int frame_size = 300;
long int total = 0;

const int NUMBER_OF_LEDS = 6;
int leds[NUMBER_OF_LEDS] = {7, 6, 5, 4, 3, 2};

int thresholds[NUMBER_OF_LEDS] = {5, 10, 15, 20, 25, 30};

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

  for (int i = 0; i < NUMBER_OF_LEDS; i++) {
    pinMode(leds[i], OUTPUT);
  }
}


void loop() {
  int volume = analogRead(A0);

  long int average = total / frame_size;

  int current_threshold = 0;
  while (current_threshold < NUMBER_OF_LEDS && average > thresholds[current_threshold]) {
    current_threshold++;
  }
  show_leds(current_threshold);

  total = total - average / 2;
  total = total + volume;

  Serial.println(average);
}

void show_leds(int number) {
  for (int i = 0; i < number; i++) {
    digitalWrite(leds[i], HIGH);
  }
  for (int i = number; i < NUMBER_OF_LEDS; i++) {
    digitalWrite(leds[i], LOW);
  }
}

void run_led(int delay_ms) {
  for (int i = 0; i < 6; i++) {
    digitalWrite(leds[i], HIGH);
    delay(delay_ms);
    digitalWrite(leds[i], LOW);
  }
}

void top_up(int delay_ms) {
  disable_all();
  delay(delay_ms);

  for (int i = 0; i < 6; i++) {
    digitalWrite(i, HIGH);
    delay(delay_ms);
  }
}

void disable_all() {
  for (int i = 0; i < NUMBER_OF_LEDS; i++) {
    digitalWrite(leds[i], LOW);
  }
}