/* Copyright (c) 2010-2017. The SimGrid Team. All rights reserved.          */

/* This program is free software; you can redistribute it and/or modify it
 * under the terms of the license (GNU LGPL) which comes with this package. */

#include "smpi_comm.hpp"
#include "private.hpp"
#include "simgrid/s4u/Host.hpp"
#include "smpi_coll.hpp"
#include "smpi_datatype.hpp"
#include "smpi_process.hpp"
#include "smpi_request.hpp"
#include "smpi_status.hpp"
#include "smpi_win.hpp"
#include "src/simix/smx_private.hpp"
#include <algorithm>
#include <climits>
#include <vector>

XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_comm, smpi, "Logging specific to SMPI (comm)");

simgrid::smpi::Comm mpi_MPI_COMM_UNINITIALIZED;
MPI_Comm MPI_COMM_UNINITIALIZED=&mpi_MPI_COMM_UNINITIALIZED;

/* Support for cartesian topology was added, but there are 2 other types of topology, graph et dist graph. In order to
 * support them, we have to add a field SMPI_Topo_type, and replace the MPI_Topology field by an union. */

namespace simgrid{
namespace smpi{

std::unordered_map<int, smpi_key_elem> Comm::keyvals_;
int Comm::keyval_id_=0;

Comm::Comm(MPI_Group group, MPI_Topology topo) : group_(group), topo_(topo)
{
  refcount_        = 1;
  topoType_        = MPI_INVALID_TOPO;
  intra_comm_      = MPI_COMM_NULL;
  leaders_comm_    = MPI_COMM_NULL;
  is_uniform_      = 1;
  non_uniform_map_ = nullptr;
  leaders_map_     = nullptr;
  is_blocked_      = 0;
}

void Comm::destroy(Comm* comm)
{
  if (comm == MPI_COMM_UNINITIALIZED){
    Comm::destroy(smpi_process()->comm_world());
    return;
  }
  delete comm->topo_; // there's no use count on topos
  Comm::unref(comm);
}

int Comm::dup(MPI_Comm* newcomm){
  if(smpi_privatize_global_variables == SMPI_PRIVATIZE_MMAP){ //we need to switch as the called function may silently touch global variables
    smpi_switch_data_segment(smpi_process()->index());
  }
  MPI_Group cp = new  Group(this->group());
  (*newcomm)   = new  Comm(cp, this->topo());
  int ret      = MPI_SUCCESS;

  if (not attributes()->empty()) {
    int flag;
    void* value_out;
    for (auto const& it : *attributes()) {
      smpi_key_elem elem = keyvals_.at(it.first);
      if (elem != nullptr && elem->copy_fn.comm_copy_fn != MPI_NULL_COPY_FN) {
        ret = elem->copy_fn.comm_copy_fn(this, it.first, nullptr, it.second, &value_out, &flag);
        if (ret != MPI_SUCCESS) {
          Comm::destroy(*newcomm);
          *newcomm = MPI_COMM_NULL;
          return ret;
        }
        if (flag){
          elem->refcount++;
          (*newcomm)->attributes()->insert({it.first, value_out});
        }
      }
    }
  }
  return ret;
}

MPI_Group Comm::group()
{
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->group();
  return group_;
}

MPI_Topology Comm::topo() {
  return topo_;
}

int Comm::size()
{
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->size();
  return group_->size();
}

int Comm::rank()
{
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->rank();
  return group_->rank(smpi_process()->index());
}

void Comm::get_name (char* name, int* len)
{
  if (this == MPI_COMM_UNINITIALIZED){
    smpi_process()->comm_world()->get_name(name, len);
    return;
  }
  if(this == MPI_COMM_WORLD) {
    strncpy(name, "WORLD",5);
    *len = 5;
  } else {
    *len = snprintf(name, MPI_MAX_NAME_STRING, "%p", this);
  }
}

void Comm::set_leaders_comm(MPI_Comm leaders){
  if (this == MPI_COMM_UNINITIALIZED){
    smpi_process()->comm_world()->set_leaders_comm(leaders);
    return;
  }
  leaders_comm_=leaders;
}

void Comm::set_intra_comm(MPI_Comm leaders){
  intra_comm_=leaders;
}

int* Comm::get_non_uniform_map(){
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->get_non_uniform_map();
  return non_uniform_map_;
}

int* Comm::get_leaders_map(){
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->get_leaders_map();
  return leaders_map_;
}

