package ru.tubryansk.tdms.service;

import jakarta.transaction.Transactional;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
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 ru.tubryansk.tdms.controller.payload.RegistrationDTO;
import ru.tubryansk.tdms.controller.payload.UserDTO;
import ru.tubryansk.tdms.entity.Role;
import ru.tubryansk.tdms.entity.Student;
import ru.tubryansk.tdms.entity.User;
import ru.tubryansk.tdms.entity.repository.GroupRepository;
import ru.tubryansk.tdms.entity.repository.StudentRepository;
import ru.tubryansk.tdms.entity.repository.UserRepository;

import java.util.ArrayList;
import java.util.List;

@Service
@Transactional
@Slf4j
public class UserService implements UserDetailsService {
    @Autowired
    private UserRepository userRepository;
    @Autowired
    private GroupRepository groupRepository;
    @Autowired
    private StudentRepository studentRepository;
    @Autowired
    private RoleService roleService;
    @Autowired
    private PasswordEncoder passwordEncoder;

    @Override
    public User loadUserByUsername(String username) throws UsernameNotFoundException {
        log.info("Loading user with username: {}", username);
        User user = userRepository.findUserByLogin(username).orElseThrow(() -> {
            log.info("User with login {} not found", username);
            return new UsernameNotFoundException("User with login " + username + " not found");
        });
        log.info("User with login {} loaded", username);
        return user;
    }

    public List<UserDTO> getAllUsers() {
        log.info("Loading all users");
        List<UserDTO> users = userRepository.findAll().stream()
            .map(UserDTO::from)
            .toList();
        log.info("{} users loaded", users.size());
        return users;
    }

    public void registerUser(RegistrationDTO registrationDTO) {
        log.info("Registering new user with login: {}", registrationDTO.getLogin());
        User user = transientUser(registrationDTO);
        Student student = transientStudent(registrationDTO.getStudentData());
        fillRoles(user, registrationDTO);

        log.info("Saving new user: {}", user);
        userRepository.save(user);
        if (student != null) {
            student.setUser(user);
            log.info("User is student, saving student: {}", student);
            studentRepository.save(student);
        }
    }

    private User transientUser(RegistrationDTO registrationDTO) {
        User user = new User();
        user.setLogin(registrationDTO.getLogin());
        user.setPassword(passwordEncoder.encode(registrationDTO.getPassword()));
        user.setFullName(registrationDTO.getFullName());
        user.setEmail(registrationDTO.getEmail());
        user.setNumberPhone(registrationDTO.getNumberPhone());
        return user;
    }

    private Student transientStudent(RegistrationDTO.StudentRegistrationDTO studentData) {
        if (studentData == null) {
            return null;
        }

        Student student = new Student();
        student.setGroup(groupRepository.findByIdThrow(studentData.getGroupId()));
        return student;
    }

    private void fillRoles(User user, RegistrationDTO registrationDTO) {
        List<Role> roles = new ArrayList<>();
        if (registrationDTO.getStudentData() != null) {
            roles.add(roleService.getRoleByAuthority(RoleService.Authority.ROLE_STUDENT));
        }
        user.setRoles(roles);
    }
}