/**
 * AKSRT Page Template
 *
 * Handles template-scoped content interactions: TOC, lightbox,
 * expandable article bodies, and one-shot query cleanup banners.
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  function slugifyHeading(text) {
    return 'heading-' + String(text || '')
      .trim()
      .toLowerCase()
      .replace(/\s+/g, '-')
      .replace(/[^\w\u4e00-\u9fff-]/g, '');
  }

  function initPostToc() {
    var content = document.querySelector('.wp-posts-content[data-nav="posts"][data-aksrt-toc="1"]');
    var tocWidget = document.querySelector('.posts-nav-box.toc-widget');
    var tocList = tocWidget ? tocWidget.querySelector('.toc-list') : null;
    var mobileToggle = document.querySelector('.toc-float-btn');
    var drawer = document.querySelector('.toc-drawer');
    var overlay = document.querySelector('.toc-drawer-overlay');
    var drawerList = drawer ? drawer.querySelector('.toc-list') : null;
    var closeBtn = drawer ? drawer.querySelector('.toc-drawer__close') : null;

    if (!content || content.dataset.aksrtTocBound === '1') return;
    if (!tocList && !drawerList && !mobileToggle) return;

    content.dataset.aksrtTocBound = '1';

    var maxDepth = parseInt(content.dataset.aksrtTocDepth || '3', 10) || 3;

    function getHeadings() {
      return Array.prototype.slice.call(content.querySelectorAll('h2, h3, h4')).filter(function (heading) {
        var level = parseInt((heading.tagName || 'H2').replace('H', ''), 10) || 2;
        return level <= maxDepth;
      });
    }

    function buildToc(container) {
      if (!container) return false;

      var headings = getHeadings();
      if (!headings.length) return false;

      var html = '';
      headings.forEach(function (heading) {
        if (!heading.id) {
          heading.id = slugifyHeading(heading.textContent);
        }

        var levelClass = '';
        if (heading.tagName === 'H3') {
          levelClass = 'toc-h3';
        } else if (heading.tagName === 'H4') {
          levelClass = 'toc-h4';
        }

        html += '<li' + (levelClass ? ' class="' + levelClass + '"' : '') + '><a href="#' + heading.id + '">' + heading.textContent.trim() + '</a></li>';
      });

      container.innerHTML = html;
      return true;
    }

    var hasToc = buildToc(tocList);
    if (drawerList && drawerList !== tocList) {
      buildToc(drawerList);
    }

    if (!hasToc) {
      if (tocWidget) tocWidget.remove();
      if (mobileToggle) mobileToggle.remove();
      if (drawer) drawer.remove();
      if (overlay) overlay.remove();
      return;
    }

    function closeDrawer() {
      if (drawer) drawer.classList.remove('is-open');
      if (overlay) overlay.classList.remove('is-open');
      document.body.style.overflow = '';
    }

    function openDrawer() {
      if (drawer) drawer.classList.add('is-open');
      if (overlay) overlay.classList.add('is-open');
      document.body.style.overflow = 'hidden';
    }

    function trackActiveHeading() {
      var headings = content.querySelectorAll('h2[id], h3[id], h4[id]');
      if (!headings.length) return;

      var activeId = '';
      var fromTop = window.scrollY + 120;
      for (var i = headings.length - 1; i >= 0; i -= 1) {
        if (headings[i].offsetTop <= fromTop) {
          activeId = headings[i].id;
          break;
        }
      }

      document.querySelectorAll('.toc-list a').forEach(function (link) {
        link.classList.toggle('is-active', link.getAttribute('href') === '#' + activeId);
      });
    }

    document.querySelectorAll('.toc-list a').forEach(function (link) {
      link.addEventListener('click', function (event) {
        var target = document.querySelector(link.getAttribute('href'));
        if (!target) return;

        event.preventDefault();
        target.scrollIntoView({
          behavior: 'smooth',
          block: 'start'
        });
        closeDrawer();
      });
    });

    if (mobileToggle) mobileToggle.addEventListener('click', openDrawer);
    if (overlay) overlay.addEventListener('click', closeDrawer);
    if (closeBtn) closeBtn.addEventListener('click', closeDrawer);

