//  libraries
#include <Stepper.h>

//  buffer containing the data
char inData[50];
//  index used for buffer
byte index;
//  set start and end of packet of data sent
#define SOP '<'
#define EOP '>'
//  and it's semaphore lights
bool started = false;
bool ended = false;
//  led
int led = 13;
//  the 3 variables of interest (default values)
int _dir = 0, _speed = 60;
unsigned int _steps = 1;
//  the stepper
Stepper myStepper(_steps, 7,8);


//  setup
void setup(){
  myStepper.setSpeed(_speed);
  Serial.begin(9600);
  pinMode(led, OUTPUT);
  memset(inData, '\0', 50);
}


//  loop
void loop() {

  readSerialData();
  processPacket();

  if (_dir == 0 && _speed == 0 && _steps == 0)
  {
    digitalWrite(led, HIGH);
    Serial.println("arduino found");
  }
  else
  {
    digitalWrite(led, LOW);
    //  Print check for values
    Serial.print("direction: ");
    Serial.print(_dir);
    Serial.print(" speed: ");
    Serial.print(_speed);
    Serial.print(" steps: ");
    Serial.println(_steps);

    //  command the stepper
    //  continuous rotation (_steps == 0)
    if (_steps == 0)
    {
      myStepper.setSpeed(_speed);
      if (_dir == 0)
      {
        while (_steps != 1)
        {
          myStepper.step(1);
          readSerialData();
          processPacket();
          resetPacket();
        }
      }
      else
      {
       while (_steps != 1)
        {
          myStepper.step(-1);
          readSerialData();
          processPacket();
          resetPacket();
        }
      }
    }
    //  explicit rotation (_steps == other value than 0)
    else {
      myStepper.setSpeed(_speed);
      if (_dir == 0)
      {
        myStepper.step(_steps);
        delay(500);
      }
      else
      {
        myStepper.step(-_steps);
        delay(500);
      }
    }
  }

  resetPacket();

}

//  saving serial data into buffer
void readSerialData()
{
  while (Serial.available() > 0)
  {
    char inChar = Serial.read();

    if (inChar == SOP)
    {
      index = 0;
      inData[index] = '\0';
      started = true;
      ended = false;
    }
    else if (inChar == EOP)
    {
      ended = true;
      break;
    }
    else
    {
      if (index < 49)
      {
        inData[index] = inChar;
        index++;
        inData[index] = '\0';
      }
    }
  }
}

//  process the packet
void processPacket()
{
  //  check packet
  if (started && ended)
  {
    //  find _dir, _speed and _steps
    char * pch;
    pch = strtok (inData, ",");
    if (pch != NULL)
    {
      _dir = atoi(pch);
      _speed = atoi(strtok(NULL, ","));
      _steps = atoi(strtok(NULL, ","));
    }
  }
}

//  reset for the next packet
void resetPacket()
{
  started = false;
  ended = false;
  index = 0;
  inData[index] = '\0';
  //  _steps = 1;
}