/*
 * Copyright 2002-2016 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.security.web.authentication;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.security.core.AuthenticationException;
import org.springframework.security.web.util.UrlUtils;
import org.springframework.util.Assert;

/**
 * Uses the internal map of exceptions types to URLs to determine the destination on
 * authentication failure. The keys are the full exception class names.
 * <p>
 * If a match isn't found, falls back to the behaviour of the parent class,
 * {@link SimpleUrlAuthenticationFailureHandler}.
 * <p>
 * The map of exception names to URLs should be injected by setting the
 * <tt>exceptionMappings</tt> property.
 *
 * @author Luke Taylor
 * @since 3.0
 */
public class ExceptionMappingAuthenticationFailureHandler extends
		SimpleUrlAuthenticationFailureHandler {
	private final Map<String, String> failureUrlMap = new HashMap<>();

	@Override
	public void onAuthenticationFailure(HttpServletRequest request,
			HttpServletResponse response, AuthenticationException exception)
			throws IOException, ServletException {
		String url = failureUrlMap.get(exception.getClass().getName());

		if (url != null) {
			getRedirectStrategy().sendRedirect(request, response, url);
		}
		else {
			super.onAuthenticationFailure(request, response, exception);
		}
	}

	/**
	 * Sets the map of exception types (by name) to URLs.
	 *
	 * @param failureUrlMap the map keyed by the fully-qualified name of the exception
	 * class, with the corresponding failure URL as the value.
	 *
	 * @throws IllegalArgumentException if the entries are not Strings or the URL is not
	 * valid.
	 */
	public void setExceptionMappings(Map<?, ?> failureUrlMap) {
		this.failureUrlMap.clear();
		for (Map.Entry<?, ?> entry : failureUrlMap.entrySet()) {
			Object exception = entry.getKey();
			Object url = entry.getValue();
			Assert.isInstanceOf(String.class, exception,
					"Exception key must be a String (the exception classname).");
			Assert.isInstanceOf(String.class, url, "URL must be a String");
			Assert.isTrue(UrlUtils.isValidRedirectUrl((String) url),
					"Not a valid redirect URL: " + url);
			this.failureUrlMap.put((String) exception, (String) url);
		}
	}
}
