/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2017 Peter W. Draper (p.w.draper@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 "collectgroup.h"

/* Local headers. */
#include "engine.h"
#include "error.h"

#ifdef WITH_MPI

/* Local collections for MPI reduces. */
struct mpicollectgroup1 {
  long long updated, g_updated, s_updated, b_updated;
  long long inhibited, g_inhibited, s_inhibited, b_inhibited;
  integertime_t ti_hydro_end_min;
  integertime_t ti_gravity_end_min;
  integertime_t ti_stars_end_min;
  integertime_t ti_black_holes_end_min;
  integertime_t ti_hydro_end_max;
  integertime_t ti_gravity_end_max;
  integertime_t ti_stars_end_max;
  integertime_t ti_black_holes_end_max;
  integertime_t ti_hydro_beg_max;
  integertime_t ti_gravity_beg_max;
  integertime_t ti_stars_beg_max;
  integertime_t ti_black_holes_beg_max;
  int forcerebuild;
  long long total_nr_cells;
  long long total_nr_tasks;
  float tasks_per_cell_max;
  struct star_formation_history sfh;
};

/* Forward declarations. */
static void mpicollect_create_MPI_type(void);

/**
 * @brief MPI datatype for the #mpicollectgroup1 structure.
 */
static MPI_Datatype mpicollectgroup1_type;

/**
 * @brief MPI operator to reduce #mpicollectgroup1 structures.
 */
static MPI_Op mpicollectgroup1_reduce_op;

#endif

/**
 * @brief Perform any once only initialisations. Must be called once.
 */
void collectgroup_init(void) {

#ifdef WITH_MPI
  /* Initialise the MPI types. */
  mpicollect_create_MPI_type();
#endif
}

/**
 * @brief Apply the collectgroup1 values to the engine by copying all the
 * values to the engine fields.
 *
 * @param grp1 The #collectgroup1
 * @param e The #engine
 */
void collectgroup1_apply(const struct collectgroup1 *grp1, struct engine *e) {

  e->ti_hydro_end_min = grp1->ti_hydro_end_min;
  e->ti_hydro_end_max = grp1->ti_hydro_end_max;
  e->ti_hydro_beg_max = grp1->ti_hydro_beg_max;
  e->ti_gravity_end_min = grp1->ti_gravity_end_min;
  e->ti_gravity_end_max = grp1->ti_gravity_end_max;
  e->ti_gravity_beg_max = grp1->ti_gravity_beg_max;
  e->ti_stars_end_min = grp1->ti_stars_end_min;
  e->ti_stars_end_max = grp1->ti_stars_end_max;
  e->ti_stars_beg_max = grp1->ti_stars_beg_max;
  e->ti_black_holes_end_min = grp1->ti_black_holes_end_min;
  e->ti_black_holes_end_max = grp1->ti_black_holes_end_max;
  e->ti_black_holes_beg_max = grp1->ti_black_holes_beg_max;
  e->ti_end_min = min4(e->ti_hydro_end_min, e->ti_gravity_end_min,
                       e->ti_stars_end_min, e->ti_black_holes_end_min);
  e->ti_end_max = max4(e->ti_hydro_end_max, e->ti_gravity_end_max,
                       e->ti_stars_end_max, e->ti_black_holes_end_max);
  e->ti_beg_max = max4(e->ti_hydro_beg_max, e->ti_gravity_beg_max,
                       e->ti_stars_beg_max, e->ti_black_holes_beg_max);
  e->updates = grp1->updated;
  e->g_updates = grp1->g_updated;
  e->s_updates = grp1->s_updated;
  e->b_updates = grp1->b_updated;
  e->nr_inhibited_parts = grp1->inhibited;
  e->nr_inhibited_gparts = grp1->g_inhibited;
  e->nr_inhibited_sparts = grp1->s_inhibited;
  e->nr_inhibited_bparts = grp1->b_inhibited;
  e->forcerebuild = grp1->forcerebuild;
  e->total_nr_cells = grp1->total_nr_cells;
  e->total_nr_tasks = grp1->total_nr_tasks;
  e->tasks_per_cell_max = grp1->tasks_per_cell_max;
  e->sfh = grp1->sfh;
}

