/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2025 Katy Proctor (katy.proctor@fysik.su.se)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#ifndef SWIFT_BASIC_SIDM_PART_H
#define SWIFT_BASIC_SIDM_PART_H

#include "timeline.h"

/**
 * @brief Particle fields for the SIDM particles.
 *
 * All quantities related to gravity are stored in the associate #gpart.
 */

struct sipart {

  /*! Particle ID. */
  long long id;

  /*! Pointer to corresponding gravity part. */
  struct gpart* gpart;

  /*! Particle position. */
  double x[3];

  /*! Particle velocity. */
  float v[3];

  /* Offset between current position and position at last tree rebuild. */
  float x_diff[3];

  /* Offset between current position and position at last tree rebuild. */
  float x_diff_sort[3];

  /*! Particle mass */
  float mass;

  /*! Particle smoothing length. */
  float h;

  struct {

    /* Number of neighbours. */
    float wcount;

    /* Number of neighbours spatial derivative. */
    float wcount_dh;

  } density;

  /*! Particle time bin */
  timebin_t time_bin;

  /*! Tree-depth at which size / 2 <= h * gamma < size */
  char depth_h;

#ifdef SWIFT_DEBUG_CHECKS

  /* Time of the last drift */
  integertime_t ti_drift;

  /* Time of the last kick */
  integertime_t ti_kick;

#endif

} SWIFT_STRUCT_ALIGN;

#endif /* SWIFT_BASIC_SIDM_PART_H */