/* Copyright (C) 2014 InfiniDB, Inc.
   Copyright (C) 2016 MariaDB Corporaton

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; version 2 of
   the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

/***********************************************************************
*   $Id$
*
*
***********************************************************************/

//#include <my_config.h>
#include <cmath>
#include <iostream>
using namespace std;

#include "udfsdk.h"

#include "treenode.h"
using namespace execplan;

#include "rowgroup.h"
using namespace rowgroup;

#include "funcexp.h"
using namespace funcexp;

namespace udfsdk
{
/**
 * UDFSDK definition
 */
UDFSDK::UDFSDK()
{
}

UDFSDK::~UDFSDK()
{
}

/**
 * All UDF functions should be registered in the function map. They will be
 * picked up by the MariaDB ColumnStore F&E framework when the servers are started. 
 * That will make sure the UDF functions runs distributedly in ColumnStore
 * engines just like the internal ColumnStore functions.
 */
FuncMap UDFSDK::UDFMap() const
{
	FuncMap fm;
	
	// first: function name
	// second: Function pointer
	// please use lower case for the function name. Because the names might be 
	// case-insensitive in MariaDB depending on the setting. In such case,
	// the function names passed to the interface is always in lower case.
	fm["mcs_add"] = new MCS_add();
	fm["mcs_isnull"] = new MCS_isnull();
	
	return fm;
}

/***************************************************************************
 * MCS_ADD implementation 
 *
 * OperationType() definition
 */
CalpontSystemCatalog::ColType MCS_add::operationType (FunctionParm& fp, 
                       CalpontSystemCatalog::ColType& resultType)
{
	// operation type of MCS_add is determined by the argument types
	assert (fp.size() == 2);
	CalpontSystemCatalog::ColType rt;
	if (fp[0]->data()->resultType() == fp[1]->data()->resultType())
	{
		rt = fp[0]->data()->resultType();
	}
	else if (fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::CHAR ||
		       fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::CHAR ||
		       fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::VARCHAR ||
		       fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::VARCHAR ||
		       fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::DOUBLE ||
		       fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::DOUBLE)
	{
		rt.colDataType = CalpontSystemCatalog::DOUBLE;
		rt.colWidth = 8;
	}
	else if (fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::DATE ||
		       fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::DATE ||
		       fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::DATETIME ||
		       fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::DATETIME)
	{
		rt.colDataType = CalpontSystemCatalog::BIGINT;
		rt.colWidth = 8;
	}
	else if (fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::DECIMAL ||
             fp[0]->data()->resultType().colDataType == CalpontSystemCatalog::UDECIMAL ||
             fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::DECIMAL ||
             fp[1]->data()->resultType().colDataType == CalpontSystemCatalog::UDECIMAL)
	{
		rt.colDataType = CalpontSystemCatalog::DECIMAL;
		rt.colWidth = 8;
	}
	else
	{
        if (isUnsigned(fp[0]->data()->resultType().colDataType) ||
            isUnsigned(fp[1]->data()->resultType().colDataType))
        {
            rt.colDataType = CalpontSystemCatalog::UBIGINT;
            rt.colWidth = 8;
        }
        else
        {
            rt.colDataType = CalpontSystemCatalog::BIGINT;
            rt.colWidth = 8;
        }
	}
	return rt;
}

/**
 * getDoubleVal API definition
 *
 * This API is called when an double value is needed to return from the UDF function
 */
double MCS_add::getDoubleVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	switch (op_ct.colDataType)
	{
		// The APIs for the evaluation of the function parameters are the same getXXXval()
		// functions. However, only two arguments are passed in, the current
		// row reference and the NULL indicator isNull.
		case CalpontSystemCatalog::BIGINT:
		case CalpontSystemCatalog::MEDINT:
		case CalpontSystemCatalog::SMALLINT:
		case CalpontSystemCatalog::TINYINT:
			return ( parm[0]->data()->getIntVal(row, isNull) +
			         parm[1]->data()->getIntVal(row, isNull));
        case CalpontSystemCatalog::UBIGINT:
        case CalpontSystemCatalog::UMEDINT:
        case CalpontSystemCatalog::USMALLINT:
        case CalpontSystemCatalog::UTINYINT:
            return ( parm[0]->data()->getUintVal(row, isNull) +
                     parm[1]->data()->getUintVal(row, isNull));
		case CalpontSystemCatalog::DOUBLE:
			return ( parm[0]->data()->getDoubleVal(row, isNull) +
			         parm[1]->data()->getDoubleVal(row, isNull));
		case CalpontSystemCatalog::DECIMAL:
        case CalpontSystemCatalog::UDECIMAL:
		{
			IDB_Decimal dec;
			IDB_Decimal op1 = parm[0]->data()->getDecimalVal(row, isNull);
			IDB_Decimal op2 = parm[1]->data()->getDecimalVal(row, isNull);
			if (op1.scale == op2.scale)
			{
				dec.scale = op1.scale;
			}
			else if (op1.scale >= op2.scale)
			{
				dec.scale = op2.scale;
				op1.value *= (int64_t)pow((double)10, op1.scale-op2.scale);
			}
			else
			{
				dec.scale = op1.scale;
				op2.value *= (int64_t)pow((double)10, op2.scale-op1.scale);
			}
			dec.value = op1.value + op2.value;
			return (double)(dec.value / pow((double)10, dec.scale));
		}
		default:
			return ( parm[0]->data()->getDoubleVal(row, isNull) +
			         parm[1]->data()->getDoubleVal(row, isNull));
	}
	return 0;
}

float MCS_add::getFloatVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (float)getDoubleVal(row, parm, isNull, op_ct);
}

