[PM-18770] Convert Organization to Business Unit (#5610)

* [NO LOGIC] Rename MultiOrganizationEnterprise to BusinessUnit

* [Core] Add IMailService.SendBusinessUnitConversionInviteAsync

* [Core] Add BusinessUnitConverter

* [Admin] Add new permission

* [Admin] Add BusinessUnitConverterController

* [Admin] Add Convert to Business Unit button to Organization edit page

* [Api] Add OrganizationBillingController.SetupBusinessUnitAsync action

* [Multi] Propagate provider type to sync response

* [Multi] Put updates behind feature flag

* [Tests] BusinessUnitConverterTests

* Run dotnet format

* Fixing post-main merge compilation failure

src/Api/AdminConsole/Models/Response/Providers/ProfileProviderResponseModel.cs

@@ -22,6 +22,7 @@ public class ProfileProviderResponseModel : ResponseModel
         UserId = provider.UserId;
         UseEvents = provider.UseEvents;
         ProviderStatus = provider.ProviderStatus;
+        ProviderType = provider.ProviderType;
     }
 
     public Guid Id { get; set; }
@@ -35,4 +36,5 @@ public class ProfileProviderResponseModel : ResponseModel
     public Guid? UserId { get; set; }
     public bool UseEvents { get; set; }
     public ProviderStatusType ProviderStatus { get; set; }
+    public ProviderType ProviderType { get; set; }
 }

src/Api/Billing/Controllers/OrganizationBillingController.cs

@@ -2,6 +2,7 @@
 using Bit.Api.AdminConsole.Models.Request.Organizations;
 using Bit.Api.Billing.Models.Requests;
 using Bit.Api.Billing.Models.Responses;
+using Bit.Core;
 using Bit.Core.Billing.Models;
 using Bit.Core.Billing.Models.Sales;
 using Bit.Core.Billing.Pricing;
@@ -18,7 +19,9 @@ namespace Bit.Api.Billing.Controllers;
 [Route("organizations/{organizationId:guid}/billing")]
 [Authorize("Application")]
 public class OrganizationBillingController(
+    IBusinessUnitConverter businessUnitConverter,
     ICurrentContext currentContext,
+    IFeatureService featureService,
     IOrganizationBillingService organizationBillingService,
     IOrganizationRepository organizationRepository,
     IPaymentService paymentService,
@@ -296,4 +299,40 @@ 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 enableOrganizationBusinessUnitConversion =
+            featureService.IsEnabled(FeatureFlagKeys.PM18770_EnableOrganizationBusinessUnitConversion);
+
+        if (!enableOrganizationBusinessUnitConversion)
+        {
+            return Error.NotFound();
+        }
+
+        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; }
+}