use crate::{actor, nature, settings};
use bevy::prelude::*;
use bevy::pbr::CascadeShadowConfigBuilder;
use bevy::render::render_resource::{AsBindGroup, ShaderRef};
use bevy::math::DVec3;
use bevy_xpbd_3d::prelude::*;
use bevy_xpbd_3d::plugins::sync::SyncConfig;
use std::f32::consts::PI;

const ASTEROID_SIZE: f32 = 100.0;
const STARS_MAX_MAGNITUDE: f32 = 5.5;

const ASSET_ASTEROID1: &str = "models/asteroid.glb#Scene0";
const ASSET_ASTEROID2: &str = "models/asteroid2.glb#Scene0";
pub fn asset_name_to_path(name: &str) -> &'static str {
    match name {
        "suit" => "models/suit.glb#Scene0",
        "asteroid1" => ASSET_ASTEROID1,
        "asteroid2" => ASSET_ASTEROID2,
        "moonlet" => "models/moonlet.glb#Scene0",
        "monolith" => "models/monolith_neon.glb#Scene0",
        "lightorb" => "models/lightorb.glb#Scene0",
        "MeteorAceGT" => "models/MeteorAceGT.glb#Scene0",
        "pizzeria" => "models/pizzeria2.glb#Scene0",
        "pizzasign" => "models/pizzasign.glb#Scene0",
        _ => "models/error.glb#Scene0",
    }
}

pub struct WorldPlugin;
impl Plugin for WorldPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, setup);
        app.add_systems(Update, handle_cheats);
        app.add_plugins(PhysicsPlugins::default());
        app.add_plugins(MaterialPlugin::<RingMaterial>::default());
        //app.add_plugins(PhysicsDebugPlugin::default());
        app.insert_resource(Gravity(DVec3::splat(0.0)));

        // Disable bevy_xpbd's position->transform sync because we have a
        // custom syncing function.
        app.insert_resource(SyncConfig {
            position_to_transform: false,
            transform_to_position: false,
        });
        app.add_systems(PreUpdate, position_to_transform);
    }
}

#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
pub struct RingMaterial {
    alpha_mode: AlphaMode,
    #[uniform(0)]
    ring_radius: f32,
    #[uniform(1)]
    jupiter_radius: f32,
}

impl Material for RingMaterial {
    fn fragment_shader() -> ShaderRef {
        "shaders/jupiters_rings.wgsl".into()
    }
    fn alpha_mode(&self) -> AlphaMode {
        self.alpha_mode
    }
}

#[derive(Component)]
pub struct Star;

pub fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut materials_custom: ResMut<Assets<RingMaterial>>,
    asset_server: Res<AssetServer>,
) {
    // Generate a bunch of asteriods
    let maxdist = 4;
    for i in -maxdist..maxdist {
        for j in -maxdist..maxdist {
            for k in -maxdist..maxdist {
                let offset = 500.0;
                let dist = 8e3;
                let wobble = dist/2.0;
                let (i, j, k) = (i as f32, j as f32, k as f32);
                let asset = match ((i+j+k) as i32) % 2 {
                    0 => ASSET_ASTEROID1,
                    _ => ASSET_ASTEROID2,
                };
                commands.spawn((
                    actor::Actor::default(),
                    RigidBody::Dynamic,
                    AngularVelocity(DVec3::new(0.1, 0.1, 0.03)),
                    LinearVelocity(DVec3::new(0.0, 0.0, 0.35)),
                    Collider::sphere(1.0),
                    SceneBundle {
                        transform: Transform {
                            translation: Vec3::new(
                                offset + dist * i + wobble * (j+k/PI).sin() * (k+j/PI).cos(),
                                offset + dist * j + wobble * (k+i/PI).sin() * (i+k/PI).cos(),
                                offset + dist * k + wobble * (i+j/PI).sin() * (j+i/PI).cos(),
                            ),
                            rotation: Quat::from_rotation_y(-PI / 3.),
                            scale: Vec3::splat(ASTEROID_SIZE),
                        },
                        scene: asset_server.load(asset),
                        ..default()
                    },
                ));
            }
        }
    }

