/**
 * AKSRT Enhancements — 全局 UI 增强
 *
 * 包含：图片灯箱、滚动方向感知
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  var lightboxEl = null;
  var lightboxImg = null;
  var lightboxCaption = null;
  var lightboxCounter = null;
  var lightboxThumbsWrap = null;
  var currentGallery = [];
  var currentIndex = 0;
  var currentZoom = 1;
  var autoplayTimer = null;
  var isAutoplay = false;
  var lastTrigger = null;
  var previousBodyOverflow = '';
  var EXCLUDE_SEL = '.no-imgbox,.no-lightbox,.avatar,.img-icon,.avatar-badge,.aksrt-avatar,[data-no-lightbox],[data-aksrt-lightbox="0"]';
  var TRIGGER_SEL = '[data-aksrt-lightbox="1"] img,.aksrt-lightbox-trigger img,.imgbox-container img,.comment-content .box-img';
  var ANCHOR_TRIGGER_SEL = 'a[data-aksrt-lightbox-trigger]';
  var GROUP_SEL = '[data-aksrt-lightbox-group],.content-gallery[data-aksrt-lightbox="1"],.aksrt-carousel-block[data-aksrt-lightbox="1"],.imgbox-container,.comment-content,.post_front_content[data-aksrt-lightbox="1"],.wp-posts-content[data-aksrt-lightbox="1"],.entry-thumb[data-aksrt-lightbox="1"],.entry-content[data-aksrt-lightbox="1"],.aksrt-lightbox-trigger,[data-aksrt-lightbox="1"]';
  var IMAGE_URL_RE = /\.(?:avif|bmp|gif|ico|jpe?g|png|svg|tiff?|webp)(?:[?#].*)?$/i;
  var MAX_ZOOM_DESKTOP = 2;
  var MAX_ZOOM_MOBILE = 3;

  function lightboxFlag(key, fallback) {
    var config = window._win || {};
    if (config[key] === undefined || config[key] === null || config[key] === '') return fallback;
    return config[key] === true || config[key] === 1 || config[key] === '1';
  }

  function lightboxEnabled() {
    return lightboxFlag('imgbox', false);
  }

  function normalizeFullUrl(url) {
    if (!url || url.indexOf('data:') === 0) return url || '';
    return url
      .replace(/-\d+x\d+(\.[a-z0-9]+)(?=([?#]|$))/i, '$1')
      .replace(/([?&])x-oss-process=[^#&]*&?/i, '$1')
      .replace(/[?&]$/, '');
  }

  function resolveFullUrl(img) {
    var explicitFull = img.getAttribute('data-full-url') || '';
    if (explicitFull) return normalizeFullUrl(explicitFull);

    var anchor = img.closest('a[href]');
    var href = anchor ? anchor.getAttribute('href') || '' : '';
    if (IMAGE_URL_RE.test(href)) return normalizeFullUrl(href);

    return normalizeFullUrl(
      img.getAttribute('data-src')
      || img.getAttribute('data-lazy-src')
      || img.currentSrc
      || img.getAttribute('src')
      || ''
    );
  }

  function resolveThumbUrl(img) {
    return img.currentSrc
      || img.getAttribute('src')
      || img.getAttribute('data-src')
      || img.getAttribute('data-lazy-src')
      || img.getAttribute('data-full-url')
      || '';
  }

  function resolveCaption(img) {
    var anchor = img.closest('a');
    var explicit = anchor ? anchor.getAttribute('data-caption') || '' : '';
    if (explicit.trim()) return explicit.trim();

    var figure = img.closest('figure');
    var figcaption = figure ? figure.querySelector('figcaption') : null;
    if (figcaption && figcaption.textContent.trim()) return figcaption.textContent.trim();

    return (img.getAttribute('alt') || '').trim();
  }

  function isNoLightbox(img) {
    if (!img || img.closest(EXCLUDE_SEL)) return true;

