use embedded_hal::digital::v2::InputPin;

pub struct Rotary<A, B> {
    pin_a: A,
    pin_b: B,
    state: u8,
}

pub enum Direction {
    Clockwise,
    CounterClockwise,
    None,
}

impl<A, B> Rotary<A, B>
where
    A: InputPin,
    B: InputPin,
{
    pub fn new(pin_a: A, pin_b: B) -> Self {
        Self {
            pin_a,
            pin_b,
            state: 0,
        }
    }

    pub fn update(&mut self) -> Direction {
        let a = self.pin_a.is_low();
        let b = self.pin_b.is_low();

        let new_state = match (a, b) {
            (Ok(true), Ok(true)) => 0b00,
            (Ok(true), Ok(false)) => 0b01,
            (Ok(false), Ok(true)) => 0b10,
            (Ok(false), Ok(false)) => 0b11,
            _ => return Direction::None,
        };

        let direction = match (self.state, new_state) {
            (0b10, 0b11) => Direction::Clockwise,
            (0b01, 0b00) => Direction::Clockwise,
            (0b01, 0b11) => Direction::CounterClockwise,
            (0b10, 0b00) => Direction::CounterClockwise,
            _ => Direction::None,
        };

        self.state = new_state;
        direction
    }
}