'use strict';

// 通用多选下拉（字段 / 店铺 / 学校共用）：按钮 + 搜索 + 复选列表 + 全选/清空
// 用法：window.createMultiSelect(rootEl, { label, items:[{key,label,hint}], selected, allowEmpty, emptyLabel, onChange })
(function () {
  function esc(value) {
    const div = document.createElement('div');
    div.textContent = String(value == null ? '' : value);
    return div.innerHTML;
  }

  function createMultiSelect(root, { label, items, selected, allowEmpty, emptyLabel, onChange }) {
    const sel = new Set(selected || []);
    let keyword = '';
    root.innerHTML = `<button type="button" class="ops-multi-btn" aria-expanded="false"></button>
      <div class="ops-multi-menu" hidden>
        <input type="text" class="ops-multi-search" placeholder="搜索${esc(label)}">
        <div class="ops-multi-list"></div>
        <div class="ops-multi-foot"><button type="button" data-all>全选</button><button type="button" data-none>清空</button></div>
      </div>`;
    const btn = root.querySelector('.ops-multi-btn');
    const menu = root.querySelector('.ops-multi-menu');
    const list = root.querySelector('.ops-multi-list');
    const search = root.querySelector('.ops-multi-search');

    function refreshButton() {
      let text;
      if (!sel.size) text = `${label} <em>${emptyLabel || '全部'}</em>`;
      else if (sel.size === 1) {
        const one = items.find((i) => sel.has(i.key));
        text = `${label} <em>${esc(one ? one.label : '1')}</em>`;
      } else text = `${label} <em>${sel.size} 项</em>`;
      btn.innerHTML = text + '<span class="ops-multi-caret">▾</span>';
    }

    function renderList() {
      const kw = keyword.trim().toLowerCase();
      const filtered = items.filter((i) => !kw
        || String(i.label).toLowerCase().includes(kw)
        || String(i.hint || '').toLowerCase().includes(kw));
      list.innerHTML = filtered.length
        ? filtered.map((i) => `<label class="ops-multi-item">
            <input type="checkbox" value="${esc(i.key)}"${sel.has(i.key) ? ' checked' : ''}>
            <span>${esc(i.label)}</span>${i.hint ? `<em>${esc(i.hint)}</em>` : ''}
          </label>`).join('')
        : '<div class="ops-multi-empty">没有匹配项</div>';
      list.querySelectorAll('input[type="checkbox"]').forEach((input) => {
        input.addEventListener('change', () => {
          if (input.checked) sel.add(input.value);
          else sel.delete(input.value);
          if (!allowEmpty && !sel.size) {
            input.checked = true;
            sel.add(input.value);
            return;
          }
          refreshButton();
          onChange([...sel]);
        });
      });
    }

    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      const willOpen = menu.hidden;
      document.querySelectorAll('.ops-multi-menu').forEach((m) => { m.hidden = true; });
      menu.hidden = !willOpen;
      btn.setAttribute('aria-expanded', String(willOpen));
      if (willOpen) { renderList(); search.focus(); }
    });
    search.addEventListener('input', () => { keyword = search.value; renderList(); });
    root.querySelector('[data-all]').addEventListener('click', () => {
      items.forEach((i) => sel.add(i.key));
      refreshButton();
      renderList();
      onChange([...sel]);
    });
    root.querySelector('[data-none]').addEventListener('click', () => {
      sel.clear();
      if (!allowEmpty && items[0]) sel.add(items[0].key);
      refreshButton();
      renderList();
      onChange([...sel]);
    });
    refreshButton();
    return { refresh: () => { refreshButton(); renderList(); } };
  }

  let dismissBound = false;
  function bindMultiSelectDismiss() {
    if (dismissBound) return;
    dismissBound = true;
    document.addEventListener('click', (event) => {
      document.querySelectorAll('.ops-multi').forEach((root) => {
        const menu = root.querySelector('.ops-multi-menu');
        if (!menu || menu.hidden) return;
        if (root.contains(event.target)) return;
        menu.hidden = true;
        const btn = root.querySelector('.ops-multi-btn');
        if (btn) btn.setAttribute('aria-expanded', 'false');
      });
    });
    document.addEventListener('keydown', (event) => {
      if (event.key !== 'Escape') return;
      document.querySelectorAll('.ops-multi-menu').forEach((menu) => { menu.hidden = true; });
    });
  }

  window.createMultiSelect = createMultiSelect;
  window.bindMultiSelectDismiss = bindMultiSelectDismiss;
})();