/**
 * Pure formatting helpers shared between the PDF document and any
 * preview / preview-text paths. Kept dependency-free so they can be
 * imported into both client and server contexts without dragging in
 * @react-pdf/renderer.
 */

/** "R 1 234.56" — the South African style used on the existing sample PDFs. */
export function formatZAR(amount: number): string {
  const safe = Number.isFinite(amount) ? amount : 0;
  const fixed = safe.toFixed(2);
  const [whole, frac] = fixed.split(".");
  // Group thousands with spaces (en-ZA locale style), keep the dot for the decimal.
  const grouped = whole.replace(/\B(?=(\d{3})+(?!\d))/g, " ");
  return `R ${grouped}.${frac}`;
}

/** "22 June 2026" — long form date for the Quote No / Date / Valid until block. */
export function formatDateLong(iso: string): string {
  if (!iso) return "";
  const d = new Date(iso);
  if (isNaN(d.getTime())) return iso;
  return d.toLocaleDateString("en-GB", {
    day: "numeric",
    month: "long",
    year: "numeric",
  });
}

/** Returns an ISO string for `iso + days`. Used for the "Valid until: +30 days" line. */
export function addDays(iso: string, days: number): string {
  const d = new Date(iso);
  d.setUTCDate(d.getUTCDate() + days);
  return d.toISOString();
}

/** Sum of selling_price * quantity across an array of quote items. */
export function quoteSubtotal(items: { quantity: number; selling_price: number }[]): number {
  return items.reduce((sum, it) => sum + it.quantity * it.selling_price, 0);
}

/** ZAR VAT is 15% — round to 2dp so the printed total matches the line items. */
export function vatAmount(subtotal: number): number {
  return Math.round(subtotal * 0.15 * 100) / 100;
}

/** Default validity period for new quotes — the existing sample PDF shows exactly 30. */
export const QUOTE_VALID_DAYS = 30;

/**
 * Effective "Date" printed on the quote PDF. Prefers the user-editable
 * `quote_date` (lets the office backdate a quote), falls back to the
 * PB row's `created` timestamp.
 */
export function effectiveQuoteDate(
  quote: { quote_date?: string; created?: string }
): string {
  return quote.quote_date || quote.created || "";
}

/**
 * Effective validity period in days. Prefers `validity_days` on the
 * quote (lets the office extend to 2 months etc.), falls back to the
 * package default.
 */
export function effectiveValidityDays(
  quote: { validity_days?: number | null }
): number {
  return quote.validity_days ?? QUOTE_VALID_DAYS;
}