/// Helpers to create a basic option menu using Feathers Radio Buttons.
/// Using these helpers requires the `bevy_feathers` feature to be enabled.
use bevy::{
    feathers::{
        controls::FeathersRadio,
        display::{caption, label},
    },
    picking::hover::Hovered,
    prelude::*,
    ui::Checked,
    ui_widgets::RadioGroup,
};

/// A component that wraps a radio button's option value
#[derive(Clone, Copy, Component, Default)]
pub struct RadioButtonOptionValue<T>(pub T)
where
    T: Clone + Default + Send + Sync + Unpin + 'static;

/// Returns a [`Node`] appropriate for the outer main UI node as a `Scene`.
///
/// This UI is in the bottom left corner and has flex column support
pub fn main_ui_node_scene() -> impl Scene {
    bsn! {
        Node {
            flex_direction: FlexDirection::Column,
            position_type: PositionType::Absolute,
            row_gap: px(6),
            left: px(10),
            bottom: px(10),
        }
    }
}

/// Spawns the radio buttons that allow configuration of a setting.
///
/// The option at index `selected_option` in the `options` list is marked as selected.
///
/// To react to changes in value, create an observer that listens to
/// `ValueChange<Entity>>`. Query for the value entity's `RadioButtonOptionValue`
/// and unwrap the new option value.
///
/// Ensure the radio button self updates its own state by adding the
/// `ui_widgets::radio_self_update` observer to the app.
pub fn feathers_option_buttons<T>(
    title: &'static str,
    options: &[(T, &str)],
    selected_option: usize,
) -> impl Scene
where
    T: Clone + Default + Send + Sync + Unpin + 'static,
{
    let buttons = options
        .iter()
        .cloned()
        .enumerate()
        .map(|(option_index, (option_value, option_name))| {
            feathers_option_button(option_value, option_name, option_index == selected_option)
        })
        .collect::<Vec<_>>();
    // Add the parent node for the row.
    bsn! {
        Node {
            align_items: AlignItems::Center,
            column_gap: px(5),
        }
        RadioGroup
        Children [
            @label(title)
            --
            {buttons}
        ]
    }
}

/// Spawns a single feathers radio button that allows configuration of a setting.
fn feathers_option_button<T>(
    option_value: T,
    option_name: &str,
    is_selected: bool,
) -> Box<dyn Scene>
where
    T: Clone + Default + Send + Sync + Unpin + 'static,
{
    if is_selected {
        Box::new(bsn! {
            @FeathersRadio {
                @caption: bsn! { @caption(option_name) }
            }
            Hovered
            Checked
            RadioButtonOptionValue<T>(option_value)
        })
    } else {
        Box::new(bsn! {
            @FeathersRadio {
                @caption: bsn! { @caption(option_name) }
            }
            Hovered
            RadioButtonOptionValue<T>(option_value)
        })
    }
}