import {
  GUEST_CART_KEY,
  GUEST_CART_URL_PARAM,
} from "@/lib/meshkee/config";
import { normalizeGuestLines } from "@/lib/meshkee/format";
import type { GuestCartLine } from "@/lib/meshkee/types";

function parseLines(raw: string | null): GuestCartLine[] {
  if (!raw) return [];
  try {
    const parsed = JSON.parse(raw);
    return Array.isArray(parsed) ? normalizeGuestLines(parsed) : [];
  } catch {
    return [];
  }
}

export function readGuestCart(): GuestCartLine[] {
  if (typeof window === "undefined") return [];
  return parseLines(localStorage.getItem(GUEST_CART_KEY));
}

export function writeGuestCart(items: GuestCartLine[]) {
  if (typeof window === "undefined") return;
  const normalized = normalizeGuestLines(items);
  localStorage.setItem(GUEST_CART_KEY, JSON.stringify(normalized));
}

export function clearGuestCart() {
  if (typeof window === "undefined") return;
  localStorage.removeItem(GUEST_CART_KEY);
}

export function encodeGuestCartForUrl(items: GuestCartLine[]): string {
  const payload = normalizeGuestLines(items).map((item) => ({
    id: item.id,
    name: item.name,
    ...(item.slug ? { slug: item.slug } : {}),
    price: item.price,
    image: item.image ?? null,
    quantity: item.quantity,
  }));
  return btoa(unescape(encodeURIComponent(JSON.stringify(payload))))
    .replace(/\+/g, "-")
    .replace(/\//g, "_")
    .replace(/=+$/g, "");
}

export { GUEST_CART_URL_PARAM };