use bevy::prelude::*;

use crate::{
	components::camera::{FollowCam, FollowTarget},
	states::play::PlaySystems,
};

pub struct FollowCamPlugin;

impl Plugin for FollowCamPlugin {
	fn build(&self, app: &mut App) {
		app.add_systems(Update, (set_cam_target, follow_cam).chain().in_set(PlaySystems));
	}
}

fn set_cam_target(transforms: Query<&GlobalTransform>, cam_target: Single<(&mut FollowTarget, &FollowCam)>) {
	let (mut tgt, cam) = cam_target.into_inner();
	if let Ok(tgt_transform) = transforms.get(cam.target) {
		tgt.pos = tgt_transform.translation();
		tgt.rot = tgt_transform.rotation();
		tgt.up = tgt_transform.up();
	}
}

fn follow_cam(cam: Single<(&mut Transform, &FollowTarget, &FollowCam)>) {
	let (mut transform, tgt, cam) = cam.into_inner();

	let offset = tgt.rot * Vec3::new(0.0, cam.height, cam.distance);
	transform.translation = offset + tgt.pos;
	*transform = transform.looking_at(tgt.pos, tgt.up);
}