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use std::cell::Cell;

#[derive(Debug, Clone, Copy, Default)]
pub struct InputState {
    pub joypad_1: JoypadState,
    pub joypad_2: JoypadState,
}

#[derive(Debug, Clone, Copy)]
pub struct JoypadState {
    pub a: bool,
    pub b: bool,
    pub start: bool,
    pub select: bool,
    pub up: bool,
    pub down: bool,
    pub left: bool,
    pub right: bool,
}

impl Default for JoypadState {
    fn default() -> Self {
        JoypadState {
            a: false,
            b: false,
            start: false,
            select: false,
            up: false,
            down: false,
            left: false,
            right: false,
        }
    }
}

pub trait Input {
    fn input_state(&self) -> InputState;
}

pub struct NullInput;

impl Input for NullInput {
    fn input_state(&self) -> InputState {
        InputState::default()
    }
}

pub struct SampledInput {
    state: Cell<InputState>,
}

impl SampledInput {
    pub fn new(state: InputState) -> Self {
        SampledInput {
            state: Cell::new(state)
        }
    }

    pub fn set_state(&self, new_state: InputState) {
        self.state.set(new_state)
    }
}

impl Input for SampledInput {
    fn input_state(&self) -> InputState {
        let state = self.state.take();
        self.state.set(state.clone());
        state
    }
}

impl<'a, I> Input for &'a I
    where I: Input
{
    fn input_state(&self) -> InputState {
        (*self).input_state()
    }
}