    window.addEventListener('scroll', trackActiveHeading, { passive: true });
    trackActiveHeading();
  }

  function initLightbox() {
    var overlay = document.getElementById('lightbox-overlay');
    var content = document.querySelector(".entry-content[data-aksrt-lightbox='1']");
    if (!overlay || !content || overlay.dataset.aksrtLightboxBound === '1') return;

    overlay.dataset.aksrtLightboxBound = '1';

    var image = overlay.querySelector('.lightbox-img');
    var caption = overlay.querySelector('.lightbox-caption');
    var closeBtn = overlay.querySelector('.lightbox-close');

    function close() {
      overlay.classList.remove('is-open');
      document.body.style.overflow = '';
      if (image) {
        image.src = '';
        image.alt = '';
      }
    }

    content.querySelectorAll('img').forEach(function (img) {
      img.style.cursor = 'zoom-in';
      img.addEventListener('click', function () {
        if (!image) return;

        image.src = img.src;
        image.alt = img.alt || '';

        if (caption) {
          var figure = img.closest('figure');
          var figureCaption = figure ? figure.querySelector('figcaption') : null;
          caption.textContent = img.alt || (figureCaption ? figureCaption.textContent : '') || '';
        }

        overlay.classList.add('is-open');
        document.body.style.overflow = 'hidden';
      });
    });

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

    if (closeBtn) {
      closeBtn.addEventListener('click', close);
    }

    document.addEventListener('keydown', function (event) {
      if (event.key === 'Escape' && overlay.classList.contains('is-open')) {
        close();
      }
    });
  }

  function initContentExpand() {
    document.querySelectorAll('.entry-content[data-nav]').forEach(function (content) {
      if (content.dataset.aksrtExpandBound === '1') return;
      content.dataset.aksrtExpandBound = '1';

      // Only expand when server enabled maxheight (data-maxheight > 0).
      var customMax = parseInt(content.getAttribute('data-maxheight') || content.dataset.maxheight || '0', 10);
      if (!(customMax > 0)) return;
      var limit = customMax;
      if (content.scrollHeight <= limit) {
        content.classList.remove('limit-height');
        content.style.maxHeight = '';
        return;
      }

      content.classList.add('limit-height');
      content.style.maxHeight = limit + 'px';

      var existingBtn = content.nextElementSibling;
      if (existingBtn && existingBtn.classList && existingBtn.classList.contains('content-expand-btn')) {
        return;
      }

      var button = document.createElement('button');
      button.type = 'button';
      button.className = 'content-expand-btn';
      button.innerHTML = '<i class="fas fa-chevron-down" aria-hidden="true"></i> <span>展开阅读全文</span>';
      content.parentNode.insertBefore(button, content.nextSibling);

      button.addEventListener('click', function () {
        var expanded = content.classList.contains('is-expanded');
        if (expanded) {
          content.classList.remove('is-expanded');
          content.style.maxHeight = limit + 'px';
          button.classList.remove('is-expanded');
          button.querySelector('span').textContent = '展开阅读全文';
          content.scrollIntoView({
            behavior: 'smooth',
            block: 'start'
          });
          return;
        }

        content.classList.add('is-expanded');
        content.style.maxHeight = content.scrollHeight + 'px';
        button.classList.add('is-expanded');
        button.querySelector('span').textContent = '收起';
      });
    });
  }

  function initFlashQueryCleanup() {
    document.querySelectorAll('[data-aksrt-flash-query]').forEach(function (node) {
      var queryKey = node.getAttribute('data-aksrt-flash-query');
      if (!queryKey || !window.history || typeof window.history.replaceState !== 'function') return;

      var url = new URL(window.location.href);
      if (!url.searchParams.has(queryKey)) return;

      url.searchParams.delete(queryKey);
      window.history.replaceState({}, '', url.toString());
    });
  }

  function init() {
    initPostToc();
    initLightbox();
    initContentExpand();
    initFlashQueryCleanup();
  }

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