source: src/main/java/com/example/rezevirajmasa/demo/service/impl/UserServiceImpl.java

package com.example.rezevirajmasa.demo.service.impl;

import com.example.rezevirajmasa.demo.dto.CredentialsDto;
import com.example.rezevirajmasa.demo.dto.SignUpDto;
import com.example.rezevirajmasa.demo.dto.UserDto;
import com.example.rezevirajmasa.demo.mappers.UserMapper;
import com.example.rezevirajmasa.demo.mappers.UserMapperImpl;
import com.example.rezevirajmasa.demo.model.MembershipLevel;
import com.example.rezevirajmasa.demo.model.Role;
import com.example.rezevirajmasa.demo.model.User;
import com.example.rezevirajmasa.demo.model.exceptions.AppException;
import com.example.rezevirajmasa.demo.repository.UserRepository;
import com.example.rezevirajmasa.demo.service.UserService;
import lombok.RequiredArgsConstructor;
import org.mapstruct.control.MappingControl;
import org.openqa.selenium.InvalidArgumentException;
import org.springframework.http.HttpStatus;
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 java.nio.CharBuffer;
import java.sql.Date;
import java.time.LocalDate;
import java.util.Optional;

@RequiredArgsConstructor
@Service
public class UserServiceImpl implements UserService, UserDetailsService {
    private final UserRepository userRepository;
    private final UserMapperImpl userMapper;
    private final PasswordEncoder passwordEncoder;
    @Override
    public UserDto findByEmail(String email) {
        User user = userRepository.findByEmail(email).orElseThrow(() -> new AppException(("Unknown user"), HttpStatus.NOT_FOUND));
        return userMapper.toUserDto(user);
    }

    @Override
    public User findByMail(String email) {
        return userRepository.findByEmail(email).orElseThrow(() -> new AppException(("Unknown user"), HttpStatus.NOT_FOUND));
    }

    public UserDto login(CredentialsDto credentialsDto) {
        User user = userRepository.findByEmail(credentialsDto.getEmail())
                .orElseThrow(() -> new AppException("Unknown user", HttpStatus.NOT_FOUND));

        if(passwordEncoder.matches(CharBuffer.wrap(credentialsDto.getPassword()), user.getPassword())) {
            return userMapper.toUserDto(user);
        }

        throw new AppException("Invalid password", HttpStatus.BAD_REQUEST);
    }

    public UserDto register(SignUpDto userDto) {
        Optional<User> optionalUser = userRepository.findByEmail(userDto.getEmail());
        if(optionalUser.isPresent()) {
            throw new AppException("Login already exists", HttpStatus.BAD_REQUEST);
        }

        User user = userMapper.signUpToUser(userDto);

        user.setPassword(passwordEncoder.encode(CharBuffer.wrap(userDto.getPassword())));

        user.setFirstName(userDto.getFirstName());
        user.setLastName(userDto.getLastName());
        user.setAddress(userDto.getAddress());
        user.setPhone(userDto.getPhone());
        user.setMembershipLevel(MembershipLevel.valueOf(userDto.getMembershipLevel()));
        user.setRegistrationDate(Date.valueOf(LocalDate.now()));
        user.setRole(Role.ROLE_USER);

        User savedUser = userRepository.save(user);

        return userMapper.toUserDto(savedUser);
    }

    @Override
    public User findUserById(Long userId) {
        return userRepository.findById(userId).orElseThrow(()->new InvalidArgumentException("Invalid user Id"));
    }

    @Override
    public UserDetails loadUserByUsername(String email) throws UsernameNotFoundException {
        User user = userRepository.findByEmail(email)
                .orElseThrow(()-> new UsernameNotFoundException("User not found"));
        return org.springframework.security.core.userdetails.User
                .withUsername(user.getEmail())
                .password(user.getPassword())
                .authorities(user.getRole().name()) // adjust if needed
                .build();
    }
}