/* -*- Mode: C; c-basic-offset:2 ; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2006      The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2006      The Technical University of Chemnitz. All
 *                         rights reserved.
 * Copyright (c) 2014-2017 Research Organization for Information Science
 *                         and Technology (RIST). All rights reserved.
 * Copyright (c) 2015      Los Alamos National Security, LLC.  All rights
 *                         reserved.
 * Copyright (c) 2017      IBM Corporation.  All rights reserved.
 * Copyright (c) 2018      FUJITSU LIMITED.  All rights reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * Author(s): Torsten Hoefler <htor@cs.indiana.edu>
 *
 */
#include "nbc_internal.h"

#ifdef NBC_CACHE_SCHEDULE
/* tree comparison function for schedule cache */
int NBC_Allgather_args_compare(NBC_Allgather_args *a, NBC_Allgather_args *b, void *param) {
  if ((a->sendbuf == b->sendbuf) &&
      (a->sendcount == b->sendcount) &&
      (a->sendtype == b->sendtype) &&
      (a->recvbuf == b->recvbuf) &&
      (a->recvcount == b->recvcount) &&
      (a->recvtype == b->recvtype) ) {
    return 0;
  }

  if( a->sendbuf < b->sendbuf ) {
    return -1;
  }

  return 1;
}
#endif

/* simple linear MPI_Iallgather
 * the algorithm uses p-1 rounds
 * each node sends the packet it received last round (or has in round 0) to it's right neighbor (modulo p)
 * each node receives from it's left (modulo p) neighbor */
static int nbc_allgather_init(const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount,
                              MPI_Datatype recvtype, struct ompi_communicator_t *comm, ompi_request_t ** request,
                              struct mca_coll_base_module_2_2_0_t *module, bool persistent)
{
  int rank, p, res;
  MPI_Aint rcvext;
  NBC_Schedule *schedule;
  char *rbuf, *sbuf, inplace;
#ifdef NBC_CACHE_SCHEDULE
  NBC_Allgather_args *args, *found, search;
#endif
  ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;

  NBC_IN_PLACE(sendbuf, recvbuf, inplace);

  rank = ompi_comm_rank (comm);
  p = ompi_comm_size (comm);

  res = ompi_datatype_type_extent(recvtype, &rcvext);
  if (MPI_SUCCESS != res) {
    return res;
  }

  if (inplace) {
    sendtype = recvtype;
    sendcount = recvcount;
  } else if (!persistent) { /* for persistent, the copy must be scheduled */
    /* copy my data to receive buffer */
    rbuf = (char *) recvbuf + rank * recvcount * rcvext;
    res = NBC_Copy (sendbuf, sendcount, sendtype, rbuf, recvcount, recvtype, comm);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
      return res;
    }
  }
  if (1 == p && (!persistent || inplace)) {
    return nbc_get_noop_request(persistent, request);
  }

#ifdef NBC_CACHE_SCHEDULE
  /* search schedule in communicator specific tree */
  search.sendbuf = sendbuf;
  search.sendcount = sendcount;
  search.sendtype = sendtype;
  search.recvbuf = recvbuf;
  search.recvcount = recvcount;
  search.recvtype = recvtype;
  found = (NBC_Allgather_args *) hb_tree_search ((hb_tree*)libnbc_module->NBC_Dict[NBC_ALLGATHER], &search);
  if (NULL == found) {
#endif
    schedule = OBJ_NEW(NBC_Schedule);
    if (OPAL_UNLIKELY(NULL == schedule)) {
      return OMPI_ERR_OUT_OF_RESOURCE;
    }

    sbuf = (char *)recvbuf + rank * recvcount * rcvext;

    if (persistent && !inplace) { /* for nonblocking, data has been copied already */
      /* copy my data to receive buffer (= send buffer of NBC_Sched_send) */
      res = NBC_Sched_copy ((void *)sendbuf, false, sendcount, sendtype,
                            sbuf, false, recvcount, recvtype, schedule, true);
      if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        OBJ_RELEASE(schedule);
        return res;
      }
    }

    /* do p-1 rounds */
    for(int r = 0 ; r < p ; ++r) {
      if(r != rank) {
        /* recv from rank r */
        rbuf = (char *)recvbuf + r * recvcount * rcvext;
        res = NBC_Sched_recv (rbuf, false, recvcount, recvtype, r, schedule, false);
        if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
          OBJ_RELEASE(schedule);
          return res;
        }

        /* send to rank r - not from the sendbuf to optimize MPI_IN_PLACE */
        res = NBC_Sched_send (sbuf, false, recvcount, recvtype, r, schedule, false);
        if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
          OBJ_RELEASE(schedule);
          return res;
        }
      }
    }

    res = NBC_Sched_commit(schedule);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
      OBJ_RELEASE(schedule);
      return res;
    }

