/**
 * Formatting helpers. API timestamps are UTC ISO strings; absolute dates render in UTC (identical on server and client),
 * relative times are rendered client-side after mount (`components/ui/live.tsx`). Missing values → em dash, never a fake number.
 */
import type { Num } from './types';

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

export const DASH = '—';

export function num(v: unknown): number | null {
  if (v === null || v === undefined || v === '') return null;
  const n = typeof v === 'number' ? v : Number(v);
  return Number.isFinite(n) ? n : null;
}
export function fmtInt(v: Num | undefined | unknown): string {
  const n = num(v);
  return n === null ? DASH : nf0.format(n);
}
export function fmt1(v: Num | undefined | unknown): string {
  const n = num(v);
  return n === null ? DASH : nf1.format(n);
}
export function fmt2(v: Num | undefined | unknown): string {
  const n = num(v);
  return n === null ? DASH : nf2.format(n);
}
export function fmtCompact(v: Num | undefined | unknown): string {
  const n = num(v);
  return n === null ? DASH : nfCompact.format(n);
}
/** 0–100 score with one decimal (API rounds to 1 decimal). */
export function fmtScore(v: Num | undefined | unknown): string {
  const n = num(v);
  return n === null ? DASH : nf1.format(n);
}
/** Percentage from a 0–1 ratio or a 0–100 value (`ratio` flag). */
export function fmtPct(v: Num | undefined | unknown, digits = 1, ratio = false): string {
  const n = num(v);
  if (n === null) return DASH;
  return `${(ratio ? n * 100 : n).toFixed(digits)} %`;
}
/** Signed percentage: +12.3 % / −4.0 % / 0.0 %. */
export function fmtPctSigned(v: Num | undefined | unknown, digits = 1): string {
  const n = num(v);
  if (n === null) return DASH;
  const sign = n > 0 ? '+' : n < 0 ? '−' : '';
  return `${sign}${Math.abs(n).toFixed(digits)} %`;
}
export function fmtSigned(v: Num | undefined | unknown, digits = 0): string {
  const n = num(v);
  if (n === null) return DASH;
  const f = digits ? Math.abs(n).toFixed(digits) : nf0.format(Math.abs(n));
  return n > 0 ? `+${f}` : n < 0 ? `−${f}` : digits ? (0).toFixed(digits) : '0';
}
export function fmtBytes(v: Num | undefined | unknown): string {
  const n = num(v);
  if (n === null) return DASH;
  if (n >= 1e12) return `${(n / 1e12).toFixed(2)} TB`;
  if (n >= 1e9) return `${(n / 1e9).toFixed(1)} GB`;
  if (n >= 1e6) return `${(n / 1e6).toFixed(0)} MB`;
  if (n >= 1e3) return `${(n / 1e3).toFixed(0)} kB`;
  return `${n} B`;
}
export function fmtUsd(v: Num | undefined | unknown, digits = 2): string {
  const n = num(v);
  return n === null ? DASH : `$${n.toFixed(digits)}`;
}
/**
 * Compact currency for stated financial facts: 130.5B USD → "$130.5B", 34.2B EUR → "€34.2B", 48T JPY → "¥48.0T".
 * Never converts between currencies; unknown ISO codes fall back to "<compact> <CODE>".
 */
export function fmtMoney(value: Num | undefined | unknown, currency: string | null | undefined): string {
  const n = num(value);
  if (n === null) return DASH;
  const code = (currency ?? '').toUpperCase();
  if (code) {
    try {
      return new Intl.NumberFormat('en-US', { style: 'currency', currency: code, notation: 'compact', maximumFractionDigits: 1, currencyDisplay: 'narrowSymbol' }).format(n);
    } catch {
      /* invalid code */
    }
  }
  return code ? `${nfCompact.format(n)} ${code}` : nfCompact.format(n);
}
export function fmtPrice(price: Num | undefined, currency: string | null | undefined, text?: string | null): string {
  const n = num(price);
  if (n === null) return text ?? DASH;
  const cur = (currency ?? 'USD').toUpperCase();
  const sym = cur === 'USD' ? '$' : cur === 'EUR' ? '€' : cur === 'GBP' ? '£' : `${cur} `;
  return `${sym}${Number.isInteger(n) ? nf0.format(n) : nf2.format(n)}`;
}

