/** Shared commerce numbers so cart, checkout and orders stay consistent. */
export const DELIVERY_FEE = 80;
export const DEMO_VOUCHER = "GISHEN10";
export const DEMO_VOUCHER_PCT = 0.1;
export const DEMO_OTP = "1234";

/** Short branch-counter code guests show to fulfill pickup at any location. */
export function generatePickupCode() {
  const alphabet = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789";
  let body = "";
  for (let i = 0; i < 4; i += 1) {
    body += alphabet[Math.floor(Math.random() * alphabet.length)];
  }
  return `GSH-${body}`;
}

export function voucherDiscount(subtotal: number, code: string | null | undefined) {
  if (!code) return 0;
  if (code.trim().toUpperCase() === DEMO_VOUCHER) {
    return Math.round(subtotal * DEMO_VOUCHER_PCT);
  }
  return 0;
}

export function orderSubtotalTotal(input: {
  subtotal: number;
  deliveryFee: number;
  discount?: number;
}) {
  return Math.max(0, input.subtotal + input.deliveryFee - (input.discount ?? 0));
}