IFC 4.3 infrastructure quantities and files

function unitScales(g) {
  // SI per one file unit for each measure: the unit assignment's SI prefix or conversion factor; the defaults are the SI units
  const out = { length: g.lengthUnit, area: 1, volume: 1, mass: 1 };
  const f = g.f;
  const proj = f.ofType('IFCPROJECT', true)[0];
  const ua = proj !== undefined ? ref(g.a(proj, 'UnitsInContext')) : (f.ofType('IFCUNITASSIGNMENT')[0] ?? null);
  if (ua === null || ua === undefined) return out;
  for (const u of refs(g.a(ua, 'Units'))) {
    const kind = enm(g.a(u, 'UnitType'));
    const key = kind === 'AREAUNIT' ? 'area' : kind === 'VOLUMEUNIT' ? 'volume' : kind === 'MASSUNIT' ? 'mass' : null;
    if (!key) continue;
    const t = f.type(u);
    if (t === 'IFCSIUNIT') {
      const p = enm(g.a(u, 'Prefix'));
      out[key] = p ? PREFIX[p] ?? 1 : 1;
      if (key === 'mass' && String(enm(g.a(u, 'Name'))) === 'GRAM') out.mass *= 1e-3;
    } else {
      const v = g.unitFactor(u, 'METRE');
      if (v) out[key] = v;
    }
  }
  return out;
}

const quantitiesOf = (id) => {
  const q = {};
  for (const rel of psetsOf.get(id) || []) {
    const def = ref(g.a(rel, 'RelatingPropertyDefinition'));
    if (def === null || file.type(def) !== 'IFCELEMENTQUANTITY') continue;
    const set = str(g.a(def, 'Name')) || 'Quantities';
    for (const qid of refs(g.a(def, 'Quantities'))) {
      const t = file.type(qid), k = KIND_OF[t];
      if (!k) continue;
      const v = num(g.a(qid, k[1]));
      if (v === null || !Number.isFinite(v)) continue;
      const si = k[0] === 'length' ? v * un.length : k[0] === 'area' ? v * un.area : k[0] === 'volume' ? v * un.volume : k[0] === 'mass' ? v * un.mass : v;
      q[set + '.' + (str(g.a(qid, 'Name')) || k[0])] = { kind: k[0], value: si };
    }
  }
  return q;
};

/** Length of an alignment curve in file units (sum of its curve segments' lengths), or null. */
function segmentLength(g, curve) {
  const f = g.f;
  const t = f.type(curve);
  if (t === 'IFCCOMPOSITECURVE' || t === 'IFCGRADIENTCURVE' || t === 'IFCSEGMENTEDREFERENCECURVE') {
    let s = 0, any = false;
    for (const seg of refs(g.a(curve, 'Segments'))) {
      if (f.type(seg) !== 'IFCCURVESEGMENT') return null;
      const l = num(g.a(seg, 'SegmentLength'));
      if (l !== null) { s += Math.abs(l); any = true; }
    }
    return any ? s : null;
  }
  return null;
}

const ROUND = (v) => Number(Number(v).toPrecision(12));

/** Totals per class and predefined type (SI: m, m², m³; a quantity is summed over the elements that have it, `counted` says how many). */
export function summary(r) {
  const rows = new Map();
  for (const e of r.elements) {
    const key = e.cls + '|' + (e.predefined || '');
    let row = rows.get(key);
    if (!row) rows.set(key, (row = { group: e.group, cls: e.cls, predefined: e.predefined || '', count: 0, length: 0, area: 0, volume: 0, counted: { length: 0, area: 0, volume: 0 } }));
    row.count++;
    const pick = (kind, names) => {
      for (const n of names) for (const [k, q] of Object.entries(e.quantities)) if (q.kind === kind && k.endsWith('.' + n)) return q.value;
      return null;
    };
    for (const [kind, names] of [['length', LENGTH_NAMES], ['area', AREA_NAMES], ['volume', VOLUME_NAMES]]) {
      const v = pick(kind, names);
      if (v !== null) { row[kind] += v; row.counted[kind]++; }
    }
  }
  return [...rows.values()].map((x) => ({ ...x, length: ROUND(x.length), area: ROUND(x.area), volume: ROUND(x.volume) })).sort((a, b) => a.group.localeCompare(b.group) || a.cls.localeCompare(b.cls) || a.predefined.localeCompare(b.predefined));
}

const R = (v, d = 9) => { const s = Number(v).toFixed(d).replace(/0+$/, ''); return /\.$/.test(s) ? s + '0' : s.includes('.') ? s : s + '.0'; };

const dx = pts[i][0] - pts[i - 1][0], dy = pts[i][1] - pts[i - 1][1], len = Math.hypot(dx, dy);
if (!(len > 0)) throw new Error('Two points of an alignment coincide.');
const line = w.ent('IfcLine', { Pnt: w.pt([0, 0]), Dir: w.ent('IfcVector', { Orientation: w.dir([1, 0]), Magnitude: '1.' }) });
segs.push(w.ent('IfcCurveSegment', { Transition: i === pts.length - 1 ? '.DISCONTINUOUS.' : '.CONTSAMEGRADIENTSAMECURVATURE.',
  Placement: w.ent('IfcAxis2Placement2D', { Location: w.pt([pts[i - 1][0], pts[i - 1][1]]), RefDirection: w.dir([dx / len, dy / len]) }),
  SegmentStart: 'IFCLENGTHMEASURE(0.)', SegmentLength: 'IFCLENGTHMEASURE(' + R(len) + ')', ParentCurve: line }));
at += len;

function profileArea(p) {
  if (!p) return 0;
  if (p.r) return Math.PI * p.r * p.r;
  if (p.poly) { let s = 0; for (let i = 0; i < p.poly.length; i++) { const a = p.poly[i], b = p.poly[(i + 1) % p.poly.length]; s += a[0] * b[1] - b[0] * a[1]; } return Math.abs(s) / 2; }
  return (p.w || 0) * (p.d || 0);
}

const q = { Length: Math.max(...dims), Width: Math.min(...dims), Height: h, GrossFootprintArea: area, GrossVolume: area * h, ...(el.qto || {}) };
const qs = Object.entries(q).filter(([, v]) => Number.isFinite(v)).map(([k, v]) => {
  const area_ = /Area$/.test(k), vol = /Volume$/.test(k);
  return w.ent(area_ ? 'IfcQuantityArea' : vol ? 'IfcQuantityVolume' : 'IfcQuantityLength', { Name: S(k), [area_ ? 'AreaValue' : vol ? 'VolumeValue' : 'LengthValue']: R(v) });
});