feat: implement AuthService and AuthController

src/main/java/com/example/bankcards/service/AuthController.java

@@ -0,0 +1,32 @@
+package com.example.bankcards.controller;
+
+import com.example.bankcards.dto.AuthResponse;
+import com.example.bankcards.dto.LoginRequest;
+import com.example.bankcards.dto.RegisterRequest;
+import com.example.bankcards.service.AuthService;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/auth")
+@RequiredArgsConstructor
+public class AuthController {
+
+    private final AuthService authService;
+
+    @PostMapping("/register")
+    public ResponseEntity<AuthResponse> register(
+        @Valid @RequestBody RegisterRequest request
+    ) {
+        return ResponseEntity.ok(authService.register(request));
+    }
+
+    @PostMapping("/login")
+    public ResponseEntity<AuthResponse> login(
+        @Valid @RequestBody LoginRequest request
+    ) {
+        return ResponseEntity.ok(authService.login(request));
+    }
+}

src/main/java/com/example/bankcards/service/AuthService.java

@@ -0,0 +1,76 @@
+package com.example.bankcards.service;
+
+import com.example.bankcards.dto.AuthResponse;
+import com.example.bankcards.dto.LoginRequest;
+import com.example.bankcards.dto.RegisterRequest;
+import com.example.bankcards.entity.Role;
+import com.example.bankcards.entity.User;
+import com.example.bankcards.exception.BadRequestException;
+import com.example.bankcards.repository.UserRepository;
+import com.example.bankcards.security.JwtService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class AuthService {
+
+    private final UserRepository userRepository;
+    private final PasswordEncoder passwordEncoder;
+    private final JwtService jwtService;
+    private final AuthenticationManager authenticationManager;
+    private final UserDetailsService userDetailsService;
+
+    public AuthResponse register(RegisterRequest request) {
+        if (userRepository.existsByUsername(request.getUsername())) {
+            throw new BadRequestException("Username already taken");
+        }
+        if (userRepository.existsByEmail(request.getEmail())) {
+            throw new BadRequestException("Email already registered");
+        }
+
+        User user = User.builder()
+            .username(request.getUsername())
+            .email(request.getEmail())
+            .password(passwordEncoder.encode(request.getPassword()))
+            .role(Role.ROLE_USER)
+            .build();
+        userRepository.save(user);
+
+        UserDetails userDetails = userDetailsService.loadUserByUsername(
+            user.getUsername()
+        );
+        String token = jwtService.generateToken(userDetails);
+        return new AuthResponse(
+            token,
+            user.getUsername(),
+            user.getRole().name()
+        );
+    }
+
+    public AuthResponse login(LoginRequest request) {
+        authenticationManager.authenticate(
+            new UsernamePasswordAuthenticationToken(
+                request.getUsername(),
+                request.getPassword()
+            )
+        );
+        UserDetails userDetails = userDetailsService.loadUserByUsername(
+            request.getUsername()
+        );
+        String token = jwtService.generateToken(userDetails);
+        User user = userRepository
+            .findByUsername(request.getUsername())
+            .orElseThrow();
+        return new AuthResponse(
+            token,
+            user.getUsername(),
+            user.getRole().name()
+        );
+    }
+}