/*!
 * NY 问卷考试系统数据平台 - 随机抽取页逻辑
 *
 * 功能：来源切换 / 班级组别筛选 / 分组均衡抽取(5:5) / 排除已抽中 /
 *       排除名单管理 / 历史记录(重置不丢失) / 白名单下载(登陆账号优先)
 */
(function () {
  'use strict';

  const $  = s => document.querySelector(s);
  const $$ = s => Array.prototype.slice.call(document.querySelectorAll(s));

  function esc(s) {
    return String(s == null ? '' : s).replace(/[&<>"']/g, c =>
      ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c]));
  }
  const sleep = ms => new Promise(r => setTimeout(r, ms));

  const LS_RESULT   = 'ny_draw_result';   // 当前抽取结果（刷新后仍可下载）
  const LS_HISTORY  = 'ny_draw_history';  // 累计抽中学号（「重置结果」清零）
  const LS_EXCLUDED = 'ny_draw_excluded'; // 手动排除的学号
  const LS_LOG      = 'ny_draw_log';      // 历史批次（重置不清，上限 50 条）
  const LS_SETTINGS = 'ny_draw_settings'; // 来源 / 项目 / 班级 / 组别 / 人数 / 开关

  const LOG_MAX = 50;

  const state = {
    roster:   [],
    projects: [],
    answers:  [],
    source:   'roster',
    picked:   [],
    history:  new Set(),   // 累计抽中（重置结果时清零）
    excluded: new Set(),   // 手动排除
    log:      [],          // 历史批次，新的在前
    customRatios: {},      // 自定义比例：{ 组名: 权重 }
    drawing:  false,
    all:       false,      // 「全部」模式：人数始终跟随当前候选池（手工改输入框即解除）
  };

  /* ---------------- 接口 ---------------- */
  async function api(action, params) {
    const q = new URLSearchParams(Object.assign({ action: action }, params || {}));
    const r = await fetch('api.php?' + q.toString(), { credentials: 'same-origin' });
    let j;
    try {
      j = await r.json();
    } catch (e) {
      throw new Error('接口返回异常（HTTP ' + r.status + '）');
    }
    if (r.status === 401 || (j && j.ok === false && /未登录/.test(j.msg || ''))) {
      location.href = 'login.php';
      throw new Error('未登录');
    }
    if (!j || !j.ok) {
      throw new Error((j && j.msg) || '请求失败');
    }
    return j.data;
  }

  /* ---------------- Toast 顶部飘窗通知（与 app.js 一致） ---------------- */
  const TOAST_DURATION = 3500;
  const TOAST_LIMIT = 5;
  function showToast(msg, type) {
    if (msg === '' || msg == null) return;
    const el = document.getElementById('toastContainer') || (function () {
      const c = document.createElement('div');
      c.id = 'toastContainer';
      c.style.cssText = 'position:fixed;top:16px;left:50%;transform:translateX(-50%);z-index:9999;display:flex;flex-direction:column;gap:8px;pointer-events:none;max-width:calc(100vw - 32px);width:560px';
      document.body.appendChild(c);
      return c;
    })();
    while (el.children.length >= TOAST_LIMIT) el.firstChild.remove();
    const t = document.createElement('div');
    const cls = type === 'error' ? 'toast-error' : (type === 'warn' ? 'toast-warn' : (type === 'info' ? 'toast-ok' : 'toast'));
    t.className = 'toast ' + cls;
    t.innerHTML = '<span>' + esc(msg).replace(/\n/g, '<br>') + '</span>';
    t.style.cssText = 'pointer-events:auto;padding:10px 16px;border-radius:10px;font-size:13px;line-height:1.55;box-shadow:0 8px 30px rgba(15,23,42,.18);animation:toastIn .25s ease;white-space:pre-wrap;word-break:break-word';
    el.appendChild(t);
    t.addEventListener('click', () => { t.style.animation = 'toastOut .2s ease forwards'; setTimeout(() => t.remove(), 200); });
    setTimeout(() => { if (t.parentNode) { t.style.animation = 'toastOut .2s ease forwards'; setTimeout(() => t.remove(), 200); } }, TOAST_DURATION);
  }
  /** 兼容旧 showAlert 调用 → 走 toast（draw.js 内部已有 esc，此处直接复用） */
  function showAlert(msg, type) {
    if (msg === '' || msg == null) return;
    const t = type === 'info' ? 'ok' : (type === 'error' ? 'error' : (type === 'warn' ? 'warn' : ''));
    showToast(msg, t);
  }

  /* ================= 抽取核心（纯函数，供测试） ================= */

  /** Fisher-Yates 洗牌（返回新数组） */
  function shuffle(arr) {
    const a = arr.slice();
    for (let i = a.length - 1; i > 0; i--) {
      const j = Math.floor(Math.random() * (i + 1));
      const t = a[i]; a[i] = a[j]; a[j] = t;
    }
    return a;
  }

