refactor to adapters

core/identity/application/use-cases/SignupUseCase.ts

@@ -0,0 +1,41 @@
+import { EmailAddress } from '../../domain/value-objects/EmailAddress';
+import { UserId } from '../../domain/value-objects/UserId';
+import { User } from '../../domain/entities/User';
+import { IAuthRepository } from '../../domain/repositories/IAuthRepository';
+import { IPasswordHashingService } from '../../domain/services/PasswordHashingService';
+
+/**
+ * Application Use Case: SignupUseCase
+ *
+ * Handles user registration.
+ */
+export class SignupUseCase {
+  constructor(
+    private authRepo: IAuthRepository,
+    private passwordService: IPasswordHashingService
+  ) {}
+
+  async execute(email: string, password: string, displayName: string): Promise<User> {
+    const emailVO = EmailAddress.create(email);
+
+    // Check if user already exists
+    const existingUser = await this.authRepo.findByEmail(emailVO);
+    if (existingUser) {
+      throw new Error('User already exists');
+    }
+
+    const hashedPassword = await this.passwordService.hash(password);
+    const passwordHash = await import('../../domain/value-objects/PasswordHash').then(m => m.PasswordHash.fromHash(hashedPassword));
+
+    const userId = UserId.create();
+    const user = User.create({
+      id: userId,
+      displayName,
+      email: emailVO.value,
+      passwordHash,
+    });
+
+    await this.authRepo.save(user);
+    return user;
+  }
+}