use bitflags::bitflags;
use core::convert::From;

pub enum Tri {
    Positive = 1,
    Zero = 0,
    Negative = -1,
}

impl From<(bool, bool)> for Tri {
    fn from(a: (bool, bool)) -> Tri {
        let b1 = a.0 as i8;
        let b2 = a.1 as i8;
        unsafe { core::mem::transmute(b2 - b1) }
    }
}

bitflags! {
    pub struct Button: u32 {
        const A = 1 << 0;
        const B = 1 << 1;
        const SELECT = 1 << 2;
        const START = 1 << 3;
        const RIGHT = 1 << 4;
        const LEFT = 1 << 5;
        const UP = 1 << 6;
        const DOWN = 1 << 7;
        const R = 1 << 8;
        const L = 1 << 9;
    }
}

const KEY_MASK: u16 = 0b1111111111;

const BUTTON_INPUT: *mut u16 = (0x04000130) as *mut u16;

// const BUTTON_INTURRUPT: *mut u16 = (0x04000132) as *mut u16;

pub struct ButtonController {
    previous: u16,
    current: u16,
}

impl Default for ButtonController {
    fn default() -> Self {
        ButtonController::new()
    }
}

impl ButtonController {
    pub fn new() -> Self {
        ButtonController {
            previous: 0,
            current: 0,
        }
    }

    pub fn update(&mut self) {
        self.previous = self.current;
        self.current = unsafe { BUTTON_INPUT.read_volatile() } ^ KEY_MASK;
    }

    pub fn x_tri(&self) -> Tri {
        let left = self.is_pressed(Button::LEFT);
        let right = self.is_pressed(Button::RIGHT);

        (left, right).into()
    }

    pub fn y_tri(&self) -> Tri {
        let up = self.is_pressed(Button::UP);
        let down = self.is_pressed(Button::DOWN);

        (up, down).into()
    }

    pub fn is_pressed(&self, keys: Button) -> bool {
        let currently_pressed = self.current as u32;
        let keys = keys.bits();
        (currently_pressed & keys) != 0
    }
    pub fn is_released(&self, keys: Button) -> bool {
        !self.is_pressed(keys)
    }

    pub fn is_just_pressed(&self, keys: Button) -> bool {
        let current = self.current as u32;
        let previous = self.previous as u32;
        let keys = keys.bits();
        ((current & keys) != 0) && ((previous & keys) == 0)
    }

    pub fn is_just_released(&self, keys: Button) -> bool {
        let current = self.current as u32;
        let previous = self.previous as u32;
        let keys = keys.bits();
        ((current & keys) == 0) && ((previous & keys) != 0)
    }
}