[Api] Add OrganizationBillingController.SetupBusinessUnitAsync action

src/Api/Billing/Controllers/OrganizationBillingController.cs

@@ -12,12 +12,14 @@ using Bit.Core.Services;
 using Bit.Core.Utilities;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
+using OneOf.Types;
 
 namespace Bit.Api.Billing.Controllers;
 
 [Route("organizations/{organizationId:guid}/billing")]
 [Authorize("Application")]
 public class OrganizationBillingController(
+    IBusinessUnitConverter businessUnitConverter,
     ICurrentContext currentContext,
     IOrganizationBillingService organizationBillingService,
     IOrganizationRepository organizationRepository,
@@ -296,4 +298,32 @@ public class OrganizationBillingController(
 
         return TypedResults.Ok();
     }
+
+    [HttpPost("setup-business-unit")]
+    [SelfHosted(NotSelfHostedOnly = true)]
+    public async Task<IResult> SetupBusinessUnitAsync(
+        [FromRoute] Guid organizationId,
+        [FromBody] SetupBusinessUnitRequestBody requestBody)
+    {
+        var organization = await organizationRepository.GetByIdAsync(organizationId);
+
+        if (organization == null)
+        {
+            return Error.NotFound();
+        }
+
+        if (!await currentContext.OrganizationUser(organizationId))
+        {
+            return Error.Unauthorized();
+        }
+
+        var providerId = await businessUnitConverter.FinalizeConversion(
+            organization,
+            requestBody.UserId,
+            requestBody.Token,
+            requestBody.ProviderKey,
+            requestBody.OrganizationKey);
+
+        return TypedResults.Ok(providerId);
+    }
 }

src/Api/Billing/Models/Requests/SetupBusinessUnitRequestBody.cs

@@ -0,0 +1,18 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Bit.Api.Billing.Models.Requests;
+
+public class SetupBusinessUnitRequestBody
+{
+    [Required]
+    public Guid UserId { get; set; }
+
+    [Required]
+    public string Token { get; set; }
+
+    [Required]
+    public string ProviderKey { get; set; }
+
+    [Required]
+    public string OrganizationKey { get; set; }
+}