use crate::*;

pub trait HasSize<E: Engine> {
    fn size (&self) -> &Measure<E>;
}

#[macro_export] macro_rules! has_size {
    (<$E:ty>|$self:ident:$Struct:ident$(<$($L:lifetime),*$($T:ident$(:$U:path)?),*>)?|$cb:expr) => {
        impl $(<$($L),*$($T $(: $U)?),*>)? HasSize<$E> for $Struct $(<$($L),*$($T),*>)? {
            fn size (&$self) -> &Measure<$E> { $cb }
        }
    }
}

impl<E: Engine> LayoutDebug<E> for E {}

pub trait LayoutDebug<E: Engine> {
    fn debug <W: Render<E>> (other: W) -> DebugOverlay<E, W> {
        DebugOverlay(Default::default(), other)
    }
}

pub struct DebugOverlay<E: Engine, W: Render<E>>(PhantomData<E>, pub W);

/// A widget that tracks its render width and height
#[derive(Default)]
pub struct Measure<E: Engine> {
    _engine: PhantomData<E>,
    pub x: Arc<AtomicUsize>,
    pub y: Arc<AtomicUsize>,
}

impl<E: Engine> Clone for Measure<E> {
    fn clone (&self) -> Self {
        Self {
            _engine: Default::default(),
            x: self.x.clone(),
            y: self.y.clone(),
        }
    }
}

impl<E: Engine> std::fmt::Debug for Measure<E> {
    fn fmt (&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        f.debug_struct("Measure")
            .field("width",  &self.x)
            .field("height", &self.y)
            .finish()
    }
}

impl<E: Engine> Measure<E> {
    pub fn w (&self) -> usize { self.x.load(Relaxed) }
    pub fn h (&self) -> usize { self.y.load(Relaxed) }
    pub fn wh (&self) -> [usize;2] { [self.w(), self.h()] }
    pub fn set_w (&self, w: impl Into<usize>) { self.x.store(w.into(), Relaxed) }
    pub fn set_h (&self, h: impl Into<usize>) { self.y.store(h.into(), Relaxed) }
    pub fn set_wh (&self, w: impl Into<usize>, h: impl Into<usize>) { self.set_w(w); self.set_h(h); }
    pub fn format (&self) -> String { format!("{}x{}", self.w(), self.h()) }
    pub fn new () -> Self {
        Self {
            _engine: PhantomData::default(),
            x: Arc::new(0.into()),
            y: Arc::new(0.into()),
        }
    }
}

impl Render<Tui> for Measure<Tui> {
    fn min_size (&self, _: [u16;2]) -> Perhaps<[u16;2]> {
        Ok(Some([0u16.into(), 0u16.into()].into()))
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        self.set_w(to.area().w());
        self.set_h(to.area().h());
        Ok(())
    }
}

impl Measure<Tui> {
    pub fn debug (&self) -> ShowMeasure {
        ShowMeasure(&self)
    }
}

pub struct ShowMeasure<'a>(&'a Measure<Tui>);
render!(<Tui>|self: ShowMeasure<'a>|render(|to|Ok({
    let w = self.0.w();
    let h = self.0.h();
    to.blit(&format!(" {w} x {h} "), to.area.x(), to.area.y(), Some(
        Style::default().bold().italic().bg(Color::Rgb(255, 0, 255)).fg(Color::Rgb(0,0,0))
    ))
})));