/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2016 Matthieu Schaller (matthieu.schaller@durham.ac.uk)
 *
 * 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/>.
 *
 ******************************************************************************/

/* Config parameters. */
#include "../config.h"

/* MPI headers. */
#ifdef WITH_MPI
#include <mpi.h>
#endif

/* This object's header. */
#include "part.h"

/* Local headers */
#include "error.h"
#include "hydro.h"
#include "threadpool.h"

/**
 * @brief Re-link the #gpart%s associated with the list of #part%s.
 *
 * @param parts The list of #part.
 * @param N The number of particles to re-link;
 * @param offset The offset of #part%s relative to the global parts list.
 */
void part_relink_gparts_to_parts(struct part *parts, const size_t N,
                                 const ptrdiff_t offset) {
  for (size_t k = 0; k < N; k++) {
    if (parts[k].gpart) {
      parts[k].gpart->id_or_neg_offset = -(k + offset);
    }
  }
}

/**
 * @brief Re-link the #gpart%s associated with the list of #spart%s.
 *
 * @param sparts The list of #spart.
 * @param N The number of s-particles to re-link;
 * @param offset The offset of #spart%s relative to the global sparts list.
 */
void part_relink_gparts_to_sparts(struct spart *sparts, const size_t N,
                                  const ptrdiff_t offset) {
  for (size_t k = 0; k < N; k++) {
    if (sparts[k].gpart) {
      sparts[k].gpart->id_or_neg_offset = -(k + offset);
    }
  }
}

/**
 * @brief Re-link the #gpart%s associated with the list of #sink%s.
 *
 * @param sinks The list of #sink.
 * @param N The number of sink-particles to re-link;
 * @param offset The offset of #sink%s relative to the global sinks list.
 */
void part_relink_gparts_to_sinks(struct sink *sinks, const size_t N,
                                 const ptrdiff_t offset) {
  for (size_t k = 0; k < N; k++) {
    if (sinks[k].gpart) {
      sinks[k].gpart->id_or_neg_offset = -(k + offset);
    }
  }
}

/**
 * @brief Re-link the #gpart%s associated with the list of #bpart%s.
 *
 * @param bparts The list of #bpart.
 * @param N The number of s-particles to re-link;
 * @param offset The offset of #bpart%s relative to the global bparts list.
 */
void part_relink_gparts_to_bparts(struct bpart *bparts, const size_t N,
                                  const ptrdiff_t offset) {
  for (size_t k = 0; k < N; k++) {
    if (bparts[k].gpart) {
      bparts[k].gpart->id_or_neg_offset = -(k + offset);
    }
  }
}

/**
 * @brief Re-link the #part%s associated with the list of #gpart%s.
 *
 * @param gparts The list of #gpart.
 * @param N The number of particles to re-link;
 * @param parts The global #part array in which to find the #gpart offsets.
 */
void part_relink_parts_to_gparts(struct gpart *gparts, const size_t N,
                                 struct part *parts) {
  for (size_t k = 0; k < N; k++) {
    if (gparts[k].type == swift_type_gas) {
      parts[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    }
  }
}

/**
 * @brief Re-link the #spart%s associated with the list of #gpart%s.
 *
 * @param gparts The list of #gpart.
 * @param N The number of particles to re-link;
 * @param sparts The global #spart array in which to find the #gpart offsets.
 */
void part_relink_sparts_to_gparts(struct gpart *gparts, const size_t N,
                                  struct spart *sparts) {
  for (size_t k = 0; k < N; k++) {
    if (gparts[k].type == swift_type_stars) {
      sparts[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    }
  }
}

/**
 * @brief Re-link the #bpart%s associated with the list of #gpart%s.
 *
 * @param gparts The list of #gpart.
 * @param N The number of particles to re-link;
 * @param bparts The global #bpart array in which to find the #gpart offsets.
 */
void part_relink_bparts_to_gparts(struct gpart *gparts, const size_t N,
                                  struct bpart *bparts) {
  for (size_t k = 0; k < N; k++) {
    if (gparts[k].type == swift_type_black_hole) {
      bparts[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    }
  }
}

