use super::*;
use crate::prelude::*;

// these methods should "not require any context" (require unit) because they're in core
widget_trait! {
    pub trait CoreWidget<Rsc: UiRsc + 'static>;

    fn pad(self, padding: impl Into<Padding>) -> impl WidgetFn<Rsc, Pad> {
        |state| Pad {
            padding: padding.into(),
            inner: self.add_strong(state),
        }
    }

    fn align(self, align: impl Into<Align>) -> impl WidgetIdFn<Rsc, WL::Widget> {
        // An axis left out keeps whatever it had, which is centered unless
        // something else set it.
        let align = align.into();
        move |state| {
            let id = self.add(state);
            let widgets = &mut state.ui_mut().widgets;
            for (axis, align) in [(Axis::X, align.x), (Axis::Y, align.y)] {
                if let Some(align) = align {
                    widgets.set_alignment(id, axis, align);
                }
            }
            id
        }
    }

    fn center(self) -> impl WidgetIdFn<Rsc, WL::Widget> {
        self.align(Align::CENTER)
    }

    fn label(self, label: impl Into<String>) -> impl WidgetIdFn<Rsc, WL::Widget> {
        |state| {
            let id = self.add(state);
            state.ui_mut().widgets.set_label(id, label.into());
            id
        }
    }

    fn region_node(self) -> impl WidgetIdFn<Rsc, WL::Widget> {
        |state| {
            let id = self.add(state);
            state.ui_mut().widgets.set_region_node(id, true);
            id
        }
    }

    fn sized(self, size: impl Into<Size>) -> impl WidgetIdFn<Rsc, WL::Widget> {
        let size = size.into();
        move |state| {
            let id = self.add(state);
            let widgets = &mut state.ui_mut().widgets;
            widgets.set_size_rule(id, Axis::X, SizeRule::Exact(size.x));
            widgets.set_size_rule(id, Axis::Y, SizeRule::Exact(size.y));
            id
        }
    }

    fn width(self, len: impl Into<Len>) -> impl WidgetIdFn<Rsc, WL::Widget> {
        let len = len.into();
        move |state| {
            let id = self.add(state);
            state
                .ui_mut()
                .widgets
                .set_size_rule(id, Axis::X, SizeRule::Exact(len));
            id
        }
    }

    fn height(self, len: impl Into<Len>) -> impl WidgetIdFn<Rsc, WL::Widget> {
        let len = len.into();
        move |state| {
            let id = self.add(state);
            state
                .ui_mut()
                .widgets
                .set_size_rule(id, Axis::Y, SizeRule::Exact(len));
            id
        }
    }

    fn offset(self, amt: impl Into<UiVec2>) -> impl WidgetFn<Rsc, Offset> {
        move |state| Offset {
            inner: self.add_strong(state),
            amt: amt.into(),
        }
    }

    fn scrollable(self) -> impl WidgetIdFn<Rsc, Scroll> where Rsc: HasEvents {
        move |state| {
            let inner = self.add(state);
            state.ui_mut().widgets.set_region_node(inner, true);
            Scroll::new(inner.upgrade(state), Axis::Y)
                .on(CursorSense::Scroll, |ctx, rsc| {
                    let delta = ctx.data.scroll_delta.y * 50.0;
                    ctx.widget(rsc).scroll(delta);
                })
                .add(state)
        }
    }

    fn masked(self) -> impl WidgetFn<Rsc, Masked> {
        move |state| Masked {
            inner: self.add_strong(state),
        }
    }

    fn background<T>(self, w: impl WidgetLike<Rsc, T>) -> impl WidgetFn<Rsc, Stack> {
        move |state| Stack {
            children: vec![w.add_strong(state), self.add_strong(state)],
            size: StackSize::Child(1),
        }
    }

    fn foreground<T>(self, w: impl WidgetLike<Rsc, T>) -> impl WidgetFn<Rsc, Stack> {
        move |state| Stack {
            children: vec![self.add_strong(state), w.add_strong(state)],
            size: StackSize::Child(0),
        }
    }

    fn layer_offset(self, offset: usize) -> impl WidgetFn<Rsc, LayerOffset> {
        move |state| LayerOffset {
            inner: self.add_strong(state),
            offset,
        }
    }

    fn to_any(self) -> impl WidgetIdFn<Rsc> {
        |state| self.add(state)
    }

    fn set_ptr(self, ptr: WeakWidget<WidgetPtr>, state: &mut Rsc) {
        let id = self.add_strong(state);
        state.ui_mut().widgets[ptr].inner = Some(id);
    }
}

pub trait CoreWidgetArr<Rsc, const LEN: usize, Wa: WidgetArrLike<Rsc, LEN, Tag>, Tag> {
    fn span(self, dir: Dir) -> SpanBuilder<Rsc, LEN, Wa, Tag>;
    fn stack(self) -> StackBuilder<Rsc, LEN, Wa, Tag>;
}

impl<State, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag>
    CoreWidgetArr<State, LEN, Wa, Tag> for Wa
{
    fn span(self, dir: Dir) -> SpanBuilder<State, LEN, Wa, Tag> {
        SpanBuilder::new(self, dir)
    }
    fn stack(self) -> StackBuilder<State, LEN, Wa, Tag> {
        StackBuilder::new(self)
    }
}