import { describe, it, expect } from "vitest";
import { formatCurrency } from "./format-currency";
import { EMPTY } from "./placeholder";

describe("formatCurrency", () => {
  it("formats numbers as USD by default", () => {
    expect(formatCurrency(1234.5)).toBe("$1,234.50");
    expect(formatCurrency(0)).toBe("$0.00");
  });

  it("coerces numeric strings (schema decimals arrive as strings)", () => {
    expect(formatCurrency("1234.5")).toBe("$1,234.50");
  });

  it("returns the canonical EMPTY placeholder for null/undefined/NaN so callers can pass raw values", () => {
    expect(formatCurrency(null)).toBe(EMPTY);
    expect(formatCurrency(undefined)).toBe(EMPTY);
    expect(formatCurrency("not a number")).toBe(EMPTY);
  });

  it("honors an explicit currency code", () => {
    expect(formatCurrency(1234.5, "EUR")).toBe("€1,234.50");
  });

  it("respects an optional maxDecimals cap", () => {
    expect(formatCurrency(1234.5678, "USD", 4)).toBe("$1,234.5678");
  });

  it("falls back to a bare localized number on an invalid currency code", () => {
    // Intl.NumberFormat throws on garbage ISO codes; we must not crash.
    expect(formatCurrency(1234.5, "NOTACODE")).toBe("1,234.50");
  });
});