#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
//#include <windows.h> /* Sleep */

/* This test checks to make sure that two MPI_Comm_connects to two different MPI ports
* match their corresponding MPI_Comm_accepts. The root process opens two MPI ports and
* sends the first port to process 1 and the second to process 2. Then the root process
* accepts a connection from the second port followed by the first port.
* Processes 1 and 2 both connect back to the root but process 2 first sleeps for three
* seconds to give process 1 time to attempt to connect to the root. The root should wait
* until process 2 connects before accepting the connection from process 1.
*/
int main( int argc, char *argv[] )
{
    int num_errors = 0;
    int rank, size;
    char port1[MPI_MAX_PORT_NAME];

    MPI_Status status;
    MPI_Comm comm1;
    int data = 0;

    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    if (size < 2)
    {
        printf("Three processes needed to run this test.\n");fflush(stdout);
        MPI_Finalize();
        return 0;
    }
// at about 2300 repeats Intel MPI crashes.
#define REPEAT 10000 

    if (rank == 0)
    {
      for(int i = 0; i < REPEAT; ++i) {
        printf("0: opening port.\n");fflush(stdout);
        MPI_Open_port(MPI_INFO_NULL, port1);
        printf("opened port1: <%s>\n", port1);
        
        MPI_Send(port1, MPI_MAX_PORT_NAME, MPI_CHAR, 1, 0, MPI_COMM_WORLD);
        
        printf("accepting port1.\n");fflush(stdout);
        MPI_Comm_accept(port1, MPI_INFO_NULL, 0, MPI_COMM_SELF, &comm1);
        MPI_Close_port(port1);
        
        printf("sending 1 to process 1 at attempt %d.\n", i);fflush(stdout);
        data = 1;
        MPI_Send(&data, 1, MPI_INT, 0, 0, comm1);
        
        MPI_Comm_disconnect(&comm1);
      }
    }
    else if (rank == 1)
    {
      for(int i = 0; i < REPEAT; ++i) {
        MPI_Recv(port1, MPI_MAX_PORT_NAME, MPI_CHAR, 0, 0, MPI_COMM_WORLD, &status);
        MPI_Comm_connect(port1, MPI_INFO_NULL, 0, MPI_COMM_SELF, &comm1);
        MPI_Recv(&data, 1, MPI_INT, 0, 0, comm1, &status);
        if (data != 1)
        {
            printf("Received %d from root when expecting 1\n", data);
            fflush(stdout);
            num_errors++;
        }
        MPI_Comm_disconnect(&comm1);
      }
    }

    MPI_Barrier(MPI_COMM_WORLD);
    MPI_Finalize();
    return 0;
}