/**
 * 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.tajo.algebra;

import com.google.common.base.Objects;
import org.apache.tajo.util.TUtil;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class CaseWhenPredicate extends Expr {
  private List<WhenExpr> whens = new ArrayList<WhenExpr>();
  private Expr elseResult;

  public CaseWhenPredicate() {
    super(OpType.CaseWhen);
  }

  public void addWhen(Expr condition, Expr result) {
    whens.add(new WhenExpr(condition, result));
  }

  public Collection<WhenExpr> getWhens() {
    return this.whens;
  }

  public void setElseResult(Expr elseResult) {
    this.elseResult = elseResult;
  }

  public Expr getElseResult() {
    return this.elseResult;
  }

  public boolean hasElseResult() {
    return elseResult != null;
  }

  @Override
  public int hashCode() {
    return Objects.hashCode(whens, elseResult);
  }

  @Override
  boolean equalsTo(Expr expr) {
    CaseWhenPredicate another = (CaseWhenPredicate) expr;
    return whens.equals(another.whens) && TUtil.checkEquals(elseResult, another.elseResult);
  }

  @Override
  public String toJson() {
    return JsonHelper.toJson(this);
  }

  public static class WhenExpr {
    Expr condition;
    Expr result;

    public WhenExpr(Expr condition, Expr result) {
      this.condition = condition;
      this.result = result;
    }

    public void setCondition(Expr condition) {
      this.condition = condition;
    }

    public Expr getCondition() {
      return this.condition;
    }

    public void setResult(Expr result) {
      this.result = result;
    }

    public Expr getResult() {
      return this.result;
    }

    public int hashCode() {
      return Objects.hashCode(condition, result);
    }

    public boolean equals(Object obj) {
      if (obj instanceof WhenExpr) {
        WhenExpr another = (WhenExpr) obj;
        return condition.equals(another.condition) && result.equals(result);
      }

      return false;
    }
  }
}