// ------------- A very simplified button class -----------
class Button {
  public:
    Button(uint8_t pin)
      : pin(pin) {}

    void begin() {
      pinMode(pin, INPUT_PULLUP);
    }

    operator bool() {
      bool current = digitalRead(pin) == LOW;
      if (current != prevState && (millis() - prevMillis >= 20)) {
        prevState = current;
        prevMillis = millis();
        return current;
      }
      return false;
    }

  private:
    uint8_t pin;
    bool prevState = true;
    uint32_t prevMillis = 0;
};
// --------------------------------------------------

const byte buttonPin = 9;
const byte ledPins[] = { 2, 3, 4, 5 };
const byte ledCnt = sizeof ledPins / sizeof * ledPins;
const byte pot1Pin = A0;
const byte pot2Pin = A1;

Button button(buttonPin);

// ---- State machine ----------------------------------
enum Mode : uint8_t { BLINK, CHASE};
enum Phase : uint8_t { LED_ON, LED_OFF};

Mode mode = BLINK;
Phase phase = LED_ON;

uint32_t stateStart = 0;  // when the current phase began
byte chaseIdx = 0;        // which LED is lit in CHASE mode

void allLeds(bool isLedON) {
  for (byte pin : ledPins) digitalWrite(pin, isLedON ? HIGH : LOW);
}

void setup() {
  for (byte pin : ledPins) pinMode(pin, OUTPUT);
  button.begin();
  stateStart = millis();
  allLeds(true);
}

void loop() {
  // --- Handle button press (toggle mode, reset state machine)
  if (button) {
    mode = (mode == BLINK) ? CHASE : BLINK;
    phase = LED_ON;
    chaseIdx = 0;
    stateStart = millis();
    allLeds(false);
    if (mode == BLINK) {
      allLeds(true);
    } else {
      allLeds(false);
      digitalWrite(ledPins[chaseIdx], HIGH);
    }
  }

  // --- Read pots every loop (non-blocking)
  uint32_t onTime = analogRead(pot1Pin);
  uint32_t offTime = analogRead(pot2Pin);

  uint32_t now = millis();
  uint32_t elapsed = now - stateStart;

  if (mode == BLINK) {
    // Two-phase: ON → OFF → ON → …
    if (phase == LED_ON && elapsed >= onTime) {
      allLeds(false);
      phase = LED_OFF;
      stateStart = now;
    } else if (phase == LED_OFF && elapsed >= offTime) {
      allLeds(true);
      phase = LED_ON;
      stateStart = now;
    }

  } else {
    // CHASE: one LED on for (pot1+pot2) ms, then advance
    uint32_t stepTime = onTime + offTime;
    if (elapsed >= stepTime) {
      digitalWrite(ledPins[chaseIdx], LOW);
      chaseIdx = (chaseIdx + 1) % ledCnt;
      digitalWrite(ledPins[chaseIdx], HIGH);
      stateStart = now;
    }
  }
}