  /**
   * 名额分配：
   *   - sizes  各组容量
   *   - n      要抽的总人数
   *   - weights 各组权重（null=均分；数组=按权重，权重<=0 视为 0）
   *     算法：最大余额法（largest remainder）—— raw_i = n * w_i / Σw；floor 后把剩余名额
   *           按小数部分降序分给还没满的组。均分模式是 weights=null 的特例（每组权重 1），
   *           余数时按"组容量小者优先"补齐，保证每组都有代表。
   */
  function allocQuotas(sizes, n, weights) {
    const g = sizes.length;
    const quota = new Array(g).fill(0);
    if (g === 0 || n <= 0) return quota;
    const total = sizes.reduce((a, b) => a + b, 0);
    if (n >= total) return sizes.slice();   // 全量

    const base = new Array(g).fill(0);
    const frac = new Array(g).fill(0);

    if (Array.isArray(weights) && weights.length === g) {
      const w = weights.map(x => (Number(x) > 0 ? Number(x) : 0));
      const wsum = w.reduce((a, b) => a + b, 0);
      if (wsum > 0) {
        // 按权重分配：最大余额法
        for (let i = 0; i < g; i++) {
          const raw = n * w[i] / wsum;
          base[i] = Math.floor(raw);
          frac[i] = raw - base[i];
        }
      } else {
        // 全 0 权重 → 退化为均分
        const b = Math.floor(n / g);
        for (let i = 0; i < g; i++) base[i] = b;
        const rem = n - b * g;
        const bySmall = sizes.map((s, i) => i)
          .sort((a, b2) => sizes[a] - sizes[b2] || a - b2);
        for (let k = 0; k < rem; k++) base[bySmall[k % g]]++;
      }
    } else {
      // 名额均分：每组 n/g，余数小组优先（保证每组都有代表）
      const b = Math.floor(n / g);
      for (let i = 0; i < g; i++) base[i] = b;
      const rem = n - b * g;
      const bySmall = sizes.map((s, i) => i)
        .sort((a, b2) => sizes[a] - sizes[b2] || a - b2);
      for (let k = 0; k < rem; k++) base[bySmall[k % g]]++;
    }

    // 余数补齐：frac 大的优先；同 frac 时剩余容量大的优先
    let rest = n - base.reduce((a, b) => a + b, 0);
    if (rest > 0) {
      const order = sizes.map((s, i) => i).sort((a, b) =>
        (frac[b] - frac[a]) || ((sizes[b] - base[b]) - (sizes[a] - base[a])) || (a - b));
      for (let k = 0; rest > 0 && k < g; k++) {
        const i = order[k % g];
        if (base[i] < sizes[i]) { base[i]++; rest--; }
      }
      // 若仍有余数（组容量限制），继续按剩余容量大者分配
      while (rest > 0) {
        let progress = false;
        const byRoom = sizes.map((s, i) => i)
          .sort((a, b) => ((sizes[b] - base[b]) - (sizes[a] - base[a])) || (a - b));
        for (const i of byRoom) {
          if (rest <= 0) break;
          if (base[i] < sizes[i]) { base[i]++; rest--; progress = true; }
        }
        if (!progress) break;
      }
    }

    // 超容量退回（极端比例时兜底）
    let overflow = 0;
    for (let i = 0; i < g; i++) {
      if (base[i] > sizes[i]) { overflow += base[i] - sizes[i]; base[i] = sizes[i]; }
    }
    while (overflow > 0) {
      let progress = false;
      const byRoom = sizes.map((s, i) => i)
        .sort((a, b) => ((sizes[b] - base[b]) - (sizes[a] - base[a])) || (a - b));
      for (const i of byRoom) {
        if (overflow <= 0) break;
        if (base[i] < sizes[i]) { base[i]++; overflow--; progress = true; }
      }
      if (!progress) break;
    }
    return base;
  }

  /**
   * 选择均衡维度：组别(>=2 个非空组)优先，其次班级，否则不均衡
   */
  function balanceKeyOf(pool) {
    const grps = new Set(pool.map(m => String(m.grp || '').trim()).filter(Boolean));
    if (grps.size >= 2) return 'grp';
    const clss = new Set(pool.map(m => String(m.cls || '').trim()).filter(Boolean));
    if (clss.size >= 2) return 'cls';
    return '';
  }

  /**
   * 分组均衡抽取：返回 { picked, detail, sizes, weights }
   *  weights 数组为各组实际权重（默认加权时=各组人数）
   *  detail 例：["A 6人", "B 4人"]，用于提示与历史记录
   */
  function pickBalanced(pool, n, key, weights) {
    const label = key === 'grp' ? '（未分组）' : '（未分班）';
    const groups = new Map();
    pool.forEach(m => {
      const k = String(m[key] || '').trim() || label;
      if (!groups.has(k)) groups.set(k, []);
      groups.get(k).push(m);
    });
    const gk = Array.from(groups.keys())
      .sort((a, b) => String(a).localeCompare(String(b), 'zh', { numeric: true }));
    const sizes = gk.map(k => groups.get(k).length);
    const w = (Array.isArray(weights) && weights.length === gk.length)
      ? weights
      : null;
    const quotas = allocQuotas(sizes, n, w);
    const picked = [];
    const detail = [];
    gk.forEach((k, i) => {
      const part = shuffle(groups.get(k)).slice(0, quotas[i]);
      picked.push(...part);
      if (quotas[i] > 0) detail.push(k + ' ' + quotas[i] + '人');
    });
    return { picked, detail, sizes, weights: w || sizes.slice() };
  }

