/*
 *  spreadspace avr utils
 *
 *
 *  Copyright (C) 2013-2019 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 <stdio.h>

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

#include <LUFA/Drivers/Peripheral/TWI.h>

#define RTC_SLAVE_ADDR 0xD0

char* i2c_error_to_string(uint8_t err) {
  switch(err) {
  case TWI_ERROR_NoError: return "success";
  case TWI_ERROR_BusFault: return "bus-fault";
  case TWI_ERROR_BusCaptureTimeout: return "bus capture timeout";
  case TWI_ERROR_SlaveResponseTimeout: return "slave response timeout";
  case TWI_ERROR_SlaveNotReady: return "slave not ready";
  case TWI_ERROR_SlaveNAK: return "slave NAK";
  }
  return "unknown";
}

void i2c_init(void)
{
  TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 100000));
}

void get_time(void)
{
  uint8_t err = TWI_StartTransmission(RTC_SLAVE_ADDR | TWI_ADDRESS_WRITE, 100);
  if(err != TWI_ERROR_NoError) {
    printf("I²C start failed: %s\r\n", i2c_error_to_string(err));
    return;
  }

  err = TWI_SendByte(0x00);
  if(err != TWI_ERROR_NoError)
    goto i2c_error;

  err = TWI_StartTransmission(RTC_SLAVE_ADDR | TWI_ADDRESS_READ, 10);
  if(err != TWI_ERROR_NoError)
    goto i2c_error;

  uint8_t time[4];
  for(int i = 0; i < sizeof(time); ++i) {
    time[i] = 0xFF;
    err = TWI_ReceiveByte(&(time[i]), (i+1 == sizeof(time)) ? true : false);
    if(err != TWI_ERROR_NoError)
      goto i2c_error;
  }
  TWI_StopTransmission();

  for(int i = 0; i < sizeof(time); ++i) {
    printf("%s0x%02X%s", ((i==0) ? "" : " "), time[i], (i+1 == sizeof(time)) ? "\r\n" : "");
  }
  return;

i2c_error:
  TWI_StopTransmission();
  printf("I2C error: %s\r\n", i2c_error_to_string(err));
  return;
}


void handle_cmd(uint8_t cmd)
{
  switch(cmd) {
  case '0': led_off(); printf("ok\r\n"); break;
  case '1': led_on(); printf("ok\r\n"); break;
  case 't': get_time(); break;
  case 'r': reset2bootloader(); break;
  default: printf("error\r\n"); return;
  }

}

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

  cpu_init();
  jtag_disable();

  led_init();
  usbio_init();
  i2c_init();
  sei();

  led_on();
  for(;;) {
    int16_t BytesReceived = usbio_bytes_received();
    while(BytesReceived > 0) {
      int ReceivedByte = fgetc(stdin);
      if(ReceivedByte != EOF) {
        handle_cmd(ReceivedByte);
      }
      BytesReceived--;
    }

    usbio_task();
  }
}