/*
 * Copyright 2015-2016 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.integration.transformer;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Collections;

import org.junit.Test;

import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.integration.codec.Codec;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.GenericMessage;

/**
 * @author Gary Russell
 * @since 4.2
 *
 */
public class CodecTransformerTests {

	@Test
	public void testCodec() throws Exception {
		MyCodec codec = new MyCodec();
		EncodingPayloadTransformer<String> enc = new EncodingPayloadTransformer<String>(codec);
		Message<?> message = new GenericMessage<String>("bar");
		byte[] transformed = enc.doTransform(message);
		assertArrayEquals("foo".getBytes(), transformed);
		DecodingTransformer<?> dec = new DecodingTransformer<String>(codec, String.class);
		assertEquals("foo", dec.doTransform(new GenericMessage<byte[]>(transformed)));

		dec = new DecodingTransformer<Integer>(codec, new SpelExpressionParser().parseExpression("T(Integer)"));
		dec.setEvaluationContext(new StandardEvaluationContext());
		assertEquals(42, dec.doTransform(new GenericMessage<byte[]>(transformed)));

		dec = new DecodingTransformer<Integer>(codec, new SpelExpressionParser().parseExpression("headers['type']"));
		dec.setEvaluationContext(new StandardEvaluationContext());
		assertEquals(42, dec.doTransform(new GenericMessage<byte[]>(transformed,
				Collections.singletonMap("type", Integer.class))));
	}

	public static class MyCodec implements Codec {

		@Override
		public void encode(Object object, OutputStream outputStream) throws IOException {
		}

		@Override
		public byte[] encode(Object object) throws IOException {
			return "foo".getBytes();
		}

		@Override
		public <T> T decode(InputStream inputStream, Class<T> type) throws IOException {
			return null;
		}

		@SuppressWarnings("unchecked")
		@Override
		public <T> T decode(byte[] bytes, Class<T> type) throws IOException {
			return (T) (type.equals(String.class) ? new String(bytes) :
				type.equals(Integer.class) ? Integer.valueOf(42) : Integer.valueOf(43));
		}

	}

}