//   ▄████████▄      +        ███ +  ▄█████████ ███     +
//  ███▀    ▀███ +         +  ███    ███▀  +    ███ +       +
//  ███  +   ███ ███   ███ █████████ ███        ███  ███   ███
//  ███     +███ ███   ███    ███    ███▐██████ ███  ███   ███
//  ███ +    ███ ███+  ███   +███    ███     +  ███  ███ + ███
//  ███▄    ▄███ ███▄  ███    ███ +  ███  +     ███  ███▄  ███
//   ▀████████▀ + ▀███████    ███▄   ███▄       ▀████ ▀███████
//       +                  +                +             ███
//  +   ▀████████████████████████████████████████████████████▀

use bevy::ecs::system::EntityCommands;
use bevy::prelude::*;

pub struct SkeletonPlugin;
impl Plugin for SkeletonPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Update, animate_skeleton_parts);
    }
}

pub fn asset_name_to_path(name: &str) -> &'static str {
    match name {
        "suit_ar_chefhat" => "models/suit_v1/ar_chefhat.glb#Scene0",
        "asteroid1" => "models/asteroid.glb#Scene0",
        "asteroid2" => "models/asteroid2.glb#Scene0",
        "asteroid_lum" => "models/asteroid_lum.glb#Scene0",
        "moonlet" => "models/moonlet.glb#Scene0",
        "monolith" => "models/monolith_neon.glb#Scene0",
        "lightorb" => "models/lightorb.glb#Scene0",
        "orb_busstop" => "models/orb_busstop.glb#Scene0",
        "orb_busstop_dim" => "models/orb_busstop_dim.glb#Scene0",
        "MeteorAceGT" => "models/MeteorAceGT.glb#Scene0",
        "satellite" => "models/satellite.glb#Scene0",
        "pizzeria" => "models/pizzeria2.glb#Scene0",
        "pizzasign" => "models/pizzasign.glb#Scene0",
        "selectagon" => "models/selectagon.glb#Scene0",
        "orbitring" => "models/orbitring.glb#Scene0",
        "clippy" => "models/clippy/clippy.glb#Scene0",
        "clippy_ar" => "models/clippy/ar_happy.glb#Scene0",
        "whale" => "models/whale.glb#Scene0",
        "point_of_interest" => "models/point_of_interest.glb#Scene0",
        _ => "models/error.glb#Scene0",
    }
}

pub fn skeleton_name_to_skeletondef(name: &str) -> Option<SkeletonDef> {
    // x: positive: left, negative: right
    // y: positive: upward, negative: downward
    // z: positive: forward, negative: backward
    match name {
        "suitv1" => Some(SkeletonDef::Human(HumanDef {
            collider: "models/suit_v1/collider.glb#Scene0".into(),
            base: "models/suit_v1/base.glb#Scene0".into(),
            limbs: vec![
                LimbDef {
                    class: Limb::Head,
                    path: "models/suit_v1/head.glb#Scene0".into(),
                    pos: Vec3::new(0.0, 0.46, 0.0),
                    ..default()
                },
                LimbDef {
                    class: Limb::UpperArmLeft,
                    path: "models/suit_v1/upper_arm.glb#Scene0".into(),
                    pos: Vec3::new(0.22, 0.3, 0.0),
                    mirror: true,
                    children: vec![LimbDef {
                        class: Limb::LowerArmLeft,
                        path: "models/suit_v1/lower_arm.glb#Scene0".into(),
                        pos: Vec3::new(-0.33, 0.0, 0.0),
                        ..default()
                    }],
                    ..default()
                },
                LimbDef {
                    class: Limb::UpperArmRight,
                    path: "models/suit_v1/upper_arm.glb#Scene0".into(),
                    pos: Vec3::new(-0.22, 0.3, 0.0),
                    children: vec![LimbDef {
                        class: Limb::LowerArmRight,
                        path: "models/suit_v1/lower_arm.glb#Scene0".into(),
                        pos: Vec3::new(-0.33, 0.0, 0.0),
                        ..default()
                    }],
                    ..default()
                },
                LimbDef {
                    class: Limb::UpperLegLeft,
                    path: "models/suit_v1/upper_leg.glb#Scene0".into(),
                    pos: Vec3::new(0.15, -0.25, 0.1),
                    mirror: true,
                    children: vec![LimbDef {
                        class: Limb::LowerLegLeft,
                        path: "models/suit_v1/lower_leg.glb#Scene0".into(),
                        pos: Vec3::new(0.0, -0.3, 0.0),
                        ..default()
                    }],
                    ..default()
                },
                LimbDef {
                    class: Limb::UpperLegRight,
                    path: "models/suit_v1/upper_leg.glb#Scene0".into(),
                    pos: Vec3::new(-0.15, -0.25, 0.1),
                    children: vec![LimbDef {
                        class: Limb::LowerLegRight,
                        path: "models/suit_v1/lower_leg.glb#Scene0".into(),
                        pos: Vec3::new(0.0, -0.3, 0.0),
                        ..default()
                    }],
                    ..default()
                },
            ],
        })),
        _ => None,
    }
}

#[derive(Component)] pub struct SkeletonLimb;
#[derive(Component)] pub struct MirroredLimb;
pub enum SkeletonDef {
    Human(HumanDef)
}

pub struct HumanDef {
    collider: String,
    base: String,
    limbs: Vec<LimbDef>,
}

#[derive(Default)]
pub struct LimbDef {
    path: String,
    pos: Vec3,
    class: Limb,
    mirror: bool,
    children: Vec<LimbDef>,
}

