"use client";

import React, { createContext, useContext, useState, useCallback, ReactNode } from "react";

type CartItem = {
  productId: string;
  title: string;
  price: number;
  quantity: number;
  sku?: string;
  itc1?: string;
  itn?: string;
};

type CartContextType = {
  items: CartItem[];
  addItem: (item: Omit<CartItem, "quantity"> & { quantity?: number }) => void;
  removeItem: (productId: string) => void;
  updateQuantity: (productId: string, quantity: number) => void;
  clearCart: () => void;
  totalItems: number;
  totalPrice: number;
};

const CartContext = createContext<CartContextType | undefined>(undefined);

export function CartProvider({ children }: { children: ReactNode }) {
  const [items, setItems] = useState<CartItem[]>([]);

  const addItem = useCallback(
    (item: Omit<CartItem, "quantity"> & { quantity?: number }) => {
      setItems((prev) => {
        const existing = prev.find((i) => i.productId === item.productId);
        if (existing) {
          return prev.map((i) =>
            i.productId === item.productId
              ? { ...i, quantity: i.quantity + (item.quantity || 1) }
              : i
          );
        }
        return [...prev, { ...item, quantity: item.quantity || 1 }];
      });
    },
    []
  );

  const removeItem = useCallback((productId: string) => {
    setItems((prev) => prev.filter((i) => i.productId !== productId));
  }, []);

  const updateQuantity = useCallback((productId: string, quantity: number) => {
    if (quantity <= 0) {
      removeItem(productId);
      return;
    }
    setItems((prev) =>
      prev.map((i) => (i.productId === productId ? { ...i, quantity } : i))
    );
  }, [removeItem]);

  const clearCart = useCallback(() => {
    setItems([]);
  }, []);

  const totalItems = items.reduce((sum, item) => sum + item.quantity, 0);
  const totalPrice = items.reduce((sum, item) => sum + item.price * item.quantity, 0);

  return (
    <CartContext.Provider
      value={{
        items,
        addItem,
        removeItem,
        updateQuantity,
        clearCart,
        totalItems,
        totalPrice,
      }}
    >
      {children}
    </CartContext.Provider>
  );
}

export function useCart() {
  const context = useContext(CartContext);
  if (context === undefined) {
    throw new Error("useCart must be used within a CartProvider");
  }
  return context;
}