add email signup flow

backend/app/User/UseCases/ConfirmUserEmail/ConfirmUserEmail.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace App\User\UseCases\ConfirmUserEmail;
+
+use App\Auth\Clock;
+use App\Auth\PasswordHasher;
+use App\Email\EmailConfirmationToken\EmailConfirmationTokenRepository;
+use App\Exceptions\BadRequestException;
+use App\User\User;
+use App\User\UserRepository;
+use DomainException;
+
+class ConfirmUserEmail
+{
+    public function __construct(
+        private EmailConfirmationTokenRepository $tokenRepository,
+        private UserRepository $userRepository,
+        private PasswordHasher $passwordHasher,
+        private Clock $clock,
+    ) {}
+
+    /**
+     * @throws BadRequestException
+     * @throws DomainException
+     */
+    public function execute(ConfirmUserEmailRequest $request): User
+    {
+        if ($request->token === null || $request->token === '') {
+            throw new BadRequestException('token is required');
+        }
+        if ($request->password === null || $request->password === '') {
+            throw new BadRequestException('password is required');
+        }
+        if (strlen($request->password) < 8) {
+            throw new BadRequestException(
+                'password must be at least 8 characters',
+            );
+        }
+
+        $token = $this->tokenRepository->findByToken($request->token);
+        if ($token === null) {
+            throw new DomainException('token not found');
+        }
+        if ($token->getAvailableTo() < $this->clock->now()) {
+            throw new DomainException('token expired');
+        }
+
+        $user = $token->getUser();
+        if ($user->getPasswordHash() !== null) {
+            throw new DomainException('account already confirmed');
+        }
+
+        $user->setPasswordHash(
+            $this->passwordHasher->hash($request->password),
+        );
+        $confirmedUser = $this->userRepository->update($user);
+        $this->tokenRepository->delete($token->getId());
+
+        return $confirmedUser;
+    }
+}