/*
 * Copyright 2014-2015 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.config.annotation;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.List;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.integration.annotation.BridgeFrom;
import org.springframework.integration.annotation.BridgeTo;
import org.springframework.integration.endpoint.AbstractEndpoint;
import org.springframework.integration.handler.BridgeHandler;
import org.springframework.integration.util.MessagingAnnotationUtils;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Post-processor for the {@link BridgeTo @BridgeTo} annotation.
 *
 * @author Artem Bilan
 * @since 4.0
 */
public class BridgeToAnnotationPostProcessor extends AbstractMethodAnnotationPostProcessor<BridgeTo> {

	public BridgeToAnnotationPostProcessor(ConfigurableListableBeanFactory beanFactory) {
		super(beanFactory);
	}

	@Override
	public boolean shouldCreateEndpoint(Method method, List<Annotation> annotations) {
		boolean isBean = AnnotatedElementUtils.isAnnotated(method, Bean.class.getName());
		Assert.isTrue(isBean, "'@BridgeTo' is eligible only for '@Bean' methods");

		boolean isMessageChannelBean = MessageChannel.class.isAssignableFrom(method.getReturnType());
		Assert.isTrue(isMessageChannelBean, "'@BridgeTo' is eligible only for 'MessageChannel' '@Bean' methods");

		boolean hasBridgeFrom = AnnotatedElementUtils.isAnnotated(method, BridgeFrom.class.getName());

		Assert.isTrue(!hasBridgeFrom, "'@BridgeFrom' and '@BridgeTo' are mutually exclusive 'MessageChannel' " +
				"'@Bean' method annotations");

		return true;
	}

	@Override
	protected MessageHandler createHandler(Object bean, Method method, List<Annotation> annotations) {
		BridgeHandler handler = new BridgeHandler();
		String outputChannelName = MessagingAnnotationUtils.resolveAttribute(annotations, "value", String.class);
		if (StringUtils.hasText(outputChannelName)) {
			handler.setOutputChannelName(outputChannelName);
		}
		return handler;
	}

	@Override
	protected AbstractEndpoint createEndpoint(MessageHandler handler, Method method, List<Annotation> annotations) {
		Object inputChannel = this.resolveTargetBeanFromMethodWithBeanAnnotation(method);
		Assert.isInstanceOf(MessageChannel.class, inputChannel);
		return doCreateEndpoint(handler, (MessageChannel) inputChannel, annotations);
	}

}