package fr.ippon.tatami.security;

import fr.ippon.tatami.domain.User;
import fr.ippon.tatami.service.UserService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.env.Environment;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;

/**
 * Finds a user in Cassandra.
 *
 * @author Julien Dubois
 */
@Component("userDetailsService")
public class TatamiUserDetailsService implements UserDetailsService {

    private final Logger log = LoggerFactory.getLogger(TatamiUserDetailsService.class);

    private final Collection<GrantedAuthority> userGrantedAuthorities = new ArrayList<GrantedAuthority>();

    private final Collection<GrantedAuthority> adminGrantedAuthorities = new ArrayList<GrantedAuthority>();

    private Collection<String> adminUsers = null;

    @Inject
    private UserService userService;

    @Inject
    Environment env;

    @PostConstruct
    public void init() {
        if (userGrantedAuthorities.size() == 0) { // to prevent a bug that makes this bean initialized twice
            //Roles for "normal" users
            GrantedAuthority roleUser = new SimpleGrantedAuthority("ROLE_USER");
            userGrantedAuthorities.add(roleUser);

            //Roles for "admin" users, configured in tatami.properties
            GrantedAuthority roleAdmin = new SimpleGrantedAuthority("ROLE_ADMIN");
            adminGrantedAuthorities.add(roleUser);
            adminGrantedAuthorities.add(roleAdmin);

            String adminUsersList = env.getProperty("tatami.admin.users");
            String[] adminUsersArray = adminUsersList.split(",");
            adminUsers = new ArrayList<String>(Arrays.asList(adminUsersArray));
            if (log.isDebugEnabled()) {
                for (String admin : adminUsers) {
                    log.debug("Initialization : user \"{}\" is an administrator", admin);
                }
            }
        }
    }

    @Override
    public UserDetails loadUserByUsername(final String login) throws UsernameNotFoundException {
        log.debug("Authenticating {} with Cassandra", login);
        String lowercaseLogin = login.toLowerCase();
        User userFromCassandra = userService.getUserByLogin(lowercaseLogin);
        if (userFromCassandra == null) {
            throw new UsernameNotFoundException("User " + lowercaseLogin + " was not found in Cassandra");
        }
        else if ( userFromCassandra.getActivated() != null && userFromCassandra.getActivated() == false ) {
            throw new UsernameNotFoundException("User " + lowercaseLogin + " is deactivated. Contact administrator for further details." );
        }
        return getTatamiUserDetails(lowercaseLogin, userFromCassandra.getPassword());
    }

    protected org.springframework.security.core.userdetails.User getTatamiUserDetails(String login, String password) {
        Collection<GrantedAuthority> grantedAuthorities;
        if (adminUsers.contains(login)) {
            log.debug("User \"{}\" is an administrator", login);

            grantedAuthorities = adminGrantedAuthorities;
        } else {
            grantedAuthorities = userGrantedAuthorities;
        }

        return new org.springframework.security.core.userdetails.User(login, password,
                grantedAuthorities);
    }

    public Collection<String> getAdminUsers() {
        return adminUsers;
    }
}