use crate::client::Me;
use crate::ecs::{CursorWorldCoordinates, DragRequestEvent, Part};
use bevy::prelude::*;
use bevy_rapier2d::dynamics::MassProperties;
use bevy_rapier2d::prelude::{AdditionalMassProperties, ReadMassProperties, RigidBody};
use std::fmt::Debug;

pub fn parts_plugin(app: &mut App) {
    app.insert_resource(DragResource(None));
    app.add_systems(Update, (handle_incoming_parts, handle_updated_parts));
    app.add_observer(on_part_release);
}

fn handle_incoming_parts(
    mut commands: Commands,
    new_parts: Query<(Entity, &Part), Added<Part>>,
    asset_server: Res<AssetServer>,
) {
    for (new_entity, new_part) in new_parts.iter() {
        trace!(?new_entity, ?new_part, "new part");
        let mut sprite = Sprite::from_image(asset_server.load(&new_part.sprite));
        sprite.custom_size = Some(Vec2::new(new_part.width, new_part.height));

        commands
            .entity(new_entity)
            .insert(sprite)
            .insert(AdditionalMassProperties::MassProperties(MassProperties {
                local_center_of_mass: Vec2::ZERO,
                mass: new_part.mass,
                principal_inertia: 7.5,
            }))
            .insert(ReadMassProperties::default())
            .insert(RigidBody::Dynamic)
            .insert(Pickable::default())
            .observe(on_part_click);

        trace!(?new_part, ?new_entity, "prepared new part");
    }
}
fn handle_updated_parts(
    mut commands: Commands,
    updated_parts: Query<(Entity, &Part), Changed<Part>>,
    asset_server: Res<AssetServer>,
) {
    for (updated_entity, updated_part) in updated_parts.iter() {
        let mut sprite = Sprite::from_image(asset_server.load(&updated_part.sprite));
        sprite.custom_size = Some(Vec2::new(updated_part.width, updated_part.height));

        commands
            .entity(updated_entity)
            .remove::<Sprite>()
            .remove::<AdditionalMassProperties>()
            .insert(sprite)
            .insert(AdditionalMassProperties::MassProperties(MassProperties {
                local_center_of_mass: Vec2::ZERO,
                mass: updated_part.mass,
                principal_inertia: 7.5,
            }));
        trace!(?updated_part, ?updated_entity, "updated part");
    }
}

#[derive(Resource)]
struct DragResource(Option<Entity>);

fn on_part_click(
    ev: Trigger<Pointer<Pressed>>,
    sprites: Query<&Sprite, Without<Me>>,
    mut drag: ResMut<DragResource>,
) {
    if ev.button != PointerButton::Primary {
        return;
    };
    let Ok(sprite) = sprites.get(ev.target()) else {
        return;
    };
    drag.0 = Some(ev.target());
}

fn on_part_release(
    ev: Trigger<Pointer<Released>>,
    mut drag: ResMut<DragResource>,
    mut events: EventWriter<DragRequestEvent>,
    cursor: Res<CursorWorldCoordinates>,
) {
    if ev.button != PointerButton::Primary {
        return;
    };

    if let Some(e) = drag.0
        && let Some(c) = cursor.0
    {
        debug!(?e, ?c, "sending drag request");
        events.write(DragRequestEvent(e, c));
    }

    drag.0 = None;
}