/** Formatting helpers. All API timestamps are UTC ISO strings; we render UTC explicitly (orbital convention). */

const nf0 = new Intl.NumberFormat('en-US', { maximumFractionDigits: 0 });
const nf1 = new Intl.NumberFormat('en-US', { maximumFractionDigits: 1, minimumFractionDigits: 1 });
const nf2 = new Intl.NumberFormat('en-US', { maximumFractionDigits: 2, minimumFractionDigits: 2 });
const nfCompact = new Intl.NumberFormat('en-US', { notation: 'compact', maximumFractionDigits: 1 });

export function fmtInt(v: number | string | null | undefined): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? nf0.format(n) : '—';
}
export function fmt1(v: number | string | null | undefined): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? nf1.format(n) : '—';
}
export function fmt2(v: number | string | null | undefined): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? nf2.format(n) : '—';
}
export function fmtCompact(v: number | string | null | undefined): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? nfCompact.format(n) : '—';
}
export function fmtKm(v: number | string | null | undefined, digits = 0): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  if (!Number.isFinite(n)) return '—';
  return `${digits ? nf1.format(n) : nf0.format(n)} km`;
}
export function fmtDeg(v: number | string | null | undefined): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? `${nf2.format(n)}°` : '—';
}
export function fmtMinutes(v: number | string | null | undefined): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  if (!Number.isFinite(n)) return '—';
  if (n >= 1440) return `${nf1.format(n / 1440)} d`;
  if (n >= 120) return `${nf1.format(n / 60)} h`;
  return `${nf1.format(n)} min`;
}
export function fmtPct(v: number | string | null | undefined, digits = 1): string {
  if (v === null || v === undefined || v === '') return '—';
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? `${n.toFixed(digits)}%` : '—';
}

export function fmtDate(v: string | null | undefined): string {
  if (!v) return '—';
  const d = new Date(v.length === 10 ? `${v}T00:00:00Z` : v);
  if (Number.isNaN(d.getTime())) return '—';
  return d.toLocaleDateString('en-GB', { year: 'numeric', month: 'short', day: '2-digit', timeZone: 'UTC' });
}
export function fmtDateTime(v: string | null | undefined): string {
  if (!v) return '—';
  const d = new Date(v);
  if (Number.isNaN(d.getTime())) return '—';
  return `${d.toLocaleDateString('en-GB', { year: 'numeric', month: 'short', day: '2-digit', timeZone: 'UTC' })} ${d.toLocaleTimeString('en-GB', { hour: '2-digit', minute: '2-digit', timeZone: 'UTC' })} UTC`;
}
export function fmtAgo(v: string | null | undefined, now: number = Date.now()): string {
  if (!v) return 'unavailable';
  const t = new Date(v).getTime();
  if (Number.isNaN(t)) return 'unavailable';
  const s = Math.max(0, Math.round((now - t) / 1000));
  if (s < 60) return 'just now';
  const m = Math.round(s / 60);
  if (m < 60) return `${m} min ago`;
  const h = Math.round(m / 60);
  if (h < 48) return `${h} h ago`;
  const d = Math.round(h / 24);
  if (d < 60) return `${d} d ago`;
  return fmtDate(v);
}
export function fmtYear(v: string | null | undefined): string {
  return v ? v.slice(0, 4) : '—';
}
export function titleCase(s: string | null | undefined): string {
  if (!s) return '—';
  return s.replace(/[-_]/g, ' ').replace(/\b\w/g, (c) => c.toUpperCase());
}
export function num(v: number | string | null | undefined): number | null {
  if (v === null || v === undefined || v === '') return null;
  const n = typeof v === 'string' ? Number(v) : v;
  return Number.isFinite(n) ? n : null;
}