/**
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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 jp.co.yahoo.dataplatform.mds.hadoop.hive.pushdown;

import java.util.List;

import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeConstantDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeGenericFuncDesc;

import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableVoidObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantBooleanObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantStringObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantByteObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantShortObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantIntObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantLongObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantFloatObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.WritableConstantDoubleObjectInspector;

import jp.co.yahoo.dataplatform.schema.objects.ByteObj;
import jp.co.yahoo.dataplatform.schema.objects.ShortObj;
import jp.co.yahoo.dataplatform.schema.objects.IntegerObj;
import jp.co.yahoo.dataplatform.schema.objects.LongObj;
import jp.co.yahoo.dataplatform.schema.objects.FloatObj;
import jp.co.yahoo.dataplatform.schema.objects.DoubleObj;

import jp.co.yahoo.dataplatform.mds.spread.expression.ExecuterNode;
import jp.co.yahoo.dataplatform.mds.spread.expression.IExtractNode;
import jp.co.yahoo.dataplatform.mds.spread.column.ColumnType;
import jp.co.yahoo.dataplatform.mds.spread.column.filter.IFilter;
import jp.co.yahoo.dataplatform.mds.spread.column.filter.BooleanFilter;
import jp.co.yahoo.dataplatform.mds.spread.column.filter.NullFilter;
import jp.co.yahoo.dataplatform.mds.spread.column.filter.NumberFilter;
import jp.co.yahoo.dataplatform.mds.spread.column.filter.NumberFilterType;
import jp.co.yahoo.dataplatform.mds.spread.column.filter.PerfectMatchStringFilter;
import jp.co.yahoo.dataplatform.mds.spread.expression.IExpressionNode;

import jp.co.yahoo.dataplatform.mds.hadoop.hive.MDSColumnTypeUtil;

public class EqualsHiveExpr implements IHiveExprNode{

  private final List<ExprNodeDesc> nodeDescList;

  public EqualsHiveExpr( final List<ExprNodeDesc> nodeDescList ){
    this.nodeDescList = nodeDescList;
  }

  public static IExpressionNode getEqualsExecuter( final ExprNodeConstantDesc constDesc , final IExtractNode targetColumn , final ColumnType targetColumnType ){
    ObjectInspector objectInspector = constDesc.getWritableObjectInspector();
    if( objectInspector.getCategory() != ObjectInspector.Category.PRIMITIVE ){
      return null;
    }
    PrimitiveObjectInspector primitiveObjectInspector = (PrimitiveObjectInspector)objectInspector;
    IFilter filter = null;
    switch( primitiveObjectInspector.getPrimitiveCategory() ){
      case STRING:
        filter = new PerfectMatchStringFilter( ( (WritableConstantStringObjectInspector)primitiveObjectInspector ).getWritableConstantValue().toString() );
        break;
      case BINARY:
        filter = null;
        break;
      case BOOLEAN:
        boolean booleanObj = ( (WritableConstantBooleanObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new BooleanFilter( booleanObj );
        break;
      case BYTE:
        byte byteObj = ( (WritableConstantByteObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new NumberFilter( NumberFilterType.EQUAL , new ByteObj( byteObj ) );
        break;
      case SHORT:
        short shortObj = ( (WritableConstantShortObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new NumberFilter( NumberFilterType.EQUAL , new ShortObj( shortObj ) );
        break;
      case INT:
        int intObj = ( (WritableConstantIntObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new NumberFilter( NumberFilterType.EQUAL , new IntegerObj( intObj ) );
        break;
      case LONG:
        long longObj = ( (WritableConstantLongObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new NumberFilter( NumberFilterType.EQUAL , new LongObj( longObj ) );
        break;
      case FLOAT:
        float floatObj = ( (WritableConstantFloatObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new NumberFilter( NumberFilterType.EQUAL , new FloatObj( floatObj ) );
        break;
      case DOUBLE:
        double doubleObj = ( (WritableConstantDoubleObjectInspector)primitiveObjectInspector ).getWritableConstantValue().get();
        filter = new NumberFilter( NumberFilterType.EQUAL , new DoubleObj( doubleObj ) );
        break;
      case DATE:
      case DECIMAL:
      case TIMESTAMP:
        filter = null;
        break;
      case VOID:
        Object voidObj = ( (WritableVoidObjectInspector)primitiveObjectInspector ).getWritableConstantValue();
        if( voidObj == null ){
          filter = new NullFilter( targetColumnType );
        }
        else{
          filter = null;
        }
        break;
      default:
        filter = null;
        break;
    }
    if( filter == null ){
      return null;
    }
    return new ExecuterNode( targetColumn , filter );
  }

  @Override
  public void addChildNode( final ExprNodeGenericFuncDesc exprNodeDesc ){
    throw new UnsupportedOperationException( "IHiveExprNode node can not have child node." );
  }

  @Override
  public IExpressionNode getPushDownFilterNode(){
    if( nodeDescList.size() != 2 ){
      return null;
    }
    ExprNodeDesc exprNode1 = nodeDescList.get( 0 );
    ExprNodeDesc exprNode2 = nodeDescList.get( 1 );

    ExprNodeDesc columnDesc;
    ExprNodeConstantDesc constantDesc;

    if( exprNode1 instanceof ExprNodeConstantDesc ){
      columnDesc = exprNode2;
      constantDesc = (ExprNodeConstantDesc)exprNode1;
    } 
    else if( exprNode2 instanceof ExprNodeConstantDesc ){
      columnDesc = exprNode1;
      constantDesc = (ExprNodeConstantDesc)exprNode2;
    }
    else{
      return null;
    } 

    IExtractNode extractNode = CreateExtractNodeUtil.getExtractNode( columnDesc ); 
    if( extractNode == null ){
      return null;
    }

    ColumnType targetColumnType = MDSColumnTypeUtil.typeInfoToColumnType( columnDesc.getTypeInfo() );

    return getEqualsExecuter( constantDesc , extractNode , targetColumnType );
  }

}