from machine import Pin

class Counter:
    _dir = [
        0, -1, 1, 0, 1, 0, 0, -1,
        -1, 0, 0, 1, 0, 1, -1, 0,
    ]

    def __init__(self, A: int, B: int, flip_dir: bool = False, on_change = None):
        self.A = Pin(A, Pin.IN, Pin.PULL_UP)
        self.B = Pin(B, Pin.IN, Pin.PULL_UP)
        self._flip = flip_dir
        self._state = 0
        self._value = 0
        self._on_change = on_change

        self.A.irq(trigger=Pin.IRQ_FALLING | Pin.IRQ_RISING, handler=self._button_handler)
        self.B.irq(trigger=Pin.IRQ_FALLING | Pin.IRQ_RISING, handler=self._button_handler)

    def _button_handler(self, _):
        a, b = self.A.value(), self.B.value()
        if self._flip:
            a, b = b, a
        new_state = (self._state << 2) | (a << 1) | b
        self._state = new_state & 0x0f
        self._value += self._dir[self._state]

        if self._on_change:
            self._on_change(self._value)

    def value(self, v: int = None):
        current_value = self._value
        if v is not None:
            self._value = v
        return current_value


c = Counter(25, 26, on_change=lambda v: print(v))