// Define names for each LED pin
#define YELLOW D2
#define WHITE  D0


// Define button pin
#define BUTTON D8

// Time delay between LED changes (in milliseconds)
#define time   100

// Store all LED pins inside an array
// This lets us control them using a loop
int leds[] = {YELLOW, WHITE};

// Total number of LEDs in the array
int numLeds = 2;

void setup() { 

  // Set all LED pins as OUTPUT (they send voltage out)
  pinMode(YELLOW, OUTPUT);
  pinMode(WHITE, OUTPUT);



  // Set button as INPUT with internal pulldown resistor
  // When pressed, reads HIGH
  // When not pressed, reads LOW
  pinMode(BUTTON, INPUT_PULLDOWN);
}

void loop() {

  // Check if button is pressed
  if (digitalRead(BUTTON) == HIGH) {

    // If pressed, run LED chase pattern
    chase_2();
  }
  else {

    // If not pressed, turn all LEDs OFF
    // Loop goes through each LED one by one
    for (int i = 0; i < numLeds; i++) {

      // leds[i] selects LED number 0,1,2,3
      digitalWrite(leds[i], LOW);
    }
  }
}

// Function to run LEDs one after another
void chase_2() {

  // Loop through each LED
  for (int i = 0; i < numLeds; i++) {

    // Turn current LED ON
    digitalWrite(leds[i], HIGH);  

    // Wait for defined time
    delay(time);

    // Turn current LED OFF before moving to next
    digitalWrite(leds[i], LOW);   
  }
}