/*
 * Copyright 2002-2012 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 static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.util.Arrays;

import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.util.ClassUtils;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ExceptionResolver;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.method.annotation.ModelMethodProcessor;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.servlet.ModelAndView;

/**
 * Test fixture with {@link ExceptionHandlerExceptionResolver}.
 *
 * @author Rossen Stoyanchev
 * @author Arjen Poutsma
 * @since 3.1
 */
public class ExceptionHandlerExceptionResolverTests {

	private static int RESOLVER_COUNT;

	private static int HANDLER_COUNT;

	private ExceptionHandlerExceptionResolver resolver;

	private MockHttpServletRequest request;

	private MockHttpServletResponse response;

	@BeforeClass
	public static void setupOnce() {
		ExceptionHandlerExceptionResolver r = new ExceptionHandlerExceptionResolver();
		r.afterPropertiesSet();
		RESOLVER_COUNT = r.getArgumentResolvers().getResolvers().size();
		HANDLER_COUNT = r.getReturnValueHandlers().getHandlers().size();
	}

	@Before
	public void setUp() throws Exception {
		this.resolver = new ExceptionHandlerExceptionResolver();
		this.request = new MockHttpServletRequest("GET", "/");
		this.response = new MockHttpServletResponse();
	}

	@Test
	public void nullHandler() {
		Object handler = null;
		this.resolver.afterPropertiesSet();
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handler, null);
		assertNull("Exception can be resolved only if there is a HandlerMethod", mav);
	}

	@Test
	public void setCustomArgumentResolvers() throws Exception {
		HandlerMethodArgumentResolver resolver = new ServletRequestMethodArgumentResolver();
		this.resolver.setCustomArgumentResolvers(Arrays.asList(resolver));
		this.resolver.afterPropertiesSet();

		assertTrue(this.resolver.getArgumentResolvers().getResolvers().contains(resolver));
		assertMethodProcessorCount(RESOLVER_COUNT + 1, HANDLER_COUNT);
	}

	@Test
	public void setArgumentResolvers() throws Exception {
		HandlerMethodArgumentResolver resolver = new ServletRequestMethodArgumentResolver();
		this.resolver.setArgumentResolvers(Arrays.asList(resolver));
		this.resolver.afterPropertiesSet();

		assertMethodProcessorCount(1, HANDLER_COUNT);
	}

	@Test
	public void setCustomReturnValueHandlers() {
		HandlerMethodReturnValueHandler handler = new ViewNameMethodReturnValueHandler();
		this.resolver.setCustomReturnValueHandlers(Arrays.asList(handler));
		this.resolver.afterPropertiesSet();

		assertTrue(this.resolver.getReturnValueHandlers().getHandlers().contains(handler));
		assertMethodProcessorCount(RESOLVER_COUNT, HANDLER_COUNT + 1);
	}

	@Test
	public void setReturnValueHandlers() {
		HandlerMethodReturnValueHandler handler = new ModelMethodProcessor();
		this.resolver.setReturnValueHandlers(Arrays.asList(handler));
		this.resolver.afterPropertiesSet();

		assertMethodProcessorCount(RESOLVER_COUNT, 1);
	}

	@Test
	public void resolveNoExceptionHandlerForException() throws NoSuchMethodException {
		Exception npe = new NullPointerException();
		HandlerMethod handlerMethod = new HandlerMethod(new IoExceptionController(), "handle");
		this.resolver.afterPropertiesSet();
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, npe);

		assertNull("NPE should not have been handled", mav);
	}

	@Test
	public void resolveExceptionModelAndView() throws NoSuchMethodException {
		IllegalArgumentException ex = new IllegalArgumentException("Bad argument");
		HandlerMethod handlerMethod = new HandlerMethod(new ModelAndViewController(), "handle");
		this.resolver.afterPropertiesSet();
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);

		assertNotNull(mav);
		assertFalse(mav.isEmpty());
		assertEquals("errorView", mav.getViewName());
		assertEquals("Bad argument", mav.getModel().get("detail"));
	}

