/**
 * Copyright 2005-2013 The Kuali Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
 *
 * 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.kuali.rice.kim.api.test;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.io.StringWriter;

import static org.junit.Assert.assertEquals;

/**
 * A class with some assertion utilities for JAXB-related operations. 
 * 
 * TODO - copied this from the core api test module, find a better way to share this code!
 * 
 * @author Kuali Rice Team (rice.collab@kuali.org)
 */
public final class JAXBAssert {
	
	private JAXBAssert() {}
	
	/**
	 * Performs the following steps and assertions:
	 * 
	 * <ol>
	 *   <li>Creates a new JAXBContext with the given list of classesToBeBound.</li>
	 *   <li>Marshals the provided objectToMarshall to XML.</li>
	 *   <li>Unmarshals the marshaled XML to recreate the original object.<li>
	 *   <li>Asserts that the newly unmarhsaled object and the original provided object are equal by invoking {@link Object#equals(Object)}.</li>
	 *   <li>Unmarshals the given expectedXml to an object and asserts that it is equal with the original unmarshaled object by invoking {@link Object#equals(Object)}.</li>
	 * </ol>  
	 *  
	 * @param objectToMarshal the object to marshal to XML using JAXB
	 * @param expectedXml an XML string that will be unmarshaled to an Object and compared with objectToMarshal using {@link Object#equals(Object)}
	 * @param classesToBeBound - list of java classes to be recognized by the created JAXBContext
	 * 
	 */
	public static void assertEqualXmlMarshalUnmarshal(Object objectToMarshal, String expectedXml, Class<?> ... classesToBeBound) {
		String marshaledXml = null;
		try {
		  JAXBContext jaxbContext = JAXBContext.newInstance(classesToBeBound);
		  Marshaller marshaller = jaxbContext.createMarshaller();
		  
		  StringWriter stringWriter = new StringWriter();
		  
		  marshaller.marshal(objectToMarshal, stringWriter);

		  marshaledXml = stringWriter.toString();
		  
		  Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
		  
		  Object actual = unmarshaller.unmarshal(new StringReader(stringWriter.toString()));
		  assertEquals("Unmarshalled object should be equal to original objectToMarshall.", objectToMarshal, actual);
		  
		  Object expected = unmarshaller.unmarshal(new StringReader(expectedXml.trim()));
		  assertEquals("Unmarshalled objects should be equal.", expected, actual);
		} catch (Throwable e) {
			System.err.println("Outputting marshaled XML from failed assertion:\n" + marshaledXml);
			if (e instanceof RuntimeException) {
				throw (RuntimeException)e;
			} else if (e instanceof Error) {
				throw (Error)e;
			}
			throw new RuntimeException("Failed to marshall/unmarshall with JAXB.  See the nested exception for details.", e);
		}
	}
	
	public static void assertEqualXmlMarshalUnmarshalWithResource(Object objectToMarshal, InputStream expectedXml, Class<?> ... classesToBeBound) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(expectedXml));
		StringWriter writer = new StringWriter();
		int data = -1;
		while ((data = reader.read()) != -1) {
			writer.write(data);
		}
		assertEqualXmlMarshalUnmarshal(objectToMarshal, writer.toString(), classesToBeBound);
	}
	

}
