/* 简航 SimpleNav —— 前台交互：搜索引擎切换 + 联想下拉 + 合集标签页 */
(function () {
  'use strict';
  var cfg = window.SIMPLENAV || {};

  /* ---------- 搜索引擎切换 ---------- */
  var tabs = document.querySelectorAll('#engine-tabs .s-engine');
  var form = document.getElementById('search-form');
  var input = document.getElementById('search-text');

  function activateEngine(el) {
    tabs.forEach(function (t) { t.classList.remove('active'); });
    el.classList.add('active');
    var search = el.getAttribute('data-search');
    var param = el.getAttribute('data-param');
    var slug = el.getAttribute('data-slug');
    var ph = el.getAttribute('data-placeholder') || '搜索';
    if (form) { form.setAttribute('action', search); }
    if (input) { input.setAttribute('name', param); input.setAttribute('placeholder', ph); }
    form.setAttribute('data-slug', slug);
    hideWord();
  }
  tabs.forEach(function (el) {
    el.addEventListener('click', function () { activateEngine(el); input && input.focus(); });
  });

  /* ---------- 联想下拉 ---------- */
  var word = document.getElementById('word');
  var timer = null;
  var lastQ = '';

  function hideWord() { if (word) { word.innerHTML = ''; word.style.display = 'none'; } }
  function showWord(items) {
    if (!word) return;
    if (!items || !items.length) { hideWord(); return; }
    word.innerHTML = items.map(function (t) {
      var d = document.createElement('div');
      d.textContent = t;
      return '<li>' + d.innerHTML + '</li>';
    }).join('');
    word.style.display = 'block';
  }

  if (input) {
    input.addEventListener('input', function () {
      var q = input.value.trim();
      if (q === '') { hideWord(); return; }
      if (q === lastQ) return;
      lastQ = q;
      clearTimeout(timer);
      timer = setTimeout(function () {
        var slug = form ? (form.getAttribute('data-slug') || '') : '';
        fetch(cfg.suggest + '?slug=' + encodeURIComponent(slug) + '&q=' + encodeURIComponent(q))
          .then(function (r) { return r.json(); })
          .then(function (data) { showWord(data && data.items); })
          .catch(function () { hideWord(); });
      }, 180);
    });

    input.addEventListener('keydown', function (e) {
      if (e.key === 'Enter' && word && word.style.display === 'block' && word.firstChild) {
        // 默认走第一条建议
        input.value = word.firstChild.textContent;
        hideWord();
      }
    });
  }

  document.addEventListener('click', function (e) {
    if (word && !word.contains(e.target) && e.target !== input) { hideWord(); }
    var li = e.target.closest ? e.target.closest('#word li') : null;
    if (li) {
      input.value = li.textContent;
      hideWord();
      if (form) { form.submit(); }
    }
  });

  /* ---------- 合集标签页 ---------- */
  var collTabs = document.querySelectorAll('#coll-tabs .tab');
  collTabs.forEach(function (tab) {
    tab.addEventListener('click', function () {
      collTabs.forEach(function (t) { t.classList.remove('active'); });
      tab.classList.add('active');
      document.querySelectorAll('.tab-panel').forEach(function (p) { p.classList.remove('active'); });
      var panel = document.getElementById(tab.getAttribute('data-target'));
      if (panel) { panel.classList.add('active'); }
    });
  });
})();