/*
 * Copyright 2005-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.ws.soap.security.xwss.callback.jaas;

import javax.security.auth.Subject;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.auth.login.LoginContext;
import javax.security.auth.login.LoginException;

import com.sun.xml.wss.impl.callback.PasswordValidationCallback;

import org.springframework.ws.soap.security.callback.AbstractCallbackHandler;

/**
 * Provides basic support for integrating with JAAS and plain text passwords.
 *
 * <p>This class only handles {@code PasswordValidationCallback}s that contain a
 * {@code PlainTextPasswordRequest}, and throws an {@code UnsupportedCallbackException} for others.
 *
 * @author Arjen Poutsma
 * @see #getLoginContextName()
 * @since 1.0.0
 */
public class JaasPlainTextPasswordValidationCallbackHandler extends AbstractJaasValidationCallbackHandler {

	/**
	 * Handles {@code PasswordValidationCallback}s that contain a {@code PlainTextPasswordRequest}, and throws
	 * an {@code UnsupportedCallbackException} for others.
	 *
	 * @throws UnsupportedCallbackException when the callback is not supported
	 */
	@Override
	protected final void handleInternal(Callback callback) throws UnsupportedCallbackException {
		if (callback instanceof PasswordValidationCallback) {
			PasswordValidationCallback validationCallback = (PasswordValidationCallback) callback;
			if (validationCallback.getRequest() instanceof PasswordValidationCallback.PlainTextPasswordRequest) {
				validationCallback.setValidator(new JaasPlainTextPasswordValidator());
				return;
			}
		}
		throw new UnsupportedCallbackException(callback);
	}

	private class JaasPlainTextPasswordValidator implements PasswordValidationCallback.PasswordValidator {

		@Override
		public boolean validate(PasswordValidationCallback.Request request)
				throws PasswordValidationCallback.PasswordValidationException {
			PasswordValidationCallback.PlainTextPasswordRequest plainTextRequest =
					(PasswordValidationCallback.PlainTextPasswordRequest) request;

			final String username = plainTextRequest.getUsername();
			final String password = plainTextRequest.getPassword();

			LoginContext loginContext;
			try {
				loginContext = new LoginContext(getLoginContextName(), new AbstractCallbackHandler() {

					@Override
					protected void handleInternal(Callback callback) throws UnsupportedCallbackException {
						if (callback instanceof NameCallback) {
							((NameCallback) callback).setName(username);
						}
						else if (callback instanceof PasswordCallback) {
							((PasswordCallback) callback).setPassword(password.toCharArray());
						}
						else {
							throw new UnsupportedCallbackException(callback);
						}
					}
				});
			}
			catch (LoginException ex) {
				throw new PasswordValidationCallback.PasswordValidationException(ex);
			}
			catch (SecurityException ex) {
				throw new PasswordValidationCallback.PasswordValidationException(ex);
			}

			try {
				loginContext.login();
				Subject subject = loginContext.getSubject();
				if (!subject.getPrincipals().isEmpty()) {
					if (logger.isDebugEnabled()) {
						logger.debug("Authentication request for user '" + username + "' successful");
					}
					return true;
				}
				else {
					if (logger.isDebugEnabled()) {
						logger.debug("Authentication request for user '" + username + "' failed");
					}
					return false;
				}
			}
			catch (LoginException ex) {
				if (logger.isDebugEnabled()) {
					logger.debug("Authentication request for user '" + username + "' failed");
				}
				return false;
			}
		}


	}
}