import type { Order } from "@/lib/stores/ordersStore";
import { formatETB } from "@/lib/utils";

/** 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 GSH-XXXX reference guests share with a pharmacist.
 * Pharmacist enters the code on the admin page to create / fulfill the order.
 */
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}`;
}

/** Alias used for guest → admin pharmacist order codes (same format as pickup). */
export const generatePharmacistOrderCode = generatePickupCode;

/** Plain-text payload for copy / share / WhatsApp (admin-friendly). */
export function buildPharmacistOrderShareText(order: Pick<
  Order,
  | "pickupCode"
  | "customerName"
  | "customerPhone"
  | "items"
  | "total"
  | "selfPay"
  | "paymentMethod"
  | "notes"
>) {
  const code = order.pickupCode ?? "—";
  const lines = order.items
    .map((i) => `• ${i.name} ×${i.quantity} — ${formatETB(i.price * i.quantity)}`)
    .join("\n");
  const due = order.selfPay ?? order.total;
  return [
    "Gishen Pharmacy — Pharmacist order code",
    "",
    `Code: ${code}`,
    "",
    `Customer: ${order.customerName ?? "—"}`,
    `Phone: ${order.customerPhone ?? "—"}`,
    "",
    "Items:",
    lines || "• (no items)",
    "",
    `Total: ${formatETB(due)}`,
    `Payment: ${order.paymentMethod === "pay_at_branch" ? "Pay at branch" : order.paymentMethod}`,
    order.notes ? `Notes: ${order.notes}` : "",
    "",
    "Enter this code on the Gishen admin page to create the order.",
  ]
    .filter((line) => line !== undefined)
    .join("\n");
}

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));
}