/*
 * 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.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.List;


import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pig.ComparisonFunc;
import org.apache.pig.FuncSpec;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.Result;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhyPlanVisitor;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.PigContext;
import org.apache.pig.impl.plan.NodeIdGenerator;
import org.apache.pig.impl.plan.OperatorKey;
import org.apache.pig.impl.plan.VisitorException;

//We intentionally skip type checking in backend for performance reasons
@SuppressWarnings("unchecked")
public class POUserComparisonFunc extends ExpressionOperator {
    private final static Log log = LogFactory.getLog(POUserComparisonFunc.class);

    /**
     *
     */
    private static final long serialVersionUID = 1L;
    FuncSpec funcSpec;
    Tuple t1, t2;
    transient ComparisonFunc func;

    public POUserComparisonFunc(OperatorKey k, int rp, List inp, FuncSpec funcSpec, ComparisonFunc func) {
        super(k, rp);
        super.setInputs(inp);
        this.funcSpec = funcSpec;
        this.func = func;
        if(func==null)
            instantiateFunc();
    }

    public POUserComparisonFunc(OperatorKey k, int rp, List inp, FuncSpec funcSpec) {
        this(k, rp, inp, funcSpec, null);
    }

    private void instantiateFunc() {
        this.func = (ComparisonFunc) PigContext.instantiateFuncFromSpec(this.funcSpec);
        this.func.setReporter(getReporter());
    }

    public ComparisonFunc getComparator() {
        return func;
    }

    @Override
    public Result getNextInteger() throws ExecException {
        Result result = new Result();

        result.result = func.compare(t1, t2);
        result.returnStatus = (t1 != null && t2 != null) ? POStatus.STATUS_OK
                : POStatus.STATUS_ERR;
        // the two attached tuples are used up now. So we set the
        // inputAttached flag to false
        inputAttached = false;
        if (result.returnStatus == POStatus.STATUS_OK)
            illustratorMarkup(null, result.result,
                (Integer) result.result == 0 ? 0 : (Integer) result.result > 0 ? 1 : 2);
        return result;

    }

    private Result getNext() {
        Result res = null;
        log.error("getNext being called with non-integer");
        return res;
    }

    @Override
    public Result getNextBoolean() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextDataBag() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextDataByteArray() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextDouble() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextFloat() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextLong() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextDateTime() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextMap() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextString() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextTuple() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextBigInteger() throws ExecException {
        return getNext();
    }

    @Override
    public Result getNextBigDecimal() throws ExecException {
        return getNext();
    }

    public void attachInput(Tuple t1, Tuple t2) {
        this.t1 = t1;
        this.t2 = t2;
        inputAttached = true;

    }

    private void readObject(ObjectInputStream is) throws IOException, ClassNotFoundException{
        is.defaultReadObject();
        instantiateFunc();
    }

    @Override
    public void visit(PhyPlanVisitor v) throws VisitorException {
        v.visitComparisonFunc(this);
    }

    @Override
    public String name() {
        return "POUserComparisonFunc" + "(" + func.getClass().getName() + ")" + "[" + DataType.findTypeName(resultType) + "]" + " - " + mKey.toString();
    }

    @Override
    public boolean supportsMultipleInputs() {
        return false;
    }

    public FuncSpec getFuncSpec() {
        return funcSpec;
    }

    @Override
    public POUserComparisonFunc clone() throws CloneNotSupportedException {
        FuncSpec cloneFs = null;
        if (funcSpec != null) {
            cloneFs = funcSpec.clone();
        }
        POUserComparisonFunc clone =
            new POUserComparisonFunc(new OperatorKey(mKey.scope,
            NodeIdGenerator.getGenerator().getNextNodeId(mKey.scope)),
            requestedParallelism, null, cloneFs);
        clone.cloneHelper(this);
        return clone;
    }

    /**
     * Get child expressions of this expression
     */
    @Override
    public List<ExpressionOperator> getChildExpressions() {
        return null;
    }

    @Override
    public Tuple illustratorMarkup(Object in, Object out, int eqClassIndex) {
        if(illustrator != null) {
            illustrator.getInputs().add(t1);
            illustrator.getEquivalenceClasses().get(eqClassIndex).add(t1);
            illustrator.getInputs().add(t2);
            illustrator.getEquivalenceClasses().get(eqClassIndex).add(t2);
        }
        return null;
    }
}