use crate::{Axis, Len, Painter, Size};
use std::any::Any;

mod data;
mod handle;
mod like;
mod tag;
mod view;
mod widgets;

pub use data::*;
pub use handle::*;
pub use like::*;
pub use tag::*;
pub use view::*;
pub use widgets::*;

pub trait Widget: Any {
    fn draw(&mut self, painter: &mut Painter) -> Size;

    /// An exact, context-free length known without drawing or inspecting children.
    fn size_hint(&self, _axis: Axis) -> Option<Len> {
        None
    }

    /// Whether the draw result is independent of the offered region.
    fn is_size_independent(&self) -> bool {
        false
    }

    fn requires_exact_region(&self) -> bool {
        false
    }

    /// The AccessKit role for a labelled widget.
    fn access_role(&self) -> accesskit::Role {
        accesskit::Role::Unknown
    }

    /// Advance an animation and report whether it needs another frame.
    #[allow(unused_variables)]
    fn tick(&mut self, now: std::time::Instant) -> bool {
        false
    }
}

impl Widget for () {
    fn draw(&mut self, _: &mut Painter) -> Size {
        Size::ZERO
    }

    fn is_size_independent(&self) -> bool {
        true
    }

    fn size_hint(&self, _axis: Axis) -> Option<Len> {
        Some(Len::ZERO)
    }
}

impl dyn Widget {
    pub fn as_any(&self) -> &dyn Any {
        self
    }

    pub fn as_any_mut(&mut self) -> &mut dyn Any {
        self
    }
}

/// A function that returns a widget given a UI.
/// Useful for defining trait functions on widgets that create a parent widget so that the children
/// don't need to be IDs yet
pub trait WidgetFn<State, W: Widget + ?Sized>: FnOnce(&mut State) -> W {}
impl<State, W: Widget + ?Sized, F: FnOnce(&mut State) -> W> WidgetFn<State, W> for F {}

pub struct WidgetArr<const LEN: usize> {
    pub arr: [StrongWidget; LEN],
}

impl<const LEN: usize> WidgetArr<LEN> {
    pub fn new(arr: [StrongWidget; LEN]) -> Self {
        Self { arr }
    }
}

pub trait WidgetOption<State> {
    fn get(self, state: &mut State) -> Option<StrongWidget>;
}

impl<State> WidgetOption<State> for () {
    fn get(self, _: &mut State) -> Option<StrongWidget> {
        None
    }
}

impl<State, F: FnOnce(&mut State) -> Option<StrongWidget>> WidgetOption<State> for F {
    fn get(self, state: &mut State) -> Option<StrongWidget> {
        self(state)
    }
}