/*
 * 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.drill.exec.planner.physical;

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

import org.apache.calcite.rel.core.Join;
import org.apache.calcite.rel.metadata.RelMetadataQuery;
import org.apache.drill.common.logical.data.JoinCondition;
import org.apache.drill.exec.physical.base.PhysicalOperator;
import org.apache.drill.exec.physical.config.HashJoinPOP;
import org.apache.drill.exec.physical.impl.join.JoinUtils;
import org.apache.drill.exec.physical.impl.join.JoinUtils.JoinCategory;
import org.apache.drill.exec.record.BatchSchema.SelectionVectorMode;
import org.apache.calcite.rel.InvalidRelException;
import org.apache.calcite.rel.core.JoinRelType;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptCost;
import org.apache.calcite.plan.RelOptPlanner;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rex.RexNode;

import com.google.common.collect.Lists;

public class HashJoinPrel  extends JoinPrel {

  private boolean swapped = false;

  public HashJoinPrel(RelOptCluster cluster, RelTraitSet traits, RelNode left, RelNode right, RexNode condition,
                      JoinRelType joinType) throws InvalidRelException {
    this(cluster, traits, left, right, condition, joinType, false);
  }

  public HashJoinPrel(RelOptCluster cluster, RelTraitSet traits, RelNode left, RelNode right, RexNode condition,
      JoinRelType joinType, boolean swapped) throws InvalidRelException {
    super(cluster, traits, left, right, condition, joinType);
    this.swapped = swapped;
    joincategory = JoinUtils.getJoinCategory(left, right, condition, leftKeys, rightKeys, filterNulls);
  }

  @Override
  public Join copy(RelTraitSet traitSet, RexNode conditionExpr, RelNode left, RelNode right, JoinRelType joinType, boolean semiJoinDone) {
    try {
      return new HashJoinPrel(this.getCluster(), traitSet, left, right, conditionExpr, joinType, this.swapped);
    }catch (InvalidRelException e) {
      throw new AssertionError(e);
    }
  }

  @Override
  public RelOptCost computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq) {
    if (PrelUtil.getSettings(getCluster()).useDefaultCosting()) {
      return super.computeSelfCost(planner, mq).multiplyBy(.1);
    }
    if (joincategory == JoinCategory.CARTESIAN || joincategory == JoinCategory.INEQUALITY) {
      return planner.getCostFactory().makeInfiniteCost();
    }
    return computeHashJoinCost(planner, mq);
  }

  @Override
  public PhysicalOperator getPhysicalOperator(PhysicalPlanCreator creator) throws IOException {
    // Depending on whether the left/right is swapped for hash inner join, pass in different
    // combinations of parameters.
    if (! swapped) {
      return getHashJoinPop(creator, left, right, leftKeys, rightKeys);
    } else {
      return getHashJoinPop(creator, right, left, rightKeys, leftKeys);
    }
  }

  @Override
  public SelectionVectorMode[] getSupportedEncodings() {
    return SelectionVectorMode.DEFAULT;
  }

  @Override
  public SelectionVectorMode getEncoding() {
    return SelectionVectorMode.NONE;
  }

  private PhysicalOperator getHashJoinPop(PhysicalPlanCreator creator, RelNode left, RelNode right,
                                          List<Integer> leftKeys, List<Integer> rightKeys) throws IOException{
    final List<String> fields = getRowType().getFieldNames();
    assert isUnique(fields);

    final List<String> leftFields = left.getRowType().getFieldNames();
    final List<String> rightFields = right.getRowType().getFieldNames();

    PhysicalOperator leftPop = ((Prel)left).getPhysicalOperator(creator);
    PhysicalOperator rightPop = ((Prel)right).getPhysicalOperator(creator);

    JoinRelType jtype = this.getJoinType();

    List<JoinCondition> conditions = Lists.newArrayList();

    buildJoinConditions(conditions, leftFields, rightFields, leftKeys, rightKeys);

    HashJoinPOP hjoin = new HashJoinPOP(leftPop, rightPop, conditions, jtype);
    return creator.addMetadata(this, hjoin);
  }

  public void setSwapped(boolean swapped) {
    this.swapped = swapped;
  }

  public boolean isSwapped() {
    return this.swapped;
  }

}
