/**
 * 购物车状态管理（多门店版）
 * 按门店分组存储菜品，支持跨门店下单
 */
import { defineStore } from 'pinia'
import { ref, computed } from 'vue'

export const useCartStore = defineStore('cart', () => {
	// 按门店分组存储: { shopId: { shopInfo, items: [{ dish, quantity }] } }
	const shops = ref({})

	// 当前门店 ID（门店详情页使用）
	const currentShopId = ref(null)

	// ==================== 计算属性 ====================

	/** 所有门店列表 */
	const shopList = computed(() => {
		return Object.values(shops.value).filter(s => s.items.length > 0)
	})

	/** 当前门店的商品列表 */
	const items = computed(() => {
		if (!currentShopId.value || !shops.value[currentShopId.value]) return []
		return shops.value[currentShopId.value].items
	})

	/** 当前门店信息 */
	const shopInfo = computed(() => {
		if (!currentShopId.value || !shops.value[currentShopId.value]) return null
		return shops.value[currentShopId.value].shopInfo
	})

	/** 所有门店总数量 */
	const totalCount = computed(() => {
		let count = 0
		for (const shop of Object.values(shops.value)) {
			count += shop.items.reduce((sum, item) => sum + item.quantity, 0)
		}
		return count
	})

	/** 所有门店商品总价（不含打包费） */
	const totalPrice = computed(() => {
		let price = 0
		for (const shop of Object.values(shops.value)) {
			price += shop.items.reduce((sum, item) => sum + item.quantity * item.dish.price, 0)
		}
		return price
	})

	/** 所有门店打包费总和 */
	const packingFee = computed(() => {
		let fee = 0
		for (const shop of Object.values(shops.value)) {
			if (shop.items.length === 0) continue
			const { packingFeeType, packingFeeAmount } = shop.shopInfo
			if (!packingFeeAmount) continue
			if (packingFeeType === 'Fixed') {
				fee += packingFeeAmount
			} else {
				const shopCount = shop.items.reduce((s, i) => s + i.quantity, 0)
				fee += shopCount * packingFeeAmount
			}
		}
		return fee
	})

	/** 含打包费的总金额 */
	const totalPriceWithFee = computed(() => {
		return totalPrice.value + packingFee.value
	})

	/** 当前门店的商品数量 */
	const currentShopCount = computed(() => {
		if (!currentShopId.value || !shops.value[currentShopId.value]) return 0
		return shops.value[currentShopId.value].items.reduce((sum, item) => sum + item.quantity, 0)
	})

	// ==================== 方法 ====================

	/** 设置当前门店信息 */
	function setShopInfo(info) {
		currentShopId.value = info.id
		if (!shops.value[info.id]) {
			shops.value[info.id] = { shopInfo: info, items: [] }
		} else {
			// 更新门店信息
			shops.value[info.id].shopInfo = info
		}
	}

	/** 获取菜品在当前门店购物车中的数量 */
	function getQuantity(dishId) {
		if (!currentShopId.value || !shops.value[currentShopId.value]) return 0
		const item = shops.value[currentShopId.value].items.find(i => i.dish.id === dishId)
		return item ? item.quantity : 0
	}

	/** 添加菜品到当前门店购物车 */
	function addItem(dish) {
		if (!currentShopId.value) return
		const shop = shops.value[currentShopId.value]
		if (!shop) return
		const existing = shop.items.find(i => i.dish.id === dish.id)
		if (existing) {
			existing.quantity += 1
		} else {
			shop.items.push({ dish: { ...dish }, quantity: 1 })
		}
	}

	/** 减少当前门店菜品数量 */
	function removeItem(dishId) {
		if (!currentShopId.value) return
		const shop = shops.value[currentShopId.value]
		if (!shop) return
		const index = shop.items.findIndex(i => i.dish.id === dishId)
		if (index === -1) return
		shop.items[index].quantity -= 1
		if (shop.items[index].quantity <= 0) {
			shop.items.splice(index, 1)
		}
		// 如果门店购物车为空，移除门店
		if (shop.items.length === 0) {
			delete shops.value[currentShopId.value]
		}
	}

	/** 清空所有购物车 */
	function clearCart() {
		shops.value = {}
		currentShopId.value = null
	}

	/** 获取所有门店的 foodItems（下单用） */
	function getAllFoodItems() {
		const foodItems = []
		for (const shop of Object.values(shops.value)) {
			for (const item of shop.items) {
				foodItems.push({
					shopId: shop.shopInfo.id,
					dishId: item.dish.id,
					quantity: item.quantity,
					unitPrice: item.dish.price
				})
			}
		}
		return foodItems
	}

	return {
		shops, currentShopId, shopList, items, shopInfo,
		totalCount, totalPrice, packingFee, totalPriceWithFee, currentShopCount,
		setShopInfo, getQuantity, addItem, removeItem, clearCart, getAllFoodItems
	}
})