// database.h: simple database interface
//
// Author:	Gongbing
//
// Date:	2020-09-11

#pragma once
#ifndef _INCLUDED_REF_
#define _INCLUDED_REF_
#include "../ref/ref.h"
#endif
#include <OAIdl.h>		// for VARIANT

#define MAX_TABLE_FIELD_NAME_LEN	20

namespace db_util
{
	enum	// Driver type
	{
		DBDRIVER_ODBC_DBASE = 533,
		DBDRIVER_ODBC_EXCEL = 790,
		DBDRIVER_ODBC_ACCESS = 25,
		DBDRIVER_ODBC_VFDB,
		DBDRIVER_ODBC_VFTABLE,
		DBDRIVER_FILE_SQLITE = 1000,
	};
	typedef struct _table_fields
	{
		wchar_t	name[MAX_TABLE_FIELD_NAME_LEN];
		VARIANT	default_val;						// the field 'type' is defining the field type too.
													//		NOW support VT_BOOL, VT_BSTR, VT_DATE, VT_I1(to VT_I8), VT_R4, VT_R8
													//		VT_DATE use function VariantTimeToSystemTime to convert !!!
		int		length;								// 0 is not set, always for TEXT field
		bool	unique;
		bool	not_null;
		bool	primary_key;
		bool	foreign_key;
		bool	use_default_val;					// whether use the 'default_val' in table as the field's default value
	}TBLFLD;

	__declspec(novtable) struct IRecordset : public ref_util::IRef
	{
		COM_API_DECLARE(int, get_rows(void));	// get count of records
		COM_API_DECLARE(int, get_cols(void));	// get count of record fields
		COM_API_DECLARE(bool, get_value(int row, int col, bool* boolean));
		COM_API_DECLARE(bool, get_value(int row, int col, int* integer));
		COM_API_DECLARE(bool, get_value(int row, int col, double* decimal));
		COM_API_DECLARE(bool, get_value(int row, int col, wchar_t* buf, int* words/*[in] - words in buf; [out] - real length of the value. you should provide greater buffer if it was greater than in*/));
		COM_API_DECLARE(bool, get_value(int row, int col, inter_module_data::set_data set_val/*data: pointed to an unicode string*/, void* param));
	};

	__declspec(novtable) struct IDatabase : public ref_util::IRef
	{
		COM_API_DECLARE(int, open(const wchar_t* db_name, const wchar_t* user_name = 0, const wchar_t* password = 0));
		COM_API_DECLARE(int, create_table(const wchar_t* table_name, db_util::TBLFLD* fields, int fields_num, int *composed_primary_key_index = NULL));
		COM_API_DECLARE(int, close(void));
		COM_API_DECLARE(int, execute_sql(const wchar_t* sql, IRecordset** record = 0));
		COM_API_DECLARE(int, get_error_msg(inter_module_data::set_data set_msg/*data: pointed to an unicode string*/, void* param));	// return error code
	};

	// exports ...
	PORT_API(bool) add_database(const wchar_t* db_name, const wchar_t* db_file, int driver_type);
	PORT_API(bool) del_database(const wchar_t* db_name, int driver_type = DBDRIVER_ODBC_ACCESS);
	PORT_API(IDatabase*) create_database_instance(int driver_type = DBDRIVER_ODBC_ACCESS);
	PORT_API(bool) create_table_sql(const wchar_t* table_name, TBLFLD* fields, int fields_num
		, inter_module_data::set_data set_msg/*data: pointed to an unicode string*/, void* param
		, int *composed_primary_key_index = NULL);	// -1 is over
};