  // 测试钩子（node 端 eval 后通过 window.__nyDrawTest 调用）
  if (typeof window !== 'undefined') {
    window.__nyDrawTest = { shuffle, allocQuotas, balanceKeyOf, pickBalanced };
  }

  /* ================= 数据加载 ================= */
  async function loadRoster() {
    const d = await api('roster');
    state.roster = (d && d.students ? d.students : []).map(s => ({
      sid:   String(s.sid || ''),
      name:  String(s.name || ''),
      cls:   String(s.cls || ''),
      grp:   String(s.grp || ''),
      login: String(s.login || ''),
    }));
    const badge = $('#rosterBadge');
    if (badge) badge.textContent = state.roster.length;
  }

  async function loadProjects() {
    try {
      state.projects = (await api('projects')) || [];
    } catch (e) {
      state.projects = [];
    }
    const sel = $('#projectSel');
    if (!sel) return;

    const isFolder = p => (p.mode || '').toLowerCase().indexOf('folder') >= 0;
    const parentIds = new Set();
    state.projects.forEach(p => {
      const pid = String(p.parent_id || '0');
      if (pid !== '0' && pid !== '') parentIds.add(pid);
    });
    const folderSet = new Set();
    state.projects.forEach(p => { if (isFolder(p) || parentIds.has(p.id)) folderSet.add(p.id); });

    const nameOf = id => {
      const f = state.projects.filter(p => p.id === id)[0];
      return f ? String(f.name || '') : '';
    };

    const items = state.projects.filter(p => !folderSet.has(p.id));
    if (!items.length) {
      sel.innerHTML = '<option value="">（无可用的问卷 / 考试）</option>';
      return;
    }
    sel.innerHTML = items.map(p => {
      const pid = String(p.parent_id || '0');
      const fn = (pid !== '0' && pid !== '' && folderSet.has(pid)) ? nameOf(pid) : '';
      const label = fn ? fn + ' / ' + p.name : p.name;
      return '<option value="' + esc(p.id) + '">' + esc(label) + '</option>';
    }).join('');
  }

  async function loadAnswers(pid) {
    const d = await api('data', { projectId: pid });
    const loginOf = {};
    state.roster.forEach(s => { if (s.login) loginOf[s.sid] = s.login; });
    state.answers = ((d && d.rows) ? d.rows : []).map(r => ({
      sid:   String(r.sid || ''),
      name:  String(r.name || ''),
      cls:   String(r.cls || ''),
      grp:   String(r.grp || ''),
      login: String(loginOf[r.sid] || ''),
    }));
  }

  /* ================= 候选池 ================= */
  function baseList() {
    return state.source === 'project' ? state.answers : state.roster;
  }

  function currentPool() {
    let list = baseList().slice();
    const cls = $('#clsSel').value;
    const grp = $('#grpSel').value;
    if (cls) list = list.filter(x => (x.cls || '') === cls);
    if (grp) list = list.filter(x => (x.grp || '') === grp);
    list = list.filter(x => !state.excluded.has(String(x.sid)));
    if ($('#excludePicked').checked) {
      list = list.filter(x => !state.history.has(String(x.sid)));
    }
    return list;
  }

  function uniqSorted(arr) {
    const seen = {};
    const out = [];
    arr.forEach(v => { if (v && !seen[v]) { seen[v] = 1; out.push(v); } });
    out.sort((a, b) => String(a).localeCompare(String(b), 'zh', { numeric: true }));
    return out;
  }

  function fillSel(sel, values, allLabel) {
    if (!sel) return;
    const cur = sel.value;
    sel.innerHTML = '<option value="">' + esc(allLabel) + '</option>' +
      values.map(v => '<option value="' + esc(v) + '">' + esc(v) + '</option>').join('');
    sel.value = (values.indexOf(cur) >= 0) ? cur : '';
  }

  function populateFilters() {
    const list = baseList();
    fillSel($('#clsSel'), uniqSorted(list.map(x => x.cls || '')), '全部班级');
    fillSel($('#grpSel'), uniqSorted(list.map(x => x.grp || '')), '全部组别');
  }

  function rangeText() {
    const cls = $('#clsSel').value, grp = $('#grpSel').value;
    const parts = [];
    if (cls) parts.push(cls);
    if (grp) parts.push(grp + '组');
    return parts.length ? parts.join(' / ') : '全部';
  }

