use crate::*;
#[derive(Debug, Copy, Clone, Default)]
pub enum Alignment { #[default] Center, X, Y, NW, N, NE, E, SE, S, SW, W }
pub struct Align<E, A>(PhantomData<E>, Alignment, A);
impl<E, A> Align<E, A> {
    pub fn c  (a: A) -> Self { Self(Default::default(), Alignment::Center, a) }
    pub fn x  (a: A) -> Self { Self(Default::default(), Alignment::X,      a) }
    pub fn y  (a: A) -> Self { Self(Default::default(), Alignment::Y,      a) }
    pub fn n  (a: A) -> Self { Self(Default::default(), Alignment::N,      a) }
    pub fn s  (a: A) -> Self { Self(Default::default(), Alignment::S,      a) }
    pub fn e  (a: A) -> Self { Self(Default::default(), Alignment::E,      a) }
    pub fn w  (a: A) -> Self { Self(Default::default(), Alignment::W,      a) }
    pub fn nw (a: A) -> Self { Self(Default::default(), Alignment::NW,     a) }
    pub fn sw (a: A) -> Self { Self(Default::default(), Alignment::SW,     a) }
    pub fn ne (a: A) -> Self { Self(Default::default(), Alignment::NE,     a) }
    pub fn se (a: A) -> Self { Self(Default::default(), Alignment::SE,     a) }
}
impl<E: Output, A: Content<E>> Content<E> for Align<E, A> {
    fn content (&self) -> impl Render<E> {
        &self.2
    }
    fn layout (&self, on: E::Area) -> E::Area {
        use Alignment::*;
        let it = Render::layout(&self.content(), on).xywh();
        let cx = on.x()+(on.w().minus(it.w())/2.into());
        let cy = on.y()+(on.h().minus(it.h())/2.into());
        let fx = (on.x()+on.w()).minus(it.w());
        let fy = (on.y()+on.h()).minus(it.h());
        let [x, y] = match self.1 {
            Center => [cx, cy],
            X =>  [cx, it.y()],
            Y =>  [it.x(), cy],
            NW => [on.x(), on.y()],
            N  => [cx,     on.y()],
            NE => [fx,     on.y()],
            W  => [on.x(), cy],
            E  => [fx,     cy],
            SW => [on.x(), fy],
            S  => [cx,     fy],
            SE => [fx,     fy],
        }.into();
        [x, y, it.w(), it.h()].into()
    }
    fn render (&self, to: &mut E) {
        to.place(Content::layout(self, to.area()), &self.content())
    }
}
impl<'a, E: Output + 'a, T: EdnViewData<'a, E>> TryFromEdn<'a, T> for Align<E, RenderBox<'a, E>> {
    fn try_from_edn (state: &'a T, head: &EdnItem<&str>, tail: &'a [EdnItem<&str>]) -> Option<Self> {
        use EdnItem::*;
        Some(match (head, tail) {
            (Key("align/c"),  [a]) => Self::c(state.get_content(a).expect("no content")),
            (Key("align/x"),  [a]) => Self::x(state.get_content(a).expect("no content")),
            (Key("align/y"),  [a]) => Self::y(state.get_content(a).expect("no content")),
            (Key("align/n"),  [a]) => Self::n(state.get_content(a).expect("no content")),
            (Key("align/s"),  [a]) => Self::s(state.get_content(a).expect("no content")),
            (Key("align/e"),  [a]) => Self::e(state.get_content(a).expect("no content")),
            (Key("align/w"),  [a]) => Self::w(state.get_content(a).expect("no content")),
            (Key("align/nw"), [a]) => Self::nw(state.get_content(a).expect("no content")),
            (Key("align/ne"), [a]) => Self::ne(state.get_content(a).expect("no content")),
            (Key("align/sw"), [a]) => Self::sw(state.get_content(a).expect("no content")),
            (Key("align/se"), [a]) => Self::se(state.get_content(a).expect("no content")),
            _ => return None
        })
    }
}