const isNum = (v: unknown): v is number => typeof v === "number" && Number.isFinite(v);
const toNum = (v: unknown): number | null => {
  if (isNum(v)) return v;
  if (typeof v === "string" && v.trim() !== "" && Number.isFinite(Number(v))) return Number(v);
  return null;
};

export const fmtNum = (v: unknown, digits = 2): string => {
  const n = toNum(v);
  return n === null ? "—" : n.toLocaleString("en-US", { minimumFractionDigits: digits, maximumFractionDigits: digits });
};
export const fmtPrice = (v: unknown): string => {
  const n = toNum(v);
  if (n === null) return "—";
  const d = n >= 1000 ? 1 : n >= 10 ? 2 : n >= 1 ? 3 : 5;
  return n.toLocaleString("en-US", { minimumFractionDigits: d, maximumFractionDigits: d });
};
export const fmtPct = (v: unknown, digits = 2, alreadyPct = false): string => {
  const n = toNum(v);
  if (n === null) return "—";
  const p = alreadyPct ? n : n * 100;
  return `${p >= 0 ? "+" : ""}${p.toFixed(digits)}%`;
};
export const fmtPctPlain = (v: unknown, digits = 1): string => {
  const n = toNum(v);
  return n === null ? "—" : `${(n * 100).toFixed(digits)}%`;
};
export const fmtBps = (v: unknown, digits = 1): string => {
  const n = toNum(v);
  return n === null ? "—" : `${n.toFixed(digits)} bps`;
};
export const fmtUsd = (v: unknown, digits = 2): string => {
  const n = toNum(v);
  return n === null ? "—" : n.toLocaleString("en-US", { style: "currency", currency: "USD", minimumFractionDigits: digits, maximumFractionDigits: digits });
};
export const fmtRatio = (v: unknown, digits = 2): string => {
  const n = toNum(v);
  if (n === null) return "—";
  if (!Number.isFinite(n)) return n > 0 ? "∞" : "—";
  return n.toFixed(digits);
};
export const fmtTs = (ts: unknown): string => {
  const n = toNum(ts);
  if (n === null) return "—";
  const ms = n > 1e12 ? n : n * 1000;
  return new Date(ms).toISOString().replace("T", " ").slice(0, 19) + "Z";
};
export const fmtDate = (ts: unknown): string => {
  const n = toNum(ts);
  if (n === null) return "—";
  return new Date((n > 1e12 ? n : n * 1000)).toISOString().slice(0, 10);
};
export const fmtIso = (s: unknown): string => (typeof s === "string" ? s.replace("T", " ").slice(0, 19) : "—");
export const fmtAge = (s: unknown): string => {
  const n = toNum(s);
  if (n === null) return "—";
  if (n < 60) return `${n.toFixed(0)}s`;
  if (n < 3600) return `${(n / 60).toFixed(0)}m`;
  return `${(n / 3600).toFixed(1)}h`;
};
export const signClass = (v: unknown): string => {
  const n = toNum(v);
  if (n === null || n === 0) return "text-fg-muted";
  return n > 0 ? "text-up" : "text-down";
};
export { toNum };