	@Test
	public void resolveExceptionResponseBody() throws UnsupportedEncodingException, NoSuchMethodException {
		IllegalArgumentException ex = new IllegalArgumentException();
		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
		this.resolver.afterPropertiesSet();
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);

		assertNotNull(mav);
		assertTrue(mav.isEmpty());
		assertEquals("IllegalArgumentException", this.response.getContentAsString());
	}

	@Test
	public void resolveExceptionResponseWriter() throws UnsupportedEncodingException, NoSuchMethodException {
		IllegalArgumentException ex = new IllegalArgumentException();
		HandlerMethod handlerMethod = new HandlerMethod(new ResponseWriterController(), "handle");
		this.resolver.afterPropertiesSet();
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);

		assertNotNull(mav);
		assertTrue(mav.isEmpty());
		assertEquals("IllegalArgumentException", this.response.getContentAsString());
	}

	@Test
	public void resolveExceptionGlobalHandler() throws UnsupportedEncodingException, NoSuchMethodException {
		AnnotationConfigApplicationContext cxt = new AnnotationConfigApplicationContext(MyConfig.class);
		this.resolver.setApplicationContext(cxt);
		this.resolver.setGlobalExceptionHandlers(new GlobalExceptionHandler());
		this.resolver.afterPropertiesSet();

		IllegalStateException ex = new IllegalStateException();
		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);

		assertNotNull("Exception was not handled", mav);
		assertTrue(mav.isEmpty());
		assertEquals("IllegalStateException", this.response.getContentAsString());
	}

	@Test
	public void resolveExceptionGlobalHandlerOrdered() throws UnsupportedEncodingException, NoSuchMethodException {
		AnnotationConfigApplicationContext cxt = new AnnotationConfigApplicationContext(MyConfig.class);
		this.resolver.setApplicationContext(cxt);
		GlobalExceptionHandler globalHandler = new GlobalExceptionHandler();
		globalHandler.setOrder(2);
		this.resolver.setGlobalExceptionHandlers(globalHandler);
		this.resolver.afterPropertiesSet();

		IllegalStateException ex = new IllegalStateException();
		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);

		assertNotNull("Exception was not handled", mav);
		assertTrue(mav.isEmpty());
		assertEquals("@ExceptionResolver: IllegalStateException", this.response.getContentAsString());
	}


	private void assertMethodProcessorCount(int resolverCount, int handlerCount) {
		assertEquals(resolverCount, this.resolver.getArgumentResolvers().getResolvers().size());
		assertEquals(handlerCount, this.resolver.getReturnValueHandlers().getHandlers().size());
	}

	@Controller
	static class ModelAndViewController {

		public void handle() {}

		@ExceptionHandler
		public ModelAndView handle(Exception ex) throws IOException {
			return new ModelAndView("errorView", "detail", ex.getMessage());
		}
	}

	@Controller
	static class ResponseWriterController {

		public void handle() {}

		@ExceptionHandler
		public void handleException(Exception ex, Writer writer) throws IOException {
			writer.write(ClassUtils.getShortName(ex.getClass()));
		}
	}

	@Controller
	static class ResponseBodyController {

		public void handle() {}

		@ExceptionHandler
		@ResponseBody
		public String handleException(IllegalArgumentException ex) {
			return ClassUtils.getShortName(ex.getClass());
		}
	}

	@Controller
	static class IoExceptionController {

		public void handle() {}

		@ExceptionHandler(value=IOException.class)
		public void handleException() {
		}
	}

	static class GlobalExceptionHandler implements Ordered {

		private int order;

		public int getOrder() {
			return order;
		}

		public void setOrder(int order) {
			this.order = order;
		}

		@ExceptionHandler
		@ResponseBody
		public String handleException(IllegalStateException ex) {
			return ClassUtils.getShortName(ex.getClass());
		}
	}

	@ExceptionResolver
	@Order(1)
	static class AnnotatedExceptionResolver {

		@ExceptionHandler
		@ResponseBody
		public String handleException(IllegalStateException ex) {
			return "@ExceptionResolver: " + ClassUtils.getShortName(ex.getClass());
		}
	}

	@Configuration
	static class MyConfig {

		@Bean public AnnotatedExceptionResolver exceptionResolver() {
			return new AnnotatedExceptionResolver();
		}
	}

}