  function renderStats() {
    const pool = currentPool();
    // 「全部」模式：候选池变化（改筛选 / 改来源 / 改排除）时人数跟着变
    if (state.all) {
      const ni = $('#numInput');
      if (ni) ni.value = String(Math.max(1, pool.length));
    }
    $('#dPool').textContent = pool.length;
    $('#dPicked').textContent = state.picked.length;
    $('#dHistory').textContent = state.history.size;
    $('#dExcluded').textContent = state.excluded.size;
    $('#dSource').textContent = state.source === 'project' ? '已提交人员' : '学号名单';
    $('#drawHint').textContent = '候选 ' + pool.length + ' 人（' + rangeText() + '）';
    const lb = $('#logBadge');
    if (lb) lb.textContent = state.log.length;
    const ec = $('#exclCount');
    if (ec) ec.textContent = '已排除 ' + state.excluded.size + ' 人';
  }

  /**
   * 计算当前候选池的分组信息：{ key, gk[], sizes[] }
   *  key = 'grp' | 'cls' | ''
   *  gk   按字典序排序后的组名
   *  sizes 每组成员数
   */
  function poolGroups(pool) {
    const key = balanceKeyOf(pool);
    if (!key) return { key: '', gk: [], sizes: [] };
    const label = key === 'grp' ? '（未分组）' : '（未分班）';
    const groups = new Map();
    pool.forEach(m => {
      const k = String(m[key] || '').trim() || label;
      if (!groups.has(k)) groups.set(k, 0);
      groups.set(k, groups.get(k) + 1);
    });
    const gk = Array.from(groups.keys())
      .sort((a, b) => String(a).localeCompare(String(b), 'zh', { numeric: true }));
    return { key, gk, sizes: gk.map(k => groups.get(k)) };
  }

  /** 把对象 {gk:weight} 读成与当前池分组顺序一致的数组，缺组视为 0 */
  function readCustomWeights(gk) {
    const src = state.customRatios || {};
    return gk.map(k => {
      const v = parseFloat(src[k]);
      return Number.isFinite(v) && v > 0 ? v : 0;
    });
  }

  /* ================= 抽取 ================= */
  async function doDraw() {
    if (state.drawing) return;
    const pool = currentPool();
    if (!pool.length) {
      showAlert('当前筛选下没有可抽取的人员（可关闭「排除已抽中」、调整班级 / 组别或排除名单）');
      return;
    }
    // 「全部」模式：人数始终等于当前候选池，切换筛选后不会沿用旧数字
    let n = state.all ? pool.length : parseInt($('#numInput').value, 10);
    if (!n || n < 1) n = 1;
    let capped = false;
    if (n > pool.length) { n = pool.length; capped = true; }

    state.drawing = true;
    const stage = $('#drawStage');
    const btn = $('#btnDraw');
    btn.disabled = true;
    showAlert('');

    // 滚动动画：先快速闪动若干次
    stage.className = 'draw-stage rolling';
    const rounds = Math.min(24, 10 + n);
    for (let i = 0; i < rounds; i++) {
      const p = pool[Math.floor(Math.random() * pool.length)];
      stage.textContent = p.name || p.sid || '—';
      await sleep(40 + i * 7);
    }

    // 真正抽取：均衡（按模式分组） 或整池随机
    let picked, detail = [];
    const mode = $('#balanceMode').value;
    if (mode === 'off') {
      picked = shuffle(pool).slice(0, n);
    } else {
      const g = poolGroups(pool);
      if (g.key) {
        let weights = null;
        if (mode === 'weight') weights = g.sizes.slice();           // 默认按组人数加权
        else if (mode === 'custom') weights = readCustomWeights(g.gk);
        // mode === 'even' 走 allocQuotas(null) → 均分
        const res = pickBalanced(pool, n, g.key, weights);
        picked = res.picked; detail = res.detail;
      } else {
        picked = shuffle(pool).slice(0, n);
      }
    }

    state.picked = picked;
    picked.forEach(m => state.history.add(String(m.sid)));

    stage.className = 'draw-stage done';
    if (n === 1 && picked.length) {
      // 只抽 1 人时把学号 / 班级 / 组别一起显示出来，教师不用再去表里找
      const p0 = picked[0];
      const meta = [p0.sid, p0.cls, p0.grp ? (p0.grp + '组') : ''].filter(Boolean).join(' · ');
      stage.innerHTML = '<div>' + esc(p0.name || p0.sid) +
        (meta ? '<div class="draw-stage-sub">' + esc(meta) + '</div>' : '') + '</div>';
    } else {
      stage.textContent = '🎉 已抽取 ' + n + ' 人';
    }

    renderResult();
    renderStats();
    pushLog(picked, detail, mode);
    saveState();

    state.drawing = false;
    btn.disabled = false;
    const tail = detail.length ? '（' + detail.join(' / ') + '）' : '';
    if (capped) {
      showAlert('候选池只有 ' + pool.length + ' 人，已按 ' + n + ' 人抽取（可关闭「排除已抽中」或调整筛选扩大候选）', 'warn');
    } else {
      showAlert('已抽取 ' + n + ' 人' + tail + (n > 1 ? '，可点击右上角按钮下载白名单' : ''), 'info');
    }
  }

