Rocky_Mountain_Vending/lib/cart/context.tsx

'use client'

import { createContext, useContext, useState, useEffect, ReactNode, useMemo, useCallback } from 'react'

export interface CartItem {
  id: string
  name: string
  price: number
  priceId: string
  image: string
  quantity: number
}

interface CartContextType {
  items: CartItem[]
  addItem: (item: Omit<CartItem, 'quantity'> & { quantity?: number }) => void
  removeItem: (id: string) => void
  updateQuantity: (id: string, quantity: number) => void
  clearCart: () => void
  getTotal: () => number
  getItemCount: () => number
}

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

const CART_STORAGE_KEY = 'rmv-cart'

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

  // Load cart from localStorage on mount
  useEffect(() => {
    try {
      const stored = localStorage.getItem(CART_STORAGE_KEY)
      if (stored) {
        setItems(JSON.parse(stored))
      }
    } catch (error) {
      console.error('Error loading cart from localStorage:', error)
    } finally {
      setIsLoaded(true)
    }
  }, [])

  // Save cart to localStorage whenever it changes
  useEffect(() => {
    if (isLoaded) {
      try {
        localStorage.setItem(CART_STORAGE_KEY, JSON.stringify(items))
      } catch (error) {
        console.error('Error saving cart to localStorage:', error)
      }
    }
  }, [items, isLoaded])

  const addItem = (item: Omit<CartItem, 'quantity'> & { quantity?: number }) => {
    setItems((prevItems) => {
      const existingItem = prevItems.find((i) => i.id === item.id)
      if (existingItem) {
        return prevItems.map((i) =>
          i.id === item.id
            ? { ...i, quantity: i.quantity + (item.quantity || 1) }
            : i
        )
      }
      return [...prevItems, { ...item, quantity: item.quantity || 1 }]
    })
  }

  const removeItem = (id: string) => {
    setItems((prevItems) => prevItems.filter((i) => i.id !== id))
  }

  const updateQuantity = (id: string, quantity: number) => {
    if (quantity <= 0) {
      removeItem(id)
      return
    }
    setItems((prevItems) =>
      prevItems.map((i) => (i.id === id ? { ...i, quantity } : i))
    )
  }

  const clearCart = () => {
    setItems([])
  }

  // Memoize cart totals to prevent unnecessary re-renders in consuming components
  const cartTotal = useMemo(() => {
    return items.reduce((total, item) => total + item.price * item.quantity, 0)
  }, [items])

  const cartItemCount = useMemo(() => {
    return items.reduce((count, item) => count + item.quantity, 0)
  }, [items])

  const value: CartContextType = {
    items,
    addItem,
    removeItem,
    updateQuantity,
    clearCart,
    getTotal: () => cartTotal,
    getItemCount: () => cartItemCount,
  }

  return (
    <CartContext.Provider value={value}>
      {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
}

export { CartProvider }