use crate::data::ComponentSet;
use crate::dynamics::{JointGraphEdge, JointIndex, MultibodyJointSet, RigidBodyType};
use crate::geometry::{ContactManifold, ContactManifoldIndex};

pub(crate) fn categorize_contacts(
    _bodies: &impl ComponentSet<RigidBodyType>, // Unused but useful to simplify the parallel code.
    multibody_joints: &MultibodyJointSet,
    manifolds: &[&mut ContactManifold],
    manifold_indices: &[ContactManifoldIndex],
    out_ground: &mut Vec<ContactManifoldIndex>,
    out_not_ground: &mut Vec<ContactManifoldIndex>,
    out_generic: &mut Vec<ContactManifoldIndex>,
    _unused: &mut Vec<ContactManifoldIndex>, // Unused but useful to simplify the parallel code.
) {
    for manifold_i in manifold_indices {
        let manifold = &manifolds[*manifold_i];

        if manifold
            .data
            .rigid_body1
            .map(|rb| multibody_joints.rigid_body_link(rb))
            .is_some()
            || manifold
                .data
                .rigid_body1
                .map(|rb| multibody_joints.rigid_body_link(rb))
                .is_some()
        {
            out_generic.push(*manifold_i);
        } else if manifold.data.relative_dominance != 0 {
            out_ground.push(*manifold_i)
        } else {
            out_not_ground.push(*manifold_i)
        }
    }
}

pub(crate) fn categorize_joints(
    bodies: &impl ComponentSet<RigidBodyType>,
    multibody_joints: &MultibodyJointSet,
    impulse_joints: &[JointGraphEdge],
    joint_indices: &[JointIndex],
    ground_joints: &mut Vec<JointIndex>,
    nonground_joints: &mut Vec<JointIndex>,
    generic_ground_joints: &mut Vec<JointIndex>,
    generic_nonground_joints: &mut Vec<JointIndex>,
) {
    for joint_i in joint_indices {
        let joint = &impulse_joints[*joint_i].weight;
        let status1 = bodies.index(joint.body1.0);
        let status2 = bodies.index(joint.body2.0);

        if multibody_joints.rigid_body_link(joint.body1).is_some()
            || multibody_joints.rigid_body_link(joint.body2).is_some()
        {
            if !status1.is_dynamic() || !status2.is_dynamic() {
                generic_ground_joints.push(*joint_i);
            } else {
                generic_nonground_joints.push(*joint_i);
            }
        } else if !status1.is_dynamic() || !status2.is_dynamic() {
            ground_joints.push(*joint_i);
        } else {
            nonground_joints.push(*joint_i);
        }
    }
}