#ifdef NBC_CACHE_SCHEDULE
    /* save schedule to tree */
    args = (NBC_Allgather_args *) malloc (sizeof (args));
    args->sendbuf = sendbuf;
    args->sendcount = sendcount;
    args->sendtype = sendtype;
    args->recvbuf = recvbuf;
    args->recvcount = recvcount;
    args->recvtype = recvtype;
    args->schedule = schedule;

    res = hb_tree_insert ((hb_tree *) libnbc_module->NBC_Dict[NBC_ALLGATHER], args, args, 0);
    if (res != 0) {
      free (args);
    } else {
      OBJ_RETAIN(schedule);
    }

    /* increase number of elements for A2A */
    if (++libnbc_module->NBC_Dict_size[NBC_ALLGATHER] > NBC_SCHED_DICT_UPPER) {
      NBC_SchedCache_dictwipe ((hb_tree *) libnbc_module->NBC_Dict[NBC_ALLGATHER], &libnbc_module->NBC_Dict_size[NBC_ALLGATHER]);
    }
  } else {
    /* found schedule */
    schedule = found->schedule;
    OBJ_RETAIN(schedule);
  }
#endif

  res = NBC_Schedule_request(schedule, comm, libnbc_module, persistent, request, NULL);
  if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
    OBJ_RELEASE(schedule);
    return res;
  }

  return OMPI_SUCCESS;
}

int ompi_coll_libnbc_iallgather(const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount,
                                MPI_Datatype recvtype, struct ompi_communicator_t *comm, ompi_request_t ** request,
                                struct mca_coll_base_module_2_2_0_t *module)
{
    int res = nbc_allgather_init(sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype,
                                 comm, request, module, false);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        return res;
    }
  
    res = NBC_Start(*(ompi_coll_libnbc_request_t **)request);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        NBC_Return_handle (*(ompi_coll_libnbc_request_t **)request);
        *request = &ompi_request_null.request;
        return res;
    }

    return OMPI_SUCCESS;
}

static int nbc_allgather_inter_init(const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount,
                                    MPI_Datatype recvtype, struct ompi_communicator_t *comm, ompi_request_t ** request,
                                    struct mca_coll_base_module_2_2_0_t *module, bool persistent)
{
  int res, rsize;
  MPI_Aint rcvext;
  NBC_Schedule *schedule;
  char *rbuf;
  ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;

  res = ompi_datatype_type_extent(recvtype, &rcvext);
  if (MPI_SUCCESS != res) {
    NBC_Error ("MPI Error in ompi_datatype_type_extent() (%i)", res);
    return res;
  }

  rsize = ompi_comm_remote_size (comm);

  /* set up schedule */
  schedule = OBJ_NEW(NBC_Schedule);
  if (OPAL_UNLIKELY(NULL == schedule)) {
    return OMPI_ERR_OUT_OF_RESOURCE;
  }

  /* do rsize - 1 rounds */
  for (int r = 0 ; r < rsize ; ++r) {
    /* recv from rank r */
    rbuf = (char *) recvbuf + r * recvcount * rcvext;
    res = NBC_Sched_recv (rbuf, false, recvcount, recvtype, r, schedule, false);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
      OBJ_RELEASE(schedule);
      return res;
    }

    /* send to rank r */
    res = NBC_Sched_send (sendbuf, false, sendcount, sendtype, r, schedule, false);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
      OBJ_RELEASE(schedule);
      return res;
    }
  }

  res = NBC_Sched_commit (schedule);
  if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
    OBJ_RELEASE(schedule);
    return res;
  }

  res = NBC_Schedule_request(schedule, comm, libnbc_module, persistent, request, NULL);
  if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
    OBJ_RELEASE(schedule);
    return res;
  }

  return OMPI_SUCCESS;
}

int ompi_coll_libnbc_iallgather_inter(const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount,
				      MPI_Datatype recvtype, struct ompi_communicator_t *comm, ompi_request_t ** request,
				      struct mca_coll_base_module_2_2_0_t *module) {
    int res = nbc_allgather_inter_init(sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype,
                                       comm, request, module, false);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        return res;
    }

    res = NBC_Start(*(ompi_coll_libnbc_request_t **)request);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        NBC_Return_handle (*(ompi_coll_libnbc_request_t **)request);
        *request = &ompi_request_null.request;
        return res;
    }

    return OMPI_SUCCESS;
}

int ompi_coll_libnbc_allgather_init(const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount,
                                    MPI_Datatype recvtype, struct ompi_communicator_t *comm, MPI_Info info, ompi_request_t ** request,
                                    struct mca_coll_base_module_2_2_0_t *module) {
    int res = nbc_allgather_init(sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype,
                                 comm, request, module, true);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        return res;
    }

    return OMPI_SUCCESS;
}

int ompi_coll_libnbc_allgather_inter_init(const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount,
                                          MPI_Datatype recvtype, struct ompi_communicator_t *comm, MPI_Info info, ompi_request_t ** request,
                                          struct mca_coll_base_module_2_2_0_t *module) {
    int res = nbc_allgather_inter_init(sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype,
                                       comm, request, module, true);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
        return res;
    }

    return OMPI_SUCCESS;
}