  function renderResult() {
    const tb = $('#drawBody');
    if (!state.picked.length) {
      tb.innerHTML = '<tr><td colspan="6" class="empty">尚未抽取</td></tr>';
      return;
    }
    // 抽取结果表不显示登陆账号（仅导出白名单才含该列），故只渲染 5 个数据列 + 操作列
    tb.innerHTML = state.picked.map((m, i) => {
      return '<tr>' +
        '<td class="num">' + (i + 1) + '</td>' +
        '<td class="sid">' + esc(m.sid) + '</td>' +
        '<td class="name">' + esc(m.name) + '</td>' +
        '<td>' + esc(m.cls || '') + '</td>' +
        '<td>' + esc(m.grp || '') + '</td>' +
        '<td class="act"><button class="btn sm danger" data-drop="' + i + '" title="移出结果并加入排除名单">排除</button></td>' +
        '</tr>';
    }).join('');
  }

  /* ================= 历史记录 ================= */
  function pushLog(picked, detail, mode) {
    const modeTxt = ({ weight: '按人数加权', even: '均分', custom: '自定义比例', off: '不分组' })[mode] || '';
    state.log.unshift({
      ts: new Date().toLocaleString('zh-CN', { hour12: false }),
      source: state.source === 'project' ? '已提交人员' : '学号名单',
      range: rangeText(),
      balance: (modeTxt ? modeTxt + '：' : '') + (detail || []).join(' / '),
      count: picked.length,
      members: picked.map(m => ({
        sid: m.sid, name: m.name, cls: m.cls || '', grp: m.grp || '', login: m.login || '',
      })),
    });
    if (state.log.length > LOG_MAX) state.log.length = LOG_MAX;
    saveLog();
  }

  function renderLog() {
    const box = $('#logList');
    if (!box) return;
    if (!state.log.length) {
      box.innerHTML = '<p class="empty" style="text-align:center;padding:30px 0">暂无历史记录</p>';
      return;
    }
    box.innerHTML = state.log.map((e, i) => {
      const rows = (e.members || []).map((m, j) =>
        '<tr>' +
        '<td class="num">' + (j + 1) + '</td>' +
        '<td class="sid">' + esc(m.sid) + '</td>' +
        '<td>' + esc(m.name) + '</td>' +
        '<td>' + esc(m.cls || '') + '</td>' +
        '<td>' + esc(m.grp || '') + '</td>' +
        '</tr>').join('');
      const meta = [e.ts, e.source, '范围：' + e.range, e.count + ' 人'];
      if (e.balance) meta.push('均衡：' + e.balance);
      return '<div class="log-item">' +
        '<div class="log-head">' +
        '<label class="log-summary"><span>' + esc(meta.join(' · ')) + '</span></label>' +
        '<span class="log-actions">' +
        '<button class="btn sm" data-log-restore="' + i + '">恢复结果</button>' +
        '<button class="btn sm danger" data-log-del="' + i + '">删除</button>' +
        '</span></div>' +
        '<details class="log-detail"><summary>查看成员（' + e.count + '）</summary>' +
        '<div class="table-scroll short"><table class="grid compact">' +
        '<thead><tr><th style="width:8%;text-align:right">序号</th><th style="width:28%">学号</th><th style="width:26%">姓名</th><th style="width:24%">班级</th><th style="width:14%">组别</th></tr></thead>' +
        '<tbody>' + rows + '</tbody></table></div>' +
        '</details>' +
        '</div>';
    }).join('');
  }

  /* ================= 排除管理 ================= */
  let exclQuery = '';

  function renderExcl() {
    const tb = $('#exclBody');
    if (!tb) return;
    let list = baseList().slice();
    if (exclQuery) {
      const q = exclQuery.toLowerCase();
      list = list.filter(x =>
        String(x.sid).toLowerCase().includes(q) ||
        String(x.name).toLowerCase().includes(q) ||
        String(x.cls || '').toLowerCase().includes(q));
    }
    if (!list.length) {
      tb.innerHTML = '<tr><td colspan="5" class="empty">' +
        (baseList().length ? '没有匹配的人员' : '当前来源暂无人员') + '</td></tr>';
      return;
    }
    tb.innerHTML = list.map(m => {
      const on = state.excluded.has(String(m.sid)) ? ' checked' : '';
      return '<tr>' +
        '<td style="text-align:center"><input type="checkbox" data-excl="' + esc(m.sid) + '"' + on + '></td>' +
        '<td class="sid">' + esc(m.sid) + '</td>' +
        '<td>' + esc(m.name) + '</td>' +
        '<td>' + esc(m.cls || '') + '</td>' +
        '<td>' + esc(m.grp || '') + '</td>' +
        '</tr>';
    }).join('');
  }

