package zti;

import java.io.*;
import java.util.*;
import java.security.Principal;
import javax.security.auth.Subject;
import javax.security.auth.callback.*;
import javax.security.auth.spi.LoginModule;
import javax.security.auth.login.LoginException;

public class MyLoginModule implements LoginModule {
	  private Subject subject;
	  private MyPrincipal entity;
	  private CallbackHandler callbackhandler;

	  private static final int NOT = 0, OK = 1, COMMIT = 2;
	  private int status;

	  public void initialize(Subject subject, CallbackHandler callbackhandler, Map state, Map options) {
	    status = NOT;
	    entity = null;
	    this.subject = subject;
	    this.callbackhandler = callbackhandler;
	  }

	  public boolean login() throws LoginException {

	    if(callbackhandler == null) {
	      throw new LoginException();
	    }
	    Callback callbacks[] = new Callback[1];
	    callbacks[0] = new NameCallback("Podaj nazwę użytkownika?");
	    String username = null;
	    try {
	      callbackhandler.handle(callbacks);
	      username = ((NameCallback)callbacks[0]).getName();
	    } catch(java.io.IOException ioe) {
	      throw new LoginException(ioe.toString());
	    } catch(UnsupportedCallbackException ce) {
	      throw new LoginException("Error: "+ce.getCallback().toString());
	    }
	    if(username.equals("admin")) {
	      entity = new MyPrincipal(username);
	      status = OK;
	      return true;
	    } else
	      return false;
	  }

	  public boolean commit() throws LoginException {
	    if(status == NOT || subject == null) {
	      return false;
	    } else {
	      Set entities = subject.getPrincipals();
	      if(!entities.contains(entity)) {
	        entities.add(entity);
	      }
	      status = COMMIT;
	      return true;
	    }
	  }

	  public boolean abort() throws LoginException {
	    if((subject != null) && (entity != null)) {
	      Set entities = subject.getPrincipals();
	      if(entities.contains(entity)) {
	        entities.remove(entity);
	      }
	    }
	    subject = null;
	    entity = null;
	    status = NOT;
	    return true;
	  }

	  public boolean logout() throws LoginException {
	    subject.getPrincipals().remove(entity);
	    status = NOT;
	    subject = null;
	    return true;
	  }
	}