/* 
 *  Copyright (C) 2000 - 2010 TagServlet Ltd
 *
 *  This file is part of Open BlueDragon (OpenBD) CFML Server Engine.
 *  
 *  OpenBD is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  Free Software Foundation,version 3.
 *  
 *  OpenBD 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 General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with OpenBD.  If not, see http://www.gnu.org/licenses/
 *  
 *  Additional permission under GNU GPL version 3 section 7
 *  
 *  If you modify this Program, or any covered work, by linking or combining 
 *  it with any of the JARS listed in the README.txt (or a modified version of 
 *  (that library), containing parts covered by the terms of that JAR, the 
 *  licensors of this Program grant you additional permission to convey the 
 *  resulting work. 
 *  README.txt @ http://www.openbluedragon.org/license/README.txt
 *  
 *  http://www.openbluedragon.org/
 */

package com.naryx.tagfusion.cfm.parser.script;

import java.util.HashSet;
import java.util.Map;

import com.naryx.tagfusion.cfm.engine.cfSession;
import com.naryx.tagfusion.cfm.engine.cfmRunTimeException;
import com.naryx.tagfusion.cfm.engine.dataNotSupportedException;
import com.naryx.tagfusion.cfm.parser.CFContext;
import com.naryx.tagfusion.cfm.parser.CFException;
import com.naryx.tagfusion.cfm.parser.CFExpression;
import com.naryx.tagfusion.cfm.parser.ParseException;
import com.naryx.tagfusion.cfm.tag.cfLOCK;
import com.naryx.tagfusion.cfm.tag.cfLockingObject;
import com.naryx.tagfusion.cfm.tag.cfTag;


public class CFLockStatement extends CFParsedAttributeStatement implements java.io.Serializable {

	private static final long serialVersionUID = 1L;

	private CFScriptStatement body;

	private static HashSet<String> supportedAttributes;

	static {
		supportedAttributes = new HashSet<String>();
		supportedAttributes.add( "TYPE" );
		supportedAttributes.add( "TIMEOUT" );
		supportedAttributes.add( "NAME" );
		supportedAttributes.add( "SCOPE" );
		supportedAttributes.add( "THROWONTIMEOUT" );
	}


	public CFLockStatement( org.antlr.runtime.Token _t, Map<String, CFExpression> _attr, CFScriptStatement _body ) {
		super( _t, _attr );

		validateAttributes( _t, supportedAttributes );

		// minimal requirement is the timeout attribute
		if ( !containsAttribute( "TIMEOUT" ) )
			throw new ParseException( _t, "Lock requires the TIMEOUT attribute" );

		if ( containsAttribute( "NAME" ) && containsAttribute( "SCOPE" ) )
			throw new ParseException( _t, "Invalid Attributes: specify either SCOPE or NAME, but not both" );

		body = _body;
	}


	public void setHostTag( cfTag _parentTag ) {
		super.setHostTag( _parentTag );
		body.setHostTag( _parentTag );
	}


	@Override
	public CFStatementResult Exec( CFContext context ) throws cfmRunTimeException {
		setLineCol( context );

		CFStatementResult result = null;
		cfSession session = context.getSession();

		String type = getAttributeValueString( context, "TYPE", cfLOCK.TYPE_EXCLUSIVE );
		int timeOut = getAttributeValue( context, "TIMEOUT" ).getInt() * 1000;
		if ( timeOut < 0 ) {
			throw new CFException( "Invalid attribute value. The TIMEOUT must be greater than or equal to 0 (zero)", context );
		}

		String lockName = getLockName( context );
		cfLockingObject lock = cfLOCK.getLock( session, lockName );
		try {
			if ( lock.lock( type, timeOut ) ) {
				try {
					result = body.Exec( context );
				} finally {
					lock.unlock( type );
				}
			} else {
				if ( getAttributeValueBoolean( context, "THROWONTIMEOUT", true ) )
					throw new CFException( "CFLOCK lock timed out", context );
			}
		} finally {
			cfLOCK.freeLock( session, lockName, lock );
		}

		return result;
	}


	@Override
	public String Decompile( int indent ) {
		StringBuilder sb = new StringBuilder();
		sb.append( "lock " );
		DecompileAttributes( sb );
		sb.append( body.Decompile( 0 ) );

		return sb.toString();
	}


	private String getLockName( CFContext context ) throws dataNotSupportedException, cfmRunTimeException {
		String nameOfLock;
		if ( containsAttribute( "SCOPE" ) ) {
			String scope = getAttributeValueString( context, "SCOPE" ).toLowerCase();
			if ( !scope.equals( "application" ) && !scope.equals( "server" ) && !scope.equals( "session" ) ) {
				throw new CFException( "Invalid attribute value. The SCOPE must be one of Server/Application/Session.", context );
			}
			nameOfLock = scope + ".lockingobject";
			if ( context.getSession().getData( scope ) == null ) {
				throw new CFException( "Cannot initiate lock on " + scope.toUpperCase() + " scope. Make sure the scope has been enabled via the CFAPPLICATION tag.", context );
			}
		} else if ( containsAttribute( "NAME" ) ) {
			nameOfLock = getAttributeValueString( context, "NAME" ).toLowerCase().trim();
			nameOfLock = "server." + cfLOCK.cleanupLockName( nameOfLock );
		} else {
			nameOfLock = "server.lockingobject";
		}

		return nameOfLock;
	}

}