(function () {
  'use strict';

  var overlay = null;
  var content = null;
  var closeBtn = null;
  var lastFocus = null;
  var isOpen = false;
  var currentMedia = null;

  function dispatch(name) {
    document.dispatchEvent(new CustomEvent(name, { bubbles: true }));
  }

  function ensureDom() {
    if (overlay) return;

    overlay = document.createElement('div');
    overlay.className = 'lb';
    overlay.setAttribute('role', 'dialog');
    overlay.setAttribute('aria-modal', 'true');
    overlay.setAttribute('aria-label', 'プレビュー');
    overlay.hidden = true;

    closeBtn = document.createElement('button');
    closeBtn.type = 'button';
    closeBtn.className = 'lb__close';
    closeBtn.setAttribute('aria-label', '閉じる');
    closeBtn.innerHTML = '×';

    content = document.createElement('div');
    content.className = 'lb__content';

    overlay.appendChild(closeBtn);
    overlay.appendChild(content);
    document.body.appendChild(overlay);

    overlay.addEventListener('click', function (e) {
      if (e.target === overlay || e.target === content) {
        close();
      }
    });
    closeBtn.addEventListener('click', close);
  }

  function lockScroll(lock) {
    document.documentElement.classList.toggle('lb-open', lock);
    document.body.style.overflow = lock ? 'hidden' : '';
  }

  function clearMedia() {
    if (!content) return;
    content.innerHTML = '';
    currentMedia = null;
  }

  function isImageUrl(url) {
    return /\.(jpe?g|png|gif|webp|avif|svg)(\?|#|$)/i.test(url);
  }

  function toYoutubeEmbed(url) {
    try {
      var u = new URL(url, location.href);
      var host = u.hostname.replace(/^www\./, '');
      var id = null;

      if (host === 'youtu.be') {
        id = u.pathname.replace(/^\//, '').split('/')[0];
      } else if (host === 'youtube.com' || host === 'm.youtube.com' || host === 'youtube-nocookie.com') {
        if (u.pathname.indexOf('/embed/') === 0) {
          id = u.pathname.split('/')[2];
        } else if (u.searchParams.get('v')) {
          id = u.searchParams.get('v');
        }
      }

      if (!id) return null;

      var params = new URLSearchParams();
      // 既存クエリから主要パラメータを引き継ぎ
      ['autoplay', 'mute', 'controls', 'rel', 'playsinline'].forEach(function (key) {
        if (u.searchParams.has(key)) params.set(key, u.searchParams.get(key));
      });
      if (!params.has('autoplay')) params.set('autoplay', '1');
      if (!params.has('rel')) params.set('rel', '0');

      return 'https://www.youtube.com/embed/' + id + '?' + params.toString();
    } catch (err) {
      return null;
    }
  }

  function openImage(src, alt) {
    var img = document.createElement('img');
    img.className = 'lb__img';
    img.alt = alt || '';
    img.addEventListener('load', function () {
      img.classList.add('is-ready');
    });
    img.addEventListener('error', function () {
      img.classList.add('is-ready');
    });
    content.appendChild(img);
    currentMedia = img;
    requestAnimationFrame(function () {
      img.src = src;
    });
  }

  function openIframe(src) {
    var wrap = document.createElement('div');
    wrap.className = 'lb__iframe-wrap';
    var iframe = document.createElement('iframe');
    iframe.className = 'lb__iframe';
    iframe.src = src;
    iframe.title = '埋め込みコンテンツ';
    iframe.setAttribute('allowfullscreen', '');
    iframe.setAttribute(
      'allow',
      'accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture'
    );
    wrap.appendChild(iframe);
    content.appendChild(wrap);
    currentMedia = iframe;
  }

  function open(src, alt) {
    ensureDom();
    lastFocus = document.activeElement;
    isOpen = true;
    clearMedia();

    var yt = toYoutubeEmbed(src);
    if (yt) {
      content.classList.add('lb__content--video');
      openIframe(yt);
    } else if (isImageUrl(src)) {
      content.classList.remove('lb__content--video');
      openImage(src, alt);
    } else if (/^https?:/i.test(src)) {
      content.classList.add('lb__content--video');
      openIframe(src);
    } else {
      content.classList.remove('lb__content--video');
      openImage(src, alt);
    }

    overlay.hidden = false;
    lockScroll(true);
    closeBtn.focus({ preventScroll: true });
    dispatch('lightbox:open');
  }

  function close() {
    if (!isOpen || !overlay) return;
    isOpen = false;
    overlay.hidden = true;
    clearMedia();
    content.classList.remove('lb__content--video');
    lockScroll(false);
    dispatch('lightbox:close');
    if (lastFocus && typeof lastFocus.focus === 'function') {
      lastFocus.focus({ preventScroll: true });
    }
    lastFocus = null;
  }

  function onKeydown(e) {
    if (!isOpen) return;
    if (e.key === 'Escape') {
      e.preventDefault();
      close();
    }
  }

  function onClick(e) {
    var a = e.target.closest('a[data-lightbox], a[data-lity]');
    if (!a) return;

    var href = a.getAttribute('href');
    if (!href || href === '#') return;

    e.preventDefault();
    var thumb = a.querySelector('img');
    var alt = (thumb && thumb.getAttribute('alt')) || '';
    open(href, alt);
  }

  document.addEventListener('click', onClick);
  document.addEventListener('keydown', onKeydown);

  window.GuririLightbox = {
    open: open,
    close: close,
    isOpen: function () {
      return isOpen;
    }
  };
})();