/*
 * JBoss, Home of Professional Open Source.
 * See the COPYRIGHT.txt file distributed with this work for information
 * regarding copyright ownership.  Some portions may be licensed
 * to Red Hat, Inc. under one or more contributor license agreements.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */

package org.teiid.jdbc;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.sql.ConnectionEvent;
import javax.sql.ConnectionEventListener;
import javax.sql.StatementEventListener;
import javax.sql.XAConnection;
import javax.transaction.xa.XAException;
import javax.transaction.xa.XAResource;
import javax.transaction.xa.Xid;

import org.teiid.client.security.InvalidSessionException;
import org.teiid.client.util.ExceptionUtil;
import org.teiid.client.xa.XATransactionException;
import org.teiid.client.xa.XidImpl;
import org.teiid.net.CommunicationException;
import org.teiid.net.ServerConnection;
import org.teiid.net.socket.SingleInstanceCommunicationException;

/**
 * Implementation of XAConnection.
 */
public class XAConnectionImpl implements XAConnection, XAResource {
	
    private final class CloseInterceptor implements
                                        InvocationHandler {
        
        private ConnectionImpl proxiedConnection;
        
        CloseInterceptor(ConnectionImpl connection) {
            this.proxiedConnection = connection; 
        }

        public Object invoke(Object proxy,
                             Method method,
                             Object[] args) throws Throwable {
            if ("close".equals(method.getName())) {  //$NON-NLS-1$
                close();
                return null;
            }
            
            try {
				return method.invoke(this.proxiedConnection, args);
			} catch (InvocationTargetException e) {
				Exception ex = ExceptionUtil.getExceptionOfType(e, InvalidSessionException.class);
				if (ex == null) {
					ex = ExceptionUtil.getExceptionOfType(e, CommunicationException.class);
					if (ex instanceof SingleInstanceCommunicationException) {
						ServerConnection sc = proxiedConnection.getServerConnection();
						if (!sc.isOpen(ServerConnection.PING_INTERVAL)) {
							ex = null;
						}
					}
				}
				if (ex != null) {
					SQLException se = null;
					if (e.getCause() instanceof SQLException) {
						se = (SQLException)e.getCause();
					} else {
						se = TeiidSQLException.create(e.getCause());
					}
					notifyListener(se);
				} 
				throw e.getTargetException();
			}
        }

		void close() {
			this.proxiedConnection.recycleConnection(loadBalance);
			XAConnectionImpl.this.notifyListener(null);
		}
    }

	private static Logger logger = Logger.getLogger("org.teiid.jdbc"); //$NON-NLS-1$

	private int timeOut;
    private Set<ConnectionEventListener> listeners;
	private ConnectionImpl connection;
	private CloseInterceptor handler;
    private boolean isClosed;
    private boolean loadBalance = true;
        
	public XAConnectionImpl(ConnectionImpl conn){
	    this.connection = conn;
	}
	
	public void setLoadBalance(boolean loadBalance) {
		this.loadBalance = loadBalance;
	}
		
	public Connection getConnection() throws SQLException{
        ConnectionImpl conn = getConnectionImpl();
		if (handler != null) {
			handler.close();
		}
		handler = new CloseInterceptor(conn);
		Connection result = (Connection)Proxy.newProxyInstance(this.getClass().getClassLoader(), new Class[] {Connection.class}, handler);
		return result;
	}
	
	ConnectionImpl getConnectionImpl() throws SQLException {
	    if(isClosed){
            throw new SQLException(JDBCPlugin.Util.getString("MMXAConnection.connection_is_closed")); //$NON-NLS-1$
        }
        
        return connection;
	}
	    
	public synchronized void addConnectionEventListener(ConnectionEventListener listener){
		if(listeners == null){
			listeners = Collections.newSetFromMap(new IdentityHashMap<ConnectionEventListener, Boolean>());
		}
		this.listeners.add(listener);
	}
	
	public synchronized void removeConnectionEventListener(ConnectionEventListener listener){
		if(listeners == null){
			return;
		}
		this.listeners.remove(listener);
	}
	
	public XAResource getXAResource() throws SQLException{
		return this;
	}
	
	public void close()throws SQLException{		
		if(connection != null && !connection.isClosed()){
			connection.close();			
		}
        isClosed = true;
	}
	
