/* Copyright 2012-2013 SpringSource.
 *
 * 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 grails.plugin.cache;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.cache.annotation.AnnotationCacheOperationSource;

/**
 * Changes the bean class of the org.springframework.cache.annotation.AnnotationCacheOperationSource#0
 * bean to a custom subclass.
 *
 * @author Burt Beckwith
 */
public class CacheBeanPostProcessor implements BeanDefinitionRegistryPostProcessor {

	protected Logger log = LoggerFactory.getLogger(getClass());

	public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
		log.info("postProcessBeanDefinitionRegistry start");

		AbstractBeanDefinition beanDef = findBeanDefinition(registry);
		if (beanDef == null) {
			log.error("Unable to find the AnnotationCacheOperationSource bean definition");
			return;
		}

		// change the class to the plugin's subclass
		beanDef.setBeanClass(GrailsAnnotationCacheOperationSource.class);

		// wire in the dependency for the grailsApplication
		MutablePropertyValues props = beanDef.getPropertyValues();
		if (props == null) {
			props = new MutablePropertyValues();
			beanDef.setPropertyValues(props);
		}
		props.addPropertyValue("grailsApplication", new RuntimeBeanReference("grailsApplication", true));

		log.debug("updated {}", beanDef);
	}

	protected AbstractBeanDefinition findBeanDefinition(BeanDefinitionRegistry registry) {

		AbstractBeanDefinition beanDef = null;
		String beanName = null;

		if (registry.containsBeanDefinition(GrailsAnnotationCacheOperationSource.BEAN_NAME)) {
			beanDef = (AbstractBeanDefinition)registry.getBeanDefinition(
					GrailsAnnotationCacheOperationSource.BEAN_NAME);
			beanName = GrailsAnnotationCacheOperationSource.BEAN_NAME;
		}
		else {
			String className = AnnotationCacheOperationSource.class.getName();
			for (String name : registry.getBeanDefinitionNames()) {
				if (className.equals(registry.getBeanDefinition(name).getBeanClassName())) {
					beanDef = (AbstractBeanDefinition)registry.getBeanDefinition(name);
					beanName = name;
					break;
				}
			}
		}

		if (beanDef != null) {
			// make it easier to work with
			if (!"cacheOperationSource".equals(beanName)) {
				registry.registerAlias(beanName, "cacheOperationSource");
			}
		}

		return beanDef;
	}

	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		log.info("postProcessBeanFactory");
	}
}