/**
 * getIntVal API definition
 *
 * This API is called when an integer value is needed to return from the UDF function
 *
 * Because the result type MCS_add is double(real), all the other API can simply call 
 * getDoubleVal and apply the conversion. This method may not fit for all the UDF
 * implementation.
 */
int64_t MCS_add::getIntVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (int64_t)getDoubleVal(row, parm, isNull, op_ct);
}

string MCS_add::getStrVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	// One will need a more efficient implementation if this API is frequently
	// called for this UDF function. This code is for demonstration purpose.
	ostringstream oss;
	oss << getDoubleVal(row, parm, isNull, op_ct);
	return oss.str();
}

IDB_Decimal MCS_add::getDecimalVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	IDB_Decimal dec;
	dec.value = getIntVal(row, parm, isNull, op_ct);
	dec.scale = 0;
	return dec;
}

/**
 * This API should never be called for MCS_add, because the latter
 * is not for date/datetime values addition. In such case, one can
 * either not implement this API and an IDB-5001 error will be thrown,
 * or throw a customized exception here.
 */
int32_t MCS_add::getDateIntVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	throw logic_error("Invalid API called for MCS_ADD");
}

/**
 * This API should never be called for MCS_add, because the latter
 * is not for date/datetime values addition. In such case, one can
 * either not implement this API and an IDB-5001 error will be thrown,
 * or throw a customized exception here.
 */
int64_t MCS_add::getDatetimeIntVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (int64_t)getDoubleVal(row, parm, isNull, op_ct);
}

bool MCS_add::getBoolVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return false;
}

/***************************************************************************
 * MCS_ISNULL implementation 
 *
 * OperationType() definition
 */
CalpontSystemCatalog::ColType MCS_isnull::operationType (FunctionParm& fp, 
                       CalpontSystemCatalog::ColType& resultType)
{
	// operation type of MCS_isnull should be the same as the argument type
	assert (fp.size() == 1);
	return fp[0]->data()->resultType();
}

/**
 * getBoolVal API definition
 *
 * This would be the most commonly called API for MCS_isnull function
 */
bool MCS_isnull::getBoolVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	switch (op_ct.colDataType)
	{
		// For the purpose of this function, one does not need to get the value of
		// the argument. One only need to know if the argument is NULL. The passed
		// in parameter isNull will be set if the parameter is evaluated NULL. 
		// Please note that before this function returns, isNull should be set to 
		// false, otherwise the result of the function would be considered NULL,
		// which is not possible for MCS_isnull().
		case CalpontSystemCatalog::DECIMAL:
        case CalpontSystemCatalog::UDECIMAL:
			parm[0]->data()->getDecimalVal(row, isNull);
			break;
		case CalpontSystemCatalog::CHAR:
		case CalpontSystemCatalog::VARCHAR:
			parm[0]->data()->getStrVal(row, isNull);
			break;
		default:
			parm[0]->data()->getIntVal(row, isNull);
	}
	bool ret = isNull;
	// It's important to reset isNull indicator.
	isNull = false;
	return ret;
}

/**
 * getDoubleVal API definition
 *
 * This API is called when a double value is needed to return from the UDF function
 */
double MCS_isnull::getDoubleVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (getBoolVal(row, parm, isNull, op_ct) ? 1 : 0);
}

float MCS_isnull::getFloatVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (getBoolVal(row, parm, isNull, op_ct) ? 1 : 0);
}

/**
 * getIntVal API definition
 *
 * This API is called when an integer value is needed to return from the UDF function
 *
 * Because the result type MCS_add is double(real), all the other API can simply call 
 * getDoubleVal and apply the conversion. This method may not fit for all the UDF
 * implementations.
 */
int64_t MCS_isnull::getIntVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (getBoolVal(row, parm, isNull, op_ct) ? 1 : 0);
}

string MCS_isnull::getStrVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	// This needs to be more efficient if this API will be frequently
	// called for this UDF function. 
		return (getBoolVal(row, parm, isNull, op_ct) ? "1" : "0");

}

IDB_Decimal MCS_isnull::getDecimalVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	IDB_Decimal dec;
	dec.value = (getBoolVal(row, parm, isNull, op_ct) ? 1 : 0);
	dec.scale = 0;
	return dec;
}

int32_t MCS_isnull::getDateIntVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (getBoolVal(row, parm, isNull, op_ct) ? 1 : 0);
}

int64_t MCS_isnull::getDatetimeIntVal(Row& row,
							FunctionParm& parm,
							bool& isNull,
							CalpontSystemCatalog::ColType& op_ct)
{
	return (getBoolVal(row, parm, isNull, op_ct) ? 1 : 0);
}

}
// vim:ts=4 sw=4: