#include <FastLED.h>

FASTLED_USING_NAMESPACE

#define DATA_PIN    5
#define LED_TYPE    WS2812
#define COLOR_ORDER GRB
#define NUM_LEDS    24
CRGB leds[NUM_LEDS];

#define BRIGHTNESS          96

#define NOTE_C4  262
#define NOTE_C5  523
#define NOTE_C6  1047
#define END -1

int melody[] = {
  NOTE_C4, NOTE_C5, NOTE_C6, END
};

// note durations: 8 = quarter note, 4 = 8th note, etc.
int noteDurations[] = {       //duration of the notes
  12, 8, 4, 0
};

const int trigPin = 4;
const int echoPin = 2;
const int distance_threshold = 155; //cm

int speed = 90; //higher value, slower notes

float duration_us, distance_cm;

void setup() {
  Serial.begin(9600);

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  delay(3000); // 3 second delay for recovery

  FastLED.addLeds<LED_TYPE, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration_us = pulseIn(echoPin, HIGH);
  distance_cm = 0.017 * duration_us;

  if (distance_cm > distance_threshold) {
    ShowLight(95);

    int noteDuration = speed * noteDurations[3];
    tone(3, melody[3], noteDuration);
    delay(noteDuration);
    noTone(3);
  }

  if (distance_cm > 100 && distance_cm <= distance_threshold) {
    ShowLight(60);

    int noteDuration = speed * noteDurations[0];
    tone(3, melody[0], noteDuration);
    delay(noteDuration);
    noTone(3);
  }

  if (distance_cm > 50 && distance_cm <= 100) {
    ShowLight(22);

    int noteDuration = speed * noteDurations[1];
    tone(3, melody[1], noteDuration);
    delay(noteDuration);
    noTone(3);
  }

  if (distance_cm <= 50) {
    ShowLight(0);

    int noteDuration = speed * noteDurations[2];
    tone(3, melody[2], noteDuration);
    delay(noteDuration);
    noTone(3);
  }
}

void ShowLight(uint8_t hue) {
  for (int i = 0; i < NUM_LEDS - 1; i++) {
    leds[i] = CHSV(hue, 255, 255);
  }

  FastLED.show();
  FastLED.delay(9);
}