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),
            exact_region: false,
        }
    }

    fn align(self, align: impl Into<Align>) -> impl WidgetFn<Rsc, Aligned> {
        move |state| Aligned {
            inner: self.add_strong(state),
            align: align.into(),
        }
    }

    fn center(self) -> impl WidgetFn<Rsc, Aligned> {
        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 sized(self, size: impl Into<Size>) -> impl WidgetFn<Rsc, Sized> {
        let size = size.into();
        move |state| Sized {
            inner: self.add_strong(state),
            x: Some(size.x),
            y: Some(size.y),
        }
    }

    fn max_width(self, len: impl Into<Len>) -> impl WidgetFn<Rsc, MaxSize> {
        let len = len.into();
        move |state| MaxSize {
            inner: self.add_strong(state),
            x: Some(len),
            y: None,
        }
    }

    fn max_height(self, len: impl Into<Len>) -> impl WidgetFn<Rsc, MaxSize> {
        let len = len.into();
        move |state| MaxSize {
            inner: self.add_strong(state),
            x: None,
            y: Some(len),
        }
    }

    fn width(self, len: impl Into<Len>) -> impl WidgetFn<Rsc, Sized> {
        let len = len.into();
        move |state| Sized {
            inner: self.add_strong(state),
            x: Some(len),
            y: None,
        }
    }

    fn height(self, len: impl Into<Len>) -> impl WidgetFn<Rsc, Sized> {
        let len = len.into();
        move |state| Sized {
            inner: self.add_strong(state),
            x: None,
            y: Some(len),
        }
    }

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

    /// Wrap this widget in a [`ScrollArea`] that pans along `axis`, with
    /// the wheel and a finger drag both registered -- how anything with a
    /// fixed layout becomes scrollable.
    ///
    /// `pin` says which end the area opens at and clings to as its content
    /// grows, and it is spelled out rather than defaulted because the two
    /// cases are not variations on each other: a composer wants the end,
    /// where what is being typed is, and a code fence opened at the end of
    /// its longest line, which is the middle of a word (seen in
    /// `iris/run-headless.sh phone`, 2026-09-08).
    ///
    /// One method with the axis and the pin passed in, rather than the
    /// three named variants this used to be (Iris, 2026-09-08: "can we
    /// make both scroll methods become `.scrollable`, and it takes an axis
    /// and a pin instead of having two?"). A code fence pans across its
    /// own long lines exactly the way a transcript pans down its rows, so
    /// the two are one mechanism with the direction passed in --
    /// `DragArbiter::on` is the other half.
    ///
    /// A [`LazySpan`] has an inherent `scrollable` of its own that this
    /// does not reach: it owns a controller already and must not be
    /// wrapped in an area that would slide it about as a lump.
    fn scrollable(self, axis: Axis, pin: Pin) -> impl WidgetIdFn<Rsc, ScrollArea> where Rsc: HasEvents {
        move |state| {
            let area = ScrollArea::new(self.add_strong(state), axis, pin);
            scroll_senses(area, axis)(state)
        }
    }

    fn masked(self) -> impl WidgetFn<Rsc, Masked> {
        move |state| Masked {
            shape: None,
            inner: self.add_strong(state),
        }
    }

    /// Clip to `shape` rather than to a plain box: `shape` is drawn
    /// behind this widget, filling the same region, and what clips is the
    /// primitive it drew -- so a rounded background and the corner its
    /// content is cut to are one rect, with no radius passed twice.
    /// Replaces `.masked().background(w)`, which drew the two but clipped
    /// to the box.
    fn masked_by<T>(self, shape: impl WidgetLike<Rsc, T>) -> impl WidgetFn<Rsc, Masked> {
        move |state| Masked {
            shape: Some(shape.add_strong(state)),
            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)
    }
}