auth-service/src/main/java/com/danielbohry/authservice/service/auth/AuthService.java

package com.danielbohry.authservice.service.auth;

import com.danielbohry.authservice.api.dto.AuthenticationRequest;
import com.danielbohry.authservice.api.dto.AuthenticationResponse;
import com.danielbohry.authservice.client.MailClient;
import com.danielbohry.authservice.domain.ApplicationUser;
import com.danielbohry.authservice.service.user.UserService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.stereotype.Service;

import static com.danielbohry.authservice.service.auth.UserConverter.convert;
import static java.time.Instant.now;

@Slf4j
@Service
@RequiredArgsConstructor
public class AuthService implements UserDetailsService {

    private final UserService service;
    private final JwtService jwtService;
    private final AuthenticationManager authenticationManager;
    private final PasswordEncoder passwordEncoder;
    private final MailClient mailClient;

    @Value("${host.name:localhost}")
    private String host;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        var user = service.findByUsername(username);
        var authorities = user.getRoles().stream().map(role -> new SimpleGrantedAuthority("ROLE_" + role)).toList();

        return new User(user.getUsername(), user.getPassword(), authorities);
    }

    public AuthenticationResponse register(AuthenticationRequest request) {
        UserDetails user = buildUserDetails(request);
        ApplicationUser toSave = convert(user, request.getEmail());
        toSave.setCreatedAt(now());
        toSave.setUpdatedAt(now());
        toSave.setLastLoginAt(now());
        ApplicationUser saved = service.create(toSave);
        Authentication authentication = jwtService.generateToken(saved);
        log.info("Username [{}] registered", request.getUsername());
        return buildResponse(saved, authentication);
    }

    public AuthenticationResponse authenticate(AuthenticationRequest request) {
        authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(
                request.getUsername(), request.getPassword())
        );
        ApplicationUser user = service.findByUsername(request.getUsername());
        Authentication authentication = jwtService.generateToken(user);
        log.info("Username [{}] authenticated", request.getUsername());
        user.setLastLoginAt(now());
        service.update(user.getId(), user);
        return buildResponse(user, authentication);
    }

    public AuthenticationResponse refresh(ApplicationUser applicationUser) {
        if (!applicationUser.isActive()) {
            return null;
        }

        ApplicationUser user = service.findByUsername(applicationUser.getUsername());
        Authentication authentication = jwtService.generateToken(user);
        user.setLastLoginAt(now());
        service.update(user.getId(), user);
        return buildResponse(user, authentication);
    }

    public AuthenticationResponse changePassword(String userId, String currentPassword, String newPassword) {
        ApplicationUser user = service.changePassword(userId, currentPassword, newPassword, passwordEncoder);
        Authentication authentication = jwtService.generateToken(user);
        return buildResponse(user, authentication);
    }

    public AuthenticationResponse resetPassword(String userId, String newPassword) {
        ApplicationUser user = service.resetPassword(userId, newPassword, passwordEncoder);
        Authentication authentication = jwtService.generateToken(user);
        return buildResponse(user, authentication);
    }

    public AuthenticationResponse updateProfile(String userId, String currentPassword, String newPassword, String email) {
        ApplicationUser user = service.updateProfile(userId, currentPassword, newPassword, email, passwordEncoder);
        Authentication authentication = jwtService.generateToken(user);
        return buildResponse(user, authentication);
    }

    public void sendResetPasswordEmail(String username) {
        try {
            ApplicationUser user = service.findByUsername(username);
            Authentication systemAuth = jwtService.generateSystemToken();
            Authentication userAuth = jwtService.generateToken(user, 10);

            if (user.getEmail() != null && !user.getEmail().isEmpty()) {
                String resetUrl = host + "/?reset-password&token=" + userAuth.token();
                String emailContent = buildContent(user.getUsername(), resetUrl);
                mailClient.sendMail(user.getEmail(), "Password Reset Request - Auth Service", emailContent, "Bearer " + systemAuth.token());
            }
        } catch (Exception ignored) {
        }
    }

    private UserDetails buildUserDetails(AuthenticationRequest request) {
        return User.builder()
                .username(request.getUsername())
                .password(passwordEncoder.encode(request.getPassword()))
                .build();
    }

    private static AuthenticationResponse buildResponse(ApplicationUser user, Authentication authentication) {
        return AuthenticationResponse.builder()
                .id(user.getId())
                .username(authentication.username())
                .email(user.getEmail())
                .token(authentication.token())
                .expirationDate(authentication.expirationDate())
                .roles(authentication.authorities())
                .build();
    }

    private String buildContent(String username, String resetUrl) {
        return String.format("""
            Hello %s,

            You requested a password reset for your account.

            Click here to reset your password: %s

            This link expires in 10 minutes.
            If you didn't request this, please ignore this email.

            Auth Service Team
            """, username, resetUrl);
    }

}