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

#include <cstring>
#include <codecvt>
#include <locale>
#include <iostream>

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

#include "SqlException.h"
#include "OdbcCommon.h"

namespace relpipe {
namespace tr {
namespace sql {

SqlException::SqlException(std::wstring message) : message(message) {
}

SqlException::SqlException(std::wstring message, SQLRETURN resultCode, SQLSMALLINT handleType, SQLHANDLE handle, bool freeHandle) : message(message), resultCode(resultCode) {
	std::wstring_convert < std::codecvt_utf8<wchar_t>> convertor("", L"conversion failed"); // TODO: support also other encodings
	SQLCHAR buffer[SQL_MAX_MESSAGE_LENGTH + 1];
	SQLCHAR sqlstate[SQL_SQLSTATE_SIZE + 1];
	memset(buffer, 0, sizeof (buffer));
	memset(sqlstate, 0, sizeof (sqlstate));
	SQLINTEGER sqlcode;
	SQLSMALLINT length;
	for (SQLSMALLINT i = 1; SQLGetDiagRec(handleType, handle, i, sqlstate, &sqlcode, buffer, SQL_MAX_MESSAGE_LENGTH + 1, &length) == SQL_SUCCESS; i++) {
		std::wstring diagMessage = convertor.from_bytes((char*) buffer);
		if (diagMessage == L"conversion failed") {
			for (size_t i = 0; i < sizeof (buffer); i++) if (buffer[i] > 126 || buffer[i] == '\r') buffer[i] = '?'; // keep only ASCII characters and avoid CR which breaks the output
			diagMessage = convertor.from_bytes((char*) buffer);
		}
		diagnostics.push_back({convertor.from_bytes((char*) sqlstate), sqlcode, diagMessage});
		// FIXME: character encoding in SQLGetDiagRec()
		//
		// sometimes we get valid UTF-8 string
		// sometimes we get valid ISO-8859-1 string (which is not valid UTF-8)
		//
		// Temporary workaround: try UTF-8 decoding and if it fails, remove all non-ASCII characters and try again
		//
		// See also: DriverManager/SQLGetDiagRec.c:
		//   else if ( !__get_connection( head ) -> unicode_driver
		// and DriverManager/__info.c:
		//   char *asc[] = { "char", "char", "ISO8859-1", "ISO-8859-1", "8859-1", "iso8859_1", "ASCII", NULL };
		// in unixODBC
		//
		// We get valid UTF-8 if "PostgreSQL Unicode" driver is used and connection is successful: e.g. SELECT * FROM žádná_taková_tabulka_neexistuje;
		// We get valid ISO-8859-1 if "PostgreSQL Unicode" driver is used and connection is not successful and LANG=cs_CZ.UTF-8 e.g. [unixODBC]could not connect to server: Spojení odmítnuto
		// n.b. character í is present in ISO-8859-1, but other Czech characters (čřš etc.) are not (they are in ISO-8859-2)
		//
		// SQLGetDiagRec() behavior differs from other functions like SQLGetData(). Maybe use SQLGetDiagRecW() and decode UCS-2 / UTF-16.

	}
	if (freeHandle) OdbcCommon::freeHandle(handleType, handle);
}

std::vector<SqlException::SqlDiagnosticsRecord> SqlException::getDiagnostics() const {
	return diagnostics;
}

std::wstring SqlException::getMessage() const {
	if (resultCode) return message + L" SQLRETURN=" + std::to_wstring(resultCode);
	else return message;
}

SQLRETURN SqlException::getResultCode() const {
	return resultCode;
}



}
}
}