[AC-2488] Add billing endpoint to determine SM standalone for organization (#4014)

* Add billing endpoint to determine SM standalone for org.

* Add missing attribute

src/Api/Billing/Controllers/OrganizationBillingController.cs

@@ -0,0 +1,27 @@
+using Bit.Api.Billing.Models.Responses;
+using Bit.Core.Billing.Queries;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Bit.Api.Billing.Controllers;
+
+[Route("organizations/{organizationId:guid}/billing")]
+[Authorize("Application")]
+public class OrganizationBillingController(
+    IOrganizationBillingQueries organizationBillingQueries) : Controller
+{
+    [HttpGet("metadata")]
+    public async Task<IResult> GetMetadataAsync([FromRoute] Guid organizationId)
+    {
+        var metadata = await organizationBillingQueries.GetMetadata(organizationId);
+
+        if (metadata == null)
+        {
+            return TypedResults.NotFound();
+        }
+
+        var response = OrganizationMetadataResponse.From(metadata);
+
+        return TypedResults.Ok(response);
+    }
+}

src/Api/Billing/Models/Responses/OrganizationMetadataResponse.cs

@@ -0,0 +1,10 @@
+using Bit.Core.Billing.Models;
+
+namespace Bit.Api.Billing.Models.Responses;
+
+public record OrganizationMetadataResponse(
+    bool IsOnSecretsManagerStandalone)
+{
+    public static OrganizationMetadataResponse From(OrganizationMetadataDTO metadataDTO)
+        => new(metadataDTO.IsOnSecretsManagerStandalone);
+}

src/Core/Billing/Constants/StripeConstants.cs

@@ -16,6 +16,11 @@ public static class StripeConstants
         public const string SendInvoice = "send_invoice";
     }
 
+    public static class CouponIDs
+    {
+        public const string SecretsManagerStandalone = "sm-standalone";
+    }
+
     public static class ProrationBehavior
     {
         public const string AlwaysInvoice = "always_invoice";

src/Core/Billing/Extensions/ServiceCollectionExtensions.cs

@@ -12,6 +12,7 @@ public static class ServiceCollectionExtensions
     public static void AddBillingOperations(this IServiceCollection services)
     {
         // Queries
+        services.AddTransient<IOrganizationBillingQueries, OrganizationBillingQueries>();
         services.AddTransient<IProviderBillingQueries, ProviderBillingQueries>();
         services.AddTransient<ISubscriberQueries, SubscriberQueries>();
 

src/Core/Billing/Models/OrganizationMetadataDTO.cs

@@ -0,0 +1,4 @@
+namespace Bit.Core.Billing.Models;
+
+public record OrganizationMetadataDTO(
+    bool IsOnSecretsManagerStandalone);

src/Core/Billing/Queries/IOrganizationBillingQueries.cs

@@ -0,0 +1,8 @@
+using Bit.Core.Billing.Models;
+
+namespace Bit.Core.Billing.Queries;
+
+public interface IOrganizationBillingQueries
+{
+    Task<OrganizationMetadataDTO> GetMetadata(Guid organizationId);
+}

src/Core/Billing/Queries/Implementations/OrganizationBillingQueries.cs

@@ -0,0 +1,65 @@
+using Bit.Core.AdminConsole.Entities;
+using Bit.Core.Billing.Constants;
+using Bit.Core.Billing.Models;
+using Bit.Core.Repositories;
+using Bit.Core.Utilities;
+using Stripe;
+
+namespace Bit.Core.Billing.Queries.Implementations;
+
+public class OrganizationBillingQueries(
+    IOrganizationRepository organizationRepository,
+    ISubscriberQueries subscriberQueries) : IOrganizationBillingQueries
+{
+    public async Task<OrganizationMetadataDTO> GetMetadata(Guid organizationId)
+    {
+        var organization = await organizationRepository.GetByIdAsync(organizationId);
+
+        if (organization == null)
+        {
+            return null;
+        }
+
+        var customer = await subscriberQueries.GetCustomer(organization, new CustomerGetOptions
+        {
+            Expand = ["discount.coupon.applies_to"]
+        });
+
+        var subscription = await subscriberQueries.GetSubscription(organization);
+
+        if (customer == null || subscription == null)
+        {
+            return null;
+        }
+
+        var isOnSecretsManagerStandalone = IsOnSecretsManagerStandalone(organization, customer, subscription);
+
+        return new OrganizationMetadataDTO(isOnSecretsManagerStandalone);
+    }
+
+    private static bool IsOnSecretsManagerStandalone(
+        Organization organization,
+        Customer customer,
+        Subscription subscription)
+    {
+        var plan = StaticStore.GetPlan(organization.PlanType);
+
+        if (!plan.SupportsSecretsManager)
+        {
+            return false;
+        }
+
+        var hasCoupon = customer.Discount?.Coupon?.Id == StripeConstants.CouponIDs.SecretsManagerStandalone;
+
+        if (!hasCoupon)
+        {
+            return false;
+        }
+
+        var subscriptionProductIds = subscription.Items.Data.Select(item => item.Plan.ProductId);
+
+        var couponAppliesTo = customer.Discount?.Coupon?.AppliesTo?.Products;
+
+        return subscriptionProductIds.Intersect(couponAppliesTo ?? []).Any();
+    }
+}