/*
 * Copyright (C) 2005 Alfresco, Inc.
 *
 * Licensed under the Mozilla Public License version 1.1 
 * with a permitted attribution clause. You may obtain a
 * copy of the License at
 *
 *   http://www.alfresco.org/legal/license.txt
 *
 * 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.alfresco.repo.search.transaction;

import java.io.UnsupportedEncodingException;

import javax.transaction.HeuristicMixedException;
import javax.transaction.HeuristicRollbackException;
import javax.transaction.NotSupportedException;
import javax.transaction.RollbackException;
import javax.transaction.Synchronization;
import javax.transaction.SystemException;
import javax.transaction.xa.XAResource;

import org.alfresco.util.GUID;

public class SimpleTransaction implements XidTransaction
{
    private static final int DEFAULT_TIMEOUT = 600;

    private boolean isRollBackOnly;

    private int timeout;

    public static final int FORMAT_ID = 12321;

    private static final String CHAR_SET = "UTF-8";

    private byte[] globalTransactionId;

    private byte[] branchQualifier;

    // This is the transactoin id
    private String guid;

    private static ThreadLocal<SimpleTransaction> transaction = new ThreadLocal<SimpleTransaction>();

    private SimpleTransaction(int timeout)
    {
        super();
        this.timeout = timeout;
        guid = GUID.generate();
        try
        {
            globalTransactionId = guid.getBytes(CHAR_SET);
        }
        catch (UnsupportedEncodingException e)
        {
            throw new XidException(e);
        }
        branchQualifier = new byte[0];
    }

    private SimpleTransaction()
    {
        this(DEFAULT_TIMEOUT);
    }

    public static SimpleTransaction getTransaction()
    {
        return (SimpleTransaction) transaction.get();
    }

    public void commit() throws RollbackException, HeuristicMixedException, HeuristicRollbackException,
            SecurityException, SystemException
    {
        try
        {
            if (isRollBackOnly)
            {
                throw new RollbackException("Commit failed: Transaction marked for rollback");
            }

        }
        finally
        {
            transaction.set(null);
        }
    }

    public boolean delistResource(XAResource arg0, int arg1) throws IllegalStateException, SystemException
    {
        // TODO Auto-generated method stub
        throw new UnsupportedOperationException();
    }

    public boolean enlistResource(XAResource arg0) throws RollbackException, IllegalStateException, SystemException
    {
        // TODO Auto-generated method stub
        throw new UnsupportedOperationException();
    }

    public int getStatus() throws SystemException
    {
        // TODO Auto-generated method stub
        throw new UnsupportedOperationException();
    }

    public void registerSynchronization(Synchronization arg0) throws RollbackException, IllegalStateException,
            SystemException
    {
        // TODO Auto-generated method stub
        throw new UnsupportedOperationException();
    }

    public void rollback() throws IllegalStateException, SystemException
    {
        // TODO Auto-generated method stub
        throw new UnsupportedOperationException();
    }

    public void setRollbackOnly() throws IllegalStateException, SystemException
    {
        isRollBackOnly = true;
    }

    /*
     * Support for suspend, resume and begin.
     */

    /* package */static SimpleTransaction suspend()
    {
        SimpleTransaction tx = getTransaction();
        transaction.set(null);
        return tx;
    }

    /* package */static void begin() throws NotSupportedException
    {
        if (getTransaction() != null)
        {
            throw new NotSupportedException("Nested transactions are not supported");
        }
        transaction.set(new SimpleTransaction());
    }

    /* package */static void resume(SimpleTransaction tx)
    {
        if (getTransaction() != null)
        {
            throw new IllegalStateException("A transaction is already associated with the thread");
        }
        transaction.set((SimpleTransaction) tx);
    }

    public String getGUID()
    {
        return guid;
    }

    public boolean equals(Object o)
    {
        if (this == o)
        {
            return true;
        }
        if (!(o instanceof SimpleTransaction))
        {
            return false;
        }
        SimpleTransaction other = (SimpleTransaction) o;
        return this.getGUID().equals(other.getGUID());
    }

    public int hashCode()
    {
        return getGUID().hashCode();
    }

    public String toString()
    {
        StringBuffer buffer = new StringBuffer(128);
        buffer.append("Simple Transaction GUID = " + getGUID());
        return buffer.toString();
    }

    public int getFormatId()
    {
        return FORMAT_ID;
    }

    public byte[] getGlobalTransactionId()
    {
        return globalTransactionId;
    }

    public byte[] getBranchQualifier()
    {
        return branchQualifier;
    }
}