/**
 * Tischlerei Staffenberger - Main JavaScript
 * Handles navigation active state, gallery filtering, and lightbox on Bilder page.
 */

(function () {
  'use strict';

  /**
   * Set active state on the current page's nav link based on URL pathname.
   */
  function setActiveNav() {
    var navLinks = document.querySelectorAll('.main-nav a');
    var path = window.location.pathname;
    var page = path.split('/').pop() || 'index.html';

    navLinks.forEach(function (link) {
      var href = link.getAttribute('href');
      if (!href) return;
      var linkPage = href.split('/').pop() || 'index.html';
      if (linkPage === page || (page === '' && linkPage === 'index.html')) {
        link.classList.add('active');
      } else {
        link.classList.remove('active');
      }
    });
  }

  /**
   * Gallery filter: show/hide items by data-category.
   */
  function initGalleryFilter() {
    var filters = document.querySelectorAll('.gallery-filters button');
    var items = document.querySelectorAll('.gallery-item');

    if (!filters.length || !items.length) return;

    filters.forEach(function (btn) {
      btn.addEventListener('click', function () {
        var category = this.getAttribute('data-filter');

        // Update active button
        filters.forEach(function (b) {
          b.classList.toggle('active', b === btn);
        });

        // Show/hide items
        items.forEach(function (item) {
          var itemCategory = item.getAttribute('data-category');
          var show = category === 'all' || itemCategory === category;
          item.style.display = show ? '' : 'none';
        });
      });
    });
  }

  /**
   * Lightbox on Bilder page: open on gallery image click, navigate with swipe / arrow
   * keys / prev+next buttons, close via X, backdrop or ESC.
   * Respects the active gallery filter – only visible items are part of the sequence.
   */
  function initLightbox() {
    var lightbox = document.getElementById('lightbox');
    var lightboxImg = document.getElementById('lightbox-img');
    if (!lightbox || !lightboxImg) return;

    var closeBtn = lightbox.querySelector('.lightbox-close');
    var backdrop = lightbox.querySelector('.lightbox-backdrop');
    var prevBtn  = lightbox.querySelector('.lightbox-prev');
    var nextBtn  = lightbox.querySelector('.lightbox-next');

    var currentIndex = 0;
    var sequence = []; // visible gallery links at the time the lightbox was opened

    function getVisibleLinks() {
      return Array.from(document.querySelectorAll('.gallery-item'))
        .filter(function (item) { return item.style.display !== 'none'; })
        .map(function (item) { return item.querySelector('.gallery-image-link'); })
        .filter(Boolean);
    }

    function showImage(index) {
      var link = sequence[index];
      if (!link) return;
      currentIndex = index;
      lightboxImg.src = link.getAttribute('data-lightbox-src') || link.getAttribute('href');
      lightboxImg.alt = link.getAttribute('data-lightbox-alt') || '';
      var multiple = sequence.length > 1;
      if (prevBtn) prevBtn.hidden = !multiple;
      if (nextBtn) nextBtn.hidden = !multiple;
    }

    function navigate(dir) {
      showImage((currentIndex + dir + sequence.length) % sequence.length);
    }

    function openLightbox(index) {
      sequence = getVisibleLinks();
      showImage(index);
      lightbox.classList.add('is-open');
      document.addEventListener('keydown', onKeydown);
    }

    function closeLightbox() {
      lightbox.classList.remove('is-open');
      document.removeEventListener('keydown', onKeydown);
    }

    function onKeydown(e) {
      if (e.key === 'Escape')      closeLightbox();
      if (e.key === 'ArrowRight')  navigate(1);
      if (e.key === 'ArrowLeft')   navigate(-1);
    }

    // Touch swipe
    var touchStartX = 0;
    lightbox.addEventListener('touchstart', function (e) {
      touchStartX = e.changedTouches[0].clientX;
    }, { passive: true });
    lightbox.addEventListener('touchend', function (e) {
      var dx = e.changedTouches[0].clientX - touchStartX;
      if (Math.abs(dx) > 50) navigate(dx < 0 ? 1 : -1);
    }, { passive: true });

    // Open on gallery click
    document.querySelectorAll('.gallery-image-link').forEach(function (link) {
      link.addEventListener('click', function (e) {
        e.preventDefault();
        var visibles = getVisibleLinks();
        var idx = visibles.indexOf(link);
        openLightbox(idx >= 0 ? idx : 0);
      });
    });

    if (prevBtn)  prevBtn.addEventListener('click',  function () { navigate(-1); });
    if (nextBtn)  nextBtn.addEventListener('click',  function () { navigate(1); });
    if (closeBtn) closeBtn.addEventListener('click', closeLightbox);
    if (backdrop) backdrop.addEventListener('click', closeLightbox);
  }

  /**
   * "Request" buttons on shop page – open mailto with product name in subject.
   */
  function initShopRequests() {
    var requestBtns = document.querySelectorAll('.product-card .btn[data-product]');
    requestBtns.forEach(function (btn) {
      btn.addEventListener('click', function (e) {
        var product = this.getAttribute('data-product');
        if (product) {
          // Open mail with subject line (no real checkout) – replace email with your address
          var mailto = 'mailto:info@tischlerei-staffenberger.example?subject=Anfrage%20Produkt%3A%20' + encodeURIComponent(product);
          window.location.href = mailto;
        }
      });
    });
  }

  /**
   * Shop empty state: show message when no products are present.
   */
  function initShopEmptyState() {
    var emptyMsg = document.getElementById('shop-empty-message');
    var grid = document.getElementById('shop-grid');
    if (!emptyMsg || !grid) return;

    var hasCards = grid.querySelectorAll('.product-card').length > 0;
    emptyMsg.hidden = hasCards;
  }

  /**
   * Run on DOM ready.
   */
  function init() {
    setActiveNav();
    initGalleryFilter();
    initLightbox();
    initShopRequests();
    initShopEmptyState();
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init);
  } else {
    init();
  }
})();