/* 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); form.setAttribute('data-slug', slug); }
    if (input) { input.setAttribute('name', param); input.setAttribute('placeholder', ph); }
    hideWord();
    // 已经输了字就顺手换一份建议（auto 模式下各引擎来源不同）
    if (input && input.value.trim() !== '') { askSuggest(); }
  }
  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 = null;
  var seq = 0;          // 请求序号：防止先发的慢响应覆盖后发的快响应
  var items = [];       // 当前展示的建议词
  var active = -1;      // 选中项下标（键盘 ↓/↑ 与鼠标划过共用）；-1 = 没选中

  function hideWord() {
    if (word) { word.innerHTML = ''; word.style.display = 'none'; }
    items = [];
    active = -1;
  }

  function showWord(list) {
    if (!word) return;
    items = (list || []).slice();
    active = -1;                 // 换了新建议就取消选中：此时回车应当用输入框原文
    if (!items.length) { hideWord(); return; }
    word.innerHTML = items.map(function (t) {
      var d = document.createElement('li');
      d.textContent = t;
      return d.outerHTML;
    }).join('');
    word.style.display = 'block';
  }

  /** 把 .active 标到当前选中项上（键盘与鼠标共用这一个状态） */
  function paintWord() {
    if (!word) return;
    Array.prototype.forEach.call(word.children, function (li, i) {
      if (i === active) { li.classList.add('active'); } else { li.classList.remove('active'); }
    });
  }

  function askSuggest() {
    if (!input) return;
    var q = input.value.trim();
    if (q === '') { lastQ = null; hideWord(); return; }
    if (q === lastQ) { return; }
    lastQ = q;
    var mine = ++seq;
    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) { if (mine === seq) { showWord(data && data.items); } })
      .catch(function () { if (mine === seq) { hideWord(); } });
  }

  if (input) {
    input.addEventListener('input', function () {
      clearTimeout(timer);
      active = -1;                 // 一开始打字就取消选中：之后回车应当用输入框原文
      paintWord();
      timer = setTimeout(askSuggest, 180);
    });

    input.addEventListener('keydown', function (e) {
      var open = !!word && word.style.display === 'block' && items.length > 0;

      // ↓ / ↑：在下拉里移动选中项（只动高亮，不动输入框；回车时才落到输入框）
      if (e.key === 'ArrowDown' || e.key === 'ArrowUp') {
        if (!open) { return; }
        e.preventDefault();         // 别让光标跳到文本首尾、也别让页面跟着滚
        if (active < 0) {
          active = e.key === 'ArrowDown' ? 0 : items.length - 1;
        } else {
          active = (active + (e.key === 'ArrowDown' ? 1 : -1) + items.length) % items.length;
        }
        paintWord();
        return;
      }

      if (e.key === 'Escape') { hideWord(); return; }

      if (e.key === 'Enter') {
        // 只有**用 ↓/↑ 选中**了某条建议，回车才按建议词搜索。
        // 没选中就一律用输入框里的原文 —— 老实现是「回车就套用第一条建议」，
        // 会把用户自己输入、而建议里没有的词悄悄换掉。
        if (open && active >= 0) {
          input.value = items[active];
          hideWord();
          e.preventDefault();
          if (form) { form.submit(); }
        }
        // active < 0：不拦截，交给浏览器默认的表单提交（即用输入框原文搜）
        return;
      }
    });
  }

  /* 鼠标划过某条建议 → 同步高亮（与 ↓/↑ 共用 active，回车即可确认） */
  document.addEventListener('mouseover', function (e) {
    if (!word || !e.target.closest) { return; }
    var hovered = e.target.closest('#word li');
    if (!hovered) { return; }
    Array.prototype.forEach.call(word.children, function (li, i) {
      if (li === hovered) { active = i; }
    });
    paintWord();
  });

  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) {
      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');
        t.setAttribute('aria-selected', 'false');
      });
      tab.classList.add('active');
      tab.setAttribute('aria-selected', 'true');
      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'); }
    });
  });

  /* ---------- 图标加载失败 → 退回首字母块（与 PHP 端配色一致） ---------- */
  var PALETTE = ['#2F6BF7', '#5B8DEF', '#0EA5E9', '#10B981', '#F59E0B', '#EF4444', '#8B5CF6', '#EC4899', '#14B8A6', '#F97316'];
  function colorOf(s) {
    var h = 0;
    for (var i = 0; i < s.length; i++) { h = (h * 31 + s.charCodeAt(i)) | 0; }
    return PALETTE[Math.abs(h) % PALETTE.length];
  }
  document.querySelectorAll('.mylist img.icon').forEach(function (img) {
    img.addEventListener('error', function () {
      var a = img.closest('a');
      if (!a) { img.style.visibility = 'hidden'; return; }
      var nameEl = a.querySelector('.name');
      var label = (nameEl ? nameEl.textContent : '?').trim() || '?';
      var span = document.createElement('span');
      span.className = 'ico-letter';
      span.style.background = colorOf(label);
      span.textContent = label.charAt(0);
      img.parentNode.replaceChild(span, img);
    }, { once: true });
  });
})();