#include <Servo.h>

const int RED_PIN = 13; //set a button pin for the red flashing led
const int PUSH_BUTTON = 4; //set a button statet when thebutton gets activated
const int TRIG = 6; //..We are setting the TRIG on the ultrasonic sensor to port 23
const int ECHO = 5; //set a button state for the echo pin



long previousMillis = 0; //start timer to activate the ultrasonic motion sensor starts from 0msec

void setup() {
  // put your setup code here, to run once:
  pinMode(RED_PIN, OUTPUT);


   // initialize the LED pins as an output:

 
  pinMode(TRIG, OUTPUT);    // set the TRIG pin of the ultrasonic motion sensor as output
  pinMode(ECHO, INPUT);     // set the ECHO pin as input to the ultrasonic motion sensor
  Serial.begin(9600); //serial.bein to start it for 9600msec
  Serial.println("Train Crossing Active!"); //to idicate that the train is crossing
}



//define a function that is called get distance gets distance of ultrasonic wave that is sent
long getDistance()// #define a function that is called get distanc
{
  digitalWrite(TRIG, HIGH);  // Start the ultrasonic pulse
  delayMicroseconds(10);     // Send a 10-microsecond pulse
  digitalWrite(TRIG, LOW);   // Stop the pulse

  unsigned long startTime = 0; //start timer for the ultrasonic motion sensor
  unsigned long endTime = 0;   //end timmer for the ultrasonic motion sensor

  // Wait for ECHO to go HIGH and record the start time
  unsigned long timeout = millis(); //the amount of time needthe timmer to timeout for
  while (digitalRead(ECHO) == LOW) { //while the digital read pin for the echo is pressed
    startTime = micros();      //start the timer and set it to micros
    if (millis() - timeout > 50) return -1; // Exit if timeout (no response) if millis() - timeout >50ms, timer is out of bound than this is invalid
  }

  // Wait for ECHO to go LOW and record the end time
  timeout = millis();  
  while (digitalRead(ECHO) == HIGH) {
    endTime = micros();
    if (millis() - timeout > 50) return -1; // Exit if timeout
  }

  // Calculate the duration in microseconds
  long duration = endTime - startTime;

  // Convert duration to distance in centimeters
  long distance_cm = duration / 58; // 58 us per cm for sound in air
  
  return distance_cm; //return the distance in mm from the ulltrasonic motion sensor
}

//function that turns on the led whenit is callled
void red_light() 
{
    digitalWrite(RED_PIN, HIGH);       // Turn on red light
}

//function that turns off the led when it is called
void no_light() 
{
    digitalWrite(RED_PIN, LOW);     
}

//set the button state to false to indicate that the button has not been activated yet
bool buttonPressed = false;


// delay(flashDelay)
void loop() 
{
  if (digitalRead(PUSH_BUTTON) == HIGH && !buttonPressed) {
    buttonPressed = true; // Track that the button was pressed
  }
  if(buttonPressed)
  {
    
  // put your main code here, to run repeatedly:
    long distance = getDistance();
    // start the crossing guard actions
    if(distance >=90)
    {
      no_light();
      //noTone(BUZZER_BUTTON); 
    }
    else if(distance > 40 && distance < 90)
    {
      //greenLight();
      //FlashLEDs(2, 200, false);
      //CrossingGuardsUp();
      //noTone(BUZZER_BUTTON); 

    }
    else if(distance > 16 && distance < 40)
    {
      // flash the LEDs x number of times for YY milliseconds
      //yellow_light();
      //noTone(BUZZER_BUTTON); 
    }
    else if(distance <=15)
    {
      red_light();
      //FlashLEDs(2, 200, true);
      //CrossingGuardsDown();
      // flash the LEDs x number of times for YY milliseconds
      /*if(millis() - previousMillis > interval)
      {
        tone(BUZZER_BUTTON, 500);
        previousMillis = millis(); // Reset the timer
      }
      */
    }
    // Check if the buzzer should be turned off
  }

}