    var parentA = img.closest('a[href]');
    if (parentA) {
      var href = parentA.getAttribute('href') || '';
      if (href && !IMAGE_URL_RE.test(href) && !parentA.hasAttribute('data-aksrt-lightbox-trigger')) {
        return true;
      }
    }

    return resolveFullUrl(img) === '';
  }

  function createLightbox() {
    if (!lightboxEnabled()) return null;
    if (lightboxEl) return lightboxEl;

    lightboxEl = document.createElement('div');
    lightboxEl.className = 'aksrt-lightbox';
    lightboxEl.setAttribute('role', 'dialog');
    lightboxEl.setAttribute('aria-modal', 'true');
    lightboxEl.setAttribute('aria-hidden', 'true');
    lightboxEl.setAttribute('aria-label', '图片预览');
    lightboxEl.setAttribute('tabindex', '-1');
    lightboxEl.innerHTML =
      '<div class="aksrt-lightbox__toolbar">' +
        '<span class="aksrt-lightbox__counter" aria-live="polite"></span>' +
        '<button type="button" class="aksrt-lightbox__tool toggle-zoom" title="缩放" aria-label="缩放"><i class="fa fas fa-search-plus" aria-hidden="true"></i></button>' +
        '<button type="button" class="aksrt-lightbox__tool toggle-thumbs" title="缩略图" aria-label="显示或隐藏缩略图"><i class="fa fas fa-th" aria-hidden="true"></i></button>' +
        '<button type="button" class="aksrt-lightbox__tool toggle-play" title="幻灯片" aria-label="播放幻灯片"><i class="fa fas fa-play" aria-hidden="true"></i></button>' +
        '<button type="button" class="aksrt-lightbox__tool toggle-full" title="全屏" aria-label="切换全屏"><i class="fa fas fa-expand" aria-hidden="true"></i></button>' +
        '<a class="aksrt-lightbox__tool aksrt-lightbox__download" title="下载" aria-label="下载图片" download><i class="fa fas fa-download" aria-hidden="true"></i></a>' +
        '<button type="button" class="aksrt-lightbox__tool aksrt-lightbox__close" title="关闭" aria-label="关闭"><i class="fa fas fa-times" aria-hidden="true"></i></button>' +
      '</div>' +
      '<button type="button" class="aksrt-lightbox__nav aksrt-lightbox__nav--prev" aria-label="上一张"><i class="fa fas fa-chevron-left" aria-hidden="true"></i></button>' +
      '<div class="aksrt-lightbox__stage"><img class="aksrt-lightbox__img" src="" alt=""></div>' +
      '<button type="button" class="aksrt-lightbox__nav aksrt-lightbox__nav--next" aria-label="下一张"><i class="fa fas fa-chevron-right" aria-hidden="true"></i></button>' +
      '<div class="aksrt-lightbox__caption" aria-live="polite"></div>' +
      '<div class="aksrt-lightbox__thumbs" hidden></div>';

    document.body.appendChild(lightboxEl);

    lightboxImg = lightboxEl.querySelector('.aksrt-lightbox__img');
    lightboxCaption = lightboxEl.querySelector('.aksrt-lightbox__caption');
    lightboxCounter = lightboxEl.querySelector('.aksrt-lightbox__counter');
    lightboxThumbsWrap = lightboxEl.querySelector('.aksrt-lightbox__thumbs');

    lightboxEl.querySelector('.aksrt-lightbox__close').addEventListener('click', function (event) {
      event.stopPropagation();
      closeLightbox();
    });
    lightboxEl.addEventListener('click', function (event) {
      if (event.target === lightboxEl || event.target.classList.contains('aksrt-lightbox__stage')) closeLightbox();
    });
    lightboxEl.querySelector('.aksrt-lightbox__nav--prev').addEventListener('click', function (event) {
      event.stopPropagation();
      navigateLightbox(-1);
    });
    lightboxEl.querySelector('.aksrt-lightbox__nav--next').addEventListener('click', function (event) {
      event.stopPropagation();
      navigateLightbox(1);
    });

