#include <petscsys.h>

/*@C
    PetscStartMatlab - starts up MATLAB with a MATLAB script

    Logically Collective, but only processor zero in the communicator does anything

    Input Parameters:
+     comm - MPI communicator
.     machine - optional machine to run MATLAB on
-     script - name of script (without the .m)

    Output Parameter:
.     fp - a file pointer returned from `PetscPOpen()`

    Level: intermediate

    Notes:
     This overwrites your matlab/startup.m file

     The script must be in your MATLAB path or current directory

     Assumes that all machines share a common file system

.seealso: `PetscPOpen()`, `PetscPClose()`
@*/
PetscErrorCode PetscStartMatlab(MPI_Comm comm, const char machine[], const char script[], FILE **fp) {
  FILE *fd;
  char  command[512];
#if defined(PETSC_HAVE_UCBPS) && defined(PETSC_HAVE_POPEN)
  char        buf[1024], *found;
  PetscMPIInt rank;
#endif

  PetscFunctionBegin;
#if defined(PETSC_HAVE_UCBPS) && defined(PETSC_HAVE_POPEN)
  /* check if MATLAB is not already running */
  PetscCall(PetscPOpen(comm, machine, "/usr/ucb/ps -ugxww | grep matlab | grep -v grep", "r", &fd));
  PetscCallMPI(MPI_Comm_rank(comm, &rank));
  if (rank == 0) found = fgets(buf, 1024, fd);
  PetscCallMPI(MPI_Bcast(&found, 1, MPI_CHAR, 0, comm));
  PetscCall(PetscPClose(comm, fd));
  if (found) PetscFunctionReturn(0);
#endif

  if (script) {
    /* the remote machine won't know about current directory, so add it to MATLAB path */
    /* the extra \" are to protect possible () in the script command from the shell */
    sprintf(command, "echo \"delete ${HOMEDIRECTORY}/matlab/startup.m ; path(path,'${WORKINGDIRECTORY}'); %s  \" > ${HOMEDIRECTORY}/matlab/startup.m", script);
#if defined(PETSC_HAVE_POPEN)
    PetscCall(PetscPOpen(comm, machine, command, "r", &fd));
    PetscCall(PetscPClose(comm, fd));
#endif
  }
#if defined(PETSC_HAVE_POPEN)
  PetscCall(PetscPOpen(comm, machine, "xterm -display ${DISPLAY} -e matlab -nosplash", "r", fp));
#endif
  PetscFunctionReturn(0);
}