/**
 * AKSRT 文章导航页 — admin settings modal + HTML5 drag-sort (no SortableJS dependency).
 * TOC generation is handled by section-navs.js via [data-nav] + .posts-nav-box.
 *
 * @package AKSRT
 */
(function () {
  'use strict';

  function qs(sel, root) {
    if (root && root.nodeType === 1 && root.matches(sel)) return root;
    return (root || document).querySelector(sel);
  }

  function qsa(sel, root) {
    var nodes = Array.prototype.slice.call((root || document).querySelectorAll(sel));
    if (root && root.nodeType === 1 && root.matches(sel)) nodes.unshift(root);
    return nodes;
  }

  function ajaxUrl() {
    if (window.aksrtData && window.aksrtData.ajaxUrl) return window.aksrtData.ajaxUrl;
    if (window.ajaxurl) return window.ajaxurl;
    return '/wp-admin/admin-ajax.php';
  }

  function initModal(root) {
    var modal = qs('#post-navs-sz', root);
    if (!modal) return;

    if (modal.dataset.aksrtPostsNavModalBound === '1') return;
    modal.dataset.aksrtPostsNavModalBound = '1';

    function openModal(e) {
      if (e) e.preventDefault();
      modal.classList.add('is-open', 'show');
      modal.setAttribute('aria-hidden', 'false');
    }

    function closeModal(e) {
      if (e) e.preventDefault();
      modal.classList.remove('is-open', 'show');
      modal.setAttribute('aria-hidden', 'true');
    }

    qsa('[data-toggle="modal"][data-target="#post-navs-sz"], a[href="#post-navs-sz"]', root).forEach(function (el) {
      el.addEventListener('click', openModal);
    });
    // Title [设置] uses data-target.
    qsa('[data-target="#post-navs-sz"]', root).forEach(function (el) {
      el.addEventListener('click', openModal);
    });
    qsa('[data-dismiss="modal"]', modal).forEach(function (btn) {
      btn.addEventListener('click', closeModal);
    });
    modal.addEventListener('click', function (e) {
      if (e.target === modal) closeModal(e);
    });
    document.addEventListener('keydown', function (e) {
      if (e.key === 'Escape' && modal.classList.contains('is-open')) closeModal(e);
    });
  }

  function initDragSort(root) {
    var left = qs('#cat-sortable', root);
    var right = qs('#cat-sortable-ok', root);
    if (!left || !right) return;

    var dragEl = null;

    function onDragStart(e) {
      dragEl = e.currentTarget;
      dragEl.classList.add('is-dragging');
      try {
        e.dataTransfer.effectAllowed = 'move';
        e.dataTransfer.setData('text/plain', dragEl.getAttribute('data-id') || '');
      } catch (err) { /* IE */ }
    }

    function onDragEnd() {
      if (dragEl) dragEl.classList.remove('is-dragging');
      dragEl = null;
      qsa('.cat-group').forEach(function (g) {
        g.classList.remove('is-drop-target');
      });
    }

    function bindItem(el) {
      el.setAttribute('draggable', 'true');
      el.addEventListener('dragstart', onDragStart);
      el.addEventListener('dragend', onDragEnd);
    }

    qsa('.sortable-cat-item', left).forEach(bindItem);
    qsa('.sortable-cat-item', right).forEach(bindItem);

    [left, right].forEach(function (group) {
      group.addEventListener('dragover', function (e) {
        e.preventDefault();
        group.classList.add('is-drop-target');
        if (!dragEl) return;
        var after = getDragAfterElement(group, e.clientY);
        if (after == null) {
          group.appendChild(dragEl);
        } else {
          group.insertBefore(dragEl, after);
        }
      });
      group.addEventListener('dragleave', function () {
        group.classList.remove('is-drop-target');
      });
      group.addEventListener('drop', function (e) {
        e.preventDefault();
        group.classList.remove('is-drop-target');
      });
    });

