chore: Add guard guardUserDoesNotExists in CreateUserCommandHandler

src/languages/application/user/command/create/createUserCommandHandler.ts

@@ -5,20 +5,25 @@ import Email from '@src/shared/domain/valueObjects/email';
 import User from '@src/languages/domain/user/user';
 import { Inject } from '@src/shared/domain/injector/inject.decorator';
 import { CommandHandler, ICommandHandler } from '@src/shared/domain/bus/commandBus/commandHandler';
+import UserAlreadyExistsException from '@src/languages/domain/user/userAlreadyExistsException';
 
 @CommandHandler(CreateUserCommand)
 export default class CreateUserCommandHandler implements ICommandHandler<CreateUserCommand> {
   constructor(@Inject(USER_REPOSITORY) private readonly userRepository: UserRepository) {}
 
   async execute(command: CreateUserCommand): Promise<void> {
-    const user = User.create(
-      UserId.of(command.id),
-      command.name,
-      command.provider,
-      Email.of(command.email),
-      command.photo,
-    );
+    const userId = UserId.of(command.id);
+    await this.guardUserDoesNotExists(userId);
+
+    const user = User.create(userId, command.name, command.provider, Email.of(command.email), command.photo);
 
     await this.userRepository.save(user);
   }
+
+  private async guardUserDoesNotExists(userId: UserId): Promise<void> {
+    const user = await this.userRepository.findById(userId);
+    if (!user) {
+      throw new UserAlreadyExistsException(userId.value);
+    }
+  }
 }

src/languages/domain/user/userAlreadyExistsException.ts

@@ -0,0 +1,7 @@
+import ConflictException from '@src/shared/domain/exceptions/conflictException';
+
+export default class UserAlreadyExistsException extends ConflictException {
+  constructor(id: string) {
+    super(`User with id ${id} already exists`, 'user_already_exists');
+  }
+}