#include <util/delay.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>

#include <avr/eeprom.h>
#include <avr/pgmspace.h>   /* required by usbdrv.h */

#include "usbdrv/usbdrv.h"


/* ------------------------------------------------------------------------- */
/* ----------------------------- USB interface ----------------------------- */
/* ------------------------------------------------------------------------- */

PROGMEM const char usbHidReportDescriptor[22] = {    /* USB report descriptor */
    0x06, 0x00, 0xff,              // USAGE_PAGE (Generic Desktop)
    0x09, 0x01,                    // USAGE (Vendor Usage 1)
    0xa1, 0x01,                    // COLLECTION (Application)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x26, 0xff, 0x00,              //   LOGICAL_MAXIMUM (255)
    0x75, 0x08,                    //   REPORT_SIZE (8)
    0x95, 0x80,                    //   REPORT_COUNT (128)
    0x09, 0x00,                    //   USAGE (Undefined)
    0xb2, 0x02, 0x01,              //   FEATURE (Data,Var,Abs,Buf)
    0xc0                           // END_COLLECTION
};
/* Since we define only one feature report, we don't use report-IDs (which
 * would be the first byte of the report). The entire report consists of 128
 * opaque data bytes.
 */

/* The following variables store the status of the current data transfer */
static uchar    currentAddress;
static uchar    bytesRemaining;

/* ------------------------------------------------------------------------- */

/* usbFunctionRead() is called when the host requests a chunk of data from
 * the device. For more information see the documentation in usbdrv/usbdrv.h.
 */
uchar   usbFunctionRead(uchar *data, uchar len)
{
    if(len > bytesRemaining)
        len = bytesRemaining;
    eeprom_read_block(data, (uchar *)0 + currentAddress, len);
    currentAddress += len;
    bytesRemaining -= len;
    return len;
}

/* usbFunctionWrite() is called when the host sends a chunk of data to the
 * device. For more information see the documentation in usbdrv/usbdrv.h.
 */
uchar   usbFunctionWrite(uchar *data, uchar len)
{
    if(bytesRemaining == 0)
        return 1;               /* end of transfer */
    if(len > bytesRemaining)
        len = bytesRemaining;
    eeprom_write_block(data, (uchar *)0 + currentAddress, len);
    currentAddress += len;
    bytesRemaining -= len;
    return bytesRemaining == 0; /* return 1 if this was the last chunk */
}

/* ------------------------------------------------------------------------- */

usbMsgLen_t usbFunctionSetup(uchar data[8])
{
usbRequest_t    *rq = (void *)data;

    if((rq->bmRequestType & USBRQ_TYPE_MASK) == USBRQ_TYPE_CLASS){    /* HID class request */
        if(rq->bRequest == USBRQ_HID_GET_REPORT){  /* wValue: ReportType (highbyte), ReportID (lowbyte) */
            /* since we have only one report type, we can ignore the report-ID */
            bytesRemaining = 128;
            currentAddress = 0;
            return USB_NO_MSG;  /* use usbFunctionRead() to obtain data */
        }else if(rq->bRequest == USBRQ_HID_SET_REPORT){
            /* since we have only one report type, we can ignore the report-ID */
            bytesRemaining = 128;
            currentAddress = 0;
            return USB_NO_MSG;  /* use usbFunctionWrite() to receive data from host */
        }
    }else{
        /* ignore vendor type requests, we don't use any */
    }
    return 0;
}

/* ------------------------------------------------------------------------- */


void setupLed() {
	DDRB |= 1;
	PORTB &= ~1; // turn led off initially
}

void toggleLed() {
	PORTB ^= 1;
}

int main() {
	uchar i;
	
	setupLed();
	wdt_enable(WDTO_1S); // enable 1s watchdog timer

	usbInit();
	usbDeviceDisconnect(); // enforce re-enumeration
	toggleLed();
	for(i = 0; i<250; i++) {
		wdt_reset(); // keep watchdog happy
		_delay_ms(1);
	}
	toggleLed();
	usbDeviceConnect();
	sei();	
	while(1) {
		wdt_reset();
		usbPoll();
	}

	return 0;
}