import AsyncStorage from "@react-native-async-storage/async-storage";
import { create } from "zustand";
import { createJSONStorage, persist } from "zustand/middleware";
import type { Product } from "@/lib/data/products";

export type CartItem = {
  productId: string;
  slug: string;
  name: string;
  price: number;
  image: string;
  unit: string;
  quantity: number;
  requiresPrescription?: boolean;
};

type CartState = {
  items: CartItem[];
  voucherCode: string | null;
  addProduct: (product: Product, qty?: number) => void;
  removeItem: (productId: string) => void;
  setQuantity: (productId: string, quantity: number) => void;
  clear: () => void;
  setVoucher: (code: string | null) => void;
  totalItems: () => number;
  subtotal: () => number;
};

export const useCartStore = create<CartState>()(
  persist(
    (set, get) => ({
      items: [],
      voucherCode: null,
      addProduct: (product, qty = 1) => {
        const items = [...get().items];
        const idx = items.findIndex((i) => i.productId === product.id);
        if (idx >= 0) {
          items[idx] = {
            ...items[idx],
            quantity: items[idx].quantity + qty,
          };
        } else {
          items.push({
            productId: product.id,
            slug: product.slug,
            name: product.name,
            price: product.price,
            image: product.image,
            unit: product.unit,
            quantity: qty,
            requiresPrescription: product.requiresPrescription,
          });
        }
        set({ items });
      },
      removeItem: (productId) =>
        set({ items: get().items.filter((i) => i.productId !== productId) }),
      setQuantity: (productId, quantity) => {
        if (quantity <= 0) {
          get().removeItem(productId);
          return;
        }
        set({
          items: get().items.map((i) =>
            i.productId === productId ? { ...i, quantity } : i
          ),
        });
      },
      clear: () => set({ items: [], voucherCode: null }),
      setVoucher: (code) => set({ voucherCode: code }),
      totalItems: () => get().items.reduce((n, i) => n + i.quantity, 0),
      subtotal: () =>
        get().items.reduce((n, i) => n + i.price * i.quantity, 0),
    }),
    {
      name: "gishen-cart",
      storage: createJSONStorage(() => AsyncStorage),
    }
  )
);