import { create } from 'zustand'
import { persist } from 'zustand/middleware'

export interface CartItem {
  product_id: string
  name: string
  price: number
  quantity: number
  image?: string
}

interface CartState {
  items: CartItem[]
  total: number
  addItem: (item: CartItem) => void
  removeItem: (product_id: string) => void
  updateQuantity: (product_id: string, qty: number) => void
  clearCart: () => void
}

function calcTotal(items: CartItem[]): number {
  return items.reduce((sum, item) => sum + item.price * item.quantity, 0)
}

export const useCartStore = create<CartState>()(
  persist(
    (set, get) => ({
      items: [],
      total: 0,

      addItem: (item: CartItem) => {
        const existing = get().items.find(i => i.product_id === item.product_id)
        let newItems: CartItem[]
        if (existing) {
          newItems = get().items.map(i =>
            i.product_id === item.product_id
              ? { ...i, quantity: i.quantity + item.quantity }
              : i
          )
        } else {
          newItems = [...get().items, item]
        }
        set({ items: newItems, total: calcTotal(newItems) })
      },

      removeItem: (product_id: string) => {
        const newItems = get().items.filter(i => i.product_id !== product_id)
        set({ items: newItems, total: calcTotal(newItems) })
      },

      updateQuantity: (product_id: string, qty: number) => {
        if (qty <= 0) {
          get().removeItem(product_id)
          return
        }
        const newItems = get().items.map(i =>
          i.product_id === product_id ? { ...i, quantity: qty } : i
        )
        set({ items: newItems, total: calcTotal(newItems) })
      },

      clearCart: () => {
        set({ items: [], total: 0 })
      },
    }),
    {
      name: 'cart',
    }
  )
)