    document.addEventListener('keydown', function (event) {
      if (!lightboxEl || !lightboxEl.classList.contains('is-open')) return;
      if (event.key === 'Escape') closeLightbox();
      if (event.key === 'ArrowLeft') navigateLightbox(-1);
      if (event.key === 'ArrowRight') navigateLightbox(1);
      if (event.key === 'Tab') trapFocus(event);
    });

    lightboxEl.addEventListener('wheel', function (event) {
      if (!lightboxEl.classList.contains('is-open') || currentZoom > 1 || currentGallery.length < 2) return;
      event.preventDefault();
      navigateLightbox(event.deltaY > 0 ? 1 : -1);
    }, { passive: false });

    lightboxImg.addEventListener('click', function (event) {
      event.stopPropagation();
      if (lightboxFlag('imgbox_zoom', true)) toggleZoom();
    });
    lightboxImg.addEventListener('dblclick', function (event) {
      if (!lightboxFlag('imgbox_zoom', true)) return;
      event.stopPropagation();
      var maxZoom = window.innerWidth < 768 ? MAX_ZOOM_MOBILE : MAX_ZOOM_DESKTOP;
      setZoom(currentZoom < maxZoom ? maxZoom : 1);
    });

    bindTouchGestures();

    lightboxEl.querySelector('.toggle-zoom').addEventListener('click', function (event) {
      event.stopPropagation();
      toggleZoom();
    });
    lightboxEl.querySelector('.toggle-thumbs').addEventListener('click', function (event) {
      event.stopPropagation();
      lightboxThumbsWrap.hidden = !lightboxThumbsWrap.hidden;
    });
    lightboxEl.querySelector('.toggle-play').addEventListener('click', function (event) {
      event.stopPropagation();
      toggleAutoplay();
    });
    lightboxEl.querySelector('.toggle-full').addEventListener('click', function (event) {
      event.stopPropagation();
      toggleFullscreen();
    });

    document.addEventListener('fullscreenchange', syncFullscreenState);
    document.addEventListener('webkitfullscreenchange', syncFullscreenState);

    return lightboxEl;
  }

  function bindTouchGestures() {
    var pinchStart = 0;
    var touchStartY = 0;
    var touchStartX = 0;
    var pullDistance = 0;

    lightboxEl.addEventListener('touchstart', function (event) {
      if (event.touches.length === 2 && lightboxFlag('imgbox_zoom', true)) {
        pinchStart = Math.hypot(
          event.touches[1].clientX - event.touches[0].clientX,
          event.touches[1].clientY - event.touches[0].clientY
        );
        return;
      }
      if (event.touches.length === 1 && currentZoom <= 1.05) {
        touchStartY = event.touches[0].clientY;
        touchStartX = event.touches[0].clientX;
        pullDistance = 0;
      }
    }, { passive: true });

    lightboxEl.addEventListener('touchmove', function (event) {
      if (event.touches.length === 2 && pinchStart > 0 && lightboxFlag('imgbox_zoom', true)) {
        var distance = Math.hypot(
          event.touches[1].clientX - event.touches[0].clientX,
          event.touches[1].clientY - event.touches[0].clientY
        );
        var maxZoom = window.innerWidth < 768 ? MAX_ZOOM_MOBILE : MAX_ZOOM_DESKTOP;
        setZoom(Math.min(maxZoom, Math.max(1, currentZoom * (distance / pinchStart))));
        pinchStart = distance;
        return;
      }
      if (event.touches.length !== 1 || currentZoom > 1.05) return;

      var dy = event.touches[0].clientY - touchStartY;
      var dx = event.touches[0].clientX - touchStartX;
      if (Math.abs(dy) > Math.abs(dx) && dy > 30) {
        pullDistance = dy;
        lightboxImg.style.transform = 'translate3d(0, ' + dy + 'px, 0) scale(' + currentZoom + ')';
        lightboxImg.style.opacity = String(Math.max(0.2, Math.min(1, (150 - dy) / 80)));
      }
    }, { passive: true });

