// defines pins numbers
const int led1 = 12;
const int led2 = 14;
const int led3 = 27;
const int led4 = 26;
const int trigPin = 4;
const int echoPin = 5;
const int buzzer = 33;

// defines variables
long duration;
int distance;
int safetyDistance;

void setup() {
 
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT);  // Sets the echoPin as an Input
  pinMode(buzzer, OUTPUT);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  Serial.begin(9600); // Starts the serial communication
}

void loop() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Sets the trigPin on HIGH state for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // Calculating the distance
  distance = duration * 0.034 / 2;

  safetyDistance = distance;

  // Check water level and activate buzzer and LEDs accordingly
  if (safetyDistance <= 40) {
    activateAlarm(led4);
  } else if (safetyDistance <= 80) {
    activateAlarm(led3);
    slowblink(led3);
  } else if (safetyDistance <= 120) {
    activateAlarm(led2);
    slowblink(led2);
  } else if (safetyDistance <= 160) {
    activateAlarm(led1);
  } else {
    deactivateAlarm();
  }

  // Blinking LEDs and printing messages based on water level
  if (safetyDistance >= 161) {
    fastblink(led1);
    playWarningTuneHigh();
    Serial.println("Warning: Water Level is too High");
    Serial.println(distance);
  } else if (safetyDistance <= 39) {
    blink(led4);
    playWarningTuneLow();
    Serial.println("Warning: Water Level is Low");
  } else {
    Serial.println(distance);
  }
}

void activateAlarm(int pin) {
  digitalWrite(buzzer, HIGH);
  digitalWrite(pin, HIGH);
}

void deactivateAlarm() {
  digitalWrite(buzzer, LOW);
  digitalWrite(led1, LOW);
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);
}

void slowblink(int pin) {
  digitalWrite(pin, HIGH);
  delay(1500);
  digitalWrite(pin, LOW);
  delay(1500);
}

void blink(int pin) {
  digitalWrite(pin, HIGH);
  delay(700);
  digitalWrite(pin, LOW);
  delay(700);
}

void fastblink(int pin) {
  digitalWrite(pin, HIGH);
  delay(200);
  digitalWrite(pin, LOW);
  delay(200);
}

void playWarningTuneLow() {
tone(buzzer, 600, 500);
  tone(buzzer, 600, 500);
  delay(200);
}

void playWarningTuneHigh(){
tone(buzzer, 390, 500);
    tone(buzzer, 587, 500); // Adjust the frequency as needed
    delay(100);
}