Cleaned up the architecture

src/main/java/auth_service/domain/login/controller/LoginController.java

@@ -1,13 +1,12 @@
 package auth_service.domain.login.controller;
 
-import auth_service.domain.login.controller.dtos.LoginRequest;
-import auth_service.domain.login.controller.dtos.LoginResponse;
-import auth_service.domain.login.repository.UserRepository;
+import auth_service.domain.login.controller.dtos.request.LoginRequest;
+import auth_service.domain.login.controller.dtos.response.LoginResponse;
+import auth_service.domain.login.controller.mapper.ApiMapper;
+import auth_service.domain.login.service.LoginService;
 import io.micrometer.core.annotation.Timed;
 import lombok.RequiredArgsConstructor;
-import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
-import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -21,8 +20,7 @@ import org.springframework.web.bind.annotation.RestController;
 @RequiredArgsConstructor
 public class LoginController {
 
-    private final UserRepository userRepository;
-    private final PasswordEncoder passwordEncoder;
+    private final LoginService loginService;
 
     /**
      * Authenticates a user based on email and password.
@@ -34,13 +32,8 @@ public class LoginController {
     @Timed(value = "auth.login.requests.time", description = "Time taken to process login requests")
     public ResponseEntity<LoginResponse> login(@RequestBody LoginRequest request) {
 
-        return userRepository.findByEmail(request.email())
-                .filter(user -> passwordEncoder.matches(request.password(), user.getPassword()))
-                .map(user -> ResponseEntity.ok(
-                        new LoginResponse("Login successful", user.getEmail())
-                ))
-                .orElseGet(() -> ResponseEntity.status(HttpStatus.UNAUTHORIZED).body(
-                        new LoginResponse("Invalid credentials", null)
-                ));
+        var user = ApiMapper.toModel(request);
+        loginService.login(user);
+        return ResponseEntity.ok(new LoginResponse("Login successful", user.getEmail()));
     }
 }

src/main/java/auth_service/domain/login/controller/LoginExceptionController.java

@@ -0,0 +1,48 @@
+package auth_service.domain.login.controller;
+
+import auth_service.domain.login.controller.dtos.response.ErrorResponse;
+import auth_service.domain.login.exception.InvalidCredentialsException;
+import auth_service.domain.login.exception.UserNotFoundException;
+import lombok.NonNull;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.core.annotation.Order;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+@Order(value = 1)
+@Slf4j
+public class LoginExceptionController {
+    private static @NonNull ResponseEntity<ErrorResponse> response500(ErrorResponse body) {
+        log.error(body.message(), body.code());
+        return ResponseEntity.status(500)
+                .contentType(org.springframework.http.MediaType.APPLICATION_JSON)
+                .body(body);
+    }
+
+    private static @NonNull ResponseEntity<ErrorResponse> response400(ErrorResponse body) {
+        return ResponseEntity.status(400)
+                .contentType(org.springframework.http.MediaType.APPLICATION_JSON)
+                .body(body);
+    }
+
+    /*
+   ######## CLIENT ERRORS (500-599)
+    */
+
+    /*
+   ######## CLIENT ERRORS (400-499)
+    */
+    @ExceptionHandler(UserNotFoundException.class)
+    public ResponseEntity<ErrorResponse> clientError(UserNotFoundException ex) {
+        var body = new ErrorResponse("USER_NOT_FOUND", ex.getMessage());
+        return response400(body);
+    }
+
+    @ExceptionHandler(InvalidCredentialsException.class)
+    public ResponseEntity<ErrorResponse> clientError(InvalidCredentialsException ex) {
+        var body = new ErrorResponse("INVALID_CREDENTIALS", ex.getMessage());
+        return response400(body);
+    }
+}

src/main/java/auth_service/domain/login/controller/dtos/LoginRequest.java

@@ -1,7 +0,0 @@
-package auth_service.domain.login.controller.dtos;
-
-/**
- * DTO (Data Transfer Object) representing the incoming login request.
- */
-public record LoginRequest(String email, String password) {
-}

src/main/java/auth_service/domain/login/controller/dtos/request/LoginRequest.java

@@ -0,0 +1,10 @@
+package auth_service.domain.login.controller.dtos.request;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+
+/**
+ * DTO (Data Transfer Object) representing the incoming login request.
+ */
+public record LoginRequest(@NotNull String email, @NotNull @NotBlank String password) {
+}

src/main/java/auth_service/domain/login/controller/dtos/response/ErrorResponse.java

@@ -0,0 +1,4 @@
+package auth_service.domain.login.controller.dtos.response;
+
+public record ErrorResponse(String code, String message) {
+}

src/main/java/auth_service/domain/login/controller/dtos/response/LoginResponse.java

@@ -1,4 +1,4 @@
-package auth_service.domain.login.controller.dtos;
+package auth_service.domain.login.controller.dtos.response;
 
 /**
  * DTO representing the outgoing login response.

src/main/java/auth_service/domain/login/controller/mapper/ApiMapper.java

@@ -0,0 +1,13 @@
+package auth_service.domain.login.controller.mapper;
+
+import auth_service.domain.login.controller.dtos.request.LoginRequest;
+import auth_service.domain.login.model.User;
+
+public abstract class ApiMapper {
+    private ApiMapper() {
+    }
+
+    public static User toModel(LoginRequest loginRequest) {
+        return User.builder().email(loginRequest.email()).encryptedPassword(loginRequest.password()).build();
+    }
+}

src/main/java/auth_service/domain/login/exception/InvalidCredentialsException.java