    lightboxEl.addEventListener('touchend', function () {
      pinchStart = 0;
      if (pullDistance > 100) {
        closeLightbox();
      } else if (pullDistance > 0) {
        setZoom(1);
      }
      lightboxImg.style.opacity = '';
      pullDistance = 0;
    }, { passive: true });
  }

  function trapFocus(event) {
    var focusable = Array.prototype.filter.call(
      lightboxEl.querySelectorAll('a[href],button:not([hidden]):not([disabled]),[tabindex]:not([tabindex="-1"])'),
      function (element) { return element.offsetParent !== null; }
    );
    if (!focusable.length) {
      event.preventDefault();
      lightboxEl.focus();
      return;
    }

    var first = focusable[0];
    var last = focusable[focusable.length - 1];
    if (event.shiftKey && document.activeElement === first) {
      event.preventDefault();
      last.focus();
    } else if (!event.shiftKey && document.activeElement === last) {
      event.preventDefault();
      first.focus();
    }
  }

  function setZoom(zoom) {
    if (!lightboxImg || !lightboxEl) return;
    currentZoom = zoom;
    lightboxImg.style.transform = 'scale(' + zoom + ')';
    lightboxEl.classList.toggle('is-zoomed', zoom > 1);
  }

  function toggleZoom() {
    if (!lightboxFlag('imgbox_zoom', true)) return;
    var maxZoom = window.innerWidth < 768 ? MAX_ZOOM_MOBILE : MAX_ZOOM_DESKTOP;
    setZoom(currentZoom > 1 ? 1 : maxZoom);
  }

  function toggleAutoplay() {
    if (!lightboxEl) return;
    var icon = lightboxEl.querySelector('.toggle-play i');
    if (isAutoplay) {
      clearInterval(autoplayTimer);
      autoplayTimer = null;
      isAutoplay = false;
      icon.className = 'fa fas fa-play';
      return;
    }
    if (currentGallery.length < 2) return;

    isAutoplay = true;
    icon.className = 'fa fas fa-pause';
    autoplayTimer = setInterval(function () { navigateLightbox(1); }, 3000);
  }

  function toggleFullscreen() {
    if (!lightboxEl || !lightboxFlag('imgbox_full', true)) return;
    var fullscreenElement = document.fullscreenElement || document.webkitFullscreenElement;
    if (fullscreenElement) {
      var exit = document.exitFullscreen || document.webkitExitFullscreen;
      if (exit) exit.call(document);
      return;
    }

    var request = lightboxEl.requestFullscreen || lightboxEl.webkitRequestFullscreen;
    if (request) request.call(lightboxEl);
  }

  function syncFullscreenState() {
    if (!lightboxEl) return;
    var active = Boolean(document.fullscreenElement || document.webkitFullscreenElement);
    var icon = lightboxEl.querySelector('.toggle-full i');
    lightboxEl.classList.toggle('full-screen', active);
    icon.className = active ? 'fa fas fa-compress' : 'fa fas fa-expand';
  }

  function buildThumbnails() {
    if (!lightboxThumbsWrap) return;
    lightboxThumbsWrap.innerHTML = '';
    currentGallery.forEach(function (item, index) {
      var button = document.createElement('button');
      var thumb = document.createElement('img');
      button.type = 'button';
      button.className = 'aksrt-lightbox__thumb' + (index === currentIndex ? ' is-active' : '');
      button.setAttribute('aria-label', '查看第 ' + (index + 1) + ' 张图片');
      thumb.src = item.thumbSrc || item.src;
      thumb.alt = '';
      button.appendChild(thumb);
      button.addEventListener('click', function (event) {
        event.stopPropagation();
        showLightboxImage(index);
      });
      lightboxThumbsWrap.appendChild(button);
    });
  }

  function syncThumbActive() {
    if (!lightboxThumbsWrap) return;
    var thumbs = lightboxThumbsWrap.querySelectorAll('.aksrt-lightbox__thumb');
    thumbs.forEach(function (thumb, index) {
      thumb.classList.toggle('is-active', index === currentIndex);
    });
    var active = thumbs[currentIndex];
    if (active) active.scrollIntoView({ inline: 'center', block: 'nearest' });
  }

