/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *  (C) 2014 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

/* Look for regressions in aggregator code.  A more simple access pattern than
 * aggregation1 */

/* Uses nonblocking collective I/O.*/

#include <mpi.h>

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#include <sys/types.h>
#include <unistd.h>

#include <string.h>

#define BUFSIZE 512

static void handle_error(int errcode, const char *str)
{
    char msg[MPI_MAX_ERROR_STRING];
    int resultlen;
    MPI_Error_string(errcode, msg, &resultlen);
    fprintf(stderr, "%s: %s\n", str, msg);
    MPI_Abort(MPI_COMM_WORLD, 1);
}

int main(int argc, char **argv)
{
    MPI_Info info = MPI_INFO_NULL;
    MPI_File fh;
    MPI_Offset off = 0;
    MPI_Status status;
    int errcode;
    int i, rank, errs = 0, toterrs, buffer[BUFSIZE], buf2[BUFSIZE];
    MPI_Request request;
    char *filename = NULL;

    filename = (argc > 1) ? argv[1] : "testfile";

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank);

    MPI_Info_create(&info);
    MPI_Info_set(info, "romio_cb_write", "enable");
    MPI_Info_set(info, "cb_nodes", "1");

    for (i = 0; i < BUFSIZE; i++) {
        buffer[i] = 10000 + rank;
    }
    off = rank * sizeof(buffer);

    errcode = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_WRONLY | MPI_MODE_CREATE, info, &fh);
    if (errcode != MPI_SUCCESS)
        handle_error(errcode, "MPI_File_open");
    errcode = MPI_File_iwrite_at_all(fh, off, buffer, BUFSIZE, MPI_INT, &request);
    if (errcode != MPI_SUCCESS)
        handle_error(errcode, "MPI_File_iwrite_at_all");
    MPI_Wait(&request, &status);
    errcode = MPI_File_close(&fh);
    if (errcode != MPI_SUCCESS)
        handle_error(errcode, "MPI_File_close");

    errcode = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_RDONLY, info, &fh);
    if (errcode != MPI_SUCCESS)
        handle_error(errcode, "MPI_File_open");
    errcode = MPI_File_iread_at_all(fh, off, buf2, BUFSIZE, MPI_INT, &request);
    if (errcode != MPI_SUCCESS)
        handle_error(errcode, "MPI_File_iread_at_all");
    MPI_Wait(&request, &status);
    errcode = MPI_File_close(&fh);
    if (errcode != MPI_SUCCESS)
        handle_error(errcode, "MPI_File_close");

    for (i = 0; i < BUFSIZE; i++) {
        if (buf2[i] != 10000 + rank)
            errs++;
    }
    MPI_Allreduce(&errs, &toterrs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
    if (rank == 0) {
        if (toterrs > 0) {
            fprintf(stderr, "Found %d errors\n", toterrs);
        }
        else {
            fprintf(stdout, " No Errors\n");
        }
    }
    MPI_Info_free(&info);
    MPI_Finalize();

    return 0;
}
