Lengths, areas and volumes as text

/** Millimetres as text. `ftin`: feet-inches to 1/16" (fractions reduced); `mm`: whole millimetres (0.1 below 10). */
export function fmtLen(mm, units = 'ftin', { unit = false } = {}) {
  if (!Number.isFinite(mm)) return '';
  if (units !== 'ftin' && FACTOR[units]) {
    const value = mm / FACTOR[units];
    const digits = units === 'mm' ? (Math.abs(value) < 10 ? 1 : 0) : units === 'in' ? 3 : 2;
    const rounded = Number(value.toFixed(digits));
    return (Object.is(rounded, -0) ? 0 : rounded) + (unit ? ' ' + (units === 'ftdec' ? 'ft' : units) : '');
  }
  const neg = mm < 0;
  let sixteenths = Math.round(Math.abs(mm) / INCH * 16);
  const ft = Math.floor(sixteenths / 192);
  sixteenths -= ft * 192;
  const inch = Math.floor(sixteenths / 16);
  let frac = sixteenths - inch * 16, den = 16;
  while (frac && frac % 2 === 0) { frac /= 2; den /= 2; }
  const whole = ft || inch || !frac;   // 10'-0 1/4", but 1/4" alone
  const inText = (whole ? String(inch) : '') + (frac ? (whole ? ' ' : '') + frac + '/' + den : '') + '"';
  const s = ft ? ft + "'-" + inText : inText;
  return (neg && sixteenths + ft ? '-' : '') + s;
}

export const INCH = 25.4;
export const FACTOR = { mm: 1, cm: 10, m: 1000, in: INCH, ftdec: 12 * INCH };

/** The number of fmtCoord alone (the unit goes beside it): decimal feet for feet-inches. */
export function coordNumber(mm, units = 'ftin') {
  if (!Number.isFinite(mm)) return '';
  const u = units === 'ftin' ? 'ftdec' : units;
  const digits = { mm: 1, cm: 2, m: 3, in: 2, ftdec: 3 }[u] ?? 3;
  const rounded = Number(((mm) / (FACTOR[u] || 1)).toFixed(digits));
  return (Object.is(rounded, -0) ? 0 : rounded).toLocaleString('en-US', { minimumFractionDigits: digits, maximumFractionDigits: digits, useGrouping: false });
}

/** A small length (a scale in length per pixel, a tolerance) with three significant figures and its unit: feet-inches shows decimal inches. */
export function fmtFine(mm, units = 'ftin') {
  if (!Number.isFinite(mm)) return '';
  const u = units === 'ftin' ? 'in' : units;
  const v = Number((mm / (FACTOR[u] || 1)).toPrecision(3));
  return (Object.is(v, -0) ? 0 : v) + ' ' + unitMark(u);
}

const AREA = { mm: ['mm²', 1, 0], cm: ['cm²', 100, 1], m: ['m²', 1e6, 2], in: ['in²', INCH * INCH, 1], ftdec: ['ft²', (12 * INCH) ** 2, 1] };
const VOL = { mm: ['mm³', 1, 0], cm: ['cm³', 1000, 0], m: ['m³', 1e9, 2], in: ['in³', INCH ** 3, 0], ftdec: ['ft³', (12 * INCH) ** 3, 1] };
const base = (units) => (units === 'ftin' ? 'ftdec' : AREA[units] ? units : 'mm');
const group = (v, digits) => v.toLocaleString('en-US', { minimumFractionDigits: digits, maximumFractionDigits: digits, useGrouping: Math.abs(v) >= 10000 });
const fmtPow = (table, v, units, withUnit) => {
  if (!Number.isFinite(v)) return '';
  const [mark, f, digits] = table[base(units)];
  const r = Number((v / f).toFixed(digits));
  return group(Object.is(r, -0) ? 0 : r, digits) + (withUnit === false ? '' : ' ' + mark);
};

export const fmtM = (m, units = 'ftin') => lenMark(m * 1000, units);
export const fmtM2 = (m2, units = 'ftin', unit) => fmtAreaMm2(m2 * 1e6, units, unit);
export const fmtM3 = (m3, units = 'ftin', unit) => fmtVolMm3(m3 * 1e9, units, unit);

/**
 * A refusal's limits ("at least 10 mm thick", "up to 12 m") in the display unit. Only plain "N mm" / "N m" are rewritten
 * (never m² m³ m/s), and a message that already gives feet-inches or inches (3'-4", 4") is left as written.
 */
export function localizeLengths(text, units = 'ftin') {
  const s = String(text ?? '');
  if (/\d\s?['"]/.test(s)) return s;
  return s.replace(/(\d+(?:\.\d+)?) ?(mm|m)\b(?![²³\/])/g, (all, n, u) => lenMark(Number(n) * (u === 'm' ? 1000 : 1), units));
}

/**
 * A calculation's sentence in the pick: lengths ("4.2 m", "300 mm"), areas ("24 m²") and volumes ("60 m³") after a number.
 * A rate or density ("W/m²", "kg/m³", "m/s", "kN/m", "mm²/m") has no number straight before its unit and is left alone. A
 * sentence that already carries feet-inches marks is left as written.
 */
export function localizeQuantities(text, units = 'ftin') {
  const s = String(text ?? '');
  if (/\d\s?['"]/.test(s)) return s;
  return s.replace(/(-?\d+(?:\.\d+)?) ?(mm|m)(²|³)?(?![A-Za-z\/²³])/g, (all, n, u, pow) => {
    const v = Number(n);
    if (!pow) return lenMark(v * (u === 'm' ? 1000 : 1), units);
    if (u === 'mm') return all;   // mm² / mm³ are the calculation's own (bar areas), not a room's
    return pow === '²' ? fmtM2(v, units) : fmtM3(v, units);
  });
}

/** A paper size's dimensions in the pick (the paper's name, A3 or Letter, stays as it is). Feet-inches → decimal inches. */
export function fmtPaper(wMm, hMm, units = 'ftin') {
  if (!Number.isFinite(wMm) || !Number.isFinite(hMm)) return '';
  const u = units === 'ftin' ? 'in' : units;
  const d = { mm: 1, cm: 1, m: 3, in: 2, ftdec: 3 }[u] ?? 1;
  const n = (v) => String(Number((v / FACTOR[u]).toFixed(d)));
  return n(wMm) + ' × ' + n(hMm) + ' ' + unitMark(u);
}