/*
 * Copyright 2002-2013 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.config.annotation.web;

import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.ApplicationContext;
import org.springframework.http.HttpMethod;
import org.springframework.security.config.annotation.ObjectPostProcessor;
import org.springframework.security.config.annotation.web.configurers.AbstractConfigAttributeRequestMatcherRegistry;
import org.springframework.security.web.servlet.util.matcher.MvcRequestMatcher;
import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
import org.springframework.security.web.util.matcher.AnyRequestMatcher;
import org.springframework.security.web.util.matcher.RegexRequestMatcher;
import org.springframework.security.web.util.matcher.RequestMatcher;
import org.springframework.util.ClassUtils;
import org.springframework.web.servlet.handler.HandlerMappingIntrospector;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * A base class for registering {@link RequestMatcher}'s. For example, it might allow for
 * specifying which {@link RequestMatcher} require a certain level of authorization.
 *
 *
 * @param <C> The object that is returned or Chained after creating the RequestMatcher
 *
 * @author Rob Winch
 * @since 3.2
 */
public abstract class AbstractRequestMatcherRegistry<C> {
	private static final String HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME = "mvcHandlerMappingIntrospector";

	private static final RequestMatcher ANY_REQUEST = AnyRequestMatcher.INSTANCE;

	private ApplicationContext context;

	protected final void setApplicationContext(ApplicationContext context) {
		this.context = context;
	}

	/**
	 * Gets the {@link ApplicationContext}
	 *
	 * @return the {@link ApplicationContext}
	 */
	protected final ApplicationContext getApplicationContext() {
		return this.context;
	}

	/**
	 * Maps any request.
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C anyRequest() {
		return requestMatchers(ANY_REQUEST);
	}

	/**
	 * Maps a {@link List} of
	 * {@link org.springframework.security.web.util.matcher.AntPathRequestMatcher}
	 * instances.
	 *
	 * @param method the {@link HttpMethod} to use for any
	 * {@link HttpMethod}.
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C antMatchers(HttpMethod method) {
		return antMatchers(method, new String[] { "/**" });
	}

	/**
	 * Maps a {@link List} of
	 * {@link org.springframework.security.web.util.matcher.AntPathRequestMatcher}
	 * instances.
	 *
	 * @param method the {@link HttpMethod} to use or {@code null} for any
	 * {@link HttpMethod}.
	 * @param antPatterns the ant patterns to create. If {@code null} or empty, then matches on nothing.
	 * {@link org.springframework.security.web.util.matcher.AntPathRequestMatcher} from
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C antMatchers(HttpMethod method, String... antPatterns) {
		return chainRequestMatchers(RequestMatchers.antMatchers(method, antPatterns));
	}

	/**
	 * Maps a {@link List} of
	 * {@link org.springframework.security.web.util.matcher.AntPathRequestMatcher}
	 * instances that do not care which {@link HttpMethod} is used.
	 *
	 * @param antPatterns the ant patterns to create
	 * {@link org.springframework.security.web.util.matcher.AntPathRequestMatcher} from
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C antMatchers(String... antPatterns) {
		return chainRequestMatchers(RequestMatchers.antMatchers(antPatterns));
	}

	/**
	 * <p>
	 * Maps an {@link MvcRequestMatcher} that does not care which {@link HttpMethod} is
	 * used. This matcher will use the same rules that Spring MVC uses for matching. For
	 * example, often times a mapping of the path "/path" will match on "/path", "/path/",
	 * "/path.html", etc.
	 * </p>
	 * <p>
	 * If the current request will not be processed by Spring MVC, a reasonable default
	 * using the pattern as a ant pattern will be used.
	 * </p>
	 *
	 * @param mvcPatterns the patterns to match on. The rules for matching are defined by
	 * Spring MVC
	 * @return the object that is chained after creating the {@link RequestMatcher}.
	 */
	public abstract C mvcMatchers(String... mvcPatterns);

	/**
	 * <p>
	 * Maps an {@link MvcRequestMatcher} that also specifies a specific {@link HttpMethod}
	 * to match on. This matcher will use the same rules that Spring MVC uses for
	 * matching. For example, often times a mapping of the path "/path" will match on
	 * "/path", "/path/", "/path.html", etc.
	 * </p>
	 * <p>
	 * If the current request will not be processed by Spring MVC, a reasonable default
	 * using the pattern as a ant pattern will be used.
	 * </p>
	 *
	 * @param method the HTTP method to match on
	 * @param mvcPatterns the patterns to match on. The rules for matching are defined by
	 * Spring MVC
	 * @return the object that is chained after creating the {@link RequestMatcher}.
	 */
	public abstract C mvcMatchers(HttpMethod method, String... mvcPatterns);