    function getDragAfterElement(container, y) {
      var els = qsa('.sortable-cat-item:not(.is-dragging)', container);
      var closest = { offset: Number.NEGATIVE_INFINITY, element: null };
      els.forEach(function (child) {
        var box = child.getBoundingClientRect();
        var offset = y - box.top - box.height / 2;
        if (offset < 0 && offset > closest.offset) {
          closest = { offset: offset, element: child };
        }
      });
      return closest.element;
    }
  }

  function initSave(root) {
    var form = qs('#aksrt-posts-navs-settings', root);
    if (!form) return;

    form.addEventListener('submit', function (e) {
      e.preventDefault();
      var ids = [];
      qsa('#cat-sortable-ok .sortable-cat-item').forEach(function (item) {
        var id = item.getAttribute('data-id');
        if (id) ids.push(id);
      });
      if (!ids.length) {
        notyf('请选择需要显示的分类', 'danger');
        return;
      }

      var fd = new FormData(form);
      fd.set('action', 'aksrt_post_navs_settings');
      // PHP accepts array; append each.
      fd.delete('navs_show_cat_id');
      ids.forEach(function (id) {
        fd.append('navs_show_cat_id[]', id);
      });

      var btn = qs('button[type="submit"]', form);
      if (btn) btn.disabled = true;

      fetch(ajaxUrl(), {
        method: 'POST',
        body: fd,
        credentials: 'same-origin',
      })
        .then(function (r) { return r.json(); })
        .then(function (data) {
          if (!data || data.error) {
            notyf((data && data.msg) || '保存失败', 'danger');
            return;
          }
          notyf(data.msg || '保存成功', 'success');
          if (data.reload) {
            window.setTimeout(function () { window.location.reload(); }, 400);
          }
        })
        .catch(function () {
          notyf('网络错误', 'danger');
        })
        .finally(function () {
          if (btn) btn.disabled = false;
        });
    });
  }

  /**
   * Build simple TOC into .posts-nav-box if section-navs hasn't already.
   * Uses category h2 headings inside .posts-navs.
   */
  function initFallbackToc(scope) {
    var box = qs('.posts-nav-box', scope);
    var root = qs('.posts-navs[data-nav]', scope);
    if (!box || !root) return;
    if (box.querySelector('.posts-nav-lists, .aksrt-section-nav, .toc-list')) return;

    var headings = qsa('.title-theme h2, h2', root);
    if (headings.length < 1) return;

    var title = box.getAttribute('data-title') || '导航目录';
    var list = '';
    headings.forEach(function (h, i) {
      if (!h.id) h.id = 'navs-sec-' + i;
      list += '<li class="n-H2"><a class="text-ellipsis" href="#' + h.id + '">' + (h.textContent || '').trim() + '</a></li>';
    });

    box.innerHTML =
      '<div class="box-body notop"><div class="title-theme">' + title + '</div></div>' +
      '<div class="aksrt-panel"><div class="posts-nav-lists scroll-y mini-scrollbar list-unstyled">' +
      '<ul class="bl relative nav">' + list + '</ul></div></div>';

    qsa('a[href^="#"]', box).forEach(function (a) {
      a.addEventListener('click', function (e) {
        var id = a.getAttribute('href');
        var el = id ? document.getElementById(id.replace(/^#/, '')) : null;
        if (!el) return;
        e.preventDefault();
        var top = el.getBoundingClientRect().top + window.pageYOffset - 90;
        window.scrollTo({ top: top, behavior: 'smooth' });
      });
    });

    function highlight() {
      var y = window.pageYOffset + 120;
      var current = headings[0];
      headings.forEach(function (h) {
        if (h.offsetTop <= y) current = h;
      });
      qsa('li', box).forEach(function (li) {
        var a = li.querySelector('a');
        if (a && current && a.getAttribute('href') === '#' + current.id) {
          li.classList.add('active');
        } else {
          li.classList.remove('active');
        }
      });
    }
    window.addEventListener('scroll', highlight, { passive: true });
    highlight();
  }

  function init(root) {
    root = root || document;
    initModal(root);
    initDragSort(root);
    initSave(root);
    // Defer so section-navs.js can own TOC first.
    window.setTimeout(function () { initFallbackToc(root); }, 50);
  }

  window.AksrtFrontend.register('aksrt-posts-navs-page', init);
})();