    // Generate starmap
    let sphere_handle = meshes.add(Sphere::new(1.0));
    let mut starcount = 0;
    for star in nature::STARS {
        let mag = star[3];
        if mag > STARS_MAX_MAGNITUDE {
            continue;
        }
        let scale_color = {|color: f32|
            if mag < -20.0 {
                color * 13.0f32 // Sun
            } else {
                color * (0.0659663 * mag * mag - 1.09862 * mag + 4.3)
            }
        };
        let scale_size = {|mag: f32|
            if mag < -20.0 {
                40000.0f32 // Sun
            } else {
                1000.0 * (0.230299 * mag * mag - 3.09013 * mag + 15.1782)
            }
        };
        let (r, g, b) = nature::star_color_index_to_rgb(star[4]);
        let star_color_handle = materials.add(StandardMaterial {
            base_color: Color::rgb(scale_color(r), scale_color(g), scale_color(b)),
            unlit: true,
            ..default()
        });
        let dist = 1e7;
        commands.spawn((
            Star,
            PbrBundle {
                mesh: sphere_handle.clone(),
                material: star_color_handle.clone(),
                transform: Transform::from_xyz(
                        dist * star[0],
                        dist * star[1],
                        dist * star[2],
                    )
                    .with_scale(Vec3::splat(scale_size(mag))),
                ..default()
            }
        ));
        starcount += 1;
    }
    info!("Generated {starcount} stars");

    // Add shaded ring
    let ring_radius = 640000.0;
    let jupiter_radius = 200000.0;
    commands.spawn((
        MaterialMeshBundle {
            mesh: meshes.add(Mesh::from(Cylinder::new(ring_radius, 1.0))),
            material: materials_custom.add(RingMaterial {
                alpha_mode: AlphaMode::Blend,
                ring_radius: ring_radius,
                jupiter_radius: jupiter_radius,
            }),
            ..default()
        },
        Position::from_xyz(0.0, 0.0, 0.0),
        Rotation::from(Quat::from_rotation_z(1f32.to_radians())),
    ));

    // Add Light from the Sun
    commands.spawn(DirectionalLightBundle {
        directional_light: DirectionalLight {
            illuminance: 1000.0,
            shadows_enabled: false,
            ..default()
        },
        transform: Transform::from_rotation(Quat::from_rotation_y(PI/2.0)),
        cascade_shadow_config: CascadeShadowConfigBuilder {
            first_cascade_far_bound: 7.0,
            maximum_distance: 25.0,
            ..default()
        }
        .into(),
        ..default()
    });
}

fn handle_cheats(
    key_input: Res<ButtonInput<KeyCode>>,
    mut q_player: Query<(&Transform, &mut Position, &mut LinearVelocity), With<actor::PlayerCamera>>,
    mut q_life: Query<(&mut actor::LifeForm, ), With<actor::Player>>,
    settings: ResMut<settings::Settings>,
) {
    if !settings.dev_mode || q_player.is_empty() || q_life.is_empty() {
        return;
    }
    let (trans, mut pos, mut v) = q_player.get_single_mut().unwrap();
    let (mut lifeform, ) = q_life.get_single_mut().unwrap();
    if key_input.just_pressed(settings.key_cheat_pizza) {
        pos.0 = DVec3::new(-3370.0, 0.0, 0.0);
    }
    if key_input.just_pressed(settings.key_cheat_farview1) {
        pos.0 = DVec3::new(-800000.0, 800000.0, 0.0);
    }
    if key_input.just_pressed(settings.key_cheat_farview2) {
        pos.0 = DVec3::new(800000.0, 400000.0, 0.0);
    }
    if key_input.just_pressed(settings.key_cheat_stop) {
        v.0 = DVec3::ZERO;
    }
    if key_input.pressed(settings.key_cheat_speed) {
        v.0 += DVec3::from(trans.rotation * Vec3::new(0.0, 0.0, 1000.0));
    }
    if key_input.pressed(settings.key_cheat_adrenaline_zero) {
        lifeform.adrenaline = 0.0;
    }
    if key_input.pressed(settings.key_cheat_adrenaline_mid) {
        lifeform.adrenaline = 0.5;
    }
    if key_input.pressed(settings.key_cheat_adrenaline_max) {
        lifeform.adrenaline = 1.0;
    }
}

// A variant of bevy_xpbd_3d::plugins::position_to_transform that adjusts
// the rendering position to center entities at the player camera.
// This avoids rendering glitches when very far away from the origin.
pub fn position_to_transform(
    q_player: Query<&Position, With<actor::PlayerCamera>>,
    mut q_trans: Query<(&mut Transform, &Position, &Rotation)>,
) {
    if let Ok(player_pos) = q_player.get_single() {
        for (mut transform, pos, rot) in &mut q_trans {
                transform.translation = Vec3::new(
                    (pos.x - player_pos.x) as f32,
                    (pos.y - player_pos.y) as f32,
                    (pos.z - player_pos.z) as f32,
                );
                transform.rotation = rot.as_quat();
        }
    }
}