/**
 * Currency formatting utilities for the WealthX design system.
 * All formatters default to AUD (en-AU locale).
 */

/**
 * Format a number as AUD currency using Intl.NumberFormat.
 *
 * @param value    The numeric value to format.
 * @param options  Optional formatting overrides.
 * @param options.decimals  Decimal places (default: 0).
 * @param options.showSign  Prefix with +/− for positive/negative (default: false).
 */
export function formatCurrency(
  value: number,
  options?: { decimals?: number; showSign?: boolean },
): string {
  const { decimals = 0, showSign = false } = options ?? {};
  const abs = Math.abs(value);
  const formatted = new Intl.NumberFormat("en-AU", {
    style: "currency",
    currency: "AUD",
    minimumFractionDigits: decimals,
    maximumFractionDigits: decimals,
  }).format(abs);
  if (!showSign) return value < 0 ? `-${formatted}` : formatted;
  if (value > 0) return `+${formatted}`;
  if (value < 0) return `-${formatted}`;
  return formatted;
}

/**
 * Abbreviated currency: $1.2B, $3.5M, $580K, $42.
 * Used primarily for chart axis ticks.
 */
export function formatCurrencyAbbrev(value: number, decimals?: number): string {
  const abs = Math.abs(value);
  const sign = value < 0 ? "-" : "";
  if (abs >= 1_000_000_000)
    return `${sign}$${(abs / 1_000_000_000).toFixed(decimals ?? 1)}B`;
  if (abs >= 1_000_000)
    return `${sign}$${(abs / 1_000_000).toFixed(decimals ?? 1)}M`;
  if (abs >= 1_000) return `${sign}$${(abs / 1_000).toFixed(decimals ?? 0)}K`;
  return `${sign}$${abs.toFixed(decimals ?? 0)}`;
}