import { defineStore } from 'pinia'
import { ref, computed } from 'vue'

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

export interface DeliveryMethod {
  id: number
  name: string
  price: number
  description: string
}

export const useCartStore = defineStore('cart', () => {
  const items = ref<CartItem[]>([])
  const selectedAddressId = ref<number | null>(null)
  const selectedDeliveryMethodId = ref<number | null>(null)
  const shippingCost = ref(0)
  const vatRate = ref(0.23) // 23% VAT

  const deliveryMethods = ref<DeliveryMethod[]>([
    { id: 1, name: 'Standard Delivery', price: 0, description: '5-7 business days' },
    { id: 2, name: 'Express Delivery', price: 15, description: '2-3 business days' },
    { id: 3, name: 'Priority Delivery', price: 30, description: 'Next business day' }
  ])

  function initMockData() {
    items.value = [
      { id: 1, productId: 101, name: 'Premium Widget Pro', image: '/img/product-1.jpg', price: 129.99, quantity: 2 },
      { id: 2, productId: 102, name: 'Ultra Gadget X', image: '/img/product-2.jpg', price: 89.50, quantity: 1 },
      { id: 3, productId: 103, name: 'Mega Tool Set', image: '/img/product-3.jpg', price: 249.00, quantity: 3 }
    ]
  }

  const productsTotal = computed(() => {
    return items.value.reduce((sum, item) => sum + (item.price * item.quantity), 0)
  })

  const vatAmount = computed(() => {
    return productsTotal.value * vatRate.value
  })

  const orderTotal = computed(() => {
    return productsTotal.value + shippingCost.value + vatAmount.value
  })

  const itemCount = computed(() => {
    return items.value.reduce((sum, item) => sum + item.quantity, 0)
  })

  function updateQuantity(itemId: number, quantity: number) {
    const item = items.value.find(i => i.id === itemId)
    if (item) {
      if (quantity <= 0) {
        removeItem(itemId)
      } else {
        item.quantity = quantity
      }
    }
  }

  function removeItem(itemId: number) {
    const index = items.value.findIndex(i => i.id === itemId)
    if (index !== -1) {
      items.value.splice(index, 1)
    }
  }

  function clearCart() {
    items.value = []
    selectedAddressId.value = null
    selectedDeliveryMethodId.value = null
    shippingCost.value = 0
  }

  function setSelectedAddress(addressId: number | null) {
    selectedAddressId.value = addressId
  }

  function setDeliveryMethod(methodId: number) {
    selectedDeliveryMethodId.value = methodId
    const method = deliveryMethods.value.find(m => m.id === methodId)
    if (method) {
      shippingCost.value = method.price
    }
  }

  initMockData()

  return {
    items,
    selectedAddressId,
    selectedDeliveryMethodId,
    shippingCost,
    vatRate,
    deliveryMethods,
    productsTotal,
    vatAmount,
    orderTotal,
    itemCount,
    updateQuantity,
    removeItem,
    clearCart,
    setSelectedAddress,
    setDeliveryMethod
  }
})