use crate::GameState;

use bevy::prelude::*;

pub struct GameMenuPlugin;

impl Plugin for GameMenuPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(OnEnter(GameState::TitleScreen), spawn_menu)
            .add_systems(OnExit(GameState::TitleScreen), despawn_menu)
            .add_systems(
                Update,
                handle_spacebar.run_if(in_state(GameState::TitleScreen)),
            );
    }
}

// Marker component for the title screen UI entity.
// This way, a query for the TitleUI can be used to despawn the title screen
#[derive(Component)]
struct TitleUI;

fn spawn_menu(mut commands: Commands) {
    commands
        .spawn((
            TitleUI,
            Node {
                flex_direction: FlexDirection::Column,
                ..Default::default()
            },
        ))
        .with_children(|cmds| {
            cmds.spawn((
                Text::new("Robert's Bad Asteroids Game"),
                TextFont::from_font_size(50.0),
            ));
            cmds.spawn((
                Text::new("Press space to begin"),
                TextFont::from_font_size(40.0),
            ));
        });
}

fn despawn_menu(mut commands: Commands, to_despawn: Query<Entity, With<TitleUI>>) {
    for entity in &to_despawn {
        commands.entity(entity).despawn();
    }
}

fn handle_spacebar(input: Res<ButtonInput<KeyCode>>, mut game_state: ResMut<NextState<GameState>>) {
    if input.just_pressed(KeyCode::Space) {
        game_state.set(GameState::GetReady);
    }
}