#include <../src/vec/pf/pfimpl.h> /*I "petscpf.h" I*/

/*
        This PF generates a function on the fly and loads it into the running
   program.
*/

static PetscErrorCode PFView_String(void *value, PetscViewer viewer)
{
  PetscBool iascii;

  PetscFunctionBegin;
  PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
  if (iascii) PetscCall(PetscViewerASCIIPrintf(viewer, "String = %s\n", (char *)value));
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode PFDestroy_String(void *value)
{
  PetscFunctionBegin;
  PetscCall(PetscFree(value));
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*
    PFStringCreateFunction - Creates a function from a string

   Collective over PF

  Input Parameters:
+    pf - the function object
-    string - the string that defines the function

  Output Parameter:
.    f - the function pointer.

.seealso: `PFSetFromOptions()`

*/
PetscErrorCode PFStringCreateFunction(PF pf, char *string, void **f)
{
#if defined(PETSC_HAVE_DYNAMIC_LIBRARIES)
  char      task[1024], tmp[PETSC_MAX_PATH_LEN], lib[PETSC_MAX_PATH_LEN], username[64];
  FILE     *fd;
  PetscBool tmpshared, wdshared, keeptmpfiles = PETSC_FALSE;
  MPI_Comm  comm;
#endif

  PetscFunctionBegin;
#if defined(PETSC_HAVE_DYNAMIC_LIBRARIES)
  PetscCall(PetscFree(pf->data));
  PetscCall(PetscStrallocpy(string, (char **)&pf->data));

  /* create the new C function and compile it */
  PetscCall(PetscSharedTmp(PetscObjectComm((PetscObject)pf), &tmpshared));
  PetscCall(PetscSharedWorkingDirectory(PetscObjectComm((PetscObject)pf), &wdshared));
  if (tmpshared) { /* do it in /tmp since everyone has one */
    PetscCall(PetscGetTmp(PetscObjectComm((PetscObject)pf), tmp, PETSC_STATIC_ARRAY_LENGTH(tmp)));
    PetscCall(PetscObjectGetComm((PetscObject)pf, &comm));
  } else if (!wdshared) { /* each one does in private /tmp */
    PetscCall(PetscGetTmp(PetscObjectComm((PetscObject)pf), tmp, PETSC_STATIC_ARRAY_LENGTH(tmp)));
    comm = PETSC_COMM_SELF;
  } else { /* do it in current directory */
    PetscCall(PetscStrncpy(tmp, ".", sizeof(tmp)));
    PetscCall(PetscObjectGetComm((PetscObject)pf, &comm));
  }
  PetscCall(PetscOptionsGetBool(((PetscObject)pf)->options, ((PetscObject)pf)->prefix, "-pf_string_keep_files", &keeptmpfiles, NULL));
  PetscCall(PetscSNPrintf(task, PETSC_STATIC_ARRAY_LENGTH(task), "cd %s ; mkdir ${USERNAME} ; cd ${USERNAME} ; \\cp -f ${PETSC_DIR}/src/pf/impls/string/makefile ./makefile ; make  MIN=%" PetscInt_FMT " NOUT=%" PetscInt_FMT " -f makefile petscdlib STRINGFUNCTION=\"%s\" ; %s ;  sync\n", tmp, pf->dimin, pf->dimout, string, keeptmpfiles ? "\\rm -f makefile petscdlib.c libpetscdlib.a" : ""));

  #if defined(PETSC_HAVE_POPEN)
  PetscCall(PetscPOpen(comm, NULL, task, "r", &fd));
  PetscCall(PetscPClose(comm, fd));
  #else
  SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP_SYS, "Cannot run external programs on this machine");
  #endif

  PetscCallMPI(MPI_Barrier(comm));

  /* load the apply function from the dynamic library */
  PetscCall(PetscGetUserName(username, PETSC_STATIC_ARRAY_LENGTH(username)));
  PetscCall(PetscSNPrintf(lib, PETSC_STATIC_ARRAY_LENGTH(lib), "%s/%s/libpetscdlib", tmp, username));
  PetscCall(PetscDLLibrarySym(comm, NULL, lib, "PFApply_String", f));
  PetscCheck(f, PetscObjectComm((PetscObject)pf), PETSC_ERR_ARG_WRONGSTATE, "Cannot find function %s", lib);
#endif
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode PFSetFromOptions_String(PF pf, PetscOptionItems *PetscOptionsObject)
{
  PetscBool flag;
  char      value[PETSC_MAX_PATH_LEN];
  PetscErrorCode (*f)(void *, PetscInt, const PetscScalar *, PetscScalar *) = NULL;

  PetscFunctionBegin;
  PetscOptionsHeadBegin(PetscOptionsObject, "String function options");
  PetscCall(PetscOptionsString("-pf_string", "Enter the function", "PFStringCreateFunction", "", value, sizeof(value), &flag));
  if (flag) {
    PetscCall(PFStringCreateFunction(pf, value, (void **)&f));
    pf->ops->apply = f;
  }
  PetscOptionsHeadEnd();
  PetscFunctionReturn(PETSC_SUCCESS);
}

typedef PetscErrorCode (*FCN)(void *, PetscInt, const PetscScalar *, PetscScalar *); /* force argument to next function to not be extern C*/

PETSC_EXTERN PetscErrorCode PFCreate_String(PF pf, void *value)
{
  FCN f = NULL;

  PetscFunctionBegin;
  if (value) PetscCall(PFStringCreateFunction(pf, (char *)value, (void **)&f));
  PetscCall(PFSet(pf, f, NULL, PFView_String, PFDestroy_String, NULL));
  pf->ops->setfromoptions = PFSetFromOptions_String;
  PetscFunctionReturn(PETSC_SUCCESS);
}