/*
 * Copyright 2002-2018 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.jca.cci.connection;

import javax.resource.NotSupportedException;
import javax.resource.ResourceException;
import javax.resource.cci.Connection;
import javax.resource.cci.ConnectionFactory;
import javax.resource.spi.LocalTransactionException;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.lang.Nullable;
import org.springframework.transaction.CannotCreateTransactionException;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionException;
import org.springframework.transaction.TransactionSystemException;
import org.springframework.transaction.support.AbstractPlatformTransactionManager;
import org.springframework.transaction.support.DefaultTransactionStatus;
import org.springframework.transaction.support.ResourceTransactionManager;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import org.springframework.util.Assert;

/**
 * {@link org.springframework.transaction.PlatformTransactionManager} implementation
 * that manages local transactions for a single CCI ConnectionFactory.
 * Binds a CCI Connection from the specified ConnectionFactory to the thread,
 * potentially allowing for one thread-bound Connection per ConnectionFactory.
 *
 * <p>Application code is required to retrieve the CCI Connection via
 * {@link ConnectionFactoryUtils#getConnection(ConnectionFactory)} instead of a standard
 * Java EE-style {@link ConnectionFactory#getConnection()} call. Spring classes such as
 * {@link org.springframework.jca.cci.core.CciTemplate} use this strategy implicitly.
 * If not used in combination with this transaction manager, the
 * {@link ConnectionFactoryUtils} lookup strategy behaves exactly like the native
 * DataSource lookup; it can thus be used in a portable fashion.
 *
 * <p>Alternatively, you can allow application code to work with the standard
 * Java EE lookup pattern {@link ConnectionFactory#getConnection()}, for example
 * for legacy code that is not aware of Spring at all. In that case, define a
 * {@link TransactionAwareConnectionFactoryProxy} for your target ConnectionFactory,
 * which will automatically participate in Spring-managed transactions.
 *
 * @author Thierry Templier
 * @author Juergen Hoeller
 * @since 1.2
 * @see ConnectionFactoryUtils#getConnection(javax.resource.cci.ConnectionFactory)
 * @see ConnectionFactoryUtils#releaseConnection
 * @see TransactionAwareConnectionFactoryProxy
 * @see org.springframework.jca.cci.core.CciTemplate
 */
@SuppressWarnings("serial")
public class CciLocalTransactionManager extends AbstractPlatformTransactionManager
                implements ResourceTransactionManager, InitializingBean {

        @Nullable
        private ConnectionFactory connectionFactory;


        /**
         * Create a new CciLocalTransactionManager instance.
         * A ConnectionFactory has to be set to be able to use it.
         * @see #setConnectionFactory
         */
        public CciLocalTransactionManager() {
        }

        /**
         * Create a new CciLocalTransactionManager instance.
         * @param connectionFactory the CCI ConnectionFactory to manage local transactions for
         */
        public CciLocalTransactionManager(ConnectionFactory connectionFactory) {
                setConnectionFactory(connectionFactory);
                afterPropertiesSet();
        }


        /**
         * Set the CCI ConnectionFactory that this instance should manage local
         * transactions for.
         */
        public void setConnectionFactory(@Nullable ConnectionFactory cf) {
                if (cf instanceof TransactionAwareConnectionFactoryProxy) {
                        // If we got a TransactionAwareConnectionFactoryProxy, we need to perform transactions
                        // for its underlying target ConnectionFactory, else JMS access code won't see
                        // properly exposed transactions (i.e. transactions for the target ConnectionFactory).
                        this.connectionFactory = ((TransactionAwareConnectionFactoryProxy) cf).getTargetConnectionFactory();
                }
                else {
                        this.connectionFactory = cf;
                }
        }

        /**
         * Return the CCI ConnectionFactory that this instance manages local
         * transactions for.
         */
        @Nullable
        public ConnectionFactory getConnectionFactory() {
                return this.connectionFactory;
        }

        private ConnectionFactory obtainConnectionFactory() {
                ConnectionFactory connectionFactory = getConnectionFactory();
                Assert.state(connectionFactory != null, "No ConnectionFactory set");
                return connectionFactory;
        }

        @Override
        public void afterPropertiesSet() {
                if (getConnectionFactory() == null) {
                        throw new IllegalArgumentException("Property 'connectionFactory' is required");
                }
        }


        @Override
        public Object getResourceFactory() {
                return obtainConnectionFactory();
        }

        @Override
        protected Object doGetTransaction() {
                CciLocalTransactionObject txObject = new CciLocalTransactionObject();
                ConnectionHolder conHolder =
                                (ConnectionHolder) TransactionSynchronizationManager.getResource(obtainConnectionFactory());
                txObject.setConnectionHolder(conHolder);
                return txObject;
        }

        @Override
        protected boolean isExistingTransaction(Object transaction) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) transaction;
                // Consider a pre-bound connection as transaction.
                return txObject.hasConnectionHolder();
        }

