#include <Wire.h>
#include <BH1750.h>

#define PinLED 2           // on-board LED
#define IN1 32
#define IN2 14

BH1750 lightMeter;

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

  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(PinLED, OUTPUT);
}

void pulsujNaprzemiennie(int czasSekundy) {
  const int steps = 150;
  int delayPerStep = (czasSekundy * 1000) / (2 * steps);  // ms

  for (int i = 0; i <= steps; i++) {
    float phase = (float)i / steps;
    float brightness1 = 1.0 - phase;
    float brightness2 = phase;

    int t_on1 = (int)(brightness1 * 2000);
    int t_on2 = (int)(brightness2 * 2000);

    digitalWrite(IN1, HIGH);
    digitalWrite(IN2, LOW);
    delayMicroseconds(t_on1);

    digitalWrite(IN1, LOW);
    digitalWrite(IN2, HIGH);
    delayMicroseconds(t_on2);

    digitalWrite(IN1, LOW);
    digitalWrite(IN2, LOW);
    delay(delayPerStep - 4);
  }

  for (int i = steps; i >= 0; i--) {
    float phase = (float)i / steps;
    float brightness1 = 1.0 - phase;
    float brightness2 = phase;

    int t_on1 = (int)(brightness1 * 2000);
    int t_on2 = (int)(brightness2 * 2000);

    digitalWrite(IN1, HIGH);
    digitalWrite(IN2, LOW);
    delayMicroseconds(t_on1);

    digitalWrite(IN1, LOW);
    digitalWrite(IN2, HIGH);
    delayMicroseconds(t_on2);

    digitalWrite(IN1, LOW);
    digitalWrite(IN2, LOW);
    delay(delayPerStep - 4);
  }
}

void loop() {
  uint16_t lux = lightMeter.readLightLevel();
  Serial.print("Light: ");
  Serial.print(lux);
  Serial.println(" lx");

  if (lux < 10) {
    digitalWrite(PinLED, LOW);
    pulsujNaprzemiennie(5); // cykl trwa teraz 5 sekund
  } else {
    digitalWrite(PinLED, HIGH);
    delay(5 000);
  }
}