fix: billing (#5483)

apps/web/modules/api/v2/management/responses/lib/organization.ts

@@ -1,5 +1,6 @@
 import { cache } from "@/lib/cache";
 import { organizationCache } from "@/lib/organization/cache";
+import { getBillingPeriodStartDate } from "@/lib/utils/billing";
 import { ApiErrorResponseV2 } from "@/modules/api/v2/types/api-error";
 import { Organization } from "@prisma/client";
 import { cache as reactCache } from "react";
@@ -133,22 +134,7 @@ export const getMonthlyOrganizationResponseCount = reactCache(async (organizatio
         }
 
         // Determine the start date based on the plan type
-        let startDate: Date;
-
-        if (billing.data.plan === "free") {
-          // For free plans, use the first day of the current calendar month
-          const now = new Date();
-          startDate = new Date(now.getFullYear(), now.getMonth(), 1);
-        } else {
-          // For other plans, use the periodStart from billing
-          if (!billing.data.periodStart) {
-            return err({
-              type: "internal_server_error",
-              details: [{ field: "organization", issue: "billing period start is not set" }],
-            });
-          }
-          startDate = billing.data.periodStart;
-        }
+        const startDate = getBillingPeriodStartDate(billing.data);
 
         // Get all environment IDs for the organization
         const environmentIdsResult = await getAllEnvironmentsFromOrganizationId(organizationId);