#[derive(Component, Default)]
pub enum Limb {
    #[default]
    Base,
    Head,
    UpperArmRight,
    UpperArmLeft,
    LowerArmRight,
    LowerArmLeft,
    UpperLegRight,
    UpperLegLeft,
    LowerLegRight,
    LowerLegLeft,
}

#[derive(Component)]
pub enum Animation {
    HumanFloat,
}

pub fn load(
    name: &str,
    entity_commands: &mut EntityCommands,
    asset_server: &AssetServer,
) {
    if let Some(skel) = skeleton_name_to_skeletondef(name) {
        match skel {
            SkeletonDef::Human(human) => {
                entity_commands.insert(load_scene_by_path(human.collider.as_str(), asset_server));
                entity_commands.with_children(|parent| {
                    parent.spawn((
                        Limb::Base,
                        Animation::HumanFloat,
                        SceneBundle {
                            scene: load_scene_by_path(human.base.as_str(), asset_server),
                            ..default()
                        }
                    ));
                    for limb in human.limbs {
                        let rot = if limb.mirror {
                            Quat::from_rotation_y(180.0f32.to_radians())
                        } else {
                            Quat::IDENTITY
                        };
                        let mut parent_limb = parent.spawn((
                            limb.class,
                            Animation::HumanFloat,
                            SceneBundle {
                                scene: load_scene_by_path(limb.path.as_str(), asset_server),
                                transform: Transform::from_translation(limb.pos).with_rotation(rot),
                                ..default()
                            }
                        ));
                        if limb.mirror {
                            parent_limb.insert(MirroredLimb);
                        }
                        if !limb.children.is_empty() {
                            parent_limb.with_children(|parent| {
                                for child_limb in limb.children {
                                    let rot = if child_limb.mirror {
                                        Quat::from_rotation_y(180.0f32.to_radians())
                                    } else {
                                        Quat::IDENTITY
                                    };
                                    let mut entity_commands = parent.spawn((
                                        child_limb.class,
                                        Animation::HumanFloat,
                                        SceneBundle {
                                            scene: load_scene_by_path(child_limb.path.as_str(), asset_server),
                                            transform: Transform::from_translation(child_limb.pos).with_rotation(rot),
                                            ..default()
                                        }
                                    ));
                                    if child_limb.mirror {
                                        entity_commands.insert(MirroredLimb);
                                    }
                                }
                            });
                        }
                    }
                });
            }
        }
    } else {
        entity_commands.insert(load_scene_by_path(asset_name_to_path(name), asset_server));
    }
}

//pub fn load_scene(
//    path: &str,
//    asset_server: &AssetServer
//) -> Handle<Scene> {
//    load_scene_by_path(asset_name_to_path(path), asset_server)
//}

#[inline]
pub fn load_scene_by_path(
    path: &str,
    asset_server: &AssetServer
) -> Handle<Scene> {
    let path_string = path.to_string();
    if let Some(handle) = asset_server.get_handle(&path_string) {
        handle
    } else {
        asset_server.load(&path_string)
    }
}

pub fn _build_body(
    _name: String,
    mut _entity_commands: EntityCommands,
) {
}

pub fn animate_skeleton_parts(
    time: Res<Time>,
    mut q_limb: Query<(&mut Transform, &Limb, &Animation, Option<&MirroredLimb>)>,
) {
    let t = time.elapsed_seconds();
    for (mut trans, limb, animation, mirror) in &mut q_limb {
        let mirror = mirror.is_some();
        match animation {
            Animation::HumanFloat =>
                animate_human_float(&mut trans, &limb, mirror, t),
        }
    }
}

fn rot(trans: &mut Transform, x: f32, y: f32, z: f32) {
    trans.rotation = Quat::from_euler(
        EulerRot::XYZ,
        x.to_radians(),
        y.to_radians(),
        z.to_radians()
    );
}

pub fn animate_human_float(mut trans: &mut Transform, limb: &Limb, mirror: bool, t: f32) {
    // x: lean head forward/backward
    // y: close/open arms together in front of the torso
    // z: spread legs sidewards
    let m = {|angle| if mirror { 180f32 + angle } else { angle }};
    match limb {
        Limb::UpperArmRight => rot(&mut trans,
            0.0,
            m(40.0 + 5.0 * (t * 0.5).sin()),
            20.0 + 10.0 * (t * 0.5).sin(),
        ),
        Limb::UpperArmLeft => rot(&mut trans,
            0.0,
            m(-(40.0 + 5.0 * (t * 0.5).sin())),
            20.0 + 10.0 * (t * 0.5).sin(),
        ),
        Limb::LowerArmRight => rot(&mut trans,
            0.0,
            m(20.0),
            -20.0,
        ),
        Limb::LowerArmLeft => rot(&mut trans,
            0.0,
            m(-20.0),
            -20.0,
        ),
        Limb::UpperLegRight => rot(&mut trans,
            -30.0 + 10.0 * (t * 0.5).sin(),
            0.0,
            -20.0 + 2.5 * (t * 0.5).cos(),
        ),
        Limb::UpperLegLeft => rot(&mut trans,
            -30.0 + 10.0 * (t * 0.5).sin(),
            0.0,
            20.0 - 2.5 * (t * 0.5).cos(),
        ),
        Limb::LowerLegRight => rot(&mut trans,
            35.0 + 5.0 * (t * 0.5).sin(),
            0.0,
            0.0,
        ),
        Limb::LowerLegLeft => rot(&mut trans,
            35.0 + 5.0 * (t * 0.5).sin(),
            0.0,
            0.0,
        ),
        _ => {},
    }
}