  function syncControls() {
    if (!lightboxEl) return;
    var multiple = currentGallery.length > 1;
    var fullscreenAvailable = Boolean(
      lightboxEl.requestFullscreen
      || lightboxEl.webkitRequestFullscreen
      || document.fullscreenEnabled
      || document.webkitFullscreenEnabled
    );
    var thumbsEnabled = multiple && lightboxFlag('imgbox_thumbs', true);

    lightboxEl.querySelector('.toggle-zoom').hidden = !lightboxFlag('imgbox_zoom', true);
    lightboxEl.querySelector('.toggle-thumbs').hidden = !thumbsEnabled;
    lightboxEl.querySelector('.toggle-play').hidden = !multiple || !lightboxFlag('imgbox_play', false);
    lightboxEl.querySelector('.toggle-full').hidden = !lightboxFlag('imgbox_full', true) || !fullscreenAvailable;
    lightboxEl.querySelector('.aksrt-lightbox__download').hidden = !lightboxFlag('imgbox_down', false);
    lightboxEl.querySelector('.aksrt-lightbox__nav--prev').hidden = !multiple;
    lightboxEl.querySelector('.aksrt-lightbox__nav--next').hidden = !multiple;
    lightboxThumbsWrap.hidden = !thumbsEnabled;
  }

  function openLightbox(src, caption, gallery, index, originEl) {
    if (!lightboxEnabled() || !createLightbox()) return false;

    currentGallery = gallery && gallery.length ? gallery : [{ src: src, fullSrc: src, thumbSrc: src, caption: caption || '' }];
    currentIndex = Number.isInteger(index) ? index : 0;
    currentZoom = 1;
    lastTrigger = originEl || document.activeElement;

    if (originEl && typeof originEl.getBoundingClientRect === 'function') {
      var rect = originEl.getBoundingClientRect();
      lightboxEl.style.setProperty('--imgbox-origin-top', (rect.top + rect.height / 2) + 'px');
      lightboxEl.style.setProperty('--imgbox-origin-left', (rect.left + rect.width / 2) + 'px');
      lightboxEl.classList.add('from-origin');
    } else {
      lightboxEl.classList.remove('from-origin');
    }

    buildThumbnails();
    syncControls();
    showLightboxImage(currentIndex);

    lightboxEl.classList.add('is-open');
    lightboxEl.setAttribute('aria-hidden', 'false');
    previousBodyOverflow = document.body.style.overflow;
    document.body.style.overflow = 'hidden';
    document.body.classList.add('aksrt-lightbox-open');
    lightboxEl.querySelector('.aksrt-lightbox__close').focus();
    lightboxEl.dispatchEvent(new CustomEvent('aksrt:lightbox-open', { bubbles: true }));
    return true;
  }

  function showLightboxImage(index) {
    if (!currentGallery.length || !lightboxImg) return;
    if (index < 0) index = currentGallery.length - 1;
    if (index >= currentGallery.length) index = 0;
    currentIndex = index;
    setZoom(1);

    var item = currentGallery[currentIndex];
    lightboxImg.src = item.fullSrc || item.src;
    lightboxImg.alt = item.caption || '';
    lightboxCaption.textContent = item.caption || '';
    lightboxCaption.hidden = !item.caption;

    if (currentGallery.length > 1) {
      lightboxCounter.textContent = (currentIndex + 1) + ' / ' + currentGallery.length;
      lightboxCounter.hidden = false;
    } else {
      lightboxCounter.textContent = '';
      lightboxCounter.hidden = true;
    }

    var download = lightboxEl.querySelector('.aksrt-lightbox__download');
    var fullSrc = item.fullSrc || item.src;
    download.href = fullSrc;
    download.download = fullSrc.substring(fullSrc.lastIndexOf('/') + 1).split(/[?#]/)[0] || 'image';
    syncThumbActive();
  }

  function navigateLightbox(direction) {
    if (currentGallery.length < 2) return;
    showLightboxImage(currentIndex + direction);
  }

