use bevy::{prelude::*, utils::HashSet};

use crate::bike::CyberBikeBody;

#[derive(Component)]
pub struct CyberCameras;

#[derive(Debug, Resource)]
pub struct DebugCamOffset {
    pub rot: f32,
    pub dist: f32,
    pub alt: f32,
}

impl Default for DebugCamOffset {
    fn default() -> Self {
        DebugCamOffset {
            rot: 60.0,
            dist: 30.0,
            alt: 4.0,
        }
    }
}

fn spawn_camera(mut commands: Commands) {
    commands.spawn(Camera3d::default()).insert(CyberCameras);
}

fn update_camera_pos(mut offset: ResMut<DebugCamOffset>, mut keys: ResMut<ButtonInput<KeyCode>>) {
    let keyset: HashSet<_> = keys.get_pressed().collect();
    let shifted = keyset.contains(&KeyCode::ShiftLeft) || keyset.contains(&KeyCode::ShiftRight);

    for key in keyset {
        match key {
            KeyCode::ArrowLeft => offset.rot -= 5.0,
            KeyCode::ArrowRight => offset.rot += 5.0,
            KeyCode::ArrowUp => {
                if shifted {
                    offset.alt += 0.5;
                } else {
                    offset.dist -= 0.5;
                }
            }
            KeyCode::ArrowDown => {
                if shifted {
                    offset.alt -= 0.5;
                } else {
                    offset.dist += 0.5;
                }
            }
            KeyCode::KeyR => {
                *offset = DebugCamOffset::default();
            }
            _ => continue,
        }
    }

    let released: Vec<_> = keys.get_just_released().copied().collect();
    for key in released {
        keys.clear_just_released(key);
    }
}

fn follow_bike(
    mut camera: Query<&mut Transform, (With<CyberCameras>, Without<CyberBikeBody>)>,
    bike: Query<&Transform, (With<CyberBikeBody>, Without<CyberCameras>)>,
    offset: Res<DebugCamOffset>,
) {
    let bike_xform = *bike.single();
    let up = Vec3::Y;

    let mut ncx = Transform::from_translation(bike_xform.translation);
    ncx.rotate(Quat::from_axis_angle(up, offset.rot.to_radians()));
    ncx.translation += ncx.forward() * offset.dist;
    ncx.translation += ncx.up() * offset.alt;
    ncx.look_at(bike_xform.translation, up);

    let mut cam_xform = camera.single_mut();
    *cam_xform = ncx;
}

pub struct CamPlug;

impl Plugin for CamPlug {
    fn build(&self, app: &mut App) {
        app.insert_resource(DebugCamOffset::default())
            .add_systems(Startup, spawn_camera)
            .add_systems(Update, (follow_bike, update_camera_pos));
    }
}