/**
 * @brief Initialises a collectgroup1 struct ready for processing.
 *
 * @param grp1 The #collectgroup1 to initialise
 * @param updated the number of updated hydro particles on this node this step.
 * @param g_updated the number of updated gravity particles on this node this
 *                  step.
 * @param s_updated the number of updated star particles on this node this step.
 * @param b_updated the number of updated black hole particles on this node this
 * step.
 * @param inhibited the number of inhibited hydro particles on this node this
 *                  step.
 * @param g_inhibited the number of inhibited gravity particles on this node
 *                    this step.
 * @param s_inhibited the number of inhibited star particles on this node this
 *                    step.
 * @param b_inhibited the number of inhibited black hole particles on this node
 * this step.
 * @param ti_hydro_end_min the minimum end time for next hydro time step after
 *                         this step.
 * @param ti_hydro_end_max the maximum end time for next hydro time step after
 *                         this step.
 * @param ti_hydro_beg_max the maximum begin time for next hydro time step after
 *                         this step.
 * @param ti_gravity_end_min the minimum end time for next gravity time step
 *                           after this step.
 * @param ti_gravity_end_max the maximum end time for next gravity time step
 *                           after this step.
 * @param ti_gravity_beg_max the maximum begin time for next gravity time step
 *                           after this step.
 * @param ti_stars_end_min the minimum end time for next stars time step
 *                           after this step.
 * @param ti_stars_end_max the maximum end time for next stars time step
 *                           after this step.
 * @param ti_stars_beg_max the maximum begin time for next stars time step
 *                           after this step.
 * @param ti_black_holes_end_min the minimum end time for next black holes time
 * step after this step.
 * @param ti_black_holes_end_max the maximum end time for next black holes time
 * step after this step.
 * @param ti_black_holes_beg_max the maximum begin time for next black holes
 * time step after this step.
 * @param forcerebuild whether a rebuild is required after this step.
 * @param total_nr_cells total number of all cells on rank.
 * @param total_nr_tasks total number of tasks on rank.
 * @param tasks_per_cell the used number of tasks per cell.
 * @param sfh The star formation history logger
 */
void collectgroup1_init(
    struct collectgroup1 *grp1, size_t updated, size_t g_updated,
    size_t s_updated, size_t b_updated, size_t inhibited, size_t g_inhibited,
    size_t s_inhibited, size_t b_inhibited, integertime_t ti_hydro_end_min,
    integertime_t ti_hydro_end_max, integertime_t ti_hydro_beg_max,
    integertime_t ti_gravity_end_min, integertime_t ti_gravity_end_max,
    integertime_t ti_gravity_beg_max, integertime_t ti_stars_end_min,
    integertime_t ti_stars_end_max, integertime_t ti_stars_beg_max,
    integertime_t ti_black_holes_end_min, integertime_t ti_black_holes_end_max,
    integertime_t ti_black_holes_beg_max, int forcerebuild,
    long long total_nr_cells, long long total_nr_tasks, float tasks_per_cell,
    const struct star_formation_history sfh) {

  grp1->updated = updated;
  grp1->g_updated = g_updated;
  grp1->s_updated = s_updated;
  grp1->b_updated = b_updated;
  grp1->inhibited = inhibited;
  grp1->g_inhibited = g_inhibited;
  grp1->s_inhibited = s_inhibited;
  grp1->b_inhibited = b_inhibited;
  grp1->ti_hydro_end_min = ti_hydro_end_min;
  grp1->ti_hydro_end_max = ti_hydro_end_max;
  grp1->ti_hydro_beg_max = ti_hydro_beg_max;
  grp1->ti_gravity_end_min = ti_gravity_end_min;
  grp1->ti_gravity_end_max = ti_gravity_end_max;
  grp1->ti_gravity_beg_max = ti_gravity_beg_max;
  grp1->ti_stars_end_min = ti_stars_end_min;
  grp1->ti_stars_end_max = ti_stars_end_max;
  grp1->ti_stars_beg_max = ti_stars_beg_max;
  grp1->ti_black_holes_end_min = ti_black_holes_end_min;
  grp1->ti_black_holes_end_max = ti_black_holes_end_max;
  grp1->ti_black_holes_beg_max = ti_black_holes_beg_max;
  grp1->forcerebuild = forcerebuild;
  grp1->total_nr_cells = total_nr_cells;
  grp1->total_nr_tasks = total_nr_tasks;
  grp1->tasks_per_cell_max = tasks_per_cell;
  grp1->sfh = sfh;
}

/**
 * @brief Do any processing necessary to the group before it can be used.
 *
 * This may involve an MPI reduction across all nodes.
 *
 * @param grp1 the #collectgroup1 struct already initialised by a call
 *             to collectgroup1_init.
 */
void collectgroup1_reduce(struct collectgroup1 *grp1) {

