int bzr_pin = 13;
int red_pin = 9;
int grn_pin = 6;
int btn_pin = 2;

int state = 1;
int old_state;
// 1-state: BUZZER: OFF && RGB: RED
// 2-state: BUZZER: TONE && RGB: GREEN

bool btn_val, btn_old_val;
bool isButtonPressed;

unsigned long currentTime, lastTime;

void setup() {
  pinMode(bzr_pin, OUTPUT);
  pinMode(red_pin, OUTPUT);
  pinMode(grn_pin, OUTPUT);
  pinMode(btn_pin, INPUT_PULLUP);
}

void loop() {
  currentTime = millis();
  readButton();

  switch(state) {
    case 1:
      if(isButtonPressed) {
        state = 2;
      }
      digitalWrite(red_pin, HIGH);
      digitalWrite(grn_pin, LOW);
      noTone(bzr_pin);
      break;
    case 2:
      if(isButtonPressed || currentTime-lastTime>5000) {
        state = 1;
      }
      digitalWrite(red_pin, LOW);
      digitalWrite(grn_pin, HIGH);
      tone(bzr_pin, 1000);
      break;
  }

  if(state != old_state) {
    lastTime = currentTime;
  }
  old_state = state;
}

void readButton() {
  btn_val = !digitalRead(btn_pin);

  if (btn_val && !btn_old_val) {
    isButtonPressed = true;
  }
  else {
    isButtonPressed = false;
    delay(50);
  }

  btn_old_val = btn_val;
}