use bevy::prelude::*;

use crate::player::Player;
use crate::player::move_player;

#[derive(Component)]
pub struct MainCamera;

fn spawn_main_camera(mut commands: Commands) {
    commands.spawn((Camera2d, MainCamera));
}

// Follow the player with the camera
fn follow_player(
    player: Single<&Transform, (With<Player>, Without<MainCamera>)>,
    mut camera: Single<&mut Transform, (With<MainCamera>, Without<Player>)>,
    // time: Res<Time>,
) {
    camera.translation.y = player.translation.y; // without delay
    // camera.translation.y = camera.translation.y
    //     + (player.translation.y - camera.translation.y) * 3.0 * time.delta_secs(); // with delay
}

pub struct CameraPlugin;

impl Plugin for CameraPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, spawn_main_camera)
            .add_systems(Update, follow_player.after(move_player));
    }
}