/*
 * Copyright (c) 2011-2015 EPFL DATA Laboratory
 * Copyright (c) 2014-2015 The Squall Collaboration (see NOTICE)
 *
 * All rights reserved.
 *
 * 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 ch.epfl.data.squall.api.sql.visitors.squall;

import java.util.ArrayList;
import java.util.List;

import ch.epfl.data.squall.expressions.Addition;
import ch.epfl.data.squall.expressions.ColumnReference;
import ch.epfl.data.squall.expressions.DateDiff;
import ch.epfl.data.squall.expressions.DateSum;
import ch.epfl.data.squall.expressions.Division;
import ch.epfl.data.squall.expressions.IntegerYearFromDate;
import ch.epfl.data.squall.expressions.Multiplication;
import ch.epfl.data.squall.expressions.StringConcatenate;
import ch.epfl.data.squall.expressions.Subtraction;
import ch.epfl.data.squall.expressions.ValueExpression;
import ch.epfl.data.squall.expressions.ValueSpecification;
import ch.epfl.data.squall.visitors.ValueExpressionVisitor;

public class ColumnRefCollectVisitor implements ValueExpressionVisitor {
    private final List<ColumnReference> _crList = new ArrayList<ColumnReference>();

    public List<ColumnReference> getColumnRefs() {
	return _crList;
    }

    @Override
    public void visit(Addition add) {
	visit(add.getInnerExpressions());
    }

    @Override
    public void visit(ColumnReference cr) {
	_crList.add(cr);
    }

    @Override
    public void visit(DateDiff dd) {
	visit(dd.getInnerExpressions());
    }

    @Override
    public void visit(DateSum ds) {
	visit(ds.getInnerExpressions());
    }

    @Override
    public void visit(Division dvsn) {
	visit(dvsn.getInnerExpressions());
    }

    @Override
    public void visit(IntegerYearFromDate iyfd) {
	visit(iyfd.getInnerExpressions());
    }

    private void visit(List<ValueExpression> veList) {
	for (final ValueExpression ve : veList)
	    ve.accept(this);
    }

    @Override
    public void visit(Multiplication mult) {
	visit(mult.getInnerExpressions());
    }

    @Override
    public void visit(StringConcatenate sc) {
	visit(sc.getInnerExpressions());
    }

    @Override
    public void visit(Subtraction sub) {
	visit(sub.getInnerExpressions());
    }

    @Override
    public void visit(ValueSpecification vs) {
	// constant
    }

}