/*
* Background -> Learning Spring Security

* Requirements -> to create a "all-in-one" authentication mechanism that allows multiple methods of authentication (e.g. authentication via username, via email, via phone number, oauth, OTP, etc.)

* Logic -> Create custom `SecurityFilterChain` to personalize access routes, custom `PasswordEncoder` for using Argon2PasswordEncoder, as well as custom `UserDetailsService` to allow loading `UserDetails` in spring via JPA/Hibernate

Problem -> I can authenticate via username just fine, but using email to authenticate throws an error, because the `myCustomAuthenticationProvider.authenticate()` method calls "loadUserByUsername()" method... which is fine if I am passing a username into it... but what if I am passing an email into it? It won't be able to load the UserDetails object, because, well.. it needs a username for it.

Further steps -> I am unable to think what to do from now. I can't think of a way to overload the `loadUserByUsername` method, nor does spring allow me to do that. Moreover the `myCustomUserDetailsService.loginUserByEmail(String email, String password)` method defined in my own custom `UserDetailsService` is calling the `loadUserByUsername` method (which I think is by design, since in spring security architecture, the authentication manager HAS to call it to authenticate the credentials?)

*/

// File - WebSecurityConfig.java

@Configuration
@EnableWebSecurity
public class WebSecurityConfig {


    @Autowired
    private AuthService authService;

    @Autowired
    private PasswordEncoder passwordEncoder;


    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity httpSecurity) throws Exception {

        httpSecurity.
            csrf(csrf -> csrf.disable()).
            authorizeHttpRequests(auth -> auth.
                    requestMatchers("/auth/register", "/auth/login/username").permitAll().
                    anyRequest().authenticated()
            ).
            authenticationManager(authenticationManager());

        return httpSecurity.build();
    }


    @Bean
    public AuthenticationManager authenticationManager() {
        DaoAuthenticationProvider authenticationProvider = new DaoAuthenticationProvider(authService);
        authenticationProvider.setPasswordEncoder(passwordEncoder);
        return new ProviderManager(authenticationProvider);

    }

    @Bean
    public PasswordEncoder encoder() {
        return new Argon2PasswordEncoder(10, 50, 100, 1024, 20);
    }


}



// File - AuthService.java

import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.stereotype.Service;

import com.ramyak.springsecuritywithjwt.dto.UserDTO;

import jakarta.servlet.http.HttpServletRequest;

@Service
public interface AuthService extends UserDetailsService {

    public UserDTO RegisterNewUser(UserDTO userDTO, String requestURL);

    public String loginUserByEmail(String email, HttpServletRequest httpServletRequest);

    public UserDetails loginUserByUsername(String username, HttpServletRequest httpServletRequest);


}


// File - AuthServiceImpl.java

@Component
public class AuthServiceImpl implements AuthService {

    @Autowired
    private AuthRepository authRepository;


     // Here is where I am facing problem, my authManager is calling this method, which I have also confirmed with the debugger. No surprises here, since its in the architecture of spring to call it, but what do I do if email comes here?
    @Override
    public UserDetails loadUserByUsername(String username) {
        System.out.println("Inside loadUserByUsername"); /// This gets printed out to console
        Optional<AppUser> u = authRepository.findByUsername(username);
        return null;
    }



    @Override
    public UserDTO RegisterNewUser(UserDTO userDTO, String requestURL) {
        Optional<AppUser> u = authRepository.findByUsername(userDTO.getUsername());
        if (u.isEmpty()) {
            AppUser u1 = new AppUser();
            u1.setPassword(new Argon2PasswordEncoder(10, 50, 100, 1024, 20).encode(userDTO.getPassword()));
            authRepository.save(u1);
            u1.setEmail(userDTO.getEmail());
            u1.setUsername(userDTO.getUsername());
            u1.setRole(userDTO.getRole());
            u = Optional.of(authRepository.save(u1));
            return UserDTO.convertEntitytoDTO(u.get());
        } else {
            System.out.println("User already exists");
            return UserDTO.convertEntitytoDTO(new AppUser(null, null, null, null, null));
        }

    }

    @Override
    public String loginUserByEmail(String email, HttpServletRequest httpServletRequest) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public UserDetails loginUserByUsername(String username, HttpServletRequest httpServletRequest) throws UsernameNotFoundException {
        System.out.println(new Argon2PasswordEncoder(10, 50, 100, 1024, 20).toString());
        Optional<AppUser> oau = authRepository.findByUsername(username);
        UserDetails u = User.withUsername(oau.get().getUsername()).password((oau.get().getPassword())).roles(oau.get().getRole()).build();
        return u;
    }


}



// File - AuthController.java

@RestController
@RequestMapping(path = "/auth")
public class AuthenticationController {

    @Autowired
    private AuthService authService;

    @Autowired
    private AuthenticationManager authenticationManager;


    @PostMapping("/register")
    public ResponseEntity<UserDTO> registerNewUser(@RequestBody UserDTO userDTO, HttpServletRequest httpServletRequest) {
        UserDTO registeredUserDto = authService.RegisterNewUser(userDTO, httpServletRequest.getRequestURL().toString());
        return new ResponseEntity<UserDTO>(registeredUserDto, HttpStatus.OK);

    }

    @PostMapping("/login/username")
    public ResponseEntity<?> loginUserByUsername(@RequestBody LoginRequestDTO loginRequestDTO, HttpServletRequest httpServletRequest) throws UsernameNotFoundException {
        UserDetails result = authService.loginUserByUsername(loginRequestDTO.getUsername(), httpServletRequest);
        if (result != null) {
            UsernamePasswordAuthenticationToken upat = new UsernamePasswordAuthenticationToken(result, result.getPassword());
            authenticationManager.authenticate(upat); // Error occurs here
        }
        return null;

    }

    @PostMapping("/login/email")
    public ResponseEntity<?> loginUserByEMail(HttpServletResponse httpServletResponse) {
        return null;

    }

}