#define LIGHT_SENSOR_PIN 36 // ESP32 pin GIOP36 (ADC0)
boolean countStatus;
int beat, bpm;
unsigned long millisBefore;
float mockupTime;
float mockupInc = 1;

void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
  randomSeed(analogRead(0));
}

void loop() {
  // reads the input on analog pin (value between 0 and 4095)
  // read the input on analog pin 36:

  // int sensorValue = analogRead(LIGHT_SENSOR_PIN);

  // Temporary use of mockup function
  int sensorValue = mockupPulse();

  if (millis() % 100 == 1) {
    // Serial.print("Analog Value = ");
    // Serial.println(sensorValue);   // the raw analog reading
  }

  if (countStatus == 0) {
    //800 - 3200 = Light - Bright
    if (sensorValue > 3200) {
      countStatus = 1;
      beat++;
      Serial.println("Beat detected!");
      Serial.print("Beat : ");
      Serial.println(beat);
    }
  } else {
    // <800 = Dim
    if (sensorValue < 800) {
      countStatus = 0;
    }
  }

  //15000 ms = 1/4 min => beat * 4 for bpm
  if (millis() - millisBefore > 15000) {
    bpm = beat * 4;
    beat = 0;
    Serial.print("BPM : ");
    Serial.println(bpm);
    millisBefore = millis();
  }

  delay(1);
}

// Mockup function for sensor values
int mockupPulse() {
  // Every ten seconds we change the tempo in a random way
  if (millis() % 10000 == 1) {
    mockupInc = (mockupInc + random(20, 180) / 100.0) / 2;
  }
  mockupTime += mockupInc;
  int iTime = (int) mockupTime;

  return (iTime % 1000) * 4;
}