#ifdef WITH_MPI

  /* Populate an MPI group struct and reduce this across all nodes. */
  struct mpicollectgroup1 mpigrp11;
  mpigrp11.updated = grp1->updated;
  mpigrp11.g_updated = grp1->g_updated;
  mpigrp11.s_updated = grp1->s_updated;
  mpigrp11.b_updated = grp1->b_updated;
  mpigrp11.inhibited = grp1->inhibited;
  mpigrp11.g_inhibited = grp1->g_inhibited;
  mpigrp11.s_inhibited = grp1->s_inhibited;
  mpigrp11.b_inhibited = grp1->b_inhibited;
  mpigrp11.ti_hydro_end_min = grp1->ti_hydro_end_min;
  mpigrp11.ti_gravity_end_min = grp1->ti_gravity_end_min;
  mpigrp11.ti_stars_end_min = grp1->ti_stars_end_min;
  mpigrp11.ti_black_holes_end_min = grp1->ti_black_holes_end_min;
  mpigrp11.ti_hydro_end_max = grp1->ti_hydro_end_max;
  mpigrp11.ti_gravity_end_max = grp1->ti_gravity_end_max;
  mpigrp11.ti_stars_end_max = grp1->ti_stars_end_max;
  mpigrp11.ti_black_holes_end_max = grp1->ti_black_holes_end_max;
  mpigrp11.ti_hydro_beg_max = grp1->ti_hydro_beg_max;
  mpigrp11.ti_gravity_beg_max = grp1->ti_gravity_beg_max;
  mpigrp11.ti_stars_beg_max = grp1->ti_stars_beg_max;
  mpigrp11.ti_black_holes_beg_max = grp1->ti_black_holes_beg_max;
  mpigrp11.forcerebuild = grp1->forcerebuild;
  mpigrp11.total_nr_cells = grp1->total_nr_cells;
  mpigrp11.total_nr_tasks = grp1->total_nr_tasks;
  mpigrp11.tasks_per_cell_max = grp1->tasks_per_cell_max;
  mpigrp11.sfh = grp1->sfh;

  struct mpicollectgroup1 mpigrp12;
  if (MPI_Allreduce(&mpigrp11, &mpigrp12, 1, mpicollectgroup1_type,
                    mpicollectgroup1_reduce_op, MPI_COMM_WORLD) != MPI_SUCCESS)
    error("Failed to reduce mpicollection1.");

  /* And update. */
  grp1->updated = mpigrp12.updated;
  grp1->g_updated = mpigrp12.g_updated;
  grp1->s_updated = mpigrp12.s_updated;
  grp1->b_updated = mpigrp12.b_updated;
  grp1->inhibited = mpigrp12.inhibited;
  grp1->g_inhibited = mpigrp12.g_inhibited;
  grp1->s_inhibited = mpigrp12.s_inhibited;
  grp1->b_inhibited = mpigrp12.b_inhibited;
  grp1->ti_hydro_end_min = mpigrp12.ti_hydro_end_min;
  grp1->ti_gravity_end_min = mpigrp12.ti_gravity_end_min;
  grp1->ti_stars_end_min = mpigrp12.ti_stars_end_min;
  grp1->ti_black_holes_end_min = mpigrp12.ti_black_holes_end_min;
  grp1->ti_hydro_end_max = mpigrp12.ti_hydro_end_max;
  grp1->ti_gravity_end_max = mpigrp12.ti_gravity_end_max;
  grp1->ti_stars_end_max = mpigrp12.ti_stars_end_max;
  grp1->ti_black_holes_end_max = mpigrp12.ti_black_holes_end_max;
  grp1->ti_hydro_beg_max = mpigrp12.ti_hydro_beg_max;
  grp1->ti_gravity_beg_max = mpigrp12.ti_gravity_beg_max;
  grp1->ti_stars_beg_max = mpigrp12.ti_stars_beg_max;
  grp1->ti_black_holes_beg_max = mpigrp12.ti_black_holes_beg_max;
  grp1->forcerebuild = mpigrp12.forcerebuild;
  grp1->total_nr_cells = mpigrp12.total_nr_cells;
  grp1->total_nr_tasks = mpigrp12.total_nr_tasks;
  grp1->tasks_per_cell_max = mpigrp12.tasks_per_cell_max;
  grp1->sfh = mpigrp12.sfh;

