/**
 * browse.js — 法规浏览页 + 原文详情
 */
const BrowsePage = {
  state: { view: 'list', laws: [], total: 0, page: 1, pageSize: 50, category: '', province: '', keyword: '', loading: false, error: null, currentLaw: null },

  render() {
    if (this.state.view === 'detail' && this.state.currentLaw) {
      return this.renderDetail();
    }
    return this.renderList();
  },

  renderList() {
    return `
      <div class="p-4 md:p-6 max-w-5xl mx-auto">
        <h2 class="text-lg font-semibold mb-4">法规浏览</h2>

        <!-- 筛选栏 -->
        <div class="bg-white rounded-xl border border-gray-200 p-4 mb-4">
          <div class="flex gap-3 flex-wrap">
            <input id="browse-keyword" type="text" placeholder="法规名关键词..."
              class="flex-1 min-w-[200px] rounded-lg border border-gray-200 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-gray-900"
              value="${this.state.keyword}" onkeydown="if(event.key==='Enter')BrowsePage.doBrowse(1)">
            <select id="browse-category" class="rounded-lg border border-gray-200 px-3 py-2 text-sm" onchange="BrowsePage.onFilterChange()">
              <option value="">全部类别</option>
              <option value="法律">法律</option>
              <option value="行政法规">行政法规</option>
              <option value="监察法规">监察法规</option>
              <option value="司法解释">司法解释</option>
              <option value="地方性法规">地方性法规</option>
            </select>
            <select id="browse-province" class="rounded-lg border border-gray-200 px-3 py-2 text-sm" onchange="BrowsePage.onFilterChange()">
              <option value="">全部省份</option>
            </select>
            <button onclick="BrowsePage.doBrowse(1)" class="px-4 py-2 bg-gray-900 text-white text-sm rounded-lg hover:bg-gray-800">查询</button>
          </div>
        </div>

        <!-- 列表 -->
        <div id="browse-list">
          ${UI.emptyState('输入条件浏览法规', '可按类别、省份、关键词筛选')}
        </div>
      </div>`;
  },

  renderDetail() {
    const law = this.state.currentLaw;
    const badge = UI.categoryBadge(law.category);
    const province = law.province ? `<span class="text-xs text-gray-400">[${law.province}${law.city ? ' · ' + law.city : ''}]</span>` : '';
    const date = law.publish_date ? `<span class="text-xs text-gray-400">发布: ${law.publish_date}</span>` : '';

    // 目录树(章节 + 条号)
    const toc = (law.clauses || []).map(c => {
      const chapter = c.chapter ? c.chapter : '';
      return `<div class="text-xs py-1 px-2 hover:bg-gray-50 cursor-pointer rounded" onclick="BrowsePage.scrollToClause(${c.clause_id})">
        <span class="text-gray-400">${chapter}</span>
        <span class="text-gray-700">${c.clause_no || ''}</span>
      </div>`;
    }).join('');

    return `
      <div class="p-4 md:p-6 max-w-5xl mx-auto">
        <button onclick="BrowsePage.backToList()" class="mb-4 text-sm text-gray-500 hover:text-gray-900 flex items-center gap-1">
          <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="m15 18-6-6 6-6"/></svg>
          返回列表
        </button>

        <div class="flex items-center gap-2 mb-2 flex-wrap">
          <h2 class="text-lg font-semibold">${law.name}</h2>
          ${badge}
          ${province}
          ${date}
        </div>

        <div class="flex gap-4">
          <!-- 目录树 -->
          ${toc ? `<aside class="w-48 shrink-0 hidden md:block">
            <div class="bg-white rounded-xl border border-gray-200 p-3 sticky top-4 max-h-[calc(100vh-120px)] overflow-y-auto scroll-thin">
              <div class="text-xs font-semibold text-gray-500 mb-2">目录</div>
              ${toc}
            </div>
          </aside>` : ''}

