//  Line Following Robot with Two LDR Sensors & Tow Stepper Motors (Algorithm 3.4)
//  Separate Functions for Each Action

const int LEFT_SENSOR_PIN  = A0;
const int RIGHT_SENSOR_PIN = A1;

const int LEFT_MOTOR_STEP_PIN  = 2;
const int LEFT_MOTOR_DIR_PIN   = 3;
const int RIGHT_MOTOR_STEP_PIN = 4;
const int RIGHT_MOTOR_DIR_PIN  = 5;

const int BLACK_THRESHOLD = 300;  // Adjust if needed
const int STEP_DELAY_US =800;    

void setup() {

  pinMode(LEFT_SENSOR_PIN, INPUT);
  pinMode(RIGHT_SENSOR_PIN, INPUT);

  pinMode(LEFT_MOTOR_STEP_PIN, OUTPUT);
  pinMode(LEFT_MOTOR_DIR_PIN, OUTPUT);
  pinMode(RIGHT_MOTOR_STEP_PIN, OUTPUT);
  pinMode(RIGHT_MOTOR_DIR_PIN, OUTPUT);

  // Forward direction
  digitalWrite(LEFT_MOTOR_DIR_PIN, LOW);
  digitalWrite(RIGHT_MOTOR_DIR_PIN, LOW);
}

void loop() {

    // مو عارف هون احط اصغر ولا اكبر لانه قرأت السنسور منخفظة ولا مرتفعة للاسود

  bool leftOnBlack  = analogRead(LEFT_SENSOR_PIN)  > BLACK_THRESHOLD; 
  bool rightOnBlack = analogRead(RIGHT_SENSOR_PIN) > BLACK_THRESHOLD;

  if (leftOnBlack && rightOnBlack) {
    moveForward();
  } 
  else if (!leftOnBlack && !rightOnBlack) {
    stopMoving();
  } 
  else if (leftOnBlack && !rightOnBlack) {
    turnLeft();
  } 
  else if (!leftOnBlack && rightOnBlack) {
    turnRight();
  }
}



// Case 1: Both sensors on black (Forward) 
void moveForward() {
  digitalWrite(LEFT_MOTOR_DIR_PIN, LOW);
  digitalWrite(RIGHT_MOTOR_DIR_PIN, LOW);
  stepBothMotors(2, 2);  // full power 
}

//  Case 2: Both sensors on white (Stop) 
void stopMoving() {
  // no steps = stop
  delay(10);
}

//  Case 3: Left on black, right on white (Turn Left) 
void turnLeft() {
  digitalWrite(LEFT_MOTOR_DIR_PIN, LOW);
  digitalWrite(RIGHT_MOTOR_DIR_PIN, LOW);
  stepBothMotors(0, 1);  // left stop, right 50
}

//  Case 4: Right on black, left on white (Turn Right) 
void turnRight() {
  digitalWrite(LEFT_MOTOR_DIR_PIN, LOW); // forward
  digitalWrite(RIGHT_MOTOR_DIR_PIN, LOW); // forward
  stepBothMotors(1, 0);  // right stop(0), left half(50)
}

//  Step Function
void stepBothMotors(int leftPower, int rightPower) {
  int maxSteps = max(leftPower, rightPower);

  for (int i = 0; i < maxSteps; i++) {
    if (i < leftPower) {
      digitalWrite(LEFT_MOTOR_STEP_PIN, HIGH);
      delayMicroseconds(STEP_DELAY_US);
      digitalWrite(LEFT_MOTOR_STEP_PIN, LOW);
      delayMicroseconds(STEP_DELAY_US);
    }
    if (i < rightPower) {
      digitalWrite(RIGHT_MOTOR_STEP_PIN, HIGH);
      delayMicroseconds(STEP_DELAY_US);
      digitalWrite(RIGHT_MOTOR_STEP_PIN, LOW);
      delayMicroseconds(STEP_DELAY_US);
    }
  }
}