/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.mapping.constraint;

import gnu.trove.map.hash.TObjectIntHashMap;

import org.simantics.db.Resource;
import org.simantics.layer0.utils.binaryPredicates.IBinaryPredicate;
import org.simantics.mapping.constraint.instructions.BinaryPredicateInstruction;
import org.simantics.mapping.constraint.instructions.BinaryPredicateObjectQuery;
import org.simantics.mapping.constraint.instructions.BinaryPredicateSubjectQuery;
import org.simantics.mapping.constraint.instructions.IInstruction;
import org.simantics.utils.datastructures.persistent.ImmutableSet;

public class BinaryPredicateConstraint implements IConstraint {

	Resource variable0;
	Resource variable1;
	IBinaryPredicate predicate;		

	public BinaryPredicateConstraint(IBinaryPredicate predicate,
			Resource variable0, Resource variable1) {
		this.predicate = predicate;
		this.variable0 = variable0;
		this.variable1 = variable1;
	}

	@Override
	public ImmutableSet<Resource> binds() {
		return ImmutableSet.of(variable0, variable1);
	}

	@Override
	public IInstruction createInstruction(
			TObjectIntHashMap<Resource> variableIds,
			ImmutableSet<Resource> bound) throws TooManyUnboundVariablesException {
		int id0 = variableIds.get(variable0);
		int id1 = variableIds.get(variable1);
		if(bound.contains(variable0)) {
			if(bound.contains(variable1))
				return new BinaryPredicateInstruction(id0, id1, predicate);
			else
				return new BinaryPredicateObjectQuery(id0, id1, predicate);
		}
		else {
			if(bound.contains(variable1))
				return new BinaryPredicateSubjectQuery(id0, id1, predicate);
			else
				throw new TooManyUnboundVariablesException();			
		}
	}

	@Override
	public int isApplicable(ImmutableSet<Resource> bound) {
		if(bound.contains(variable0)) {
			if(bound.contains(variable1))
				return Integer.MAX_VALUE;
			else if(predicate.supportsGetObjects())
				return Integer.MAX_VALUE;
			else
				return 0;
		}
		else {
			if(bound.contains(variable1) && predicate.supportsGetSubjects())
				return Integer.MAX_VALUE;
			else 
				return 0;
		}
	}

}