#ifndef _usb_operations_h
#define _usb_operations_h

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <libusb.h>

#include "lua/lua.h"
#include "lua/lauxlib.h"
#include "lua/lualib.h"

//list of included dictionaries for defining request, wValue, and wIndex fields
#include "shared_dictionaries.h"

//uncomment to DEBUG this file alone
//#define DEBUG
//"make debug" to get DEBUG msgs on entire program
#include "dbg.h"

//control transfer request types
//uint8_t libusb_control_setup::bmRequestType
//Request type.
//	Bits 0:4 determine recipient, see libusb_request_recipient. Bits 5:6 determine type, see libusb_request_type. Bit 7 determines data transfer direction, see libusb_endpoint_direction.
//
//libusb_request_types:
//LIBUSB_REQUEST_TYPE_STANDARD	Standard handled by driver during setup/etc
//LIBUSB_REQUEST_TYPE_CLASS 	Class for use with specific device classes like HID.
//LIBUSB_REQUEST_TYPE_VENDOR	Vendor application specific as we choose which is what we'll be utilizing for all transfers
//LIBUSB_REQUEST_TYPE_RESERVED	Reserved. 
//
//libusb_request_recipients:
//LIBUSB_RECIPIENT_DEVICE	Device.
//LIBUSB_RECIPIENT_INTERFACE	Interface.
//LIBUSB_RECIPIENT_ENDPOINT	Endpoint.
//LIBUSB_RECIPIENT_OTHER	Other. 
//
//LIBUSB_ENDPOINT_IN	0x80	In: device-to-host.
//LIBUSB_ENDPOINT_OUT	0x00	Out: host-to-device. 
#define USB_IN	LIBUSB_ENDPOINT_IN
#define USB_OUT LIBUSB_ENDPOINT_OUT

//USB timeout
#define TIMEOUT_1_SEC 1000
#define TIMEOUT_5_SEC 5000

//Max transfer length
#define MAX_VUSB 254		//Max VUSB transfers without long transfers enabled
#define	USB_NO_MSG 255		//designates transfer with no message
#define MAX_VUSB_LONGXFR 16384	//16KByte biggest value 16bit wLength can hold

//typedef struct USBtransfer {
//This is the primary USB request struct used by host app used for all application USB communications.
//handle is retrieved from open_usb_device gives us a means to point to the opened USB device.
//The remaining elements are all directly fed to the outgoing USB setup & data packets to/from the device.
//	Every USB transfer starts with host sending one of these setup packets to the device.
//	the setup packets are unidirectinal always coming from the bus master (host).
//	The data packet(s) for the transfer then follow and are bidirectional.
//	The drivers handle final NACK/ACK/STALL packet for the most part..
//	Note V-USB mcu driver doesn't have time to check CRC so it sends ACK assuming no corruption.
//endpoint basically this is the direction of the data packet to follow.
//	the usb device has a OUT and IN endpoint buffer and this defines which is being accessed.
//	OUT "out of host" is for writting data to the usb device.
//	IN  "in to host" is for reading data from the usb device.
//	endpoint is the only portion of setup packet's requestType field that isn't hardcoded.
//      Vendor request types used exclusively as they meet the our intent and 'hard coded' into this struct.
//	The recipient of this setup packet is also 'hard coded' to the usb device.
//request is more like request type in this scope and designates the 'dictionary' containing the command.
//	pinport is the first dictionary of commands, more to come as things develop.
//	these requests/dictionaries define how the wValue and wIndex fields are utilized.
//	anything can be placed in the 4 bytes of wValue/wIndex as defined by the dictionary.
//wValueMSB:wValueLSB
//	This is where the app places the 'command' being given to the retro programmer.
//	LSB is big enough for now and contains the actual opcode.
//	MSB is used as an overflow for operands/data if wIndex is not large enough.
//	future dicts with more than 256 opcodes could define some/all of MSB to contain the opcode as well.
//wIndexMSB:wIndexLSB
//	This typically contains the operand/data for the opcode but could be used for anything
//	as defined by the opcode.  Raw buffer data could even be placed here to cheat the 254 Byte transfer
//	limit of V-USB (w/o long xfrs), the two bytes of wIndex bring to full page of 256 Bytes.
//	Planning for this to contain the page index (aka memory addr) of the transmitted data buffer.
//wLength must be set to the size of the data transfer to follow this setup packet in Bytes.
//	if wLength is >8, drivers split data into 8byte packets and final packet of < 8Bytes if needed.
//	with 16bit wLength 16KB transfers are largest possible, requires using long xfrs on device driver.
//	The max length without long xfrs is 254Bytes, value 255 is reserved for USB_NO_MSG.
//	This means wLength's MSByte is under utilized but prob shouldn't concern ourselves with that.
//data is a pointer to the data buffer being sent for writes (OUT transfers).
//	read (IN transfers) utilize data pointer to pass location of where to dump read data.

