use crate::*;
use std::ops::*;

/// A request to the window manager for a render pass to be run.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum RenderRequest {
    /// A render is not required.
    None,
    /// A render is required.
    Render(RenderHint),
}

impl RenderRequest {
    pub const NONE:   RenderRequest = RenderRequest::None;
    pub const UPDATE: RenderRequest = RenderRequest::Render(RenderHint::Update);
    pub const REDRAW: RenderRequest = RenderRequest::Render(RenderHint::Redraw);

    pub fn is_none(&self) -> bool { *self == RenderRequest::NONE }
    pub fn is_some(&self) -> bool { *self != RenderRequest::None }
    pub fn is_update(&self) -> bool { *self == RenderRequest::UPDATE }
    pub fn is_redraw(&self) -> bool { *self == RenderRequest::REDRAW }
}

impl BitAnd for RenderRequest {
    type Output = RenderRequest;
    fn bitand(self, other: RenderRequest) -> Self::Output {
        use RenderRequest::*;
        match (self, other) {
            (None, req)  => req,
            (req, None)  => req,
            (Render(a), Render(b)) => Render(a & b),
        }
    }
}

impl BitAndAssign for RenderRequest {
    fn bitand_assign(&mut self, other: RenderRequest) {
        *self = *self & other;
    }
}