/****************************
  Connections:
  -----------------------------
  [Arduino Uno] --> [L298N Red Board]:
     11         -->   ENA
     9          -->   IN1
     8          -->   IN2
     7          -->   IN3
     6          -->   IN4
     10         -->   ENB
  [Arduino Uno] --> [Ultrasonic Sensor]:
     5V         -->   Vcc
     A1         -->   Trig
     A0         -->   Echo
     GND        -->   GND
  [Arduino Uno] --> [IR Sensor (Left)]:
     GND        -->   GND
     5V         -->   VCC
     2          -->   OUT
  [Arduino Uno] --> [IR Sensor (Center)]:
     GND        -->   GND
     5V         -->   VCC
     3          -->   OUT
  [Arduino Uno] --> [IR Sensor (Right)]:
     GND        -->   GND
     5V         -->   VCC
     4          -->   OUT
  -----------------------------
*****************************/
const int trigPin = A1;
const int echoPin = A0;
// defines variables
long duration;
int distance;

#define SensorLeft    2   //input pin of left sensor
#define SensorMiddle  3   //input pin of middle sensor
#define SensorRight   4   //input pin of right sensor
unsigned char SL;        //state of left sensor
unsigned char SM;        //state of middle sensor
unsigned char SR;        //state of right sensor



#define Lpwm_pin  10  //ENB
#define Rpwm_pin  11  //ENA
int pinLB = 6;        //IN4
int pinLF = 7;        //IN3
int pinRB = 8;        //IN2
int pinRF = 9;        //IN1
unsigned char Lpwm_val = 100;//255 = max
unsigned char Rpwm_val = 100;//255 = max

void M_Control_IO_config(void)
{
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(SensorLeft, INPUT);
  pinMode(SensorMiddle, INPUT);
  pinMode(SensorRight, INPUT);
  pinMode(pinLB, OUTPUT);
  pinMode(pinLF, OUTPUT);
  pinMode(pinRB, OUTPUT);
  pinMode(pinRF, OUTPUT);
  pinMode(Lpwm_pin, OUTPUT); // pin 11 (PWM)
  pinMode(Rpwm_pin, OUTPUT); // pin 10 (PWM)
}
void Set_Speed(unsigned char Left, unsigned char Right)
{
  analogWrite(Lpwm_pin, Left);
  analogWrite(Rpwm_pin, Right);
}

void turnR()
{
  digitalWrite(pinRB, LOW);
  digitalWrite(pinRF, HIGH);
  digitalWrite(pinLB, LOW);
  digitalWrite(pinLF, HIGH);
  Serial.println("RIGHT");
}
void back()
{
  digitalWrite(pinRB, LOW);
  digitalWrite(pinRF, HIGH);
  digitalWrite(pinLB, HIGH);
  digitalWrite(pinLF, LOW);
  Serial.println("Back");
}
void advance()
{
  digitalWrite(pinRB, HIGH);
  digitalWrite(pinRF, LOW );
  digitalWrite(pinLB, LOW);
  digitalWrite(pinLF, HIGH);
  Serial.println("Front");
}
void stopp()
{
  digitalWrite(pinRB, HIGH);
  digitalWrite(pinRF, HIGH);
  digitalWrite(pinLB, HIGH);
  digitalWrite(pinLF, HIGH);
  Serial.println("STOP!!!!!!");
}
void turnL()
{
  digitalWrite(pinRB, HIGH);
  digitalWrite(pinRF, LOW);
  digitalWrite(pinLB, HIGH);
  digitalWrite(pinLF, LOW);
  Serial.println("LEFT");
}

void hornON() {
  digitalWrite(4, 1);
}
void hornOFF() {
  digitalWrite(4, 0);
}

void setup()
{
  //Serial.begin(9600);
  pinMode(4, OUTPUT);
  M_Control_IO_config();
  Set_Speed(Lpwm_val, Rpwm_val);
  stopp();
  delay(5000);

}

void Sensor_Scan(void)
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);

  distance = duration * 0.034 / 2;
  SL = digitalRead(SensorLeft);
  SM = digitalRead(SensorMiddle);
  SR = digitalRead(SensorRight);
  //Serial.println(distance);
  //Serial.print(SL);
  //Serial.print(SM);
  //Serial.println(SR);
}

void loop()
{
  Sensor_Scan();

  if (distance > 10) {
    hornOFF();
    ///////////////////////////////////////////////////////////////////////////////
    if (SM == HIGH)// middle sensor in black area
    {
      if (SL == LOW & SR == HIGH) // black on left, white on right, turn left
      {
        turnR();
      }
      else if (SR == LOW & SL == HIGH) // white on left, black on right, turn right
      {
        turnL();
      }
      else // white on both sides, going forward
      {
        advance();

      }
    }
    ///////////////////////////////////////////////////////////////////////////////
    else // middle sensor on white area
    {
      if (SL == LOW & SR == HIGH) // black on left, white on right, turn left
      {
        turnR();

      }
      else if (SR == LOW & SL == HIGH) // white on left, black on right, turn right
      {
        turnL();


      }
      else // all white, stop
      {
        // back();
        delay(100);
        stopp() ;
      }
    }
    ///////////////////////////////////////////////////////////////////////////////
  }

  else {
    stopp();
    hornON();
    delay(1000);
    hornOFF();
    delay(1000);
  }
  // delay(1000);
}//end of loop