typedef struct USBtransfer {
	libusb_device_handle *handle;
	uint8_t		endpoint;
	uint8_t		request;
	uint16_t	wValue;
	uint16_t	wIndex;
	uint16_t	wLength;
	unsigned char	*data;
} USBtransfer;

libusb_device_handle * open_usb_device( libusb_context *context, int log_level );

void close_usb(libusb_context *context, libusb_device_handle *handle);

	//int libusb_control_transfer (libusb_device_handle *dev_handle, uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex, unsigned char *data, uint16_t wLength, unsigned int timeout)
	//
	//SETUP PACKET FIELDS:
	//bmRequestType: ORing of req type (STD/VENDOR), recipient (think we only care about DEVICE), endpoint direction IN-dev->host OUT-host->dev
	//bRequest: single byte that can signify any 'command' or 'request' we setup.
	//The wValue and wIndex fields allow parameters to be passed with the request.  Think we can do whatever we want with these
	//wLength is used the specify the number of bytes to be transferred should there be a data phase. 
	//wLength the length field for the setup packet. The data buffer should be at least this size. 
	//	USB 1.1 low speed standard limits to 8 bytes
	//	V-USB seems to break this limit with max of 254 bytes (255 designates "USB_NO_MSG"
	//	V-USB allows "LONG TRANSFERS" utilizing full 16bit wLength for upto 16384 bytes = exactly 16KBytes
	//	although considering sram on AVR doesn't explode with long transfers and read/write functions are in 8byte chunks,
	//		I think it really is limited to 8bytes
	//	One idea to squeeze more data is have a request type defined that utilizes wValue and wIndex to gain 4bytes + 8buffer = 12bytes 50% gain
	//		Not sure how to gain access to wValue/wIndex with vusb drivers...
	//		answer: usbFunctionSetup will get called for every setup packet and pass all 8 bytes of setup packet
	//	Can ultimately answer this question by counting how many startup packets are recieved by usbFunciton setup for transfers >8 bytes
	//	If when sending >8 byte control transfers, a setup packet only comes once, then there is nothing to abuse
	//		however if the same setup packet gets sent for every 8 bytes, it would be better to only perform 8byte transfers and stuff
	//		4 more bytes in wValue and wIndex fields to increase throughput by ~50%!!!
	//	Testing shows that usbFunctionSetup only gets called once for transfers of 254 bytes
	//		So there is only one setup packet for multiple data packets of 8bytes each
	//
	//Still not sure increasing transfer length doesn't simply break up into bunch of small 8byte transfers although it doesn't sound like it.
	//245byte limit is kind of a pain..  but wValue/wIndex fields could be abused to send 256 bytes
	//Long transfers apparently max out speed @ 24KBps with 300 bytes: https://forums.obdev.at/viewtopic.php?t=3059
	//
	//PAYLOAD:
	//data: a suitably-sized data buffer for either input or output (depending on direction bits within bmRequestType) 
	//
	//TIMEOUT:
	//timeout: (in millseconds) that this function should wait before giving up due to no response being received. 
	//	For an unlimited timeout, use value 0
	//	USB nutshell: A compliant host requires control transfer response within 5sec
	//
	//RETURN:
	//	Returns on success, the number of bytes actually transferred 
	//	LIBUSB_ERROR_TIMEOUT if the transfer timed out 
	//	LIBUSB_ERROR_PIPE if the control request was not supported by the device 
	//	LIBUSB_ERROR_NO_DEVICE if the device has been disconnected 
	//	another LIBUSB_ERROR code on other failures 
int usb_vendor_transfer( USBtransfer *transfer );
int lua_usb_vend_xfr(lua_State *L);

#endif