
const reveals = document.querySelectorAll('.reveal');
const observer = new IntersectionObserver((entries) => {
  entries.forEach(e => {
    if (e.isIntersecting) {
      e.target.classList.add('visible');
      observer.unobserve(e.target);
    }
  });
}, { threshold: 0.1, rootMargin: '0px 0px -40px 0px' });
reveals.forEach(el => observer.observe(el));

// ─── Active nav link on scroll ──────────────────────────────
const sections = document.querySelectorAll('section[id]');
const navLinks = document.querySelectorAll('.nav-links a');
window.addEventListener('scroll', () => {
  let current = '';
  sections.forEach(s => {
    if (window.scrollY >= s.offsetTop - 120) current = s.id;
  });
  navLinks.forEach(a => {
    a.style.color = a.getAttribute('href') === `#${current}` ? 'var(--mauve)' : '';
  });
});

// ─── Project filters ──────────────────────────────────────────────
const filterChips = document.querySelectorAll('.filter-chip');
const projectCards = document.querySelectorAll('#project-grid .project-card');
const seeMoreButton = document.querySelector('#projects-see-more');
const DEFAULT_VISIBLE_PROJECTS = 8;

if (filterChips.length > 0 && projectCards.length > 0) {
  let selectedFilter = 'all';
  let isExpanded = false;

  const applyFilter = () => {
    const visibleCards = [];

    projectCards.forEach(card => {
      const tech = (card.dataset.tech || '').split(/\s+/).filter(Boolean);
      const shouldShow = selectedFilter === 'all' || tech.includes(selectedFilter);
      card.classList.toggle('is-hidden', !shouldShow);

      if (shouldShow) {
        card.classList.remove('is-collapsed');
        visibleCards.push(card);
      }
    });

    if (!isExpanded) {
      visibleCards.slice(DEFAULT_VISIBLE_PROJECTS).forEach(card => {
        card.classList.add('is-collapsed');
      });
    }

    if (seeMoreButton) {
      const canExpand = visibleCards.length > DEFAULT_VISIBLE_PROJECTS;
      seeMoreButton.hidden = !canExpand;
      seeMoreButton.setAttribute('aria-expanded', canExpand && isExpanded ? 'true' : 'false');
      seeMoreButton.textContent = isExpanded ? 'See less' : 'See more';
    }
  };

  filterChips.forEach(chip => {
    chip.addEventListener('click', () => {
      selectedFilter = chip.dataset.filter || 'all';
      isExpanded = false;

      filterChips.forEach(other => {
        other.classList.toggle('active', other === chip);
      });

      applyFilter();
    });
  });

  if (seeMoreButton) {
    seeMoreButton.addEventListener('click', () => {
      isExpanded = !isExpanded;
      applyFilter();
    });
  }

  applyFilter();
}