MPI_Comm Comm::get_leaders_comm(){
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->get_leaders_comm();
  return leaders_comm_;
}

MPI_Comm Comm::get_intra_comm(){
  if (this == MPI_COMM_UNINITIALIZED || this==MPI_COMM_WORLD)
    return smpi_process()->comm_intra();
  else return intra_comm_;
}

int Comm::is_uniform(){
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->is_uniform();
  return is_uniform_;
}

int Comm::is_blocked(){
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->is_blocked();
  return is_blocked_;
}

MPI_Comm Comm::split(int color, int key)
{
  if (this == MPI_COMM_UNINITIALIZED)
    return smpi_process()->comm_world()->split(color, key);
  int system_tag = 123;
  int* recvbuf;

  MPI_Group group_root = nullptr;
  MPI_Group group_out  = nullptr;
  MPI_Group group      = this->group();
  int rank             = this->rank();
  int size             = this->size();
  /* Gather all colors and keys on rank 0 */
  int* sendbuf = xbt_new(int, 2);
  sendbuf[0] = color;
  sendbuf[1] = key;
  if(rank == 0) {
    recvbuf = xbt_new(int, 2 * size);
  } else {
    recvbuf = nullptr;
  }
  Coll_gather_default::gather(sendbuf, 2, MPI_INT, recvbuf, 2, MPI_INT, 0, this);
  xbt_free(sendbuf);
  /* Do the actual job */
  if(rank == 0) {
    MPI_Group* group_snd = xbt_new(MPI_Group, size);
    std::vector<std::pair<int, int>> rankmap;
    rankmap.reserve(size);
    for (int i = 0; i < size; i++) {
      if (recvbuf[2 * i] != MPI_UNDEFINED) {
        rankmap.clear();
        for (int j = i + 1; j < size; j++) {
          if(recvbuf[2 * i] == recvbuf[2 * j]) {
            recvbuf[2 * j] = MPI_UNDEFINED;
            rankmap.push_back({recvbuf[2 * j + 1], j});
          }
        }
        /* Add self in the group */
        recvbuf[2 * i] = MPI_UNDEFINED;
        rankmap.push_back({recvbuf[2 * i + 1], i});
        std::sort(begin(rankmap), end(rankmap));
        group_out = new Group(rankmap.size());
        if (i == 0) {
          group_root = group_out; /* Save root's group */
        }
        for (unsigned j = 0; j < rankmap.size(); j++) {
          int index = group->index(rankmap[j].second);
          group_out->set_mapping(index, j);
        }
        MPI_Request* requests = xbt_new(MPI_Request, rankmap.size());
        int reqs              = 0;
        for (auto const& rank : rankmap) {
          if (rank.second != 0) {
            group_snd[reqs]=new  Group(group_out);
            requests[reqs] = Request::isend(&(group_snd[reqs]), 1, MPI_PTR, rank.second, system_tag, this);
            reqs++;
          }
        }
        if(i != 0 && group_out != MPI_COMM_WORLD->group() && group_out != MPI_GROUP_EMPTY)
          Group::unref(group_out);

        Request::waitall(reqs, requests, MPI_STATUS_IGNORE);
        xbt_free(requests);
      }
    }
    xbt_free(recvbuf);
    xbt_free(group_snd);
    group_out = group_root; /* exit with root's group */
  } else {
    if(color != MPI_UNDEFINED) {
      Request::recv(&group_out, 1, MPI_PTR, 0, system_tag, this, MPI_STATUS_IGNORE);
    } /* otherwise, exit with group_out == nullptr */
  }
  return group_out!=nullptr ? new  Comm(group_out, nullptr) : MPI_COMM_NULL;
}

void Comm::ref(){
  if (this == MPI_COMM_UNINITIALIZED){
    smpi_process()->comm_world()->ref();
    return;
  }
  group_->ref();
  refcount_++;
}

