// Exercise #2 | Pouya Abbasi | 991152135

#define TRIGGER_PIN  7
#define ECHO_PIN     6
#define MAX_DISTANCE 300

#define RED_LED_PIN 9
#define GREEN_LED_PIN 10
#define BLUE_LED_PIN 11

#define SPEAKER_PIN 8

void setup() {
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(BLUE_LED_PIN, OUTPUT);
  pinMode(SPEAKER_PIN, OUTPUT);
}

void loop() {
  unsigned int duration, distance;
  

  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);


  duration = pulseIn(ECHO_PIN, HIGH);


  distance = duration / 58;

  if (distance > 300) {

    setColor(0, 0, 0);
    noTone(SPEAKER_PIN);
  } else if (distance >= 200 && distance <= 300) {

    flashRGBLed(0, 255, 0, 500);
    beep(500, 500);
  } else if (distance >= 100 && distance < 200) {

    flashRGBLed(255, 255, 0, 300);
    beep(300, 300);
  } else {

    flashRGBLed(255, 0, 0, 100);
    beep(150, 150);
  }
}

void setColor(int red, int green, int blue) {
  analogWrite(RED_LED_PIN, 255 - red);
  analogWrite(GREEN_LED_PIN, 255 - green);
  analogWrite(BLUE_LED_PIN, 255 - blue);
}

void flashRGBLed(int red, int green, int blue, int duration) {
  unsigned long currentTime = millis();
  static unsigned long previousTime = 0;
  static boolean ledState = LOW;

  if (currentTime - previousTime >= duration) {
    previousTime = currentTime;
    ledState = !ledState;

    if (ledState) {
      setColor(red, green, blue);
    } else {
      setColor(0, 0, 0);
    }
  }
}

void beep(int duration, int beepDuration) {
  static unsigned long previousTime = 0;
  unsigned long currentTime = millis();

  if (currentTime - previousTime >= duration) {
    previousTime = currentTime;
    tone(SPEAKER_PIN, 600);
    delay(beepDuration / 2);
    noTone(SPEAKER_PIN);
    delay(beepDuration / 2);
  }
}