/*
 * 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.test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;

import java.util.Iterator;
import java.util.Properties;

import org.apache.pig.ExecType;
import org.apache.pig.PigConfiguration;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.plans.MROperPlan;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POPartialAgg;
import org.apache.pig.impl.PigContext;
import org.junit.Before;
import org.junit.Test;

/**
 * Test POPartialAgg runtime
 */
public class TestPOPartialAggPlan  {
    PigContext pc;

    @Before
    public void setUp() throws ExecException {
        pc = new PigContext(ExecType.LOCAL, new Properties());
        pc.connect();
    }

    @Test
    public void testNoMapAggProp() throws Exception{
        //test with pig.exec.mapPartAgg not set
        String query = getGByQuery();

        MROperPlan mrp = Util.buildMRPlan(query, pc);
        assertEquals(mrp.size(), 1);

        assertNull("POPartialAgg should be absent",findPOPartialAgg(mrp));
    }

    @Test
    public void testMapAggPropFalse() throws Exception{
        //test with pig.exec.mapPartAgg set to false
        String query = getGByQuery();
        pc.getProperties().setProperty(PigConfiguration.PROP_EXEC_MAP_PARTAGG, "false");
        MROperPlan mrp = Util.buildMRPlan(query, pc);
        assertEquals(mrp.size(), 1);

        assertNull("POPartialAgg should be absent", findPOPartialAgg(mrp));
    }

    @Test
    public void testMapAggPropTrue() throws Exception{
        //test with pig.exec.mapPartAgg to true
        String query = getGByQuery();
        pc.getProperties().setProperty(PigConfiguration.PROP_EXEC_MAP_PARTAGG, "true");
        MROperPlan mrp = Util.buildMRPlan(query, pc);
        assertEquals(mrp.size(), 1);

        assertNotNull("POPartialAgg should be present",findPOPartialAgg(mrp));

    }


    private Object findPOPartialAgg(MROperPlan mrp) {
        PhysicalPlan mapPlan = mrp.getRoots().get(0).mapPlan;
        return findPOPartialAgg(mapPlan);
    }

    private String getGByQuery() {
        return "l = load 'x' as (a,b,c);" +
                "g = group l by a;" +
                "f = foreach g generate group, COUNT(l.b);";
    }


    @Test
    public void testMapAggNoAggFunc() throws Exception{
        //no agg func, so there should not be a POPartial
        String query = "l = load 'x' as (a,b,c);" +
                "g = group l by a;" +
                "f = foreach g generate group;";
        pc.getProperties().setProperty(PigConfiguration.PROP_EXEC_MAP_PARTAGG, "true");
        MROperPlan mrp = Util.buildMRPlan(query, pc);
        assertEquals(mrp.size(), 1);

        assertNull("POPartialAgg should be absent",findPOPartialAgg(mrp));
    }

    @Test
    public void testMapAggNotCombinable() throws Exception{
        //not combinable, so there should not be a POPartial
        String query = "l = load 'x' as (a,b,c);" +
                "g = group l by a;" +
                "f = foreach g generate group, COUNT(l.b), l.b;";
        pc.getProperties().setProperty(PigConfiguration.PROP_EXEC_MAP_PARTAGG, "true");
        MROperPlan mrp = Util.buildMRPlan(query, pc);
        assertEquals(mrp.size(), 1);

        assertNull("POPartialAgg should be absent", findPOPartialAgg(mrp));
    }

    private PhysicalOperator findPOPartialAgg(PhysicalPlan mapPlan) {
        Iterator<PhysicalOperator> it = mapPlan.iterator();
        while(it.hasNext()){
            PhysicalOperator op = it.next();
            if(op instanceof POPartialAgg){
                return op;
            }
        }
        return null;
    }


}