const int gatePin = 0;
const int ledPin1 = 3;
const int ledPin2 = 2;
const int ledPinZ = 1;
const int buttonPin = 4;
volatile unsigned long time1 = 0;
volatile unsigned long time2 = 0;
volatile unsigned long time3 = 0;
volatile int mode = 1;

volatile int gate = 1;

static inline void initInterruptChange(void) {
  GIMSK |= (1 << PCIE);    //Change Interrupt Enable Bit
  PCMSK |= (1 << PCINT4);  // Pin change interrupt PB4
}

static inline void initTimer1(void) {
  TCCR1 |= (1 << CTC1);  // clear timer on compare match
  TCCR1 |= (1 << CS13) | (1 << CS12) | (1 << CS12);
  OCR1C = 122;             // count to
  TIMSK |= (1 << OCIE1A);  // enable compare match interrupt
}

void setup() {

  pinMode(buttonPin, INPUT);
  pinMode(gatePin, OUTPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPinZ, OUTPUT);

  cli();

  initInterruptChange();
  initTimer1();

  sei();
}

ISR(PCINT0_vect) {  // Pin Change Interrupt Request

  byte buttonPressed = (PINB & (1 << PINB4)) >> PINB4;

  if (millis() - time1 > 200) {
    if (buttonPressed == 1) {

      if (mode == 1 || mode == 2) mode = 3;
      else if (mode == 3 || mode == 4) mode = 1;

      time1 = millis();
      LEDS();
    }
  }
}

ISR(TIMER1_COMPA_vect) {  // Timer/Counter1 Compare Match A
  if (millis() - time2 > 600) {

    if (mode == 1) mode = 2;
    else if (mode == 2) mode = 1;
    else if (mode == 3) mode = 4;
    else if (mode == 4) mode = 3;

    time2 = millis();
    LEDS();
  }

  if (millis() - time3 > 100) {
    if (mode == 1 || mode == 2) gate += 5;
    if (mode == 3 || mode == 4) gate -= 5;

    if (gate > 254) gate = 254;
    if (gate < 1) gate = 1;
    analogWrite(gatePin, gate);

    time3 = millis();
  }
}

void LEDS(void) {
  digitalWrite(ledPin1, mode == 1);
  digitalWrite(ledPin2, mode == 2);
  digitalWrite(ledPinZ, mode == 3);
}


void loop() {
}