void Comm::cleanup_smp(){
  if (intra_comm_ != MPI_COMM_NULL)
    Comm::unref(intra_comm_);
  if (leaders_comm_ != MPI_COMM_NULL)
    Comm::unref(leaders_comm_);
  if (non_uniform_map_ != nullptr)
    xbt_free(non_uniform_map_);
  if (leaders_map_ != nullptr)
    delete[] leaders_map_;
}

void Comm::unref(Comm* comm){
  if (comm == MPI_COMM_UNINITIALIZED){
    Comm::unref(smpi_process()->comm_world());
    return;
  }
  comm->refcount_--;
  Group::unref(comm->group_);

  if(comm->refcount_==0){
    comm->cleanup_smp();
    comm->cleanup_attr<Comm>();
    delete comm;
  }
}

void Comm::init_smp(){
  int leader = -1;

  if (this == MPI_COMM_UNINITIALIZED)
    smpi_process()->comm_world()->init_smp();

  int comm_size = this->size();

  // If we are in replay - perform an ugly hack
  // tell SimGrid we are not in replay for a while, because we need the buffers to be copied for the following calls
  bool replaying = false; //cache data to set it back again after
  if(smpi_process()->replaying()){
    replaying = true;
    smpi_process()->set_replaying(false);
  }

  if(smpi_privatize_global_variables == SMPI_PRIVATIZE_MMAP){ //we need to switch as the called function may silently touch global variables
    smpi_switch_data_segment(smpi_process()->index());
  }
  //identify neighbours in comm
  //get the indexes of all processes sharing the same simix host
  const auto& process_list = sg_host_self()->extension<simgrid::simix::Host>()->process_list;
  int intra_comm_size     = 0;
  int min_index           = INT_MAX; // the minimum index will be the leader
  for (auto const& actor : process_list) {
    int index = actor.pid - 1;
    if (this->group()->rank(index) != MPI_UNDEFINED) {
      intra_comm_size++;
      // the process is in the comm
      if (index < min_index)
        min_index = index;
    }
  }
  XBT_DEBUG("number of processes deployed on my node : %d", intra_comm_size);
  MPI_Group group_intra = new  Group(intra_comm_size);
  int i = 0;
  for (auto const& actor : process_list) {
    int index = actor.pid - 1;
    if(this->group()->rank(index)!=MPI_UNDEFINED){
      group_intra->set_mapping(index, i);
      i++;
    }
  }

  MPI_Comm comm_intra = new  Comm(group_intra, nullptr);
  leader=min_index;

  int* leaders_map = new int[comm_size];
  int* leader_list = new int[comm_size];
  std::fill_n(leaders_map, comm_size, 0);
  std::fill_n(leader_list, comm_size, -1);

  Coll_allgather_mpich::allgather(&leader, 1, MPI_INT , leaders_map, 1, MPI_INT, this);

  if(smpi_privatize_global_variables == SMPI_PRIVATIZE_MMAP){ //we need to switch as the called function may silently touch global variables
    smpi_switch_data_segment(smpi_process()->index());
  }

  if(leaders_map_==nullptr){
    leaders_map_= leaders_map;
  }else{
    delete[] leaders_map;
  }
  int j=0;
  int leader_group_size = 0;
  for(i=0; i<comm_size; i++){
    int already_done = 0;
    for (j = 0; j < leader_group_size; j++) {
      if (leaders_map_[i] == leader_list[j]) {
        already_done = 1;
      }
    }
    if (already_done == 0) {
      leader_list[leader_group_size] = leaders_map_[i];
      leader_group_size++;
    }
  }
  std::sort(leader_list, leader_list + leader_group_size);

  MPI_Group leaders_group = new  Group(leader_group_size);

  MPI_Comm leader_comm = MPI_COMM_NULL;
  if(MPI_COMM_WORLD!=MPI_COMM_UNINITIALIZED && this!=MPI_COMM_WORLD){
    //create leader_communicator
    for (i=0; i< leader_group_size;i++)
      leaders_group->set_mapping(leader_list[i], i);
    leader_comm = new  Comm(leaders_group, nullptr);
    this->set_leaders_comm(leader_comm);
    this->set_intra_comm(comm_intra);

