// utilities for transfroming options between TWAIN and sane ...
//
// Date: 2022-04-14
//

#pragma once

#include <sane/sane_ex.h>
#include <string>

class sane_helper
{
	std::string dll_root_;
	HMODULE		dll_handle_ = nullptr;

	void clear(void);

public:
	SANE_Status (*invoke_sane_init) (SANE_Int * version_code, SANE_Auth_Callback authorize) = nullptr;
	SANE_Status (*invoke_sane_init_ex)(SANE_Int* version_code, sane_callback cb, void* param) = nullptr;
	void (*invoke_sane_exit) (void) = nullptr;
	SANE_Status (*invoke_sane_get_devices) (const SANE_Device *** device_list, SANE_Bool local_only) = nullptr;
	SANE_Status (*invoke_sane_open) (SANE_String_Const devicename, SANE_Handle * handle) = nullptr;
	void (*invoke_sane_close) (SANE_Handle handle) = nullptr;
	const SANE_Option_Descriptor* (*invoke_sane_get_option_descriptor) (SANE_Handle handle, SANE_Int option) = nullptr;
	SANE_Status (*invoke_sane_control_option) (SANE_Handle handle, SANE_Int option, SANE_Action action, void *value, SANE_Int * info) = nullptr;
	SANE_Status (*invoke_sane_get_parameters) (SANE_Handle handle, SANE_Parameters * params) = nullptr;
	SANE_Status (*invoke_sane_start) (SANE_Handle handle) = nullptr;
	SANE_Status (*invoke_sane_read) (SANE_Handle handle, SANE_Byte * data, SANE_Int max_length, SANE_Int * length) = nullptr;
	void (*invoke_sane_cancel) (SANE_Handle handle) = nullptr;
	SANE_Status (*invoke_sane_set_io_mode) (SANE_Handle handle, SANE_Bool non_blocking) = nullptr;
	SANE_Status (*invoke_sane_get_select_fd) (SANE_Handle handle, SANE_Int * fd) = nullptr;
	SANE_String_Const (*invoke_sane_strstatus) (SANE_Status status) = nullptr;

public:
	sane_helper();
	~sane_helper();

	bool load_sane(const char* vendor);	// libsane_hgsane.so.1, and vendor is 'hgsane'
};

extern sane_helper* sane_helper_;