/** ISO date/timestamp → "11 Sept 2026" (UTC). */
export function fmtDate(v: string | null | undefined): string {
  if (!v) return DASH;
  const d = new Date(v.length === 10 ? `${v}T00:00:00Z` : v);
  if (Number.isNaN(d.getTime())) return v;
  return d.toLocaleDateString('en-GB', { year: 'numeric', month: 'short', day: 'numeric', timeZone: 'UTC' });
}
export function fmtDateShort(v: string | null | undefined): string {
  if (!v) return DASH;
  const d = new Date(v.length === 10 ? `${v}T00:00:00Z` : v);
  if (Number.isNaN(d.getTime())) return v;
  return d.toLocaleDateString('en-GB', { month: 'short', day: 'numeric', timeZone: 'UTC' });
}
export function fmtDateTime(v: string | null | undefined): string {
  if (!v) return DASH;
  const d = new Date(v);
  if (Number.isNaN(d.getTime())) return DASH;
  return `${d.toLocaleDateString('en-GB', { year: 'numeric', month: 'short', day: 'numeric', timeZone: 'UTC' })} ${d.toLocaleTimeString('en-GB', { hour: '2-digit', minute: '2-digit', timeZone: 'UTC' })} UTC`;
}
export function fmtTime(v: string | null | undefined): string {
  if (!v) return DASH;
  const d = new Date(v);
  if (Number.isNaN(d.getTime())) return DASH;
  return `${d.toLocaleTimeString('en-GB', { hour: '2-digit', minute: '2-digit', second: '2-digit', timeZone: 'UTC' })}`;
}
/** Day label for timeline groups: "Today", "Yesterday", else the date (UTC). */
export function fmtDayLabel(day: string, now: number = Date.now()): string {
  const today = new Date(now).toISOString().slice(0, 10);
  const yesterday = new Date(now - 86_400_000).toISOString().slice(0, 10);
  if (day === today) return 'Today';
  if (day === yesterday) return 'Yesterday';
  return fmtDate(day);
}
/** "17 sec ago" · "3 min ago" · "2 h ago" · "5 d ago" — precise at the second for the live feed. */
export function fmtAgo(v: string | null | undefined, now: number = Date.now()): string {
  if (!v) return DASH;
  const t = new Date(v).getTime();
  if (Number.isNaN(t)) return DASH;
  const s = Math.max(0, Math.round((now - t) / 1000));
  if (s < 5) return 'just now';
  if (s < 60) return `${s} sec ago`;
  const m = Math.floor(s / 60);
  if (m < 60) return `${m} min ago`;
  const h = Math.floor(m / 60);
  if (h < 48) return `${h} h ago`;
  const d = Math.floor(h / 24);
  if (d < 60) return `${d} d ago`;
  return fmtDate(v);
}
export function fmtDuration(seconds: Num | undefined | unknown): string {
  const n = num(seconds);
  if (n === null) return DASH;
  if (n < 60) return `${Math.round(n)} s`;
  if (n < 3600) return `${Math.round(n / 60)} min`;
  if (n < 86400) return `${(n / 3600).toFixed(n < 7200 ? 1 : 0)} h`;
  return `${Math.round(n / 86400)} d`;
}
export function fmtDays(days: Num | undefined | unknown): string {
  const n = num(days);
  if (n === null) return DASH;
  if (n < 1) return '< 1 day';
  if (n < 60) return `${Math.round(n)} ${plural(Math.round(n), 'day')}`;
  if (n < 730) return `${(n / 30.44).toFixed(0)} months`;
  return `${(n / 365.25).toFixed(1)} years`;
}
export function plural(n: number, one: string, many = `${one}s`): string {
  return n === 1 ? one : many;
}
export function hostOf(url: string | null | undefined): string | null {
  if (!url) return null;
  try {
    return new URL(url).hostname.replace(/^www\./, '');
  } catch {
    return null;
  }
}
export function pathOf(url: string | null | undefined): string {
  if (!url) return DASH;
  try {
    const u = new URL(url);
    return `${u.hostname.replace(/^www\./, '')}${u.pathname === '/' ? '' : u.pathname}`;
  } catch {
    return url;
  }
}
/** Constant → words: PRODUCT_LAUNCH → "Product launch"; job_count_increase → "Job count increase". */
export function humanize(s: string | null | undefined): string {
  if (!s) return DASH;
  const w = s.replace(/[_-]+/g, ' ').trim().toLowerCase();
  return w.charAt(0).toUpperCase() + w.slice(1);
}
export function titleCase(s: string | null | undefined): string {
  if (!s) return DASH;
  return s.replace(/[_-]+/g, ' ').replace(/\b\w/g, (c) => c.toUpperCase());
}
export function truncate(s: string | null | undefined, n = 140): string {
  if (!s) return '';
  return s.length > n ? `${s.slice(0, n - 1).trimEnd()}…` : s;
}
/** Significance 0–1 → band per spec §20. */
export function significanceBand(v: Num | undefined | unknown): 'noise' | 'minor' | 'meaningful' | 'major' | 'critical' | null {
  const n = num(v);
  if (n === null) return null;
  if (n < 0.2) return 'noise';
  if (n < 0.4) return 'minor';
  if (n < 0.65) return 'meaningful';
  if (n < 0.85) return 'major';
  return 'critical';
}
/** Importance 0–1 (or 0–100) → 0..3 steps for the meter. */
export function importanceSteps(v: Num | undefined | unknown): 0 | 1 | 2 | 3 {
  const n = num(v);
  if (n === null) return 0;
  const x = n > 1 ? n / 100 : n;
  if (x >= 0.8) return 3;
  if (x >= 0.55) return 2;
  if (x >= 0.3) return 1;
  return 0;
}
export function toneOf(v: Num | undefined | unknown): 'positive' | 'negative' | 'neutral' {
  const n = num(v);
  if (n === null || n === 0) return 'neutral';
  return n > 0 ? 'positive' : 'negative';
}