/*
 * 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.asterix.runtime.evaluators.functions;

import org.apache.asterix.om.functions.BuiltinFunctions;
import org.apache.asterix.om.functions.IFunctionDescriptor;
import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
import org.apache.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
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;

public class NumericATanDescriptor extends AbstractScalarFunctionDynamicDescriptor {
    private static final long serialVersionUID = 1L;
    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
        @Override
        public IFunctionDescriptor createFunctionDescriptor() {
            return new NumericATanDescriptor();
        }
    };

    @Override
    public FunctionIdentifier getIdentifier() {
        return BuiltinFunctions.NUMERIC_ATAN;
    }

    @Override
    public IScalarEvaluatorFactory createEvaluatorFactory(IScalarEvaluatorFactory[] args) {
        return new IScalarEvaluatorFactory() {
            private static final long serialVersionUID = 1L;

            @Override
            public IScalarEvaluator createScalarEvaluator(IHyracksTaskContext ctx) throws HyracksDataException {
                return new NumericATanEvaluator(ctx, args[0]);
            }
        };
    }

    private class NumericATanEvaluator extends AbstractUnaryNumericDoubleFunctionEval {

        NumericATanEvaluator(IHyracksTaskContext context, IScalarEvaluatorFactory argEvalFactory)
                throws HyracksDataException {
            super(context, argEvalFactory, NumericATanDescriptor.this.getIdentifier());
        }

        @Override
        protected void processDouble(double arg, IPointable resultPointable) throws HyracksDataException {
            aDouble.setValue(Math.atan(arg));
            serialize(aDouble, doubleSerde, resultPointable);
        }
    }

}