/**
 * @brief Re-link the #sink%s associated with the list of #gpart%s.
 *
 * @param gparts The list of #gpart.
 * @param N The number of particles to re-link;
 * @param sinks The global #sink array in which to find the #gpart offsets.
 */
void part_relink_sinks_to_gparts(struct gpart *gparts, const size_t N,
                                 struct sink *sinks) {
  for (size_t k = 0; k < N; k++) {
    if (gparts[k].type == swift_type_sink) {
      sinks[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    }
  }
}

/**
 * @brief Helper structure to pass data to the liking mapper functions.
 */
struct relink_data {
  struct part *const parts;
  struct gpart *const garts;
  struct sink *const sinks;
  struct spart *const sparts;
  struct bpart *const bparts;
};

/**
 * @brief #threadpool mapper function for the linking of all particle types
 * to the #gpart array.
 *
 * @brief map_data The array of #gpart.
 * @brief count The number of #gpart.
 * @brief extra_data the #relink_data containing pointer to the other arrays.
 */
void part_relink_all_parts_to_gparts_mapper(void *restrict map_data, int count,
                                            void *restrict extra_data) {

  /* Un-pack the data */
  struct relink_data *data = (struct relink_data *)extra_data;
  struct part *const parts = data->parts;
  struct spart *const sparts = data->sparts;
  struct bpart *const bparts = data->bparts;
  struct gpart *const gparts = (struct gpart *)map_data;
  struct sink *const sinks = data->sinks;

  for (int k = 0; k < count; k++) {
    if (gparts[k].type == swift_type_gas) {
      parts[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    } else if (gparts[k].type == swift_type_stars) {
      sparts[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    } else if (gparts[k].type == swift_type_black_hole) {
      bparts[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    } else if (gparts[k].type == swift_type_sink) {
      sinks[-gparts[k].id_or_neg_offset].gpart = &gparts[k];
    }
  }
}

/**
 * @brief Re-link both the #part%s, #sink%s, #spart%s and #bpart%s associated
 * with the list of #gpart%s.
 *
 * This function uses thread parallelism and should not be called inside
 * an already threaded section (unlike the functions linking individual arrays
 * that are designed to be called in thread-parallel code).
 *
 * @param gparts The list of #gpart.
 * @param N The number of particles to re-link;
 * @param parts The global #part array in which to find the #gpart offsets.
 * @param sinks The global #sink array in which to find the #gpart offsets.
 * @param sparts The global #spart array in which to find the #gpart offsets.
 * @param bparts The global #bpart array in which to find the #gpart offsets.
 * @param tp The #threadpool object.
 */
void part_relink_all_parts_to_gparts(struct gpart *gparts, const size_t N,
                                     struct part *parts, struct sink *sinks,
                                     struct spart *sparts, struct bpart *bparts,
                                     struct threadpool *tp) {

  struct relink_data data = {parts, /*gparts=*/NULL, sinks, sparts, bparts};
  threadpool_map(tp, part_relink_all_parts_to_gparts_mapper, gparts, N,
                 sizeof(struct gpart), 0, &data);
}

/**
 * @brief Verifies that the #gpart, #part, #sink, #spart and #bpart are
 * correctly linked together and that the particle positions match.
 *
 * This is a debugging function.
 *
 * @param parts The #part array.
 * @param gparts The #gpart array.
 * @param sinks The #sink array.
 * @param sparts The #spart array.
 * @param bparts The #bpart array.
 * @param nr_parts The number of #part in the array.
 * @param nr_gparts The number of #gpart in the array.
 * @param nr_sinks The number of #sink in the array.
 * @param nr_sparts The number of #spart in the array.
 * @param nr_bparts The number of #bpart in the array.
 * @param verbose Do we report verbosely in case of success ?
 */
void part_verify_links(struct part *parts, struct gpart *gparts,
                       struct sink *sinks, struct spart *sparts,
                       struct bpart *bparts, size_t nr_parts, size_t nr_gparts,
                       size_t nr_sinks, size_t nr_sparts, size_t nr_bparts,
                       int verbose) {

  ticks tic = getticks();

  for (size_t k = 0; k < nr_gparts; ++k) {

    /* We have a real DM particle */
    if (gparts[k].type == swift_type_dark_matter &&
        gparts[k].time_bin != time_bin_not_created) {

      /* Check that it's not linked */
      if (gparts[k].id_or_neg_offset <= 0)
        error("DM gpart particle linked to something !");
    }

