Checkout22

src/app/api/store/[slug]/coupons/validate/route.ts

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+// src/app/api/store/[slug]/coupons/validate/route.ts
+// Public storefront endpoint – validate a discount/coupon code at checkout
+
+import { NextRequest, NextResponse } from 'next/server';
+import prisma from '@/lib/prisma';
+
+type RouteContext = {
+  params: Promise<{ slug: string }>;
+};
+
+/**
+ * POST /api/store/[slug]/coupons/validate
+ * Validates a coupon code and returns the calculated discount amount.
+ * No authentication required (public storefront endpoint).
+ *
+ * Body: { code: string; orderAmount: number }
+ * Returns: { valid: true; code; discountAmount; description; type; value }
+ *       or { error: string } with a 4xx status
+ */
+export async function POST(request: NextRequest, context: RouteContext) {
+  try {
+    const { slug } = await context.params;
+
+    const body = await request.json();
+    const code: string = (body.code ?? '').toString().toUpperCase().trim();
+    const orderAmount: number = Number(body.orderAmount ?? 0);
+
+    if (!code) {
+      return NextResponse.json({ error: 'Coupon code is required' }, { status: 400 });
+    }
+
+    if (orderAmount < 0) {
+      return NextResponse.json({ error: 'Invalid order amount' }, { status: 400 });
+    }
+
+    // Find store by slug
+    const store = await prisma.store.findFirst({
+      where: { slug, deletedAt: null },
+      select: { id: true },
+    });
+
+    if (!store) {
+      return NextResponse.json({ error: 'Store not found' }, { status: 404 });
+    }
+
+    // Find active coupon for this store
+    const coupon = await prisma.discountCode.findFirst({
+      where: {
+        storeId: store.id,
+        code,
+        isActive: true,
+        deletedAt: null,
+        OR: [
+          { expiresAt: null },
+          { expiresAt: { gt: new Date() } },
+        ],
+      },
+    });
+
+    if (!coupon) {
+      return NextResponse.json(
+        { error: 'Invalid or expired coupon code' },
+        { status: 400 }
+      );
+    }
+
+    // Check max global uses
+    if (coupon.maxUses !== null && coupon.currentUses >= coupon.maxUses) {
+      return NextResponse.json(
+        { error: 'This coupon has reached its maximum usage limit' },
+        { status: 400 }
+      );
+    }
+
+    // Check minimum order amount
+    if (coupon.minOrderAmount !== null && orderAmount < coupon.minOrderAmount) {
+      // Format amount for display (divide by 100 for major units)
+      const minDisplay = (coupon.minOrderAmount / 100).toFixed(2);
+      return NextResponse.json(
+        { error: `Minimum order amount of ৳${minDisplay} is required for this coupon` },
+        { status: 400 }
+      );
+    }
+
+    // Calculate discount amount (values are stored in minor units / paisa)
+    let discountAmount: number;
+
+    if (coupon.type === 'PERCENTAGE') {
+      // value is 0-100 (e.g. 10 = 10%)
+      discountAmount = Math.round((orderAmount * coupon.value) / 100);
+      // Apply cap if set
+      if (coupon.maxDiscountAmount !== null) {
+        discountAmount = Math.min(discountAmount, coupon.maxDiscountAmount);
+      }
+    } else {
+      // FIXED – value is minor units (paisa)
+      // Cannot discount more than the order amount
+      discountAmount = Math.min(coupon.value, orderAmount);
+    }
+
+    return NextResponse.json({
+      valid: true,
+      code: coupon.code,
+      discountAmount,
+      description: coupon.description ?? coupon.name,
+      type: coupon.type,
+      value: coupon.value,
+    });
+  } catch (error) {
+    console.error('[coupon/validate] Error:', error);
+    return NextResponse.json(
+      { error: 'Failed to validate coupon. Please try again.' },
+      { status: 500 }
+    );
+  }
+}