	/**
	 * Creates {@link MvcRequestMatcher} instances for the method and patterns passed in
	 *
	 * @param method the HTTP method to use or null if any should be used
	 * @param mvcPatterns the Spring MVC patterns to match on
	 * @return a List of {@link MvcRequestMatcher} instances
	 */
	protected final List<MvcRequestMatcher> createMvcMatchers(HttpMethod method,
			String... mvcPatterns) {
		boolean isServlet30 = ClassUtils.isPresent("javax.servlet.ServletRegistration", getClass().getClassLoader());
		ObjectPostProcessor<Object> opp = this.context.getBean(ObjectPostProcessor.class);
		if(!this.context.containsBean(HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME)) {
			throw new NoSuchBeanDefinitionException("A Bean named " + HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME +" of type " + HandlerMappingIntrospector.class.getName()
				+ " is required to use MvcRequestMatcher. Please ensure Spring Security & Spring MVC are configured in a shared ApplicationContext.");
		}
		HandlerMappingIntrospector introspector = this.context.getBean(HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME,
			HandlerMappingIntrospector.class);
		List<MvcRequestMatcher> matchers = new ArrayList<MvcRequestMatcher>(
				mvcPatterns.length);
		for (String mvcPattern : mvcPatterns) {
			MvcRequestMatcher matcher = new MvcRequestMatcher(introspector, mvcPattern);
			if (isServlet30) {
				opp.postProcess(matcher);
			}
			if (method != null) {
				matcher.setMethod(method);
			}
			matchers.add(matcher);
		}
		return matchers;
	}

	/**
	 * Maps a {@link List} of
	 * {@link org.springframework.security.web.util.matcher.RegexRequestMatcher}
	 * instances.
	 *
	 * @param method the {@link HttpMethod} to use or {@code null} for any
	 * {@link HttpMethod}.
	 * @param regexPatterns the regular expressions to create
	 * {@link org.springframework.security.web.util.matcher.RegexRequestMatcher} from
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C regexMatchers(HttpMethod method, String... regexPatterns) {
		return chainRequestMatchers(RequestMatchers.regexMatchers(method, regexPatterns));
	}

	/**
	 * Create a {@link List} of
	 * {@link org.springframework.security.web.util.matcher.RegexRequestMatcher} instances
	 * that do not specify an {@link HttpMethod}.
	 *
	 * @param regexPatterns the regular expressions to create
	 * {@link org.springframework.security.web.util.matcher.RegexRequestMatcher} from
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C regexMatchers(String... regexPatterns) {
		return chainRequestMatchers(RequestMatchers.regexMatchers(regexPatterns));
	}

	/**
	 * Associates a list of {@link RequestMatcher} instances with the
	 * {@link AbstractConfigAttributeRequestMatcherRegistry}
	 *
	 * @param requestMatchers the {@link RequestMatcher} instances
	 *
	 * @return the object that is chained after creating the {@link RequestMatcher}
	 */
	public C requestMatchers(RequestMatcher... requestMatchers) {
		return chainRequestMatchers(Arrays.asList(requestMatchers));
	}

	/**
	 * Subclasses should implement this method for returning the object that is chained to
	 * the creation of the {@link RequestMatcher} instances.
	 *
	 * @param requestMatchers the {@link RequestMatcher} instances that were created
	 * @return the chained Object for the subclass which allows association of something
	 * else to the {@link RequestMatcher}
	 */
	protected abstract C chainRequestMatchers(List<RequestMatcher> requestMatchers);

	/**
	 * Utilities for creating {@link RequestMatcher} instances.
	 *
	 * @author Rob Winch
	 * @since 3.2
	 */
	private static final class RequestMatchers {

		/**
		 * Create a {@link List} of {@link AntPathRequestMatcher} instances.
		 *
		 * @param httpMethod the {@link HttpMethod} to use or {@code null} for any
		 * {@link HttpMethod}.
		 * @param antPatterns the ant patterns to create {@link AntPathRequestMatcher}
		 * from
		 *
		 * @return a {@link List} of {@link AntPathRequestMatcher} instances
		 */
		public static List<RequestMatcher> antMatchers(HttpMethod httpMethod,
				String... antPatterns) {
			String method = httpMethod == null ? null : httpMethod.toString();
			List<RequestMatcher> matchers = new ArrayList<RequestMatcher>();
			for (String pattern : antPatterns) {
				matchers.add(new AntPathRequestMatcher(pattern, method));
			}
			return matchers;
		}

		/**
		 * Create a {@link List} of {@link AntPathRequestMatcher} instances that do not
		 * specify an {@link HttpMethod}.
		 *
		 * @param antPatterns the ant patterns to create {@link AntPathRequestMatcher}
		 * from
		 *
		 * @return a {@link List} of {@link AntPathRequestMatcher} instances
		 */
		public static List<RequestMatcher> antMatchers(String... antPatterns) {
			return antMatchers(null, antPatterns);
		}

		/**
		 * Create a {@link List} of {@link RegexRequestMatcher} instances.
		 *
		 * @param httpMethod the {@link HttpMethod} to use or {@code null} for any
		 * {@link HttpMethod}.
		 * @param regexPatterns the regular expressions to create
		 * {@link RegexRequestMatcher} from
		 *
		 * @return a {@link List} of {@link RegexRequestMatcher} instances
		 */
		public static List<RequestMatcher> regexMatchers(HttpMethod httpMethod,
				String... regexPatterns) {
			String method = httpMethod == null ? null : httpMethod.toString();
			List<RequestMatcher> matchers = new ArrayList<RequestMatcher>();
			for (String pattern : regexPatterns) {
				matchers.add(new RegexRequestMatcher(pattern, method));
			}
			return matchers;
		}

		/**
		 * Create a {@link List} of {@link RegexRequestMatcher} instances that do not
		 * specify an {@link HttpMethod}.
		 *
		 * @param regexPatterns the regular expressions to create
		 * {@link RegexRequestMatcher} from
		 *
		 * @return a {@link List} of {@link RegexRequestMatcher} instances
		 */
		public static List<RequestMatcher> regexMatchers(String... regexPatterns) {
			return regexMatchers(null, regexPatterns);
		}

		private RequestMatchers() {
		}
	}

}
