From faad097915e4623113f7e70619e29178c97d7ff5 Mon Sep 17 00:00:00 2001
From: Jaanus Sellin <sellinjaanus@gmail.com>
Date: Fri, 17 Oct 2025 15:09:52 +0300
Subject: [PATCH] feat: overages should be rouned down to nearest integer
 (#10826)

---
 .../BillingInvoiceUsageRow.tsx                |  2 +-
 .../calculateEstimateTotals.test.ts           | 22 +++++++++++++++++++
 .../BillingInvoice/calculateEstimateTotals.ts |  2 +-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/BillingInvoiceUsageRow/BillingInvoiceUsageRow.tsx b/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/BillingInvoiceUsageRow/BillingInvoiceUsageRow.tsx
index a7ca07b51e..2557edf7c5 100644
--- a/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/BillingInvoiceUsageRow/BillingInvoiceUsageRow.tsx
+++ b/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/BillingInvoiceUsageRow/BillingInvoiceUsageRow.tsx
@@ -14,7 +14,7 @@ const hasValidUsageData = (consumption?: number, limit?: number): boolean => {
 
 const calculateOverage = (consumption?: number, limit?: number): number => {
     return hasValidUsageData(consumption, limit)
-        ? Math.max(0, consumption! - limit!)
+        ? Math.floor(Math.max(0, consumption! - limit!))
         : 0;
 };
 
diff --git a/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.test.ts b/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.test.ts
index f9d214acbd..cad47b7a57 100644
--- a/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.test.ts
+++ b/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.test.ts
@@ -274,5 +274,27 @@ describe('calculateEstimateTotals', () => {
                 totalAmount: 110,
             });
         });
+
+        it('rounds down overages to integers', () => {
+            const usageLines = [
+                createUsageLine(150.7, 100, 2),
+                createUsageLine(200.3, 150, 1.5),
+            ];
+            const result = calculateEstimateTotals(
+                'estimate',
+                0,
+                0,
+                0,
+                10,
+                [],
+                usageLines,
+            );
+
+            expect(result).toEqual({
+                subtotal: 175,
+                taxAmount: 17.5,
+                totalAmount: 192.5,
+            });
+        });
     });
 });
diff --git a/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.ts b/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.ts
index c0b131560c..829cd57834 100644
--- a/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.ts
+++ b/frontend/src/component/admin/billing/BillingInvoices/BillingInvoice/calculateEstimateTotals.ts
@@ -25,7 +25,7 @@ export const calculateEstimateTotals = (
     const usageLinesTotal = usageLines.reduce((sum, line) => {
         const overage =
             line.consumption && line.limit
-                ? Math.max(0, line.consumption - line.limit)
+                ? Math.floor(Math.max(0, line.consumption - line.limit))
                 : 0;
         return sum + overage * (line.unitPrice || 0);
     }, 0);