use crate::{Len, Painter, SizeCtx, Ui};
use std::any::Any;

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

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

pub trait Widget<State>: Any {
    fn draw(&mut self, painter: &mut Painter<State>);
    fn desired_width(&mut self, ctx: &mut SizeCtx<State>) -> Len;
    fn desired_height(&mut self, ctx: &mut SizeCtx<State>) -> Len;
}

impl<State> Widget<State> for () {
    fn draw(&mut self, _: &mut Painter<State>) {}
    fn desired_width(&mut self, _: &mut SizeCtx<State>) -> Len {
        Len::ZERO
    }
    fn desired_height(&mut self, _: &mut SizeCtx<State>) -> Len {
        Len::ZERO
    }
}

impl<State> dyn Widget<State> {
    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<State> + ?Sized>: FnOnce(&mut Ui<State>) -> W {}
impl<State, W: Widget<State> + ?Sized, F: FnOnce(&mut Ui<State>) -> W> WidgetFn<State, W> for F {}

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

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

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

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

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