/* 定级/撤级统一入口（修订⑦+⑧）：有上级边禁调级；有下级边可调但须高于最高下级（公司边不计入）；取消等级仍须无任何边 */
function tryLevelDrop(id, target) {
  const c = byId(id);
  if (!c) return;
  const newLv = target.kind === 'unrec' ? null : target.lv;
  if (newLv === c.level) return;
  const eff = effectiveEdges();
  const parentEdge = eff.find(e => e.child === id);
  const childEdges = eff.filter(e => e.parent === id && e.child !== COMPANY_ID);
  if (parentEdge) {
    toast('「' + c.name + '」有上级连线(' + cname(parentEdge.parent) + ')，请先取消上级连线后再调整等级', 'err');
    layoutGraph(); renderEdgesOnly(); return;
  }
  if (newLv == null) {
    if (childEdges.length) {
      toast('「' + c.name + '」存在连线，请先取消所有连线后再取消等级', 'err');
      layoutGraph(); renderEdgesOnly(); return;
    }
  } else if (childEdges.length) {
    const maxChild = Math.max.apply(null, childEdges.map(e => byId(e.child).level));
    const childNames = childEdges.filter(e => byId(e.child).level === maxChild).map(e => cname(e.child)).join('、');
    if (newLv <= maxChild) {
      toast('「' + c.name + '」最高下级为等级 ' + maxChild + '(' + childNames + ')，新等级须高于它', 'err');
      layoutGraph(); renderEdgesOnly(); return;
    }
  }
  const from = c.level == null ? '未设置' : c.level;
  c.level = newLv;
  delete G.cardPos[id];
  sanitizeManualEdges();
  layoutGraph();
  if (newLv == null) {
    addLog('数据', '「' + c.name + '」等级已取消(拖回未设置栏,原等级:' + from + ')');
    toast('已取消「' + c.name + '」的等级，移入未设置栏');
  } else {
    addLog('数据', '为「' + c.name + '」设定等级 ' + newLv + '(拖入等级格子,原等级:' + from + ')');
    toast('已为「' + c.name + '」设定等级 ' + newLv);
  }
  renderGraph(); renderGraphState();
}
/* 强制按等级归行：等级 10 在公司上方，等级 9..1 在公司下方（9 邻近公司），未定级固定右侧栏 */
function layoutGraph() {
  canvasInner.style.width = '2400px'; canvasInner.style.height = '1400px';
  renderLevelRows();
  const top = [], byLv = {}, unrec = [];
  G.contacts.forEach(c => {
    if (c.level == null) unrec.push(c);
    else if (c.level === 10) top.push(c);
    else (byLv[c.level] = byLv[c.level] || []).push(c);
  });
  const placeRow = (arr, y) => {
    const L = ROW_X + 100, R = ROW_X + ROW_W;
    const total = arr.length * CARD_W + Math.max(0, arr.length - 1) * 44;
    let x = Math.max(L, (L + R - total) / 2);
    arr.forEach(c => { G.cardPos[c.id] = { x: x, y: y }; x += CARD_W + 44; });
  };
  placeRow(top, LV10_Y);
  const lvs = Object.keys(byLv).map(Number).sort((a, b) => b - a);
  lvs.forEach(lv => placeRow(byLv[lv], lvRowY(lv)));
  const zone = $('unrecZone');
  zone.style.left = UNREC_X + 'px'; zone.style.top = UNREC_Y + 'px'; zone.style.width = UNREC_W + 'px'; zone.style.height = UNREC_H + 'px';
  unrec.forEach((c, i) => {
    G.cardPos[c.id] = { x: UNREC_X + 16 + (i % 2) * 200, y: UNREC_Y + 52 + Math.floor(i / 2) * 130 };
  });
}
/* 10 个等级格子横条 + 标签（公司行不画格子） */
function renderLevelRows() {
  canvasInner.querySelectorAll('.lv-row').forEach(el => el.remove());
  ROWS.forEach(r => {
    const el = document.createElement('div');
    el.className = 'lv-row'; el.dataset.lv = r.lv;
    el.style.left = ROW_X + 'px'; el.style.top = r.y + 'px'; el.style.width = ROW_W + 'px'; el.style.height = CARD_H + 'px';
    el.innerHTML = '<span class="row-label">等级 ' + r.lv + (r.lv === 10 ? ' · 顶层' : '') + '</span>';
    canvasInner.insertBefore(el, $('unrecZone'));
  });
}