    /* We have a background DM particle */
    if (gparts[k].type == swift_type_dark_matter_background &&
        gparts[k].time_bin != time_bin_not_created) {

      /* Check that it's not linked */
      if (gparts[k].id_or_neg_offset <= 0)
        error("Background DM gpart particle linked to something !");
    }

    /* We have a gas particle */
    else if (gparts[k].type == swift_type_gas) {

      /* Check that it is linked */
      if (gparts[k].id_or_neg_offset > 0)
        error("Gas gpart not linked to anything!");

      /* Find its link */
      const struct part *part = &parts[-gparts[k].id_or_neg_offset];

      /* Check the reverse link */
      if (part->gpart != &gparts[k]) error("Linking problem!");

      /* Check that the particles are at the same place */
      if (gparts[k].x[0] != part->x[0] || gparts[k].x[1] != part->x[1] ||
          gparts[k].x[2] != part->x[2])
        error(
            "Linked particles are not at the same position!\n"
            "gp->x=[%e %e %e] p->x=[%e %e %e] diff=[%e %e %e]",
            gparts[k].x[0], gparts[k].x[1], gparts[k].x[2], part->x[0],
            part->x[1], part->x[2], gparts[k].x[0] - part->x[0],
            gparts[k].x[1] - part->x[1], gparts[k].x[2] - part->x[2]);

      /* Check that the particles have the same mass */
      if (gparts[k].mass != hydro_get_mass(part))
        error(
            "Linked particles do not have the same mass!\n"
            "gp->m=%e p->m=%e",
            gparts[k].mass, hydro_get_mass(part));

      /* Check that the particles are at the same time */
      if (gparts[k].time_bin != part->time_bin)
        error("Linked particles are not at the same time !");
    }

    else if (gparts[k].type == swift_type_stars) {

      /* Check that it is linked */
      if (gparts[k].id_or_neg_offset > 0)
        error("Stars gpart not linked to anything !");

      /* Find its link */
      const struct spart *spart = &sparts[-gparts[k].id_or_neg_offset];

      /* Check the reverse link */
      if (spart->gpart != &gparts[k]) error("Linking problem !");

      /* Check that the particles are at the same place */
      if (gparts[k].x[0] != spart->x[0] || gparts[k].x[1] != spart->x[1] ||
          gparts[k].x[2] != spart->x[2])
        error(
            "Linked particles are not at the same position !\n"
            "gp->x=[%e %e %e] sp->x=[%e %e %e] diff=[%e %e %e]",
            gparts[k].x[0], gparts[k].x[1], gparts[k].x[2], spart->x[0],
            spart->x[1], spart->x[2], gparts[k].x[0] - spart->x[0],
            gparts[k].x[1] - spart->x[1], gparts[k].x[2] - spart->x[2]);

      /* Check that the particles have the same mass */
      if (gparts[k].mass != spart->mass)
        error(
            "Linked particles do not have the same mass!\n"
            "gp->m=%e sp->m=%e",
            gparts[k].mass, spart->mass);

      /* Check that the particles are at the same time */
      if (gparts[k].time_bin != spart->time_bin)
        error("Linked particles are not at the same time !");
    }

    else if (gparts[k].type == swift_type_black_hole) {

      /* Check that it is linked */
      if (gparts[k].id_or_neg_offset > 0)
        error("Black holes gpart not linked to anything !");

      /* Find its link */
      const struct bpart *bpart = &bparts[-gparts[k].id_or_neg_offset];

      /* Check the reverse link */
      if (bpart->gpart != &gparts[k]) error("Linking problem !");

      /* Check that the particles are at the same place */
      if (gparts[k].x[0] != bpart->x[0] || gparts[k].x[1] != bpart->x[1] ||
          gparts[k].x[2] != bpart->x[2])
        error(
            "Linked particles are not at the same position !\n"
            "gp->x=[%e %e %e] bp->x=[%e %e %e] diff=[%e %e %e]",
            gparts[k].x[0], gparts[k].x[1], gparts[k].x[2], bpart->x[0],
            bpart->x[1], bpart->x[2], gparts[k].x[0] - bpart->x[0],
            gparts[k].x[1] - bpart->x[1], gparts[k].x[2] - bpart->x[2]);

