#include <span>
#include "../grapite/etics_interface.h"
#include "../grapite/particle_manager.h"

static grapite::Active_particles* particles_i;
static grapite::Etics_interface* etics_interface;

extern "C"
void etics_external_init(const int n_total, const double length_scale)
{
    particles_i = new grapite::Active_particles{n_total};
    etics_interface = new grapite::Etics_interface{n_total};
    etics::scf::SetLengthScale(length_scale);
}

extern "C"
void etics_external_grav(const double* const A, const int n_act, double x_act[][3], double pot_act[], double a_act[][3])
{
    // Load coefficients
    std::span A_complex{reinterpret_cast<const Complex*>(A), 1024};
    std::copy(begin(A_complex), end(A_complex), etics_interface->A_h);

    // Calculate potentials and forces
    particles_i->ni_core  = 0;
    particles_i->ni_total = n_act;
    for (int i = 0; i < n_act; i++) {
        grapite::Particle_ext p{};
        p.m = 1;
        p.t = 0;
        p.pos = vec3(x_act[i][0], x_act[i][1], x_act[i][2]);
        particles_i->add_particle(i, &p);
    }
    particles_i->flush_memory();
    etics_interface->calculate_gravity(particles_i, grapite::Selector::halo, 0, pot_act, reinterpret_cast<vec3*>(a_act));
}