  function closeLightbox() {
    if (!lightboxEl || !lightboxEl.classList.contains('is-open')) return;
    if (isAutoplay) toggleAutoplay();
    lightboxEl.classList.remove('is-open', 'is-zoomed', 'from-origin');
    lightboxEl.setAttribute('aria-hidden', 'true');
    document.body.style.overflow = previousBodyOverflow;
    document.body.classList.remove('aksrt-lightbox-open');
    lightboxThumbsWrap.hidden = true;
    lightboxImg.src = '';
    lightboxImg.alt = '';

    var fullscreenElement = document.fullscreenElement || document.webkitFullscreenElement;
    var exit = document.exitFullscreen || document.webkitExitFullscreen;
    if (fullscreenElement && exit) exit.call(document);

    if (lastTrigger && typeof lastTrigger.focus === 'function' && document.contains(lastTrigger)) {
      lastTrigger.focus({ preventScroll: true });
    }
    lastTrigger = null;
  }

  function buildGallery(img) {
    var container = img.closest(GROUP_SEL);
    if (!container || container.closest('[data-no-lightbox],[data-aksrt-lightbox="0"]')) return null;

    var gallery = [];
    var foundIndex = -1;
    container.querySelectorAll('img').forEach(function (candidate) {
      if (!candidate.matches(TRIGGER_SEL) || isNoLightbox(candidate)) return;
      var fullSrc = resolveFullUrl(candidate);
      var thumbSrc = resolveThumbUrl(candidate) || fullSrc;
      if (!fullSrc) return;

      if (candidate === img) foundIndex = gallery.length;
      gallery.push({
        src: thumbSrc,
        thumbSrc: thumbSrc,
        fullSrc: fullSrc,
        caption: resolveCaption(candidate),
      });
    });

    if (foundIndex < 0 || !gallery.length) return null;
    return { items: gallery, index: foundIndex };
  }

  function openImage(img) {
    if (isNoLightbox(img)) return false;
    var gallery = buildGallery(img);
    if (!gallery) return false;
    var item = gallery.items[gallery.index];
    return openLightbox(item.fullSrc, item.caption, gallery.items, gallery.index, img);
  }

  function initLightbox() {
    document.addEventListener('click', function (event) {
      if (!lightboxEnabled() || !(event.target instanceof Element)) return;

      var anchor = event.target.closest(ANCHOR_TRIGGER_SEL);
      if (anchor && !anchor.closest(EXCLUDE_SEL)) {
        var anchorImage = anchor.querySelector('img');
        if (anchorImage && openImage(anchorImage)) {
          event.preventDefault();
          return;
        }

        var href = anchor.getAttribute('href') || '';
        if (IMAGE_URL_RE.test(href) && openLightbox(href, anchor.getAttribute('data-caption') || '', null, 0, anchor)) {
          event.preventDefault();
        }
        return;
      }

      var img = event.target.closest(TRIGGER_SEL);
      if (img && openImage(img)) event.preventDefault();
    });
  }

  window.AksrtLightbox = {
    open: openLightbox,
    close: closeLightbox,
  };

  // Scroll direction is handled by aksrt-runtime.js. Keep the prefixed
  // classes in sync for the remaining CSS consumers.
  function initScrollDirection() {
    var body = document.body;

    function sync() {
      body.classList.toggle('aksrt-body-scroll', body.classList.contains('body-scroll'));
      body.classList.toggle('aksrt-scroll-down', body.classList.contains('scroll-down'));
      body.classList.toggle('aksrt-scroll-up', body.classList.contains('scroll-up'));

      body.classList.add('aksrt-scrolling');
      clearTimeout(body._aksrtScrollTimer);
      body._aksrtScrollTimer = setTimeout(function () {
        body.classList.remove('aksrt-scrolling');
      }, 300);
    }

    window.addEventListener('scroll', function () {
      requestAnimationFrame(sync);
    }, { passive: true });
  }

  document.addEventListener('DOMContentLoaded', function () {
    initLightbox();
    initScrollDirection();
  });
})();