/*
 * Copyright 2012-2019 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.boot.actuate.autoconfigure.cloudfoundry;

import java.util.Collection;
import java.util.List;

import org.springframework.boot.actuate.endpoint.EndpointFilter;
import org.springframework.boot.actuate.endpoint.invoke.OperationInvokerAdvisor;
import org.springframework.boot.actuate.endpoint.invoke.ParameterValueMapper;
import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
import org.springframework.boot.actuate.endpoint.web.PathMapper;
import org.springframework.boot.actuate.endpoint.web.annotation.EndpointWebExtension;
import org.springframework.boot.actuate.endpoint.web.annotation.WebEndpointDiscoverer;
import org.springframework.boot.actuate.health.HealthEndpoint;
import org.springframework.context.ApplicationContext;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.core.annotation.AnnotationAttributes;

/**
 * {@link WebEndpointDiscoverer} for Cloud Foundry that uses Cloud Foundry specific
 * extensions for the {@link HealthEndpoint}.
 *
 * @author Madhura Bhave
 * @since 2.0.0
 */
public class CloudFoundryWebEndpointDiscoverer extends WebEndpointDiscoverer {

	/**
	 * Create a new {@link WebEndpointDiscoverer} instance.
	 * @param applicationContext the source application context
	 * @param parameterValueMapper the parameter value mapper
	 * @param endpointMediaTypes the endpoint media types
	 * @param endpointPathMappers the endpoint path mappers
	 * @param invokerAdvisors invoker advisors to apply
	 * @param filters filters to apply
	 */
	public CloudFoundryWebEndpointDiscoverer(ApplicationContext applicationContext,
			ParameterValueMapper parameterValueMapper,
			EndpointMediaTypes endpointMediaTypes, List<PathMapper> endpointPathMappers,
			Collection<OperationInvokerAdvisor> invokerAdvisors,
			Collection<EndpointFilter<ExposableWebEndpoint>> filters) {
		super(applicationContext, parameterValueMapper, endpointMediaTypes,
				endpointPathMappers, invokerAdvisors, filters);
	}

	@Override
	protected boolean isExtensionExposed(Object extensionBean) {
		if (isHealthEndpointExtension(extensionBean)
				&& !isCloudFoundryHealthEndpointExtension(extensionBean)) {
			// Filter regular health endpoint extensions so a CF version can replace them
			return false;
		}
		return true;
	}

	private boolean isHealthEndpointExtension(Object extensionBean) {
		AnnotationAttributes attributes = AnnotatedElementUtils
				.getMergedAnnotationAttributes(extensionBean.getClass(),
						EndpointWebExtension.class);
		Class<?> endpoint = (attributes != null) ? attributes.getClass("endpoint") : null;
		return (endpoint != null && HealthEndpoint.class.isAssignableFrom(endpoint));
	}

	private boolean isCloudFoundryHealthEndpointExtension(Object extensionBean) {
		return AnnotatedElementUtils.hasAnnotation(extensionBean.getClass(),
				EndpointCloudFoundryExtension.class);
	}

}