  /* ================= 下载（登陆账号优先） ================= */
  function dlMembers() {
    return state.picked.map(m => ({
      name: m.name,
      sid: m.sid,
      login: m.login || '',
    }));
  }

  async function download(type) {
    if (!state.picked.length) {
      showAlert('请先点击「🎲 开始抽取」');
      return;
    }
    const fname = type === 'import' ? '白名单导入模板.xlsx' : '白名单列表.xlsx';
    try {
      const r = await fetch('api.php?action=draw_export', {
        method: 'POST',
        credentials: 'same-origin',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ type: type, members: dlMembers() }),
      });
      if (!r.ok) throw new Error('HTTP ' + r.status);
      const blob = await r.blob();
      const url = URL.createObjectURL(blob);
      const a = document.createElement('a');
      a.href = url;
      a.download = fname;
      document.body.appendChild(a);
      a.click();
      a.remove();
      setTimeout(() => URL.revokeObjectURL(url), 3000);
      showAlert('已下载 ' + fname, 'info');
    } catch (e) {
      showAlert('导出失败：' + e.message);
    }
  }

  /* ================= 本地缓存 ================= */
  function saveState() {
    try {
      localStorage.setItem(LS_RESULT, JSON.stringify(state.picked));
      localStorage.setItem(LS_HISTORY, JSON.stringify(Array.from(state.history)));
    } catch (e) { /* 忽略 */ }
  }

  function saveLog() {
    try {
      localStorage.setItem(LS_LOG, JSON.stringify(state.log));
      const lb = $('#logBadge');
      if (lb) lb.textContent = state.log.length;
    } catch (e) { /* 忽略 */ }
  }

  function saveExcluded() {
    try {
      localStorage.setItem(LS_EXCLUDED, JSON.stringify(Array.from(state.excluded)));
    } catch (e) { /* 忽略 */ }
  }

  function saveSettings() {
    try {
      // 收集自定义比例输入
      const cr = {};
      $$('#ratioBox input[data-gk]').forEach(inp => {
        const k = inp.dataset.gk;
        const v = parseFloat(inp.value);
        if (k && Number.isFinite(v) && v > 0) cr[k] = v;
      });
      state.customRatios = cr;
      localStorage.setItem(LS_SETTINGS, JSON.stringify({
        source: state.source,
        projectId: $('#projectSel').value,
        cls: $('#clsSel').value,
        grp: $('#grpSel').value,
        num: $('#numInput').value,
        all: state.all,
        exclude: $('#excludePicked').checked,
        mode: $('#balanceMode').value,
        customRatios: cr,
      }));
    } catch (e) { /* 忽略 */ }
  }

  function loadState() {
    const arr = (k) => {
      try {
        const v = JSON.parse(localStorage.getItem(k) || '[]');
        return Array.isArray(v) ? v : [];
      } catch (e) { return []; }
    };
    state.picked = arr(LS_RESULT);
    state.history = new Set(arr(LS_HISTORY).map(String));
    state.excluded = new Set(arr(LS_EXCLUDED).map(String));
    state.log = arr(LS_LOG);
  }

  function loadSettings() {
    try {
      const s = JSON.parse(localStorage.getItem(LS_SETTINGS) || '{}');
      if (s && typeof s === 'object') return s;
    } catch (e) { /* 忽略 */ }
    return {};
  }

  /* ================= 事件 ================= */
  function bind() {
    $('#sourceSel').addEventListener('change', async () => {
      state.source = $('#sourceSel').value;
      $('#projectField').classList.toggle('hidden', state.source !== 'project');
      state.answers = [];
      state.picked = [];
      renderResult();
      if (state.source === 'project') {
        if (!state.projects.length) await loadProjects();
        const pid = $('#projectSel').value;
        if (pid) {
          try { await loadAnswers(pid); } catch (e) { showAlert(e.message); }
        }
      }
      populateFilters();
      renderStats();
      renderRatioBox();
      if ($('#exclModal').classList.contains('open')) renderExcl();
      saveSettings();
    });

    $('#projectSel').addEventListener('change', async () => {
      const pid = $('#projectSel').value;
      if (!pid) { state.answers = []; populateFilters(); renderStats(); renderRatioBox(); return; }
      showAlert('正在拉取已提交人员…', 'info');
      try {
        await loadAnswers(pid);
        showAlert('');
      } catch (e) {
        showAlert(e.message);
      }
      populateFilters();
      renderStats();
      renderRatioBox();
      if ($('#exclModal').classList.contains('open')) renderExcl();
      saveSettings();
    });

