/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.vxquery.runtime.functions.arithmetic;

import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
import org.apache.hyracks.api.context.IHyracksTaskContext;
import org.apache.hyracks.api.exceptions.HyracksDataException;
import org.apache.hyracks.data.std.api.IPointable;
import org.apache.vxquery.context.DynamicContext;
import org.apache.vxquery.datamodel.accessors.SequencePointable;
import org.apache.vxquery.datamodel.accessors.TaggedValuePointable;
import org.apache.vxquery.datamodel.values.ValueTag;
import org.apache.vxquery.exceptions.ErrorCode;
import org.apache.vxquery.exceptions.SystemException;
import org.apache.vxquery.runtime.functions.base.AbstractTaggedValueArgumentScalarEvaluator;
import org.apache.vxquery.runtime.functions.base.AbstractTaggedValueArgumentScalarEvaluatorFactory;
import org.apache.vxquery.runtime.functions.util.ArithmeticHelper;

public abstract class AbstractArithmeticScalarEvaluatorFactory extends
        AbstractTaggedValueArgumentScalarEvaluatorFactory {
    private static final long serialVersionUID = 1L;

    public AbstractArithmeticScalarEvaluatorFactory(IScalarEvaluatorFactory[] args) {
        super(args);
    }

    @Override
    protected IScalarEvaluator createEvaluator(IHyracksTaskContext ctx, IScalarEvaluator[] args)
            throws HyracksDataException {
        final DynamicContext dCtx = (DynamicContext) ctx.getJobletContext().getGlobalJobData();
        final ArithmeticHelper aHelper = new ArithmeticHelper(createArithmeticOperation(), dCtx);
        final SequencePointable seqp = (SequencePointable) SequencePointable.FACTORY.createPointable();

        return new AbstractTaggedValueArgumentScalarEvaluator(args) {
            @Override
            protected void evaluate(TaggedValuePointable[] args, IPointable result) throws SystemException {
                TaggedValuePointable tvp1 = args[0];
                TaggedValuePointable tvp2 = args[1];
                if (tvp1.getTag() == ValueTag.SEQUENCE_TAG) {
                    tvp1.getValue(seqp);
                    if (seqp.getEntryCount() == 0) {
                        result.set(tvp1);
                        return;
                    }
                    throw new SystemException(ErrorCode.XPTY0004);
                }
                if (tvp2.getTag() == ValueTag.SEQUENCE_TAG) {
                    tvp2.getValue(seqp);
                    if (seqp.getEntryCount() == 0) {
                        result.set(tvp2);
                        return;
                    }
                    throw new SystemException(ErrorCode.XPTY0004);
                }
                aHelper.compute(tvp1, tvp2, result);
            }
        };
    }

    protected abstract AbstractArithmeticOperation createArithmeticOperation();
}