add email signup flow

backend/app/User/UseCases/SignupUser/SignupUser.php

@@ -0,0 +1,79 @@
+<?php
+
+namespace App\User\UseCases\SignupUser;
+
+use App\Email\EmailConfirmationToken\UseCases\CreateEmailConfirmationToken;
+use App\Email\EmailConfirmationToken\UseCases\CreateEmailConfirmationTokenRequest;
+use App\Email\Emailer;
+use App\Email\EmailFactory;
+use App\Exceptions\BadRequestException;
+use App\Shared\ValueObject\EmailAddress;
+use App\User\CreateUserDto;
+use App\User\User;
+use App\User\UserRepository;
+use DomainException;
+use InvalidArgumentException;
+
+class SignupUser
+{
+    public function __construct(
+        private UserRepository $userRepository,
+        private CreateEmailConfirmationToken $createToken,
+        private Emailer $emailer,
+        private EmailFactory $emailFactory,
+    ) {}
+
+    /**
+     * @throws BadRequestException
+     * @throws DomainException
+     */
+    public function execute(SignupUserRequest $request): void
+    {
+        if ($request->email === null || trim($request->email) === '') {
+            throw new BadRequestException('email is required');
+        }
+
+        try {
+            $email = new EmailAddress($request->email);
+        } catch (InvalidArgumentException) {
+            throw new BadRequestException('email must be valid');
+        }
+
+        $user = $this->findOrCreatePendingUser($email);
+        $token = $this->createToken->execute(
+            new CreateEmailConfirmationTokenRequest(
+                user: $user,
+                minuteOffset: 10,
+            ),
+        );
+        $body = $this->emailFactory->makeConfirmationEmail(
+            $token->getToken(),
+        );
+        $this->emailer->send(
+            $user->getEmail(),
+            'Confirm your Attainly email',
+            $body,
+        );
+    }
+
+    /**
+     * @throws DomainException
+     */
+    private function findOrCreatePendingUser(EmailAddress $email): User
+    {
+        $user = $this->userRepository->findByEmail($email);
+        if ($user === null) {
+            return $this->userRepository->create(new CreateUserDto(
+                email: $email,
+                passwordHash: null,
+            ));
+        }
+        if ($user->getPasswordHash() !== null) {
+            throw new DomainException(
+                "{$email->value()} already has an account",
+            );
+        }
+
+        return $user;
+    }
+}