use bevy::input::ButtonState;
use bevy::prelude::*;
use bevy::input::mouse::MouseButtonInput;
use avian3d::prelude::*;

use crate::physics::{ProjectileData, ProjectileSpawner};
use crate::ui::camera::CameraController;
use crate::ui::cursor::CursorGrabState;

mod target_wall;
use target_wall::TargetWallPlugin;

pub struct GamePlugin;

impl Plugin for GamePlugin
{
    fn build(&self, app: &mut App)
    {
        app.add_plugins(TargetWallPlugin);

        app.add_systems(Startup, setup_level);

        app.add_systems(Update, do_shoot_on_left_click
            .run_if(in_state(CursorGrabState(true)))
            .run_if(on_event::<MouseButtonInput>))
            ;
    }
}

fn setup_level(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    const GROUND_SIZE: f32 = 100.0;

    // spawn the camera
    commands.spawn((
        CameraController {
            sensitivity: Vec2::new(0.0007, 0.0007),
        },
        Camera3d::default(),
        Transform::from_xyz(0.0, 1.75, 0.0),
    ));

    // spawn the ground plane
    commands.spawn((
        Mesh3d(meshes.add(Plane3d::new(Vec3::Y, Vec2::splat(GROUND_SIZE * 0.5)))),
        MeshMaterial3d(materials.add(StandardMaterial {
            base_color: Color::srgb(0.761, 0.698, 0.502),
            ..default()
        })),
        Transform::IDENTITY,
        Collider::cuboid(GROUND_SIZE, 0.0, GROUND_SIZE),
        RigidBody::Static,
    ));

    // spawn some boxes to shoot at
    for x in [0.0, 1.5, 3.0]
    {
        commands.spawn((
            Mesh3d(meshes.add(Cuboid::from_corners(
                Vec3::ZERO, Vec3::ONE,
            ))),
            MeshMaterial3d(materials.add(StandardMaterial {
                base_color: Color::srgb(0.7, 0.1, 0.1),
                ..default()
            })),
            Transform::from_xyz(x, 0.5, -2.0),
            Collider::cuboid(1.0, 1.0, 1.0),
            RigidBody::Dynamic,
        ));
    }

    // spawn a light source
    commands.spawn((
        DirectionalLight {
            illuminance: light_consts::lux::AMBIENT_DAYLIGHT,
            shadows_enabled: true,
            ..default()
        },
        Transform::from_xyz(100.0, 200.0, 100.0).looking_at(Vec3::ZERO, Vec3::Y),
    ));
}

fn do_shoot_on_left_click(
    camera_query: Single<&GlobalTransform, With<Camera>>,
    mut mouse_events: EventReader<MouseButtonInput>,
    mut projectiles: ResMut<ProjectileSpawner>,
) {
    let camera_transform = camera_query.into_inner();

    for _ in mouse_events.read()
        .filter(|event| event.button == MouseButton::Left)
        .filter(|event| event.state == ButtonState::Pressed)
    {
        projectiles.spawn(ProjectileData {
            position: camera_transform.translation(),
            direction: camera_transform.forward(),
            speed: 900.0,
            mass: 1.0,
        });
    }
}