#define STEP_PIN 16
#define DIR_PIN 17

const int stepsPerRevolution = 200;  // adjust if microstepping
long currentStep = 0;

int pulseDelay = 800; // speed control (lower = faster)

String inputString = "";

void setup() {
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);

  Serial.begin(115200);
  Serial.println("Stepper ready. Send angle or S<step>");
}

// Move relative steps
void moveSteps(long steps) {
  if (steps == 0) return;

  if (steps > 0) {
    digitalWrite(DIR_PIN, HIGH);
  } else {
    digitalWrite(DIR_PIN, LOW);
    steps = -steps;
  }

  for (long i = 0; i < steps; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(pulseDelay);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(pulseDelay);
  }
}

// Move to absolute step
void moveToStep(long targetStep) {
  long stepsToMove = targetStep - currentStep;
  moveSteps(stepsToMove);
  currentStep = targetStep;

  Serial.print("Now at step: ");
  Serial.println(currentStep);
}

// Move to angle
void moveToAngle(float angle) {
  long targetStep = (long)((angle / 360.0) * stepsPerRevolution);
  moveToStep(targetStep);

  Serial.print("Moved to angle: ");
  Serial.println(angle);
}

void loop() {
  while (Serial.available()) {
    char c = Serial.read();

    if (c == '\n' || c == '\r') {
      processInput(inputString);
      inputString = "";
    } else {
      inputString += c;
    }
  }
}

void processInput(String input) {
  input.trim();
  if (input.length() == 0) return;

  // If starts with S → step command
  if (input.startsWith("S") || input.startsWith("s")) {
    long stepTarget = input.substring(1).toInt();
    moveToStep(stepTarget);
  }
  else {
    // Otherwise treat as angle
    float angle = input.toFloat();
    moveToAngle(angle);
  }
}