overwrite existing users on import

src/Api/Controllers/OrganizationsController.cs

@@ -376,7 +376,8 @@ namespace Bit.Api.Controllers
                 userId.Value,
                 model.Groups.Select(g => g.ToImportedGroup(orgIdGuid)),
                 model.Users.Where(u => !u.Deleted).Select(u => u.ToImportedOrganizationUser()),
-                model.Users.Where(u => u.Deleted).Select(u => u.ExternalId));
+                model.Users.Where(u => u.Deleted).Select(u => u.ExternalId),
+                model.OverwriteExisting);
         }
 
         [HttpPost("{id}/api-key")]

src/Core/Models/Api/Request/Organizations/ImportOrganizationUsersRequestModel.cs

@@ -10,6 +10,7 @@ namespace Bit.Core.Models.Api
     {
         public Group[] Groups { get; set; }
         public User[] Users { get; set; }
+        public bool OverwriteExisting { get; set; }
 
         public class Group
         {

src/Core/Services/IOrganizationService.cs

@@ -42,7 +42,8 @@ namespace Bit.Core.Services
         Task<OrganizationLicense> GenerateLicenseAsync(Guid organizationId, Guid installationId);
         Task<OrganizationLicense> GenerateLicenseAsync(Organization organization, Guid installationId);
         Task ImportAsync(Guid organizationId, Guid importingUserId, IEnumerable<ImportedGroup> groups,
-            IEnumerable<ImportedOrganizationUser> newUsers, IEnumerable<string> removeUserExternalIds);
+            IEnumerable<ImportedOrganizationUser> newUsers, IEnumerable<string> removeUserExternalIds,
+            bool overwriteExisting);
         Task RotateApiKeyAsync(Organization organization);
     }
 }

src/Core/Services/Implementations/OrganizationService.cs

@@ -1143,7 +1143,8 @@ namespace Bit.Core.Services
             Guid importingUserId,
             IEnumerable<ImportedGroup> groups,
             IEnumerable<ImportedOrganizationUser> newUsers,
-            IEnumerable<string> removeUserExternalIds)
+            IEnumerable<string> removeUserExternalIds,
+            bool overwriteExisting)
         {
             var organization = await GetOrgById(organizationId);
             if(organization == null)
@@ -1181,6 +1182,23 @@ namespace Bit.Core.Services
                 }
             }
 
+            if(overwriteExisting)
+            {
+                // Remove existing external users that are not in new user set
+                foreach(var user in existingExternalUsers)
+                {
+                    if(!newUsersSet.Contains(user.ExternalId) &&
+                        existingExternalUsersIdDict.ContainsKey(user.ExternalId))
+                    {
+                        await _organizationUserRepository.DeleteAsync(new OrganizationUser
+                        {
+                            Id = user.Id
+                        });
+                        existingExternalUsersIdDict.Remove(user.ExternalId);
+                    }
+                }
+            }
+
             if(newUsers?.Any() ?? false)
             {
                 // Marry existing users