/*
    * Copyright 2002-2014 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.web.servlet.mvc.method.annotation;
  
  import java.io.InputStream;
  import java.io.Reader;
  import java.security.Principal;
  import java.time.ZoneId;
  import java.util.Locale;
  import java.util.TimeZone;
  import javax.servlet.ServletRequest;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  import org.springframework.core.MethodParameter;
  import org.springframework.http.HttpMethod;
  import org.springframework.lang.UsesJava8;
  import org.springframework.web.bind.support.WebDataBinderFactory;
  import org.springframework.web.context.request.NativeWebRequest;
  import org.springframework.web.context.request.ServletWebRequest;
  import org.springframework.web.context.request.WebRequest;
  import org.springframework.web.method.support.HandlerMethodArgumentResolver;
  import org.springframework.web.method.support.ModelAndViewContainer;
  import org.springframework.web.multipart.MultipartRequest;
  import org.springframework.web.servlet.support.RequestContextUtils;
  
  /**
   * Resolves request-related method argument values of the following types:
   * <ul>
   * <li>{@link WebRequest}
   * <li>{@link ServletRequest}
   * <li>{@link MultipartRequest}
   * <li>{@link HttpSession}
   * <li>{@link Principal}
   * <li>{@link Locale}
   * <li>{@link TimeZone} (as of Spring 4.0)
   * <li>{@link java.time.ZoneId} (as of Spring 4.0 and Java 8)</li>
   * <li>{@link InputStream}
   * <li>{@link Reader}
   * <li>{@link org.springframework.http.HttpMethod} (as of Spring 4.0)</li>
   * </ul>
   *
   * @author Arjen Poutsma
   * @author Rossen Stoyanchev
   * @author Juergen Hoeller
   * @since 3.1
   */
  public class ServletRequestMethodArgumentResolver implements HandlerMethodArgumentResolver {
  
  	@Override
  	public boolean supportsParameter(MethodParameter parameter) {
  		Class<?> paramType = parameter.getParameterType();
  		return (WebRequest.class.isAssignableFrom(paramType) ||
  				ServletRequest.class.isAssignableFrom(paramType) ||
  				MultipartRequest.class.isAssignableFrom(paramType) ||
  				HttpSession.class.isAssignableFrom(paramType) ||
  				Principal.class.isAssignableFrom(paramType) ||
  				Locale.class.equals(paramType) ||
  				TimeZone.class.equals(paramType) ||
  				"java.time.ZoneId".equals(paramType.getName()) ||
  				InputStream.class.isAssignableFrom(paramType) ||
  				Reader.class.isAssignableFrom(paramType) ||
  				HttpMethod.class.equals(paramType));
  	}
  
  	@Override
  	public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
  			NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
  
  		Class<?> paramType = parameter.getParameterType();
  		if (WebRequest.class.isAssignableFrom(paramType)) {
  			return webRequest;
  		}
  
  		HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
  		if (ServletRequest.class.isAssignableFrom(paramType) || MultipartRequest.class.isAssignableFrom(paramType)) {
  			Object nativeRequest = webRequest.getNativeRequest(paramType);
  			if (nativeRequest == null) {
  				throw new IllegalStateException(
  						"Current request is not of type [" + paramType.getName() + "]: " + request);
  			}
  			return nativeRequest;
  		}
  		else if (HttpSession.class.isAssignableFrom(paramType)) {
  			return request.getSession();
 		}
 		else if (HttpMethod.class.equals(paramType)) {
 			return ((ServletWebRequest) webRequest).getHttpMethod();
 		}
 		else if (Principal.class.isAssignableFrom(paramType)) {
 			return request.getUserPrincipal();
 		}
 		else if (Locale.class.equals(paramType)) {
 			return RequestContextUtils.getLocale(request);
 		}
 		else if (TimeZone.class.equals(paramType)) {
 			TimeZone timeZone = RequestContextUtils.getTimeZone(request);
 			return (timeZone != null ? timeZone : TimeZone.getDefault());
 		}
 		else if ("java.time.ZoneId".equals(paramType.getName())) {
 			return ZoneIdResolver.resolveZoneId(request);
 		}
 		else if (InputStream.class.isAssignableFrom(paramType)) {
 			return request.getInputStream();
 		}
 		else if (Reader.class.isAssignableFrom(paramType)) {
 			return request.getReader();
 		}
 		else {
 			// should never happen...
 			throw new UnsupportedOperationException(
 					"Unknown parameter type: " + paramType + " in method: " + parameter.getMethod());
 		}
 	}
 
 
 	/**
 	 * Inner class to avoid a hard-coded dependency on Java 8's {@link java.time.ZoneId}.
 	 */
 	@UsesJava8
 	private static class ZoneIdResolver {
 
 		public static Object resolveZoneId(HttpServletRequest request) {
 			TimeZone timeZone = RequestContextUtils.getTimeZone(request);
 			return (timeZone != null ? timeZone.toZoneId() : ZoneId.systemDefault());
 		}
 	}
 
 }