use rapier2d::prelude::*;
use rapier_testbed2d::Testbed;

pub fn init_world(testbed: &mut Testbed) {
    /*
     * World
     */
    let mut bodies = RigidBodySet::new();
    let mut colliders = ColliderSet::new();
    let impulse_joints = ImpulseJointSet::new();
    let multibody_joints = MultibodyJointSet::new();

    let friction = 0.7;

    /*
     * Ground
     */
    let rigid_body = RigidBodyBuilder::fixed().translation(vector![0.0, -2.0]);
    let ground_handle = bodies.insert(rigid_body);
    let collider = ColliderBuilder::cuboid(40.0, 2.0).friction(friction);
    colliders.insert_with_parent(collider, ground_handle, &mut bodies);

    /*
     * Create the cubes
     */
    let scale = 10.0;
    let card_height = 0.2 * scale;
    let card_thickness = 0.001 * scale;
    let angle0 = 25.0 * std::f32::consts::PI / 180.0;
    let angle1 = -25.0 * std::f32::consts::PI / 180.0;
    let angle2 = 0.5 * std::f32::consts::PI;

    let card_box = ColliderBuilder::cuboid(card_thickness, card_height).friction(friction);

    let mut nb = 5;
    let mut z0 = 0.0;
    let mut y = card_height - 0.02 * scale;

    while nb != 0 {
        let mut z = z0;

        for i in 0..nb {
            if i != nb - 1 {
                let rigid_body = RigidBodyBuilder::dynamic()
                    .translation(vector![z + 0.25 * scale, y + card_height - 0.015 * scale])
                    .rotation(angle2);
                let ground_handle = bodies.insert(rigid_body);
                colliders.insert_with_parent(card_box.clone(), ground_handle, &mut bodies);
            }

            let rigid_body = RigidBodyBuilder::dynamic()
                .translation(vector![z, y])
                .rotation(angle1);
            let ground_handle = bodies.insert(rigid_body);
            colliders.insert_with_parent(card_box.clone(), ground_handle, &mut bodies);

            z += 0.175 * scale;

            let rigid_body = RigidBodyBuilder::dynamic()
                .translation(vector![z, y])
                .rotation(angle0);
            let ground_handle = bodies.insert(rigid_body);
            colliders.insert_with_parent(card_box.clone(), ground_handle, &mut bodies);

            z += 0.175 * scale;
        }

        y += card_height * 2.0 - 0.03 * scale;
        z0 += 0.175 * scale;
        nb -= 1;
    }

    /*
     * Set up the testbed.
     */
    testbed.set_world(bodies, colliders, impulse_joints, multibody_joints);
    testbed.look_at(point![0.0, 2.5], 20.0);
}