      /* Check that the particles have the same mass */
      if (gparts[k].mass != bpart->mass)
        error(
            "Linked particles do not have the same mass!\n"
            "gp->m=%e sp->m=%e",
            gparts[k].mass, bpart->mass);

      /* Check that the particles are at the same time */
      if (gparts[k].time_bin != bpart->time_bin)
        error("Linked particles are not at the same time !");
    }

    else if (gparts[k].type == swift_type_sink) {

      /* Check that it is linked */
      if (gparts[k].id_or_neg_offset > 0)
        error("Sink gpart not linked to anything !");

      /* Find its link */
      const struct sink *sink = &sinks[-gparts[k].id_or_neg_offset];

      /* Check the reverse link */
      if (sink->gpart != &gparts[k]) error("Linking problem !");

      /* Check that the particles are at the same place */
      if (gparts[k].x[0] != sink->x[0] || gparts[k].x[1] != sink->x[1] ||
          gparts[k].x[2] != sink->x[2])
        error(
            "Linked particles are not at the same position !\n"
            "gp->x=[%e %e %e] sink->x=[%e %e %e] diff=[%e %e %e]",
            gparts[k].x[0], gparts[k].x[1], gparts[k].x[2], sink->x[0],
            sink->x[1], sink->x[2], gparts[k].x[0] - sink->x[0],
            gparts[k].x[1] - sink->x[1], gparts[k].x[2] - sink->x[2]);

      /* Check that the particles have the same mass */
      if (gparts[k].mass != sink->mass)
        error(
            "Linked particles do not have the same mass!\n"
            "gp->m=%e sink->m=%e",
            gparts[k].mass, sink->mass);

      /* Check that the particles are at the same time */
      if (gparts[k].time_bin != sink->time_bin)
        error("Linked particles are not at the same time !");
    }
  }

  /* Now check that all parts are linked */
  for (size_t k = 0; k < nr_parts; ++k) {

    /* Ok, there is a link */
    if (parts[k].gpart != NULL) {

      /* Check the link */
      if (parts[k].gpart->id_or_neg_offset != -(ptrdiff_t)k) {
        error("Linking problem !");
      }

      /* Check that the particles are at the same place */
      if (parts[k].x[0] != parts[k].gpart->x[0] ||
          parts[k].x[1] != parts[k].gpart->x[1] ||
          parts[k].x[2] != parts[k].gpart->x[2])
        error("Linked particles are not at the same position !");

      /* Check that the particles have the same mass */
      if (hydro_get_mass(&parts[k]) != parts[k].gpart->mass)
        error("Linked particles do not have the same mass!\n");

      /* Check that the particles are at the same time */
      if (parts[k].time_bin != parts[k].gpart->time_bin)
        error("Linked particles are not at the same time !");
    }
  }

  /* Now check that all sparts are linked */
  for (size_t k = 0; k < nr_sparts; ++k) {

    /* Ok, there is a link */
    if (sparts[k].gpart != NULL) {

      /* Check the link */
      if (sparts[k].gpart->id_or_neg_offset != -(ptrdiff_t)k) {
        error("Linking problem !");

        /* Check that the particles are at the same place */
        if (sparts[k].x[0] != sparts[k].gpart->x[0] ||
            sparts[k].x[1] != sparts[k].gpart->x[1] ||
            sparts[k].x[2] != sparts[k].gpart->x[2])
          error("Linked particles are not at the same position !");

        /* Check that the particles have the same mass */
        if (sparts[k].mass != sparts[k].gpart->mass)
          error("Linked particles do not have the same mass!\n");

        /* Check that the particles are at the same time */
        if (sparts[k].time_bin != sparts[k].gpart->time_bin)
          error("Linked particles are not at the same time !");
      }
    }
  }

  /* Now check that all bparts are linked */
  for (size_t k = 0; k < nr_bparts; ++k) {

    /* Ok, there is a link */
    if (bparts[k].gpart != NULL) {

      /* Check the link */
      if (bparts[k].gpart->id_or_neg_offset != -(ptrdiff_t)k) {
        error("Linking problem !");

        /* Check that the particles are at the same place */
        if (bparts[k].x[0] != bparts[k].gpart->x[0] ||
            bparts[k].x[1] != bparts[k].gpart->x[1] ||
            bparts[k].x[2] != bparts[k].gpart->x[2])
          error("Linked particles are not at the same position !");

