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use na::{self, DVectorSliceMut, Isometry3, RealField, Translation3, Unit, Vector3};

use crate::joint::{Joint, PrismaticJoint};
use crate::math::{JacobianSliceMut, Velocity};
use crate::solver::{ConstraintSet, GenericNonlinearConstraint, IntegrationParameters};

/// A joint that allows two translational degrees of freedom.
#[derive(Copy, Clone, Debug)]
pub struct RectangularJoint<N: RealField> {
prism1: PrismaticJoint<N>,
prism2: PrismaticJoint<N>,
}

impl<N: RealField> RectangularJoint<N> {
/// Creates a new rectangular joint allowing relative translations anlon the two provided axii.Isometry3
///
/// Both axii are expressed in the local coordinate frame on the attached multibody links.
pub fn new(axis1: Unit<Vector3<N>>, axis2: Unit<Vector3<N>>, offset1: N, offset2: N) -> Self {
RectangularJoint {
prism1: PrismaticJoint::new(axis1, offset1),
prism2: PrismaticJoint::new(axis2, offset2),
}
}
}

impl<N: RealField> Joint<N> for RectangularJoint<N> {
#[inline]
fn ndofs(&self) -> usize {
2
}

fn body_to_parent(&self, parent_shift: &Vector3<N>, body_shift: &Vector3<N>) -> Isometry3<N> {
let t = Translation3::from(parent_shift - body_shift)
* self.prism1.translation()
* self.prism2.translation();
Isometry3::from_parts(t, na::one())
}

fn update_jacobians(&mut self, body_shift: &Vector3<N>, vels: &[N]) {
self.prism1.update_jacobians(body_shift, vels);
self.prism2.update_jacobians(body_shift, &[vels[1]]);
}

fn jacobian(&self, transform: &Isometry3<N>, out: &mut JacobianSliceMut<N>) {
self.prism1.jacobian(transform, &mut out.columns_mut(0, 1));
self.prism2.jacobian(transform, &mut out.columns_mut(1, 1));
}

fn jacobian_dot(&self, _: &Isometry3<N>, _: &mut JacobianSliceMut<N>) {}

fn jacobian_dot_veldiff_mul_coordinates(
&self,
_: &Isometry3<N>,
_: &[N],
_: &mut JacobianSliceMut<N>,
) {
}

fn jacobian_mul_coordinates(&self, vels: &[N]) -> Velocity<N> {
self.prism1.jacobian_mul_coordinates(vels)
+ self.prism2.jacobian_mul_coordinates(&[vels[1]])
}

fn jacobian_dot_mul_coordinates(&self, _: &[N]) -> Velocity<N> {
Velocity::zero()
}

fn default_damping(&self, out: &mut DVectorSliceMut<N>) {
self.prism1.default_damping(&mut out.rows_mut(0, 1));
self.prism2.default_damping(&mut out.rows_mut(1, 1));
}

fn integrate(&mut self, parameters: &IntegrationParameters<N>, vels: &[N]) {
self.prism1.integrate(parameters, vels);
self.prism2.integrate(parameters, &[vels[1]]);
}

fn apply_displacement(&mut self, disp: &[N]) {
self.prism1.apply_displacement(disp);
self.prism2.apply_displacement(&[disp[1]]);
}

#[inline]
fn clone(&self) -> Box<dyn Joint<N>> {
Box::new(*self)
}

fn num_velocity_constraints(&self) -> usize {
self.prism1.num_velocity_constraints() + self.prism2.num_velocity_constraints()
}

fn velocity_constraints(
&self,
parameters: &IntegrationParameters<N>,
multibody: &Multibody<N>,
assembly_id: usize,
dof_id: usize,
ext_vels: &[N],
ground_j_id: &mut usize,
jacobians: &mut [N],
constraints: &mut ConstraintSet<N, (), (), usize>,
) {
self.prism1.velocity_constraints(
parameters,
multibody,
assembly_id,
dof_id,
ext_vels,
ground_j_id,
jacobians,
constraints,
);
self.prism2.velocity_constraints(
parameters,
multibody,
assembly_id,
dof_id + 1,
ext_vels,
ground_j_id,
jacobians,
constraints,
);
}

fn num_position_constraints(&self) -> usize {
// NOTE: we don't test if constraints exist to simplify indexing.
2
}

fn position_constraint(
&self,
i: usize,
multibody: &Multibody<N>,
handle: BodyPartHandle<()>,
dof_id: usize,
jacobians: &mut [N],
) -> Option<GenericNonlinearConstraint<N, ()>> {
if i == 0 {
self.prism1
.position_constraint(0, multibody, link, handle, dof_id, jacobians)
} else {
self.prism2
.position_constraint(0, multibody, link, handle, dof_id + 1, jacobians)
}
}
}

prismatic_motor_limit_methods_1!(RectangularJoint, prism1);
prismatic_motor_limit_methods_2!(RectangularJoint, prism2);