export function fmtCurrency(value?: number | null, decimals = 2): string {
  if (value === null || value === undefined || Number.isNaN(value)) return "-";
  return `$${value.toLocaleString(undefined, { maximumFractionDigits: decimals, minimumFractionDigits: decimals })}`;
}

export function fmtNumber(value?: number | null, decimals = 2): string {
  if (value === null || value === undefined || Number.isNaN(value)) return "-";
  return value.toLocaleString(undefined, { maximumFractionDigits: decimals, minimumFractionDigits: decimals });
}

export function fmtLarge(value?: number | null): string {
  if (value === null || value === undefined || Number.isNaN(value)) return "-";
  const abs = Math.abs(value);
  const sign = value < 0 ? "-" : "";
  if (abs >= 1e12) return `${sign}$${(abs / 1e12).toFixed(2)}T`;
  if (abs >= 1e9) return `${sign}$${(abs / 1e9).toFixed(2)}B`;
  if (abs >= 1e6) return `${sign}$${(abs / 1e6).toFixed(1)}M`;
  return `${sign}$${abs.toLocaleString(undefined, { maximumFractionDigits: 0 })}`;
}

export function fmtPct(value?: number | null, decimals = 2, signed = false): string {
  if (value === null || value === undefined || Number.isNaN(value)) return "-";
  const pct = value * 100;
  const sign = signed && pct > 0 ? "+" : "";
  return `${sign}${pct.toFixed(decimals)}%`;
}

export function deltaClass(value?: number | null): string {
  if (value === null || value === undefined) return "neutral";
  return value >= 0 ? "positive" : "negative";
}

export function formatNewsTimestamp(iso: string): { display: string; iso: string } {
  const date = new Date(iso);
  const now = new Date();
  const tz: Intl.DateTimeFormatOptions = { timeZone: "America/Los_Angeles" };
  const diffMs = now.getTime() - date.getTime();
  const diffMins = Math.floor(diffMs / 60_000);
  const diffHours = Math.floor(diffMs / 3_600_000);

  if (diffMins < 1) {
    return { display: "Just now", iso };
  }
  if (diffMins < 60) {
    return { display: `${diffMins}m ago`, iso };
  }
  if (diffHours < 24) {
    return { display: `${diffHours}h ago`, iso };
  }

  const inTz = (options: Intl.DateTimeFormatOptions) =>
    date.toLocaleString("en-US", { ...options, ...tz });

  if (diffHours < 48) {
    const time = inTz({ hour: "numeric", minute: "2-digit" });
    return { display: `Yesterday ${time}`, iso };
  }

  const yearNow = Number(now.toLocaleString("en-US", { year: "numeric", ...tz }));
  const yearDate = Number(inTz({ year: "numeric" }));

  if (yearDate === yearNow) {
    return { display: inTz({ month: "short", day: "numeric" }), iso };
  }
  return { display: inTz({ month: "short", day: "numeric", year: "numeric" }), iso };
}