MEP check messages: units and rounding

const f1 = (x) => (Number.isFinite(x) ? Math.round(x * 10) / 10 : x);
const f2 = (x) => (Number.isFinite(x) ? Math.round(x * 100) / 100 : x);

const gpm = (q) => f1(q / 0.003785411784 * 60), lps = (q) => f2(q * 1000), fl = (q) => (imperial ? gpm(q) + ' gpm' : lps(q) + ' L/s');
const vel = (v) => (imperial ? f1(v / 0.3048) + ' ft/s' : f2(v) + ' m/s');

/** analyzePipes() result → problems. `unit` { len: 'mm' | 'in', ... } is only for words; numbers are SI in the result. */
export function pipeProblems(res, { labelOf = (id) => id, guidOf = (id) => id, imperial = false } = {}) {
  const out = networkProblems('pipes', res, labelOf, guidOf);
  const gpm = (q) => f1(q / 0.003785411784 * 60), lps = (q) => f2(q * 1000), fl = (q) => (imperial ? gpm(q) + ' gpm' : lps(q) + ' L/s');
  const vel = (v) => (imperial ? f1(v / 0.3048) + ' ft/s' : f2(v) + ' m/s');
  for (const s of res.segs) {
    const about = [run(guidOf(s.run), labelOf(s.run))];
    if (s.status === 'small') out.push(P('pipes', 'pipe.small', 'warning', `${labelOf(s.run)} (${s.size}) carries ${fl(s.flow)} at ${vel(s.V)}; the velocity limit of ${vel(res.opts.vmax)}${res.opts.rateMax ? ' or the friction limit' : ''} needs ${s.need}.`,
      { part: s.run + '#' + s.id, about, vars: { run: s.run, flow: s.flow, need: s.need }, req: { op: '<=', value: f2(res.opts.vmax), unit: 'm/s' }, found: { value: f2(s.V), unit: 'm/s' }, fixes: [{ id: 'size', text: `Set the size to ${s.need}`, action: 'run-size', args: { run: s.run, size: s.need } }] }));
    else if (s.status === 'toobig') out.push(P('pipes', 'pipe.toobig', 'error', `${labelOf(s.run)} carries ${fl(s.flow)}: no size of its material keeps the velocity under ${vel(res.opts.vmax)}.`, { part: s.run + '#' + s.id, about, req: { op: '<=', value: f2(res.opts.vmax), unit: 'm/s' }, found: { value: f2(s.V), unit: 'm/s' } }));
    if (s.beyond) out.push(P('pipes', 'pipe.beyond', 'note', `${labelOf(s.run)}: ${f1(s.fu)} fixture units is beyond the last point of the demand curve; the curve's last slope was continued.`, { part: s.run + '#' + s.id, about }));
  }
  for (const l of res.loads) {
    if (l.reached === false) out.push(P('pipes', 'pipe.noroute', 'warning', `${l.label || l.key} is not joined to the source by pipe.`, { part: 'load:' + l.key, about: [] }));
    else if (l.short) out.push(P('pipes', 'pipe.pressure', 'warning', `${l.label || l.key}: ${f1(l.leftKpa)} kPa left at the fixture after ${f1(l.dpKpa)} kPa of loss; ${f1(res.opts.minKpa)} kPa is needed.`,
      { part: 'load:' + l.key, about: l.path.slice(0, 50).map((id) => run(guidOf(res.segs.find((s) => s.id === id)?.run), labelOf(res.segs.find((s) => s.id === id)?.run))), req: { op: '>=', value: f1(res.opts.minKpa), unit: 'kPa' }, found: { value: f1(l.leftKpa), unit: 'kPa' } }));
  }
  if (res.curve?.example) out.push(P('pipes', 'pipe.curve', 'note', 'The demand comes from the built-in example curve, not from a code table. Type the table of the code in force before relying on these sizes.', { part: 'curve' }));
  return out;
}

/** analyzeDucts() result → problems. */
export function ductProblems(res, { labelOf = (id) => id, guidOf = (id) => id, imperial = false } = {}) {
  const out = networkProblems('ducts', res, labelOf, guidOf);
  const vel = (v) => (imperial ? Math.round(v / 0.00508) + ' fpm' : f1(v) + ' m/s');
  for (const s of res.segs) {
    const about = [run(guidOf(s.run), labelOf(s.run))];
    if (s.status === 'small' || s.status === 'fast') out.push(P('ducts', 'duct.' + s.status, 'warning', `${labelOf(s.run)} (${s.size}) carries ${f1(s.flow * 1000)} L/s at ${vel(s.V)}; ${res.opts.method === 'velocity' ? 'the velocity limit' : 'the friction rate'} needs a round equivalent of at least ${Math.round(s.needDeMm)} mm.`,
      { part: s.run + '#' + s.id, about, req: res.opts.method === 'velocity' ? { op: '<=', value: res.opts.vmax, unit: 'm/s' } : { op: '<=', value: res.opts.rate, unit: 'Pa/m' }, found: res.opts.method === 'velocity' ? { value: f2(s.V), unit: 'm/s' } : { value: f2(s.rate), unit: 'Pa/m' } }));
    if (s.aspectHigh) out.push(P('ducts', 'duct.aspect', 'note', `${labelOf(s.run)} (${s.size}) is ${f1(s.aspect)}:1; ${res.opts.maxAspect}:1 is the usual limit.`, { part: s.run + '#' + s.id, about, req: { op: '<=', value: res.opts.maxAspect, unit: ':1' }, found: { value: f1(s.aspect), unit: ':1' } }));
  }
  for (const t of res.terminals) if (t.reached === false) out.push(P('ducts', 'duct.noroute', 'warning', `${t.label || t.key} is not joined to the source by duct.`, { part: 'term:' + t.key }));
  out.push(P('ducts', 'duct.defaults', 'note', 'Fitting losses use rounded default coefficients (elbows, tees, transitions), not a fitting database. Replace them with your project table for a final fan selection.', { part: 'defaults' }));
  return out;
}