/*
 * Copyright (C) by Argonne National Laboratory
 *     See COPYRIGHT in top-level directory
 */

#include "mpi.h"
#include <stdio.h>
#include <string.h>
#include "mpitest.h"

/* Check that Comm_create detects the case where the group is not a subset of
   the group of the input communicator */

void abortMsg(const char *, int);

void abortMsg(const char *str, int code)
{
    char msg[MPI_MAX_ERROR_STRING];
    int class, resultLen;

    MPI_Error_class(code, &class);
    MPI_Error_string(code, msg, &resultLen);
    fprintf(stderr, "%s: errcode = %d, class = %d, msg = %s\n", str, code, class, msg);
    MPI_Abort(MPI_COMM_WORLD, code);
}

int main(int argc, char *argv[])
{
    MPI_Comm evencomm, lowcomm, newcomm;
    int wrank, wsize, gsize, err, errs = 0;
    int ranges[1][3], mygrank;
    MPI_Group wGroup, godd, ghigh, geven;

    MTest_Init(&argc, &argv);

    MPI_Comm_set_errhandler(MPI_COMM_WORLD, MPI_ERRORS_RETURN);

    MPI_Comm_size(MPI_COMM_WORLD, &wsize);
    MPI_Comm_rank(MPI_COMM_WORLD, &wrank);

    /* Create some communicators */
    MPI_Comm_split(MPI_COMM_WORLD, wrank % 2, wrank, &evencomm);
    MPI_Comm_split(MPI_COMM_WORLD, wrank < wsize / 2, wsize - wrank, &lowcomm);
    MPI_Comm_set_errhandler(evencomm, MPI_ERRORS_RETURN);
    MPI_Comm_set_errhandler(lowcomm, MPI_ERRORS_RETURN);

    /* Create some groups */
    MPI_Comm_group(MPI_COMM_WORLD, &wGroup);

    ranges[0][0] = 2 * (wsize / 2) - 1;
    ranges[0][1] = 1;
    ranges[0][2] = -2;
    err = MPI_Group_range_incl(wGroup, 1, ranges, &godd);
    if (err)
        abortMsg("Failed to create odd group: ", err);
    err = MPI_Group_size(godd, &gsize);
    if (err)
        abortMsg("Failed to get size of odd group: ", err);
    if (gsize != wsize / 2) {
        fprintf(stderr, "Group godd size is %d should be %d\n", gsize, wsize / 2);
        errs++;
    }

    ranges[0][0] = wsize / 4;
    ranges[0][1] = wsize - 1;
    ranges[0][2] = 1;
    err = MPI_Group_range_incl(wGroup, 1, ranges, &ghigh);
    if (err)
        abortMsg("Failed to create high group\n", err);
    ranges[0][0] = 0;
    ranges[0][1] = wsize - 1;
    ranges[0][2] = 2;
    err = MPI_Group_range_incl(wGroup, 1, ranges, &geven);
    if (err)
        abortMsg("Failed to create even group:", err);

    /* Check that a correct case returns success */
    if ((wrank % 2) == 0) {
        err = MPI_Group_rank(geven, &mygrank);
        if (err) {
            errs++;
            fprintf(stderr, "Could not get rank from geven group\n");
        } else if (mygrank == MPI_UNDEFINED) {
            errs++;
            fprintf(stderr, "mygrank should be %d but is undefined\n", wrank / 2);
        }
        err = MPI_Comm_create(evencomm, geven, &newcomm);
        /* printf("Created new even comm\n"); */
        if (err != MPI_SUCCESS) {
            errs++;
            fprintf(stderr, "Failed to allow creation from even group\n");
        } else {
            MPI_Comm_free(&newcomm);
        }
    }

    /* Now, test that these return errors when we try to use them to create
     * groups */
    if ((wrank % 2) == 0) {
        /* printf("Even comm...\n"); */
        /* evencomm is the comm of even-ranked processed in comm world */
        err = MPI_Comm_create(evencomm, godd, &newcomm);
        MPI_Group_rank(godd, &mygrank);
        if (err == MPI_SUCCESS) {
            if (mygrank != MPI_UNDEFINED) {
                errs++;
                fprintf(stderr, "Did not detect group of odd ranks in even comm\n");
            }
            MPI_Comm_free(&newcomm);
        }
    }
    if (wrank < wsize / 2) {
        /* printf("low comm...\n"); */
        err = MPI_Comm_create(lowcomm, ghigh, &newcomm);
        MPI_Group_rank(ghigh, &mygrank);
        if (err == MPI_SUCCESS) {
            if (mygrank != MPI_UNDEFINED) {
                errs++;
                fprintf(stderr, "Did not detect group of high ranks in low comm\n");
            }
            MPI_Comm_free(&newcomm);
        }
    }

    MPI_Comm_free(&lowcomm);
    MPI_Comm_free(&evencomm);
    MPI_Group_free(&ghigh);
    MPI_Group_free(&godd);
    MPI_Group_free(&geven);
    MPI_Group_free(&wGroup);

    MTest_Finalize(errs);

    return MTestReturnValue(errs);
}
