/**
 * 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.physical.config;

import java.util.Iterator;
import java.util.List;

import org.apache.drill.common.logical.data.JoinCondition;
import org.apache.drill.exec.physical.base.AbstractBase;
import org.apache.drill.exec.physical.base.PhysicalOperator;
import org.apache.drill.exec.physical.base.PhysicalVisitor;
import org.apache.drill.exec.proto.UserBitShared.CoreOperatorType;
import org.apache.calcite.rel.core.JoinRelType;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.google.common.base.Preconditions;
import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;

@JsonTypeName("merge-join")
public class MergeJoinPOP extends AbstractBase{
  static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(MergeJoinPOP.class);


  private final PhysicalOperator left;
  private final PhysicalOperator right;
  private final List<JoinCondition> conditions;
  private final JoinRelType joinType;

  @JsonCreator
  public MergeJoinPOP(
      @JsonProperty("left") PhysicalOperator left,
      @JsonProperty("right") PhysicalOperator right,
      @JsonProperty("conditions") List<JoinCondition> conditions,
      @JsonProperty("joinType") JoinRelType joinType
  ) {
    this.left = left;
    this.right = right;
    this.conditions = conditions;
    Preconditions.checkArgument(joinType != null, "Join type is missing!");
    this.joinType = joinType;
    Preconditions.checkArgument(joinType != JoinRelType.FULL, "Full outer join not currently supported");
  }

  @Override
  public <T, X, E extends Throwable> T accept(PhysicalVisitor<T, X, E> physicalVisitor, X value) throws E {
    return physicalVisitor.visitMergeJoin(this, value);
  }

  @Override
  public PhysicalOperator getNewWithChildren(List<PhysicalOperator> children) {
    Preconditions.checkArgument(children.size() == 2);
    return new MergeJoinPOP(children.get(0), children.get(1), conditions, joinType);
  }

  @Override
  public Iterator<PhysicalOperator> iterator() {
    return Iterators.forArray(left, right);
  }

  public PhysicalOperator getLeft() {
    return left;
  }

  public PhysicalOperator getRight() {
    return right;
  }

  public JoinRelType getJoinType() {
    return joinType;
  }

  public List<JoinCondition> getConditions() {
    return conditions;
  }

  public MergeJoinPOP flipIfRight(){
    if(joinType == JoinRelType.RIGHT){
      List<JoinCondition> flippedConditions = Lists.newArrayList();
      for(JoinCondition c : conditions){
        flippedConditions.add(c.flip());
      }
      return new MergeJoinPOP(right, left, flippedConditions, JoinRelType.LEFT);
    }else{
      return this;
    }

  }

  @Override
  public int getOperatorType() {
    return CoreOperatorType.MERGE_JOIN_VALUE;
  }
}