#endif
}

#ifdef WITH_MPI
/**
 * @brief Do the reduction of two structs.
 *
 * @param mpigrp11 the first struct, this is updated on exit.
 * @param mpigrp12 the second struct
 */
static void doreduce1(struct mpicollectgroup1 *mpigrp11,
                      const struct mpicollectgroup1 *mpigrp12) {

  /* Do what is needed for each part of the collection. */
  /* Sum of updates. */
  mpigrp11->updated += mpigrp12->updated;
  mpigrp11->g_updated += mpigrp12->g_updated;
  mpigrp11->s_updated += mpigrp12->s_updated;
  mpigrp11->b_updated += mpigrp12->b_updated;

  /* Sum of inhibited */
  mpigrp11->inhibited += mpigrp12->inhibited;
  mpigrp11->g_inhibited += mpigrp12->g_inhibited;
  mpigrp11->s_inhibited += mpigrp12->s_inhibited;
  mpigrp11->b_inhibited += mpigrp12->b_inhibited;

  /* Minimum end time. */
  mpigrp11->ti_hydro_end_min =
      min(mpigrp11->ti_hydro_end_min, mpigrp12->ti_hydro_end_min);
  mpigrp11->ti_gravity_end_min =
      min(mpigrp11->ti_gravity_end_min, mpigrp12->ti_gravity_end_min);
  mpigrp11->ti_stars_end_min =
      min(mpigrp11->ti_stars_end_min, mpigrp12->ti_stars_end_min);
  mpigrp11->ti_black_holes_end_min =
      min(mpigrp11->ti_black_holes_end_min, mpigrp12->ti_black_holes_end_min);

  /* Maximum end time. */
  mpigrp11->ti_hydro_end_max =
      max(mpigrp11->ti_hydro_end_max, mpigrp12->ti_hydro_end_max);
  mpigrp11->ti_gravity_end_max =
      max(mpigrp11->ti_gravity_end_max, mpigrp12->ti_gravity_end_max);
  mpigrp11->ti_stars_end_max =
      max(mpigrp11->ti_stars_end_max, mpigrp12->ti_stars_end_max);
  mpigrp11->ti_black_holes_end_max =
      max(mpigrp11->ti_black_holes_end_max, mpigrp12->ti_black_holes_end_max);

  /* Maximum beg time. */
  mpigrp11->ti_hydro_beg_max =
      max(mpigrp11->ti_hydro_beg_max, mpigrp12->ti_hydro_beg_max);
  mpigrp11->ti_gravity_beg_max =
      max(mpigrp11->ti_gravity_beg_max, mpigrp12->ti_gravity_beg_max);
  mpigrp11->ti_stars_beg_max =
      max(mpigrp11->ti_stars_beg_max, mpigrp12->ti_stars_beg_max);
  mpigrp11->ti_black_holes_beg_max =
      max(mpigrp11->ti_black_holes_beg_max, mpigrp12->ti_black_holes_beg_max);

  /* Everyone must agree to not rebuild. */
  if (mpigrp11->forcerebuild || mpigrp12->forcerebuild)
    mpigrp11->forcerebuild = 1;

  /* Totals of all tasks and cells. */
  mpigrp11->total_nr_cells += mpigrp12->total_nr_cells;
  mpigrp11->total_nr_tasks += mpigrp12->total_nr_tasks;

  /* Maximum value of tasks_per_cell. */
  mpigrp11->tasks_per_cell_max =
      max(mpigrp11->tasks_per_cell_max, mpigrp12->tasks_per_cell_max);

  /* Star formation history */
  star_formation_logger_add(&mpigrp11->sfh, &mpigrp12->sfh);
}

/**
 * @brief MPI reduce operator for #mpicollectgroup1 structures.
 */
static void mpicollectgroup1_reduce(void *in, void *inout, int *len,
                                    MPI_Datatype *datatype) {

  for (int i = 0; i < *len; ++i)
    doreduce1(&((struct mpicollectgroup1 *)inout)[i],
              &((const struct mpicollectgroup1 *)in)[i]);
}

/**
 * @brief Registers any MPI collection types and reduction functions.
 */
static void mpicollect_create_MPI_type(void) {

  if (MPI_Type_contiguous(sizeof(struct mpicollectgroup1), MPI_BYTE,
                          &mpicollectgroup1_type) != MPI_SUCCESS ||
      MPI_Type_commit(&mpicollectgroup1_type) != MPI_SUCCESS) {
    error("Failed to create MPI type for mpicollection1.");
  }

  /* Create the reduction operation */
  MPI_Op_create(mpicollectgroup1_reduce, 1, &mpicollectgroup1_reduce_op);
}
#endif