    // create intracommunicator
  }else{
    for (i=0; i< leader_group_size;i++)
      leaders_group->set_mapping(leader_list[i], i);

    if(this->get_leaders_comm()==MPI_COMM_NULL){
      leader_comm = new  Comm(leaders_group, nullptr);
      this->set_leaders_comm(leader_comm);
    }else{
      leader_comm=this->get_leaders_comm();
      Group::unref(leaders_group);
    }
    smpi_process()->set_comm_intra(comm_intra);
  }

  // Are the nodes uniform ? = same number of process/node
  int my_local_size=comm_intra->size();
  if(comm_intra->rank()==0) {
    int is_uniform       = 1;
    int* non_uniform_map = xbt_new0(int,leader_group_size);
    Coll_allgather_mpich::allgather(&my_local_size, 1, MPI_INT,
        non_uniform_map, 1, MPI_INT, leader_comm);
    for(i=0; i < leader_group_size; i++) {
      if(non_uniform_map[0] != non_uniform_map[i]) {
        is_uniform = 0;
        break;
      }
    }
    if(is_uniform==0 && this->is_uniform()!=0){
      non_uniform_map_ = non_uniform_map;
    }else{
      xbt_free(non_uniform_map);
    }
    is_uniform_=is_uniform;
  }
  Coll_bcast_mpich::bcast(&(is_uniform_),1, MPI_INT, 0, comm_intra );

  if(smpi_privatize_global_variables == SMPI_PRIVATIZE_MMAP){ //we need to switch as the called function may silently touch global variables
    smpi_switch_data_segment(smpi_process()->index());
  }
  // Are the ranks blocked ? = allocated contiguously on the SMP nodes
  int is_blocked=1;
  int prev=this->group()->rank(comm_intra->group()->index(0));
  for (i = 1; i < my_local_size; i++) {
    int that = this->group()->rank(comm_intra->group()->index(i));
    if (that != prev + 1) {
      is_blocked = 0;
      break;
    }
    prev = that;
  }

  int global_blocked;
  Coll_allreduce_default::allreduce(&is_blocked, &(global_blocked), 1, MPI_INT, MPI_LAND, this);

  if(MPI_COMM_WORLD==MPI_COMM_UNINITIALIZED || this==MPI_COMM_WORLD){
    if(this->rank()==0){
      is_blocked_ = global_blocked;
    }
  }else{
    is_blocked_=global_blocked;
  }
  delete[] leader_list;

  if(replaying)
    smpi_process()->set_replaying(true);
}

MPI_Comm Comm::f2c(int id) {
  if(id == -2) {
    return MPI_COMM_SELF;
  } else if(id==0){
    return MPI_COMM_WORLD;
  } else if(F2C::f2c_lookup() != nullptr && id >= 0) {
    char key[KEY_SIZE];
    const auto& lookup = F2C::f2c_lookup();
    auto comm          = lookup->find(get_key_id(key, id));
    return comm == lookup->end() ? MPI_COMM_NULL : static_cast<MPI_Comm>(comm->second);
  } else {
    return MPI_COMM_NULL;
  }
}

void Comm::free_f(int id) {
  char key[KEY_SIZE];
  F2C::f2c_lookup()->erase(id == 0 ? get_key(key, id) : get_key_id(key, id));
}

int Comm::add_f() {
  if(F2C::f2c_lookup()==nullptr){
    F2C::set_f2c_lookup(new std::unordered_map<std::string, F2C*>);
  }
  char key[KEY_SIZE];
  (*(F2C::f2c_lookup()))[this == MPI_COMM_WORLD ? get_key(key, F2C::f2c_id()) : get_key_id(key, F2C::f2c_id())] = this;
  f2c_id_increment();
  return F2C::f2c_id()-1;
}

void Comm::add_rma_win(MPI_Win win){
  rma_wins_.push_back(win);
}

void Comm::remove_rma_win(MPI_Win win){
  rma_wins_.remove(win);
}

void Comm::finish_rma_calls(){
  for (auto const& it : rma_wins_) {
    if(it->rank()==this->rank()){//is it ours (for MPI_COMM_WORLD)?
      int finished = it->finish_comms();
      XBT_DEBUG("Barrier for rank %d - Finished %d RMA calls",this->rank(), finished);
    }
  }
}

}
}


