/*
 ============================================================================
 Name        : DBConnector.h
 Author      : Stephen Cannon
 Version     : 0.1
 Copyright   : Copyright 2011 Stephen Cannon
 Description :
 ============================================================================
 *
 * This file is part of LikelihoodWeighting.
 *
 * LikelihoodWeighting is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * LikelihoodWeighting 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 Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with LikelihoodWeighting.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef DBCONNECTOR_H_
#define DBCONNECTOR_H_

#include <windows.h>
#include <stdio.h>
#include <sql.h>
#include <sqlext.h>

#ifdef __cplusplus
extern "C" {
#endif


enum { BUFFER_SIZE = 1024, LARGE_BUFFER_SIZE = 10240 };
enum {	DBCONNECTOR_STATE_NOT_CONNECTED = 0,
		DBCONNECTOR_STATE_CONNECTED = 1,
		DBCONNECTOR_STATE_STMT_PREPARED = 2,
        DBCONNECTOR_STATE_STMT_EXECUTED = 3};
enum {	ERR_GENERAL_ERROR = -1,
		ERR_ALREADY_CONNECTED = -9,
		ERR_NOT_CONNECTED = -10,
		ERR_NO_PREPARED_STMT = -11,
		ERR_STMT_NOT_EXECUTED = -12};

/**
 * Defines a parameter binding in a prepared statement.  A parameter binding
 * defines information about the parameter being bound to a prepared statement
 * as well as holds the value to be passed into the prepared statement when it
 * is used in a DB query.  There is a parameter binding for each "?" in a
 * prepared statement.
 */
typedef struct _ParamBinding_
{
	SQLSMALLINT		ioType;
	SQLSMALLINT		valueType;
	SQLSMALLINT		paramType;
	SQLULEN			columnSize;
	SQLSMALLINT		decimalDigits;
	SQLPOINTER		paramValuePtr;
	SQLLEN			bufferLength;
	SQLLEN			*indPtr;
} ParamBinding;

/**
 * Defines a column binding in a prepared statement.  A column binding defines
 * a column's type and holds the value returned for that column after the DB
 * has been queried.
 */
typedef struct _ColBinding_
{
	SQLSMALLINT		type;
	SQLPOINTER		valuePtr;
	SQLLEN			bufferLength;
	SQLLEN			*indPtr;
} ColBinding;

/**
 * Defines a DB connection and allows one to query that DB
 */
typedef struct _DBConnector_
{
	SQLHENV h_env;
	SQLHDBC h_dbc;
	SQLHSTMT h_stmt;
	SQLCHAR *stmt;
	const char *connectionString;
	size_t state;
} DBConnector;

char DBConnector__init(DBConnector *self, const char *connectionString);
char DBConnector__connect(DBConnector *self);
char DBConnector__prepareStatement(DBConnector *self, const char *stmt, ParamBinding *paramBinding, size_t numParams, ColBinding *colBinding, size_t numCols);
char DBConnector__executePreparedStatement(DBConnector *self);
char DBConnector__fetchExecutedStatementResult(DBConnector *self, char *error);
char DBConnector__disconnect(DBConnector *self);
char DBConnector__del(DBConnector *self);
void __DBConnector__extractError(const char *fn, SQLHANDLE handle, SQLSMALLINT type);

#ifdef __cplusplus
}
#endif

#endif /* DBCONNECTOR_H_ */