    ['#clsSel', '#grpSel'].forEach(id => {
      $(id).addEventListener('change', () => {
        renderStats(); renderRatioBox(); saveSettings();
      });
    });
    $('#numInput').addEventListener('change', saveSettings);
    // 手工改人数即解除「全部」模式
    $('#numInput').addEventListener('input', () => { state.all = false; });
    $('#excludePicked').addEventListener('change', () => { renderStats(); saveSettings(); });
    $('#balanceMode').addEventListener('change', () => {
      renderRatioBox();
      saveSettings();
    });
    // 班级/组别/来源切换会改变候选池 → 比例输入框也要重画
    ['#sourceSel', '#projectSel', '#clsSel', '#grpSel'].forEach(id => {
      const el = $(id);
      if (el) el.addEventListener('change', () => {
        // 延迟一帧，等 populateFilters 填好再算
        setTimeout(renderRatioBox, 0);
      });
    });

    $$('[data-num]').forEach(b => {
      b.addEventListener('click', () => {
        const v = b.dataset.num;
        if (v === 'all') {
          state.all = true;
          $('#numInput').value = String(Math.max(1, currentPool().length));
        } else {
          state.all = false;
          $('#numInput').value = v;
        }
        saveSettings();
      });
    });

    $('#btnDraw').addEventListener('click', doDraw);

    // 重置结果：清空本次结果 + 累计已抽取（历史记录保留）
    $('#btnReset').addEventListener('click', () => {
      if (state.picked.length || state.history.size) {
        if (!confirm('确定重置？将清空本次结果与累计已抽取的 ' + state.history.size + ' 人（历史记录仍保留）。')) return;
      }
      state.picked = [];
      state.history = new Set();
      renderResult();
      renderStats();
      saveState();
      const stage = $('#drawStage');
      stage.className = 'draw-stage';
      stage.textContent = '点击「🎲 开始抽取」';
      showAlert('已重置结果与累计已抽取（历史记录仍保留）', 'info');
    });

    // 复制名单：两列「姓名 / 登陆账号」，制表符分隔，便于直接粘贴到 Excel / 微信
    $('#btnCopy').addEventListener('click', async () => {
      if (!state.picked.length) {
        showAlert('请先点击「🎲 开始抽取」再复制');
        return;
      }
      const lines = state.picked.map(m =>
        (m.name || '') + '\t' + (m.login || m.sid || ''));
      const text = lines.join('\n');
      let ok = false;
      try {
        if (navigator.clipboard && navigator.clipboard.writeText) {
          await navigator.clipboard.writeText(text);
          ok = true;
        }
      } catch (e) { /* 降级到 textarea */ }
      if (!ok) {
        try {
          const ta = document.createElement('textarea');
          ta.value = text;
          ta.style.position = 'fixed';
          ta.style.opacity = '0';
          document.body.appendChild(ta);
          ta.select();
          ok = document.execCommand('copy');
          ta.remove();
        } catch (e) { ok = false; }
      }
      showAlert(ok ? ('已复制 ' + state.picked.length + ' 人的姓名 / 登陆账号到剪贴板') : '复制失败，请手动选择结果复制', ok ? 'info' : '');
    });

    // 清空历史（顶栏）
    $('#btnClearLog').addEventListener('click', () => {
      if (!state.log.length) return showAlert('暂无历史记录');
      if (!confirm('确定清空全部 ' + state.log.length + ' 条历史记录？此操作不可恢复。')) return;
      state.log = [];
      saveLog();
      renderLog();
      renderStats();
      showAlert('已清空历史记录', 'info');
    });

    $('#btnDlImport').addEventListener('click', () => download('import'));
    $('#btnDlList').addEventListener('click', () => download('list'));

    /* --- 结果行内：排除并移除 --- */
    $('#drawBody').addEventListener('click', e => {
      const btn = e.target.closest('[data-drop]');
      if (!btn) return;
      const i = parseInt(btn.dataset.drop, 10);
      if (isNaN(i) || !state.picked[i]) return;
      const m = state.picked[i];
      state.excluded.add(String(m.sid));
      state.picked.splice(i, 1);
      saveExcluded();
      saveState();
      renderResult();
      renderStats();
      showAlert('已将「' + (m.name || m.sid) + '」加入排除名单，可点「🚫 排除管理」撤销', 'info');
    });

    /* --- 排除管理弹窗 --- */
    $('#btnExclude').addEventListener('click', () => {
      exclQuery = '';
      $('#exclSearch').value = '';
      renderExcl();
      renderStats();
      $('#exclModal').classList.add('open');
    });
    $('#exclSearch').addEventListener('input', () => {
      exclQuery = $('#exclSearch').value.trim().toLowerCase();
      renderExcl();
    });
    $('#exclBody').addEventListener('change', e => {
      const cb = e.target.closest('[data-excl]');
      if (!cb) return;
      if (cb.checked) state.excluded.add(String(cb.dataset.excl));
      else state.excluded.delete(String(cb.dataset.excl));
      saveExcluded();
      renderStats();
    });
    $('#btnClearExcl').addEventListener('click', () => {
      if (!state.excluded.size) return;
      state.excluded = new Set();
      saveExcluded();
      renderExcl();
      renderStats();
    });

