align backend auth patterns

backend/app/Auth/BcryptPasswordHasher.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Auth;
+
+class BcryptPasswordHasher implements PasswordHasher
+{
+    public function hash(string $password): string
+    {
+        return password_hash($password, PASSWORD_DEFAULT);
+    }
+
+    public function verify(string $password, string $hash): bool
+    {
+        return password_verify($password, $hash);
+    }
+}

backend/app/Auth/PasswordHasher.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace App\Auth;
+
+interface PasswordHasher
+{
+    public function hash(string $password): string;
+
+    public function verify(string $password, string $hash): bool;
+}

backend/app/Auth/RandomTokenGenerator.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Auth;
+
+class RandomTokenGenerator implements TokenGenerator
+{
+    public function generate(): string
+    {
+        return bin2hex(random_bytes(32));
+    }
+}

backend/app/Auth/TokenGenerator.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace App\Auth;
+
+interface TokenGenerator
+{
+    public function generate(): string;
+}

backend/app/Auth/UseCases/AuthenticateUser/AuthenticateUser.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Auth\UseCases\AuthenticateUser;
+
+use App\Auth\PasswordHasher;
+use App\Exceptions\BadRequestException;
+use App\Exceptions\UnauthorizedException;
+use App\Shared\ValueObject\EmailAddress;
+use App\User\User;
+use App\User\UserRepository;
+
+class AuthenticateUser
+{
+    public function __construct(
+        private UserRepository $userRepo,
+        private PasswordHasher $hasher,
+    ) {}
+
+    /**
+     * @throws BadRequestException
+     * @throws UnauthorizedException
+     */
+    public function execute(AuthenticateUserRequest $request): User
+    {
+        if ($request->email === null || $request->email === '') {
+            throw new BadRequestException('email is required');
+        }
+        if ($request->password === null || $request->password === '') {
+            throw new BadRequestException('password is required');
+        }
+
+        $user = $this->userRepo->findByEmail(
+            new EmailAddress($request->email)
+        );
+        if ($user === null) {
+            throw new UnauthorizedException('invalid credentials');
+        }
+
+        $passwordMatches = $this->hasher->verify(
+            $request->password,
+            $user->getPasswordHash(),
+        );
+        if (! $passwordMatches) {
+            throw new UnauthorizedException('invalid credentials');
+        }
+
+        return $user;
+    }
+}

backend/app/Auth/UseCases/AuthenticateUser/AuthenticateUserRequest.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Auth\UseCases\AuthenticateUser;
+
+class AuthenticateUserRequest
+{
+    public function __construct(
+        public ?string $email,
+        public ?string $password,
+    ) {}
+}

backend/app/Auth/UseCases/CreateSession/CreateSession.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace App\Auth\UseCases\CreateSession;
+
+use App\Auth\Clock;
+use App\Auth\CreateSessionDto;
+use App\Auth\Session;
+use App\Auth\SessionRepository;
+use App\Auth\TokenGenerator;
+use App\User\User;
+
+class CreateSession
+{
+    private const SESSION_LIFETIME = '+7 days';
+
+    public function __construct(
+        private SessionRepository $sessionRepo,
+        private TokenGenerator $tokenGenerator,
+        private Clock $clock,
+    ) {}
+
+    public function execute(User $user): Session
+    {
+        $now = $this->clock->now();
+        $expiresAt = $now->modify(self::SESSION_LIFETIME);
+
+        return $this->sessionRepo->create(new CreateSessionDto(
+            token: $this->tokenGenerator->generate(),
+            user: $user,
+            createdAt: $now,
+            expiresAt: $expiresAt,
+        ));
+    }
+}