#define F_CPU 8000000UL
#include <avr/io.h>
#include <util/delay.h>
#include<avr/interrupt.h>

//the variables
/*for the first traffic light*/
int red_pin1 = PINC0;
int yellow_pin1 = PINC1;
int green_pin1 = PINC2;
 
/*for the second traffic light*/
int red_pin2 = PINC3;
int yellow_pin2 = PINC4;
int green_pin2 = PINC5;

int button = PIND2; //for the interrupt

int motion_sensor1 = PINB0;
int motion_sensor2 = PINB1;

int distance_sensor1 = PIND3;
int echo1 = PIND4;
int distance_sensor2 = PIND5;
int echo2 = PIND6;

//the timer dealy method using timer 1
void T1Delay();
void T1Delay()
{
  TCNT1H = 0x85;
  TCNT1L = 0xEE;
  TCCR1A = 0x00;
  TCCR1B = 0x04;
  while((TIFR1 & (0x1 << TOV1)) == 0);
  TCCR1B = 0;
  TIFR1 = 0x1 << TOV1;
}

//the interrupt method
ISR(INT1_vect)
{
  int x = digitalRead(button);
  if(x == HIGH)
  {
    Serial.println("the button is pushed");
    if(PORTC & 0x0C)
    {
      //Serial.println("the button is pushed");
      PORTC |= 0x12;
      PORTC &= 0x12;
      T1Delay();
      
      PORTC |= 0x21;
      PORTC &= 0x21;
      T1Delay();
      //x = LOW;
    }
    else if(PORTC & 0x21)
    {
      //Serial.println("the button is pushed");
      PORTC |= 0x12;
      PORTC &= 0x12;
      T1Delay();
      
      PORTC |= 0x0C;
      PORTC &= 0x0C;
      T1Delay();
      //x = LOW;
    }
  }
}//end of the interrupt method


long readDistanceCM(int TRIG_PIN, int ECHO_PIN) {//a method from another example to calculate the distance
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

//the start of the main part of this project
void setup() {
  DDRC = 0xFF; //as an output - LEDs
  DDRD = 0x00; //as as input - distance sensors & button
  DDRB = 0x00; //as an input - motion sensors
  Serial.begin(9600); //the serial communication

  //assuming that the first traffic light has the priority
  PORTC |= 0x0C;
  PORTC &= 0x0C;
  Serial.println("the beginning");
  T1Delay(); //we dealy the time

  //configuring the intrrupt
  //EIMSK |= (1 << INT1); //enabling the serial interrupt
  //EICRA |= (1 << ISC11); // the event is rising edge
  //sei();//enabling the global interrupt
}//the end of the setup

void loop() {
    int sensor = digitalRead(motion_sensor1);
    int sensor2 = digitalRead(motion_sensor2);
    distance_sensor1 = readDistanceCM(3,4);
    distance_sensor2 = readDistanceCM(5,6);

    if(sensor == HIGH)
    {
      Serial.println("sensor 1 is activated");
      Serial.print("distance: ");
      Serial.println(distance_sensor1);

      if(distance_sensor1 < 250)//continue to go
      {
        T1Delay();
        if(PORTC & 0x21)//should we turn on the yellow light initially?
        {
          PORTC |= 0x12;
          PORTC &= 0x12;
          T1Delay();
        }

        PORTC |= 0x0C;
        PORTC &= 0x0C;
        T1Delay();
      }
      else if(distance_sensor1 >= 250)//give a way for the other traffic light
      {
        T1Delay();
        if(PORTC & 0x0C)
        {
          PORTC |= 0x12;
          PORTC &= 0x12;
          T1Delay();
        }

        PORTC |= 0x21;
        PORTC &= 0x21;
        T1Delay();
      }
      T1Delay();
    }//the end of the first if statement

    T1Delay();
    if(sensor2 == HIGH)
    {
      Serial.println("sensor 2 is activated");
      Serial.print("distance: ");
      Serial.println(distance_sensor2);

      if(distance_sensor2 < 250)//continue to go
      {
        T1Delay();
        if(PORTC & 0x0C)//should we turn on the yellow light initially?
        {
          PORTC |= 0x12;
          PORTC &= 0x12;
          T1Delay();
        }

        PORTC |= 0x21;
        PORTC &= 0x21;
        T1Delay();
      }
      else if(distance_sensor2 >= 250)//give a way for the other traffic light
      {
        T1Delay();
        if(PORTC & 0x21)
        {
          PORTC |= 0x12;
          PORTC &= 0x12;
          T1Delay();
        }

        PORTC |= 0x0C;
        PORTC &= 0x0C;
        T1Delay();
      }
    }//the end of the second if statement

    T1Delay();
}// the end of the "loop" method