/*
 *  spreadspace avr utils
 *
 *
 *  Copyright (C) 2012 Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of spreadspace avr utils.
 *
 *  spreadspace avr utils is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  spreadspace avr utils is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
 */

#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
#include <avr/power.h>

#include "util.h"
#include "led.h"

/*
             LUFA Library
     Copyright (C) Dean Camera, 2012.

  dean [at] fourwalledcubicle [dot] com
           www.lufa-lib.org
*/
#include <LUFA/Version.h>
#include <LUFA/Drivers/Peripheral/SPI.h>
#include <LUFA/Drivers/Misc/RingBuffer.h>
#include <LUFA/Drivers/USB/USB.h>
#include "lufa-descriptor-usbserial.h"

    /* Global I/O Buffers: */
static RingBuffer_t USBtoSPI_Buffer;
static uint8_t      USBtoSPI_Buffer_Data[128];
static RingBuffer_t SPItoUSB_Buffer;
static uint8_t      SPItoUSB_Buffer_Data[128];

/** LUFA CDC Class driver interface configuration and state information. This structure is
 *  passed to all CDC Class driver functions, so that multiple instances of the same class
 *  within a device can be differentiated from one another.
 */
USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
  {
    .Config =
      {
        .ControlInterfaceNumber         = 0,

        .DataINEndpointNumber           = CDC_TX_EPNUM,
        .DataINEndpointSize             = CDC_TXRX_EPSIZE,
        .DataINEndpointDoubleBank       = false,

        .DataOUTEndpointNumber          = CDC_RX_EPNUM,
        .DataOUTEndpointSize            = CDC_TXRX_EPSIZE,
        .DataOUTEndpointDoubleBank      = false,

        .NotificationEndpointNumber     = CDC_NOTIFICATION_EPNUM,
        .NotificationEndpointSize       = CDC_NOTIFICATION_EPSIZE,
        .NotificationEndpointDoubleBank = false,
      },
  };

void EVENT_USB_Device_ConfigurationChanged(void)
{
  CDC_Device_ConfigureEndpoints(&VirtualSerial_CDC_Interface);
}

void EVENT_USB_Device_ControlRequest(void)
{
  CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);
}
/* end LUFA CDC-ACM specific definitions*/


    /* Hardware Defines: */
#define SPI_CS_DDR DDRB
#define SPI_CS_PORT PORTB
#define CS   0

void SetupHardware(void)
{
  MCUSR &= ~(1 << WDRF);
  wdt_disable();

  cpu_init();
  led_init();
  USB_Init();

  TCCR0B = (1 << CS02);

  SPI_Init(SPI_SPEED_FCPU_DIV_4  | SPI_MODE_MASTER | SPI_ORDER_MSB_FIRST | 
           SPI_SCK_LEAD_RISING | SPI_SAMPLE_LEADING);
  SPI_CS_DDR |= (1<<CS);
  SPI_CS_PORT |= (1<<CS);
}

void SPI_TransferBuffer(void)
{
  SPI_CS_PORT &= ~(1<<CS);
  led_on();

  while(!(RingBuffer_IsEmpty(&USBtoSPI_Buffer))) {
    uint8_t ReceivedByte = SPI_TransferByte(RingBuffer_Remove(&USBtoSPI_Buffer));
    if (USB_DeviceState == DEVICE_STATE_Configured) {
      RingBuffer_Insert(&SPItoUSB_Buffer, ReceivedByte);
      if(RingBuffer_IsFull(&SPItoUSB_Buffer))
        break;
    }
  }

  led_off();
  SPI_CS_PORT |= (1<<CS);
}

int main(void)
{
  SetupHardware();

  RingBuffer_InitBuffer(&USBtoSPI_Buffer, USBtoSPI_Buffer_Data, sizeof(USBtoSPI_Buffer_Data));
  RingBuffer_InitBuffer(&SPItoUSB_Buffer, SPItoUSB_Buffer_Data, sizeof(SPItoUSB_Buffer_Data));

  sei();

  for (;;) {
    int16_t BytesReceived = CDC_Device_BytesReceived(&VirtualSerial_CDC_Interface);
    while(BytesReceived > 0) {
      if(!(RingBuffer_IsFull(&USBtoSPI_Buffer))) {
        int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
        if (!(ReceivedByte < 0))
          RingBuffer_Insert(&USBtoSPI_Buffer, ReceivedByte);

        BytesReceived--;
      }
    }

    uint16_t BufferCount = RingBuffer_GetCount(&SPItoUSB_Buffer);
    if ((TIFR0 & (1 << TOV0)) || (BufferCount > (uint8_t)(sizeof(SPItoUSB_Buffer_Data) * .75))) {
      TIFR0 |= (1 << TOV0);
      while (BufferCount--) {
        if (CDC_Device_SendByte(&VirtualSerial_CDC_Interface,
                                RingBuffer_Peek(&SPItoUSB_Buffer)) != ENDPOINT_READYWAIT_NoError)
          break;

        RingBuffer_Remove(&SPItoUSB_Buffer);
      }
    }

    if (!(RingBuffer_IsEmpty(&USBtoSPI_Buffer)))
      SPI_TransferBuffer();

    CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
    USB_USBTask();
  }
}