        /* Check that the particles have the same mass */
        if (bparts[k].mass != bparts[k].gpart->mass)
          error("Linked particles do not have the same mass!\n");

        /* Check that the particles are at the same time */
        if (bparts[k].time_bin != bparts[k].gpart->time_bin)
          error("Linked particles are not at the same time !");
      }
    }
  }

  /* Now check that all sinks are linked */
  for (size_t k = 0; k < nr_sinks; ++k) {

    /* Ok, there is a link */
    if (sinks[k].gpart != NULL) {

      /* Check the link */
      if (sinks[k].gpart->id_or_neg_offset != -(ptrdiff_t)k) {
        error("Linking problem !");

        /* Check that the particles are at the same place */
        if (sinks[k].x[0] != sinks[k].gpart->x[0] ||
            sinks[k].x[1] != sinks[k].gpart->x[1] ||
            sinks[k].x[2] != sinks[k].gpart->x[2])
          error("Linked particles are not at the same position !");

        /* Check that the particles have the same mass */
        if (sinks[k].mass != sinks[k].gpart->mass)
          error("Linked particles do not have the same mass!\n");

        /* Check that the particles are at the same time */
        if (sinks[k].time_bin != sinks[k].gpart->time_bin)
          error("Linked particles are not at the same time !");
      }
    }
  }

  if (verbose) message("All links OK");
  if (verbose)
    message("took %.3f %s.", clocks_from_ticks(getticks() - tic),
            clocks_getunit());
}

#ifdef WITH_MPI
/* MPI data type for the particle transfers */
MPI_Datatype part_mpi_type;
MPI_Datatype xpart_mpi_type;
MPI_Datatype gpart_mpi_type;
MPI_Datatype spart_mpi_type;
MPI_Datatype bpart_mpi_type;
MPI_Datatype lospart_mpi_type;

/**
 * @brief Registers MPI particle types.
 */
void part_create_mpi_types(void) {

  /* This is not the recommended way of doing this.
     One should define the structure field by field
     But as long as we don't do serialization via MPI-IO
     we don't really care.
     Also we would have to modify this function everytime something
     is added to the part structure. */
  if (MPI_Type_contiguous(sizeof(struct part) / sizeof(unsigned char), MPI_BYTE,
                          &part_mpi_type) != MPI_SUCCESS ||
      MPI_Type_commit(&part_mpi_type) != MPI_SUCCESS) {
    error("Failed to create MPI type for parts.");
  }
  if (MPI_Type_contiguous(sizeof(struct xpart) / sizeof(unsigned char),
                          MPI_BYTE, &xpart_mpi_type) != MPI_SUCCESS ||
      MPI_Type_commit(&xpart_mpi_type) != MPI_SUCCESS) {
    error("Failed to create MPI type for xparts.");
  }
  if (MPI_Type_contiguous(sizeof(struct gpart) / sizeof(unsigned char),
                          MPI_BYTE, &gpart_mpi_type) != MPI_SUCCESS ||
      MPI_Type_commit(&gpart_mpi_type) != MPI_SUCCESS) {
    error("Failed to create MPI type for gparts.");
  }
  if (MPI_Type_contiguous(sizeof(struct spart) / sizeof(unsigned char),
                          MPI_BYTE, &spart_mpi_type) != MPI_SUCCESS ||
      MPI_Type_commit(&spart_mpi_type) != MPI_SUCCESS) {
    error("Failed to create MPI type for sparts.");
  }
  if (MPI_Type_contiguous(sizeof(struct bpart) / sizeof(unsigned char),
                          MPI_BYTE, &bpart_mpi_type) != MPI_SUCCESS ||
      MPI_Type_commit(&bpart_mpi_type) != MPI_SUCCESS) {
    error("Failed to create MPI type for bparts.");
  }
}

void part_free_mpi_types(void) {

  MPI_Type_free(&part_mpi_type);
  MPI_Type_free(&xpart_mpi_type);
  MPI_Type_free(&gpart_mpi_type);
  MPI_Type_free(&spart_mpi_type);
  MPI_Type_free(&bpart_mpi_type);
  MPI_Type_free(&lospart_mpi_type);
}
#endif