@@ -0,0 +1,7 @@
+package auth_service.domain.login.exception;
+
+public class InvalidCredentialsException extends RuntimeException {
+    public InvalidCredentialsException(String message) {
+        super(message);
+    }
+}

src/main/java/auth_service/domain/login/exception/UserNotFoundException.java

@@ -0,0 +1,7 @@
+package auth_service.domain.login.exception;
+
+public class UserNotFoundException extends RuntimeException {
+    public UserNotFoundException(String message) {
+        super(message);
+    }
+}

src/main/java/auth_service/domain/login/model/User.java

@@ -0,0 +1,12 @@
+package auth_service.domain.login.model;
+
+import lombok.Builder;
+import lombok.Data;
+
+@Builder
+@Data
+public class User {
+    private long id;
+    private String email;
+    private String encryptedPassword;
+}

src/main/java/auth_service/domain/login/persistence/UserRepository.java

@@ -0,0 +1,18 @@
+package auth_service.domain.login.persistence;
+
+import auth_service.domain.login.model.User;
+
+import java.util.Optional;
+
+/**
+ * Repository for database operations regarding the User entity.
+ */
+public interface UserRepository {
+    /**
+     * Finds a user by their email address.
+     * * @param email The email to search for
+     *
+     * @return An Optional containing the user if found
+     */
+    Optional<User> findByEmail(String email);
+}

src/main/java/auth_service/domain/login/persistence/UserRepositoryImpl.java

@@ -0,0 +1,36 @@
+package auth_service.domain.login.persistence;
+
+import auth_service.domain.login.model.User;
+import auth_service.domain.login.persistence.entities.UserEntity;
+import auth_service.domain.login.persistence.mapper.EntityMapper;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.PersistenceContext;
+import jakarta.persistence.TypedQuery;
+import jakarta.persistence.criteria.CriteriaBuilder;
+import jakarta.persistence.criteria.CriteriaQuery;
+import jakarta.persistence.criteria.Root;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+
+@Repository
+public class UserRepositoryImpl implements UserRepository {
+    @PersistenceContext
+    private EntityManager entityManager;
+
+    @Override
+    public Optional<User> findByEmail(String email) {
+        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
+        CriteriaQuery<UserEntity> query = cb.createQuery(UserEntity.class);
+        Root<UserEntity> user = query.from(UserEntity.class);
+
+        // Build the query: SELECT u FROM UserEntity u WHERE u.email = :email
+        query.select(user).where(cb.equal(user.get("email"), email));
+
+        TypedQuery<UserEntity> typedQuery = entityManager.createQuery(query);
+
+        return typedQuery.getResultStream()
+                .findFirst()
+                .map(EntityMapper::mapToModel);
+    }
+}

src/main/java/auth_service/domain/login/persistence/entities/UserEntity.java

@@ -1,4 +1,4 @@
-package auth_service.domain.login.model;
+package auth_service.domain.login.persistence.entities;
 
 import jakarta.persistence.*;
 import lombok.*;

src/main/java/auth_service/domain/login/persistence/mapper/EntityMapper.java

@@ -0,0 +1,22 @@
+package auth_service.domain.login.persistence.mapper;
+
+import auth_service.domain.login.model.User;
+import auth_service.domain.login.persistence.entities.UserEntity;
+
+public abstract class EntityMapper {
+
+    private EntityMapper() {
+    }
+
+    public static User mapToModel(UserEntity entity) {
+        User model = User.builder().build();
+
+        if (entity != null) {
+            model.setId(entity.getId());
+            model.setEmail(entity.getEmail());
+            model.setEncryptedPassword(entity.getPassword());
+        }
+
+        return model;
+    }
+}

src/main/java/auth_service/domain/login/repository/UserRepository.java

@@ -1,22 +0,0 @@
-package auth_service.domain.login.repository;
-
-import auth_service.domain.login.model.UserEntity;
-import org.springframework.data.jpa.repository.JpaRepository;
-import org.springframework.stereotype.Repository;
-
-import java.util.Optional;
-
-/**
- * Repository for database operations regarding the User entity.
- */
-@Repository
-public interface UserRepository extends JpaRepository<UserEntity, Long> {
-
-    /**
-     * Finds a user by their email address.
-     * * @param email The email to search for
-     *
-     * @return An Optional containing the user if found
-     */
-    Optional<UserEntity> findByEmail(String email);
-}

src/main/java/auth_service/domain/login/service/LoginService.java

@@ -0,0 +1,28 @@
+package auth_service.domain.login.service;
+
+import auth_service.domain.login.exception.InvalidCredentialsException;
+import auth_service.domain.login.exception.UserNotFoundException;
+import auth_service.domain.login.model.User;
+import auth_service.domain.login.persistence.UserRepository;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+@Slf4j
+public class LoginService {
+    private final UserRepository userRepository;
+    private final PasswordEncoder passwordEncoder;
+
+    public String login(User userToLogin) {
+        var userEntity = userRepository.findByEmail(userToLogin.getEmail()).orElseThrow(() -> new UserNotFoundException("User not found with given email"));
+        var loginSuccessful = passwordEncoder.matches(userToLogin.getEncryptedPassword(), userEntity.getEncryptedPassword());
+        if (!loginSuccessful) {
+            throw new InvalidCredentialsException("Invalid credentials");
+        }
+
+        return "";
+    }
+}