#![feature(step_trait)]
#![feature(type_alias_impl_trait)]
#![feature(impl_trait_in_assoc_type)]
#![feature(const_precise_live_drops)]
#![feature(type_changing_struct_update)]
//#![feature(non_lifetime_binders)]

mod content;  pub use self::content::*;
mod draw;     pub use self::draw::*;
mod group;    pub use self::group::*;
mod layout;   pub use self::layout::*;
mod space;    pub use self::space::*;
mod thunk;    pub use self::thunk::*;
mod widget;   pub use self::widget::*;
pub(crate) use self::Direction::*;
pub(crate) use std::fmt::{Debug, Display};
pub(crate) use std::marker::PhantomData;
pub(crate) use std::ops::{Add, Sub, Mul, Div};
pub(crate) use std::sync::{Arc, RwLock, atomic::{AtomicUsize, Ordering::Relaxed}};
pub(crate) use tengri_core::*;

/// Draw target.
pub trait Out: Send + Sync + Sized {
    /// Unit of length
    type Unit: Coordinate;
    /// Rectangle without offset
    type Size: Size<Self::Unit>;
    /// Rectangle with offset
    type Area: Area<Self::Unit>;
    /// Current output area
    fn area (&self) -> Self::Area;
    /// Mutable pointer to area
    fn area_mut (&mut self) -> &mut Self::Area;
    /// Draw widget in area
    fn place_at <'t, T: Draw<Self> + ?Sized> (&mut self, area: Self::Area, content: &'t T);

    fn place <'t, T: Draw<Self> + Layout<Self> + ?Sized> (&mut self, content: &'t T) {
        self.place_at(content.layout(self.area()), content)
    }
    #[inline] fn x (&self) -> Self::Unit { self.area().x() }
    #[inline] fn y (&self) -> Self::Unit { self.area().y() }
    #[inline] fn w (&self) -> Self::Unit { self.area().w() }
    #[inline] fn h (&self) -> Self::Unit { self.area().h() }
    #[inline] fn wh (&self) -> Self::Size { self.area().wh().into() }
}

#[cfg(test)] mod test;
#[cfg(test)] pub(crate) use proptest_derive::Arbitrary;

//impl<E: Out, C: Content<E> + Layout<E>> Draw<E> for C { // if only
    //fn draw (&self, to: &mut E) {
        //if let Some(content) = self.content() {
            //to.place_at(self.layout(to.area()), &content);
        //}
    //}
//}