          <!-- 原文 -->
          <div class="flex-1 bg-white rounded-xl border border-gray-200 p-6">
            <div class="md-content text-sm leading-relaxed">${marked.parse(law.content)}</div>
          </div>
        </div>
      </div>`;
  },

  init() {
    this.loadProvinces();
    if (this.state.category) document.getElementById('browse-category').value = this.state.category;
    if (this.state.province) document.getElementById('browse-province').value = this.state.province;
    if (this.state.laws.length === 0) this.doBrowse(1);
  },

  provinces: ['北京市','天津市','河北省','山西省','内蒙古自治区','辽宁省','吉林省','黑龙江省','上海市','江苏省','浙江省','安徽省','福建省','江西省','山东省','河南省','湖北省','湖南省','广东省','广西壮族自治区','海南省','重庆市','四川省','贵州省','云南省','西藏自治区','陕西省','甘肃省','青海省','宁夏回族自治区','新疆维吾尔自治区'],

  loadProvinces() {
    const sel = document.getElementById('browse-province');
    if (!sel) return;
    this.provinces.forEach(p => {
      const opt = document.createElement('option');
      opt.value = p; opt.textContent = p;
      sel.appendChild(opt);
    });
  },

  onFilterChange() {
    this.state.category = document.getElementById('browse-category').value;
    this.state.province = document.getElementById('browse-province').value;
  },

  async doBrowse(page) {
    const kwInput = document.getElementById('browse-keyword');
    if (kwInput) this.state.keyword = kwInput.value.trim();
    this.state.page = page || 1;
    this.state.view = 'list';
    this.state.loading = true;
    this.state.error = null;
    this.renderListState();

    try {
      const params = { page: this.state.page, page_size: this.state.pageSize };
      if (this.state.category) params.category = this.state.category;
      if (this.state.province) params.province = this.state.province;
      if (this.state.keyword) params.keyword = this.state.keyword;

      const resp = await API.listLaws(params);
      this.state.laws = resp.data.results || [];
      this.state.total = resp.data.total || 0;
      this.state.loading = false;
      this.renderListState();
    } catch (e) {
      this.state.loading = false;
      this.state.error = e.message;
      this.renderListState();
    }
  },

  renderListState() {
    const el = document.getElementById('browse-list');
    if (!el) return;

    if (this.state.loading) {
      el.innerHTML = `<div class="flex items-center justify-center py-16 gap-3 text-gray-400">${UI.spinner(20)}<span class="text-sm">加载中...</span></div>`;
      return;
    }

    if (this.state.error) {
      el.innerHTML = UI.errorState(this.state.error, 'BrowsePage.doBrowse()');
      return;
    }

    if (!this.state.laws.length) {
      el.innerHTML = UI.emptyState('无法规', '试试调整筛选条件');
      return;
    }

    const rows = this.state.laws.map(l => `
      <div class="bg-white border border-gray-200 rounded-lg p-3 mb-2 hover:border-gray-300 transition cursor-pointer" onclick="BrowsePage.viewLaw(${l.law_id})">
        <div class="flex items-center gap-2 flex-wrap">
          <span class="text-sm font-medium text-gray-900">${l.name}</span>
          ${UI.categoryBadge(l.category)}
          ${l.province ? `<span class="text-xs text-gray-400">[${l.province}${l.city ? ' · ' + l.city : ''}]</span>` : ''}
          ${l.publish_date ? `<span class="text-xs text-gray-400">${l.publish_date}</span>` : ''}
          <span class="text-xs text-gray-400 ml-auto">${l.clause_count} 条</span>
        </div>
      </div>`).join('');

    const pager = UI.pagination(this.state.page, this.state.pageSize, this.state.total, 'BrowsePage.doBrowse');
    el.innerHTML = `<div class="mb-3 text-sm text-gray-500">共 ${this.state.total} 篇法规</div>${rows}${pager}`;
  },

  async viewLaw(lawId) {
    this.state.view = 'detail';
    this.state.currentLaw = null;
    const content = document.getElementById('content');
    content.innerHTML = `<div class="flex items-center justify-center py-16 gap-3 text-gray-400">${UI.spinner(20)}<span class="text-sm">加载原文...</span></div>`;

    try {
      const resp = await API.getLaw(lawId);
      this.state.currentLaw = resp.data;
      content.innerHTML = this.renderDetail();
    } catch (e) {
      content.innerHTML = UI.errorState(e.message, `BrowsePage.viewLaw(${lawId})`);
    }
  },

  backToList() {
    this.state.view = 'list';
    this.state.currentLaw = null;
    const content = document.getElementById('content');
    content.innerHTML = this.renderList();
    this.init();
    this.renderListState();
  },

  scrollToClause(clauseId) {
    // 简单实现:滚动到条文内容(原文中条文已渲染)
    // TODO: 更精确的定位需要解析原文中的条号
    const el = document.getElementById(`clause-${clauseId}`);
    if (el) {
      el.scrollIntoView({ behavior: 'smooth', block: 'center' });
      el.classList.add('clause-highlight');
      setTimeout(() => el.classList.remove('clause-highlight'), 2000);
    }
  },
};