/*
 * Copyright 2002-2017 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
 *
 *      https://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.cache.jcache.interceptor;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.aop.framework.AopProxyUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.cache.interceptor.AbstractCacheInvoker;
import org.springframework.cache.interceptor.BasicOperation;
import org.springframework.cache.interceptor.CacheOperationInvocationContext;
import org.springframework.cache.interceptor.CacheOperationInvoker;
import org.springframework.util.Assert;

/**
 * Base class for JSR-107 caching aspects, such as the {@link JCacheInterceptor}
 * or an AspectJ aspect.
 *
 * <p>Use the Spring caching abstraction for cache-related operations. No JSR-107
 * {@link javax.cache.Cache} or {@link javax.cache.CacheManager} are required to
 * process standard JSR-107 cache annotations.
 *
 * <p>The {@link JCacheOperationSource} is used for determining caching operations
 *
 * <p>A cache aspect is serializable if its {@code JCacheOperationSource} is serializable.
 *
 * @author Stephane Nicoll
 * @since 4.1
 * @see org.springframework.cache.interceptor.CacheAspectSupport
 * @see KeyGeneratorAdapter
 * @see CacheResolverAdapter
 */
public class JCacheAspectSupport extends AbstractCacheInvoker implements InitializingBean {

        protected final Log logger = LogFactory.getLog(getClass());

        private JCacheOperationSource cacheOperationSource;

        private boolean initialized = false;

        private CacheResultInterceptor cacheResultInterceptor;

        private CachePutInterceptor cachePutInterceptor;

        private CacheRemoveEntryInterceptor cacheRemoveEntryInterceptor;

        private CacheRemoveAllInterceptor cacheRemoveAllInterceptor;


        public void setCacheOperationSource(JCacheOperationSource cacheOperationSource) {
                Assert.notNull(cacheOperationSource, "JCacheOperationSource must not be null");
                this.cacheOperationSource = cacheOperationSource;
        }

        /**
         * Return the CacheOperationSource for this cache aspect.
         */
        public JCacheOperationSource getCacheOperationSource() {
                return this.cacheOperationSource;
        }

        @Override
        public void afterPropertiesSet() {
                Assert.state(getCacheOperationSource() != null, "The 'cacheOperationSource' property is required: " +
                                "If there are no cacheable methods, then don't use a cache aspect.");
                Assert.state(getErrorHandler() != null, "The 'errorHandler' property is required");

                this.cacheResultInterceptor = new CacheResultInterceptor(getErrorHandler());
                this.cachePutInterceptor = new CachePutInterceptor(getErrorHandler());
                this.cacheRemoveEntryInterceptor = new CacheRemoveEntryInterceptor(getErrorHandler());
                this.cacheRemoveAllInterceptor = new CacheRemoveAllInterceptor(getErrorHandler());

                this.initialized = true;
        }


        protected Object execute(CacheOperationInvoker invoker, Object target, Method method, Object[] args) {
                // Check whether aspect is enabled to cope with cases where the AJ is pulled in automatically
                if (this.initialized) {
                        Class<?> targetClass = AopProxyUtils.ultimateTargetClass(target);
                        JCacheOperation<?> operation = getCacheOperationSource().getCacheOperation(method, targetClass);
                        if (operation != null) {
                                CacheOperationInvocationContext<?> context =
                                                createCacheOperationInvocationContext(target, args, operation);
                                return execute(context, invoker);
                        }
                }

                return invoker.invoke();
        }

        @SuppressWarnings("unchecked")
        private CacheOperationInvocationContext<?> createCacheOperationInvocationContext(
                        Object target, Object[] args, JCacheOperation<?> operation) {

                return new DefaultCacheInvocationContext<Annotation>(
                                (JCacheOperation<Annotation>) operation, target, args);
        }

        @SuppressWarnings("unchecked")
        private Object execute(CacheOperationInvocationContext<?> context, CacheOperationInvoker invoker) {
                CacheOperationInvoker adapter = new CacheOperationInvokerAdapter(invoker);
                BasicOperation operation = context.getOperation();

                if (operation instanceof CacheResultOperation) {
                        return this.cacheResultInterceptor.invoke(
                                        (CacheOperationInvocationContext<CacheResultOperation>) context, adapter);
                }
                else if (operation instanceof CachePutOperation) {
                        return this.cachePutInterceptor.invoke(
                                        (CacheOperationInvocationContext<CachePutOperation>) context, adapter);
                }
                else if (operation instanceof CacheRemoveOperation) {
                        return this.cacheRemoveEntryInterceptor.invoke(
                                        (CacheOperationInvocationContext<CacheRemoveOperation>) context, adapter);
                }
                else if (operation instanceof CacheRemoveAllOperation) {
                        return this.cacheRemoveAllInterceptor.invoke(
                                        (CacheOperationInvocationContext<CacheRemoveAllOperation>) context, adapter);
                }
                else {
                        throw new IllegalArgumentException("Cannot handle " + operation);
                }
        }

        /**
         * Execute the underlying operation (typically in case of cache miss) and return
         * the result of the invocation. If an exception occurs it will be wrapped in
         * a {@code ThrowableWrapper}: the exception can be handled or modified but it
         * <em>must</em> be wrapped in a {@code ThrowableWrapper} as well.
         * @param invoker the invoker handling the operation being cached
         * @return the result of the invocation
         * @see CacheOperationInvoker#invoke()
         */
        protected Object invokeOperation(CacheOperationInvoker invoker) {
                return invoker.invoke();
        }


        private class CacheOperationInvokerAdapter implements CacheOperationInvoker {

                private final CacheOperationInvoker delegate;

                public CacheOperationInvokerAdapter(CacheOperationInvoker delegate) {
                        this.delegate = delegate;
                }

                @Override
                public Object invoke() throws ThrowableWrapper {
                        return invokeOperation(this.delegate);
                }
        }

}