first commit

lib/pricing.ts

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+import { prisma } from '@/lib/prisma'
+
+export interface PricingOptions {
+  userId?: string
+  userRole?: string
+  quantity?: number
+  isWholesaler?: boolean
+}
+
+export class PricingService {
+  // Get effective price for a product based on user role and quantity
+  static async getEffectivePrice(
+    productId: string, 
+    quantity: number = 1,
+    options: PricingOptions = {}
+  ): Promise<{
+    originalPrice: number
+    finalPrice: number
+    discount: number
+    discountPercentage: number
+    isWholesalePrice: boolean
+  }> {
+    // Get the product
+    const product = await prisma.product.findUnique({
+      where: { id: productId }
+    })
+
+    if (!product) {
+      throw new Error('Product not found')
+    }
+
+    const originalPrice = product.price
+    let finalPrice = originalPrice
+    let discount = 0
+    let discountPercentage = 0
+    let isWholesalePrice = false
+
+    // Apply product discount first
+    if (product.discount > 0) {
+      discount = (originalPrice * product.discount) / 100
+      finalPrice = originalPrice - discount
+      discountPercentage = product.discount
+    }
+
+    // Check if user is a wholesaler and quantity qualifies for bulk discount
+    if (options.userRole === 'WHOLESALER' && this.isQualifyingBulkOrder(quantity)) {
+      // Apply 25% wholesale discount on top of existing discount
+      const wholesaleDiscount = (originalPrice * 25) / 100
+      
+      // Use the better discount (wholesale or product discount)
+      if (wholesaleDiscount > discount) {
+        discount = wholesaleDiscount
+        finalPrice = originalPrice - discount
+        discountPercentage = 25
+        isWholesalePrice = true
+      }
+    }
+
+    return {
+      originalPrice,
+      finalPrice: Math.max(finalPrice, 0), // Ensure price doesn't go negative
+      discount,
+      discountPercentage,
+      isWholesalePrice
+    }
+  }
+
+  // Check if quantity qualifies for bulk order discount
+  static isQualifyingBulkOrder(quantity: number): boolean {
+    // Define minimum quantity for bulk orders (e.g., 10 or more items)
+    const BULK_ORDER_MIN_QUANTITY = 10
+    return quantity >= BULK_ORDER_MIN_QUANTITY
+  }
+
+  // Calculate cart total with wholesale discounts
+  static async calculateCartTotal(
+    cartItems: Array<{
+      productId: string
+      quantity: number
+    }>,
+    options: PricingOptions = {}
+  ): Promise<{
+    subtotal: number
+    totalDiscount: number
+    finalTotal: number
+    items: Array<{
+      productId: string
+      quantity: number
+      originalPrice: number
+      finalPrice: number
+      discount: number
+      discountPercentage: number
+      isWholesalePrice: boolean
+      lineTotal: number
+    }>
+    hasWholesaleDiscount: boolean
+  }> {
+    let subtotal = 0
+    let totalDiscount = 0
+    let finalTotal = 0
+    let hasWholesaleDiscount = false
+    const items = []
+
+    for (const item of cartItems) {
+      const pricing = await this.getEffectivePrice(
+        item.productId,
+        item.quantity,
+        options
+      )
+
+      const lineTotal = pricing.finalPrice * item.quantity
+      const lineDiscount = pricing.discount * item.quantity
+
+      subtotal += pricing.originalPrice * item.quantity
+      totalDiscount += lineDiscount
+      finalTotal += lineTotal
+
+      if (pricing.isWholesalePrice) {
+        hasWholesaleDiscount = true
+      }
+
+      items.push({
+        productId: item.productId,
+        quantity: item.quantity,
+        originalPrice: pricing.originalPrice,
+        finalPrice: pricing.finalPrice,
+        discount: pricing.discount,
+        discountPercentage: pricing.discountPercentage,
+        isWholesalePrice: pricing.isWholesalePrice,
+        lineTotal
+      })
+    }
+
+    return {
+      subtotal,
+      totalDiscount,
+      finalTotal,
+      items,
+      hasWholesaleDiscount
+    }
+  }
+
+  // Get user role for pricing calculations
+  static async getUserRole(userId: string): Promise<string | null> {
+    const user = await prisma.user.findUnique({
+      where: { id: userId },
+      select: { role: true }
+    })
+
+    return user?.role || null
+  }
+
+  // Get wholesale discount info for display
+  static getWholesaleDiscountInfo() {
+    return {
+      discountPercentage: 25,
+      minQuantity: 10,
+      description: 'Get 25% off on bulk orders (10+ items) as a registered wholesaler'
+    }
+  }
+
+  // Check if user is eligible for wholesale pricing
+  static async isWholesaler(userId: string): Promise<boolean> {
+    const user = await prisma.user.findUnique({
+      where: { id: userId },
+      select: { role: true, isActive: true }
+    })
+
+    return user?.role === 'WHOLESALER' && user?.isActive === true
+  }
+}
+
+export default PricingService