nes_rust_slim 0.2.0

use button;
use register::Register;

const BUTTON_NUM: u8 = 8;

pub enum Button {
    A,
    B,
    Select,
    Start,
    Up,
    Down,
    Left,
    Right,
}

fn button_index(button: Button) -> usize {
    match button {
        Button::A => 0,
        Button::B => 1,
        Button::Select => 2,
        Button::Start => 3,
        Button::Up => 4,
        Button::Down => 5,
        Button::Left => 6,
        Button::Right => 7,
    }
}

pub struct Joypad {
    register: Register<u8>,
    latch: u8,
    current_button: u8,
    pub buttons: [bool; BUTTON_NUM as usize],
}

impl Joypad {
    pub fn new() -> Self {
        Joypad {
            register: Register::<u8>::new(),
            latch: 0,
            current_button: 0,
            buttons: [false; BUTTON_NUM as usize],
        }
    }

    pub fn handle_input(&mut self, button: Button, event: button::Event) {
        match event {
            button::Event::Press => self.press_button(button),
            button::Event::Release => self.release_button(button),
        };
    }

    pub fn load_register(&mut self) -> u8 {
        let button = match self.latch == 1 {
            true => 1,
            _ => {
                let value = self.current_button;
                self.current_button += 1;
                value
            }
        };

        match button >= BUTTON_NUM || self.buttons[button as usize] {
            true => 1,
            false => 0,
        }
    }

    pub fn store_register(&mut self, mut value: u8) {
        self.register.store(value);
        value = value & 1;
        if value == 1 {
            self.current_button = 0;
        }
        self.latch = value;
    }

    pub fn press_button(&mut self, button: Button) {
        self.buttons[button_index(button)] = true;
    }

    pub fn release_button(&mut self, button: Button) {
        self.buttons[button_index(button)] = false;
    }
}