	/**
	 * Notify listeners, if there is any, about the connection status.
	 * If e is null, the connection is properly closed.
	 * @param e
	 */
	protected synchronized void notifyListener(SQLException e){
		if(listeners != null && !listeners.isEmpty()){
			Iterator<ConnectionEventListener> iter = listeners.iterator();
			while(iter.hasNext()){
				ConnectionEventListener listener = iter.next();
				if(e == null){
					//no exception
					listener.connectionClosed(new ConnectionEvent(this));
				}else{
					//exception occurred
					listener.connectionErrorOccurred(new ConnectionEvent(this, e));	
				}
			}
		}	
	}

	public void addStatementEventListener(StatementEventListener arg0) {
	}

	public void removeStatementEventListener(StatementEventListener arg0) {
	}
	
	public void commit(Xid xid, boolean onePhase) throws XAException {
    	XidImpl mmXid = getMMXid(xid);
		try{
			getMMConnection().commitTransaction(mmXid, onePhase); 	
		}catch(SQLException e){
			String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedCommitTXN", xid, onePhase ? "true":"false"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
			throw handleError(e, logMsg);
		}
    }

    private XAException handleError(Exception e,String logMsg) {
        logger.log(Level.FINE, logMsg, e);

        if(e instanceof TeiidSQLException){
            Throwable ex = ((TeiidSQLException)e).getCause();
            if(ex instanceof XAException){
                return (XAException)ex;
            }
            if (ex instanceof XATransactionException) {
                return ((XATransactionException)ex).getXAException();
            }
        }
        return new XAException(XAException.XAER_RMERR);
    }

	/**
     * @see javax.transaction.xa.XAResource#end(javax.transaction.xa.Xid, int)
     */
    public void end(Xid xid, int flag) throws XAException {
    	XidImpl mmXid = getMMXid(xid);
		try{
            getMMConnection().endTransaction(mmXid, flag); 	
		}catch(SQLException e){
            String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedEndTXN", xid, new Integer(flag)); //$NON-NLS-1$
            throw handleError(e, logMsg);
		}
    }

    /**
     * @see javax.transaction.xa.XAResource#forget(javax.transaction.xa.Xid)
     */
    public void forget(Xid xid) throws XAException {
    	XidImpl mmXid = getMMXid(xid);
		try{
            getMMConnection().forgetTransaction(mmXid); 	
        }catch(SQLException e){
            String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedForgetTXN", xid); //$NON-NLS-1$
            throw handleError(e, logMsg);
        }
    }

    public int getTransactionTimeout() throws XAException {
        return timeOut;
    }

    public boolean isSameRM(XAResource arg0) throws XAException {
    	if (arg0 == this) {
    		return true;
    	}
        if (!(arg0 instanceof XAConnectionImpl)) {
        	return false;
        }
        XAConnectionImpl other = (XAConnectionImpl)arg0;
		try {
			return this.getMMConnection().isSameProcess(other.getMMConnection());
		} catch (CommunicationException e) {
			throw handleError(e, JDBCPlugin.Util.getString("MMXAResource.FailedISSameRM")); //$NON-NLS-1$
		}
    }

    public int prepare(Xid xid) throws XAException {
    	XidImpl mmXid = getMMXid(xid);
		try{
			return getMMConnection().prepareTransaction(mmXid); 	
        }catch(SQLException e){
            String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedPrepareTXN", xid); //$NON-NLS-1$
            throw handleError(e, logMsg);
        }
    }

    /**
     * @see javax.transaction.xa.XAResource#recover(int)
     */
    public Xid[] recover(int flag) throws XAException {
        try{
			return getMMConnection().recoverTransaction(flag); 	
        }catch(SQLException e){
            String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedRecoverTXN", flag); //$NON-NLS-1$
            throw handleError(e, logMsg);
        }
    }

    public void rollback(Xid xid) throws XAException {
    	XidImpl mmXid = getMMXid(xid);
		try{
            getMMConnection().rollbackTransaction(mmXid); 	
        }catch(SQLException e){
            String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedRollbackTXN", xid); //$NON-NLS-1$
            throw handleError(e, logMsg);
        }
    }

    public boolean setTransactionTimeout(int seconds) throws XAException {
        timeOut = seconds;
        return true;
    }

    public void start(Xid xid, int flag) throws XAException {
    	XidImpl mmXid = getMMXid(xid);
		try{
			getMMConnection().startTransaction(mmXid, flag, timeOut); 	
        }catch(SQLException e){
            String logMsg = JDBCPlugin.Util.getString("MMXAResource.FailedStartTXN", xid, new Integer(flag)); //$NON-NLS-1$
            handleError(e, logMsg);
        }
    }
        
    private ConnectionImpl getMMConnection() throws XAException{
    	try{
    	    return this.getConnectionImpl();
    	}catch(SQLException e){
    		throw new XAException(XAException.XAER_RMFAIL);
    	}
    }
    
    /**
	 * @param xid
	 * @return
     * @throws XAException
	 */
	private XidImpl getMMXid(Xid originalXid) {
		return new XidImpl(originalXid);
	}
}
