Refactor: Add getPrice function to calculate final price with discount

src/app/actions/get-price.ts

@@ -0,0 +1,36 @@
+"use server";
+
+import prisma from "@/server/db";
+
+class CouponError extends Error {
+    constructor(message: string) {
+        super(message);
+        this.name = "CouponError";
+    }
+}
+
+export const getPrice = async (couponCode?: string): Promise<number> => {
+    const basePrice = 1000;
+    if (couponCode) {
+        const coupon = await prisma.referral.findUnique({
+            where: { code: couponCode },
+        });
+        if (!coupon) {
+            throw new CouponError("Coupon code not found");
+        }
+
+        if (coupon.isUsed) {
+            throw new CouponError("Coupon code is already used");
+        }
+        const discountPercentage = parseFloat(coupon.discountPercentage ?? "0");
+
+        if (isNaN(discountPercentage)) {
+            throw new CouponError("Invalid discount percentage format");
+        }
+        const discountAmount = basePrice * (discountPercentage / 100);
+        const finalPrice = Math.floor(basePrice - discountAmount);
+
+        return finalPrice;
+    }
+    return basePrice;
+};