    /* --- 历史记录弹窗 --- */
    $('#btnLog').addEventListener('click', () => {
      renderLog();
      $('#logModal').classList.add('open');
    });
    $('#logList').addEventListener('click', e => {
      const rst = e.target.closest('[data-log-restore]');
      const del = e.target.closest('[data-log-del]');
      if (rst) {
        const i = parseInt(rst.dataset.logRestore, 10);
        const entry = state.log[i];
        if (!entry) return;
        state.picked = (entry.members || []).map(m => ({
          sid: m.sid, name: m.name, cls: m.cls || '', grp: m.grp || '', login: m.login || '',
        }));
        renderResult();
        renderStats();
        saveState();
        showAlert('已恢复该批次（' + state.picked.length + ' 人），可直接下载白名单', 'info');
      }
      if (del) {
        const i = parseInt(del.dataset.logDel, 10);
        if (isNaN(i) || !state.log[i]) return;
        if (!confirm('删除这条历史记录？')) return;
        state.log.splice(i, 1);
        saveLog();
        renderLog();
        renderStats();
      }
    });

    /* --- 弹窗通用关闭：只关最上层那一个，避免连带关掉下层的弹窗 --- */
    document.addEventListener('click', e => {
      const isClose = (e.target.matches && e.target.matches('[data-close]')) ||
                      (e.target.classList && e.target.classList.contains('modal'));
      if (!isClose) return;
      const open = $$('.modal.open');
      if (!open.length) return;
      const top = open[open.length - 1];
      // 点遮罩时只响应最上层弹窗自身的遮罩
      if (e.target.classList && e.target.classList.contains('modal') && e.target !== top) return;
      top.classList.remove('open');
    });
    /* Esc 关闭最上层弹窗 */
    document.addEventListener('keydown', e => {
      if (e.key !== 'Escape' && e.key !== 'Esc') return;
      const open = $$('.modal.open');
      if (open.length) open[open.length - 1].classList.remove('open');
    });
  }

  /**
   * 渲染"自定义比例"输入框：按当前候选池的分组（组别/班级）列出，每个组一个数字输入框，
   * 默认按各组人数预填（即等价"按人数加权"），用户可改。
   */
  function renderRatioBox() {
    const box = $('#ratioBox');
    if (!box) return;
    const pool = currentPool();
    const g = poolGroups(pool);
    const mode = $('#balanceMode').value;
    const show = (mode === 'custom') && g.key;
    box.classList.toggle('hidden', !show);
    // 隐藏时必须清空：否则旧的 data-gk 输入框还会被 saveSettings 读走，
    // 下次切成自定义比例时会误用上一批分组的权重
    if (!show) { box.innerHTML = ''; return; }
    box.innerHTML =
      '<p class="hint" style="margin:0 0 6px">按上面分组的顺序填写权重，例：组A=3，组B=1。留空=不计该组。</p>' +
      g.gk.map((k, i) => {
        const def = (state.customRatios && Number.isFinite(parseFloat(state.customRatios[k])))
          ? state.customRatios[k]
          : g.sizes[i];
        return '<div class="row" style="display:flex;gap:8px;align-items:center;margin:4px 0">' +
          '<label style="min-width:120px">' + esc(k) + ' <small style="color:var(--text-3)">（' + g.sizes[i] + '人）</small></label>' +
          '<input type="number" min="0" step="0.1" data-gk="' + esc(k) + '" value="' + esc(def) + '" placeholder="' + g.sizes[i] + '" style="width:120px">' +
          '</div>';
      }).join('');
    // 改动即时保存
    box.querySelectorAll('input[data-gk]').forEach(inp => {
      inp.addEventListener('change', saveSettings);
    });
  }

  /* ---------------- 启动 ---------------- */
  document.addEventListener('DOMContentLoaded', async function () {
    loadState();
    const s = loadSettings();
    if (s.exclude === false) $('#excludePicked').checked = false;
    // 兼容旧版：s.balance === false → 不分组
    const mode = s.mode || (s.balance === false ? 'off' : 'weight');
    $('#balanceMode').value = mode;
    if (s.num) $('#numInput').value = s.num;
    state.all = !!s.all;
    if (s.source === 'project') {
      state.source = 'project';
      $('#sourceSel').value = 'project';
      $('#projectField').classList.remove('hidden');
    }
    if (s.customRatios && typeof s.customRatios === 'object') {
      state.customRatios = s.customRatios;
    }

    bind();
    renderResult();
    renderStats();
    // 第一次也要按当前池渲染自定义比例框
    renderRatioBox();

    try {
      await loadRoster();
    } catch (e) {
      showAlert('名单加载失败：' + e.message);
    }
    if (state.source === 'project') {
      await loadProjects();
      const pid = s.projectId || $('#projectSel').value;
      if (pid) {
        $('#projectSel').value = pid;
        try { await loadAnswers(pid); } catch (e) { /* 静默 */ }
      }
    }
    populateFilters();
    if (s.cls) $('#clsSel').value = s.cls;
    if (s.grp) $('#grpSel').value = s.grp;
    renderStats();
  });
})();