// CCommand.h: interface for the CConnection class.
//
//////////////////////////////////////////////////////////////////////

#pragma once

class CServerConnection;

namespace scdriver
{
	// forward declaration
	class CConnection; 
	class CRecordset;

	/// <summary>
	///	Supported parameter directions. For input output parameter, use:  DBPARAMETER_IN|DBPARAMETER_OUT.
	/// </summary>
	enum DBPARAMETER_DIRECTION
	{
		DBPARAMETER_IN		= 1,
		DBPARAMETER_OUT		= 2
	};

/// <summary>
///	Execute prepared SQL/DQL statements, stored procedures with or without parameters
/// </summary>
class __declspec( dllexport ) CCommand
{
public:
	
	CCommand();
	virtual ~CCommand();

	/**************************************
	 *
	 *    function: g e t _ c a l l _ s i z e
	 *
	 **************************************
	 *
	 * Functional description
	 *
	 *	return the size of the class
	 **************************************/
	static int get_class_size();

	/// <summary>
	///	Prepare parametrized SQL/DQL statements
	/// </summary>
	/// <param name="conn">Valid connection instance. The connection to server or embedded DB must be already established</param>
	/// <param name="cmd">SQL or DQL statement. For example: "select * from where id = @myid" is prepared SQL with a single input parameter "myid"</param>
	/// <returns>If method fails, the node_exception exception, containing the error message, will be thrown</returns>
	void PrepareText(CConnection *conn, const char *cmd);

	/// <summary>
	///	Prepare to execute stored procedure
	/// </summary>
	/// <param name="conn">Valid connection instance. The connection to server or embedded DB must be already established</param>
	/// <param name="proc">Stored procedure's name</param>
	/// <returns>If method fails, the node_exception exception, containing the error message, will be thrown</returns>
	void PrepareProcedure(CConnection *conn, const char *proc);

	/// <summary>
	///	Declare input or input/output parameter
	/// </summary>
	/// <param name="name">Name of the parameter.</param>
	/// <param name="direction">Define if parameter is input or input/output. Only output parameter should use overloaded AddParameter function without specifying the value.</param>
	/// <param name="type">Data type of the parameter. If parameter does not matching column, it will be converted.</param>
	/// <param name="data">Pointer to parameter's value. </param>
	/// <param name="size">Default - 0. For fixed length data types and strings, the parameter is ignored. The size is required for BLOB data type.</param>
	/// <returns>If method fails, the node_exception exception, containing the error message, will be thrown</returns>
	void AddParameter(const char *name, const DBPARAMETER_DIRECTION direction, const DATA_TYPE type, void *data, const int size = 0 /* set size for DB_BLOB type parameter */);

	/// <summary>
	///	Declare output parameter
	/// </summary>
	/// <param name="name">Name of the parameter.</param>
	/// <param name="direction">Define parameter direction as DBPARAMETER_OUT.</param>
	/// <param name="type">Data type of the parameter.</param>
	/// <returns>If method fails, the node_exception exception, containing the error message, will be thrown</returns>
	void AddParameter(const char *name, const DBPARAMETER_DIRECTION direction, const DATA_TYPE type);

	/// <summary>
	///	Read output parameter's value
	/// </summary>
	/// <param name="name">Name of output the parameter.</param>
	/// <param name="type">Data type of the parameter.</param>
	/// <param name="data">Pointer to the buffer to receive the patameter's value.</param>
	/// <param name="size">Size in bytes of the buffer.</param>
	/// <returns>If the value of the parameter's has been sucesfully read - returns true, if buffer size is not enough or parameter name does not exists - false.</returns>
	bool GetParameter(const char *name, DATA_TYPE *type, void *data, const int size);

	/// <summary>
	///	Execute command
	/// </summary>
	/// <returns>If method fails, the node_exception exception, containing the error message, will be thrown</returns>
	void Execute();

	/// <summary>
	///	Execute SQL,DQL or stored procedure command and initialize recordset class to handle query's output
	/// </summary>
	/// <param name="rec">Pointer to the CRecorset class instance</param>
	/// <returns>On success recordset will read output rows, otherwise, empty recordset is returned. If error occurs, the node_exception exception, containing the error message, will be thrown.</returns>
	void Open(CRecordset *rec);

	/**************************************
	 *
	 *    function: P r e p a r e T e x t
	 *
	 **************************************
	 *
	 * Functional description
	 *
	 *	prepare parametrized SQL/DQL:
	 *	select * from where id = ?myid
	 *	for UDI
	 **************************************/
	void PrepareText(CServerConnection *conn, const char *cmd);

	/**************************************
	 *
	 *    function: P r e p a r e P r o c e d u r e
	 *
	 **************************************
	 *
	 * Functional description
	 *
	 *	set procedure name for UDI
	 **************************************/
	void PrepareProcedure(CServerConnection *conn, const char *proc);

private:

	/**************************************
	 *
	 *    function: S e n d P a r a m e t e r s
	 *
	 **************************************
	 *
	 * Functional description
	 *
	 *	group all parameters to a single batch (8kb),
	 *	if parameters are top long, split to chunk them 
	 *	and send to the server
	 **************************************/
	void SendParameters(void *param);

	/**************************************
	*
	*	function: r e a d _ p a r a m s
	* 
	**************************************
	*
	* Functional description
	*	
	*	read output parameters if declared
	**************************************/
	static void __stdcall read_params(CConnection *conn, void *command);

private:
	CConnection *m_conn;
	CServerConnection *m_server_conn;
	char		 *m_stmt;
	byte		 m_storage[PAGE_SIZE];
	char		 m_output_params[PAGE_SIZE];
	int			 m_noutput_params;
	int			 m_text;
	int			 m_isend;		// number of packages of parameters already sent
};
}