        @Override
        protected void doBegin(Object transaction, TransactionDefinition definition) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) transaction;
                ConnectionFactory connectionFactory = obtainConnectionFactory();
                Connection con = null;

                try {
                        con = connectionFactory.getConnection();
                        if (logger.isDebugEnabled()) {
                                logger.debug("Acquired Connection [" + con + "] for local CCI transaction");
                        }

                        ConnectionHolder connectionHolder = new ConnectionHolder(con);
                        connectionHolder.setSynchronizedWithTransaction(true);

                        con.getLocalTransaction().begin();
                        int timeout = determineTimeout(definition);
                        if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
                                connectionHolder.setTimeoutInSeconds(timeout);
                        }

                        txObject.setConnectionHolder(connectionHolder);
                        TransactionSynchronizationManager.bindResource(connectionFactory, connectionHolder);
                }
                catch (NotSupportedException ex) {
                        ConnectionFactoryUtils.releaseConnection(con, connectionFactory);
                        throw new CannotCreateTransactionException("CCI Connection does not support local transactions", ex);
                }
                catch (LocalTransactionException ex) {
                        ConnectionFactoryUtils.releaseConnection(con, connectionFactory);
                        throw new CannotCreateTransactionException("Could not begin local CCI transaction", ex);
                }
                catch (Throwable ex) {
                        ConnectionFactoryUtils.releaseConnection(con, connectionFactory);
                        throw new TransactionSystemException("Unexpected failure on begin of CCI local transaction", ex);
                }
        }

        @Override
        protected Object doSuspend(Object transaction) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) transaction;
                txObject.setConnectionHolder(null);
                return TransactionSynchronizationManager.unbindResource(obtainConnectionFactory());
        }

        @Override
        protected void doResume(@Nullable Object transaction, Object suspendedResources) {
                ConnectionHolder conHolder = (ConnectionHolder) suspendedResources;
                TransactionSynchronizationManager.bindResource(obtainConnectionFactory(), conHolder);
        }

        protected boolean isRollbackOnly(Object transaction) throws TransactionException {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) transaction;
                return txObject.getConnectionHolder().isRollbackOnly();
        }

        @Override
        protected void doCommit(DefaultTransactionStatus status) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) status.getTransaction();
                Connection con = txObject.getConnectionHolder().getConnection();
                if (status.isDebug()) {
                        logger.debug("Committing CCI local transaction on Connection [" + con + "]");
                }
                try {
                        con.getLocalTransaction().commit();
                }
                catch (LocalTransactionException ex) {
                        throw new TransactionSystemException("Could not commit CCI local transaction", ex);
                }
                catch (ResourceException ex) {
                        throw new TransactionSystemException("Unexpected failure on commit of CCI local transaction", ex);
                }
        }

        @Override
        protected void doRollback(DefaultTransactionStatus status) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) status.getTransaction();
                Connection con = txObject.getConnectionHolder().getConnection();
                if (status.isDebug()) {
                        logger.debug("Rolling back CCI local transaction on Connection [" + con + "]");
                }
                try {
                        con.getLocalTransaction().rollback();
                }
                catch (LocalTransactionException ex) {
                        throw new TransactionSystemException("Could not roll back CCI local transaction", ex);
                }
                catch (ResourceException ex) {
                        throw new TransactionSystemException("Unexpected failure on rollback of CCI local transaction", ex);
                }
        }

        @Override
        protected void doSetRollbackOnly(DefaultTransactionStatus status) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) status.getTransaction();
                if (status.isDebug()) {
                        logger.debug("Setting CCI local transaction [" + txObject.getConnectionHolder().getConnection() +
                                        "] rollback-only");
                }
                txObject.getConnectionHolder().setRollbackOnly();
        }

        @Override
        protected void doCleanupAfterCompletion(Object transaction) {
                CciLocalTransactionObject txObject = (CciLocalTransactionObject) transaction;
                ConnectionFactory connectionFactory = obtainConnectionFactory();

                // Remove the connection holder from the thread.
                TransactionSynchronizationManager.unbindResource(connectionFactory);
                txObject.getConnectionHolder().clear();

                Connection con = txObject.getConnectionHolder().getConnection();
                if (logger.isDebugEnabled()) {
                        logger.debug("Releasing CCI Connection [" + con + "] after transaction");
                }
                ConnectionFactoryUtils.releaseConnection(con, connectionFactory);
        }


        /**
         * CCI local transaction object, representing a ConnectionHolder.
         * Used as transaction object by CciLocalTransactionManager.
         * @see ConnectionHolder
         */
        private static class CciLocalTransactionObject {

                @Nullable
                private ConnectionHolder connectionHolder;

                public void setConnectionHolder(@Nullable ConnectionHolder connectionHolder) {
                        this.connectionHolder = connectionHolder;
                }

                public ConnectionHolder getConnectionHolder() {
                        Assert.state(this.connectionHolder != null, "No ConnectionHolder available");
                        return this.connectionHolder;
                }

                public boolean hasConnectionHolder() {
                        return (this.connectionHolder != null);
                }
        }

}