/**
 * Copyright 2014 Duan Bingnan
 * 
 * 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.pinus4j.transaction.impl;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;

import javax.transaction.RollbackException;
import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.SystemException;
import javax.transaction.xa.XAResource;

import org.pinus4j.cluster.resources.IDBResource;
import org.pinus4j.cluster.resources.IResourceId;
import org.pinus4j.transaction.ITransaction;
import org.pinus4j.transaction.enums.EnumTransactionIsolationLevel;

/**
 * local transaction impelemnt.
 *
 * @author duanbn
 * @since 1.1.0
 */
public class BestEffortsOnePCJtaTransaction implements ITransaction {

    /**
     * db resource will do commit or rollback.
     */
    private Map<IResourceId, IDBResource> txRes  = new LinkedHashMap<IResourceId, IDBResource>();

    /**
     * isolation level of transaction.
     */
    private EnumTransactionIsolationLevel txLevel;

    private AtomicInteger                 status = new AtomicInteger(Status.STATUS_ACTIVE);

    @Override
    public boolean isContain(IResourceId resId) {
        return this.txRes.containsKey(resId);
    }

    @Override
    public IDBResource getDBResource(IResourceId resId) {
        return this.txRes.get(resId);
    }

    @Override
    public void flush() {
        commit(true);
    }

    @Override
    public void setIsolationLevel(EnumTransactionIsolationLevel txLevel) {
        this.txLevel = txLevel;
    }

    /**
     * do commit.
     */
    @Override
    public void commit() {
        commit(false);
    }

    private void commit(boolean isFlush) {
        // do flush
        if (isFlush) {
            for (IDBResource dbResource : txRes.values()) {
                dbResource.commit();
            }

            return;
        }

        status.set(Status.STATUS_COMMITTING);

        // do commit
        for (IDBResource dbResource : txRes.values()) {
            dbResource.commit();
            dbResource.close();
        }

        status.set(Status.STATUS_NO_TRANSACTION);
    }

    /**
     * do rollback.
     */
    @Override
    public void rollback() {
        status.set(Status.STATUS_ROLLING_BACK);

        // do rollback.
        for (IDBResource dbResource : txRes.values()) {
            dbResource.rollback();

            if (!dbResource.isClosed())
                dbResource.close();
        }

        status.set(Status.STATUS_NO_TRANSACTION);
    }

    // jta implements.
    @Override
    public boolean delistResource(XAResource xaResource, int arg1) throws IllegalStateException, SystemException {
        IDBResource dbResource = (IDBResource) xaResource;
        IResourceId resId = dbResource.getId();

        txRes.remove(resId);
        return true;
    }

    @Override
    public boolean enlistResource(XAResource xaResource) throws RollbackException, IllegalStateException,
            SystemException {
        IDBResource dbResource = (IDBResource) xaResource;
        IResourceId resId = dbResource.getId();

        if (txRes.get(resId) == null) {
            synchronized (txRes) {
                if (txRes.get(resId) == null) {
                    dbResource.setTransactionIsolationLevel(txLevel);
                    txRes.put(resId, dbResource);
                }
            }
        }

        return true;
    }

    @Override
    public int getStatus() throws SystemException {
        return status.get();
    }

    @Override
    public void registerSynchronization(Synchronization arg0) throws RollbackException, IllegalStateException,
            SystemException {
        throw new UnsupportedOperationException();
    }

    @Override
    public void setRollbackOnly() throws IllegalStateException, SystemException {
        // do nothing...
    }

}