/**

 * Relational pipes

 * Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * 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 3.

 *

 * 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, see <http://www.gnu.org/licenses/>.

 */

#include <cstring>

#include <iostream>

#include <sql.h>

#include <sqlext.h>

#include "SqlException.h"

#include "DriverManager.h"

#include "OdbcCommon.h"

namespace relpipe {

namespace tr {

namespace sql {

DriverManager::DriverManager() {

	environment = OdbcCommon::allocateHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE);

	SQLRETURN result = SQLSetEnvAttr(environment, SQL_ATTR_ODBC_VERSION, (void*) SQL_OV_ODBC3, 0);

	if (OdbcCommon::isNotSuccessful(result)) throw SqlException(L"Unable to set ODBC version", result, SQL_HANDLE_ENV, environment);

}

DriverManager::~DriverManager() {

	OdbcCommon::freeHandle(SQL_HANDLE_ENV, environment);

}

std::vector<DriverManager::DataSource> DriverManager::getDataSources() {

	std::vector<DriverManager::DataSource> list;

	SQLCHAR name[SQL_MAX_DSN_LENGTH + 1];

	SQLCHAR description[255];

	memset(name, 0, sizeof (name));

	memset(description, 0, sizeof (description));

	SQLSMALLINT nameLength;

	SQLSMALLINT descriptionLength;

	for (int i = 0; true; i++) {

		SQLRETURN result = SQLDataSources(environment, i == 0 ? SQL_FETCH_FIRST : SQL_FETCH_NEXT,

				name, sizeof (name), &nameLength,

				description, sizeof (description), &descriptionLength);

		// TODO: description field actually contains the driver name – see comments in unixODBC file: DriverManager/SQLDataSources.c

		// TODO: check nameLength and descriptionLength whether values were truncated?

		if (OdbcCommon::isSuccessful(result)) list.push_back({convertor.from_bytes((char*) name), convertor.from_bytes((char*) description)});

		else if (result == SQL_NO_DATA_FOUND) break;

		else throw SqlException(L"Unable to list data sources: " + std::to_wstring(result), result, SQL_HANDLE_ENV, environment);

	}

	return list;

}

Connection* DriverManager::getConnectionByDSN(relpipe::reader::string_t dataSourceName, relpipe::reader::string_t userName, relpipe::reader::string_t password) {

	SQLHDBC connection = OdbcCommon::allocateHandle(SQL_HANDLE_DBC, environment);

	std::string dataSourceNameBytes = convertor.to_bytes(dataSourceName);

	std::string userNameBytes = convertor.to_bytes(userName);

	std::string passwordBytes = convertor.to_bytes(password);

	SQLRETURN result = SQLConnect(connection,

			(SQLCHAR*) dataSourceNameBytes.c_str(), SQL_NTS,

			(SQLCHAR*) userNameBytes.c_str(), SQL_NTS,

			(SQLCHAR*) passwordBytes.c_str(), SQL_NTS);

	return new Connection(connection);

}

	SQLHDBC connection = OdbcCommon::allocateHandle(SQL_HANDLE_DBC, environment);

	char completeConnectionString[SQL_MAX_OPTION_STRING_LENGTH];

	memset(completeConnectionString, 0, sizeof (completeConnectionString));

	SQLSMALLINT completeConnectionStringLength = -1;

	SQLRETURN result = SQLDriverConnect(connection, nullptr,

			(SQLCHAR*) convertor.to_bytes(connectionString).c_str(), SQL_NTS,

			(SQLCHAR*) completeConnectionString, sizeof (completeConnectionString), &completeConnectionStringLength,

			SQL_DRIVER_NOPROMPT);

	return new Connection(connection);

}

}

}

}