use crate::*;

/// A three-column layout.
pub struct Tryptich<A, B, C> {
    pub top:    bool,
    pub h:      u16,
    pub left:   (u16, A),
    pub middle: (u16, B),
    pub right:  (u16, C),
}

impl Tryptich<(), (), ()> {
    pub fn center (h: u16) -> Self {
        Self { h, top: false, left: (0, ()), middle: (0, ()), right: (0, ()) }
    }
    pub fn top (h: u16) -> Self {
        Self { h, top: true, left: (0, ()), middle: (0, ()), right: (0, ()) }
    }
}

impl<A, B, C> Tryptich<A, B, C> {
    pub fn left <D> (self, w: u16, content: D) -> Tryptich<D, B, C> {
        Tryptich { left: (w, content), ..self }
    }
    pub fn middle <D> (self, w: u16, content: D) -> Tryptich<A, D, C> {
        Tryptich { middle: (w, content), ..self }
    }
    pub fn right <D> (self, w: u16, content: D) -> Tryptich<A, B, D> {
        Tryptich { right: (w, content), ..self }
    }
}

impl<A, B, C> Content<TuiOut> for Tryptich<A, B, C>
where A: Content<TuiOut>, B: Content<TuiOut>, C: Content<TuiOut> {
    fn content (&self) -> impl Render<TuiOut> {
        let Self { top, h, left: (w_a, ref a), middle: (w_b, ref b), right: (w_c, ref c) } = *self;
        Fixed::y(h, if top {
            Bsp::a(
                Fill::x(Align::n(Fixed::x(w_b, Align::x(Tui::bg(Color::Reset, b))))),
                Bsp::a(
                    Fill::x(Align::nw(Fixed::x(w_a, Tui::bg(Color::Reset, a)))),
                    Fill::x(Align::ne(Fixed::x(w_c, Tui::bg(Color::Reset, c)))),
                ),
            )
        } else {
            Bsp::a(
                Fill::xy(Align::c(Fixed::x(w_b, Align::x(Tui::bg(Color::Reset, b))))),
                Bsp::a(
                    Fill::xy(Align::w(Fixed::x(w_a, Tui::bg(Color::Reset, a)))),
                    Fill::xy(Align::e(Fixed::x(w_c, Tui::bg(Color::Reset, c)))),
                ),
            )
        })
    }
}