/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkTclUtil.cxx,v $

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

#include "vtkObject.h"
#include "vtkTclUtil.h"
#include "vtkSetGet.h"
#include "vtkCallbackCommand.h"

#include <vtkstd/string>
#include <vtksys/SystemTools.hxx>

extern "C"
{
#if (TCL_MAJOR_VERSION == 8) && (TCL_MINOR_VERSION >= 4 && TCL_RELEASE_LEVEL >= TCL_FINAL_RELEASE)
  typedef int (*vtkTclCommandType)(ClientData, Tcl_Interp *,int, CONST84 char *[]);
#else
  typedef int (*vtkTclCommandType)(ClientData, Tcl_Interp *,int, char *[]);
#endif
}

vtkTclInterpStruct *vtkGetInterpStruct(Tcl_Interp *interp)
{
  vtkTclInterpStruct *is = (vtkTclInterpStruct *)Tcl_GetAssocData(interp,(char *) "vtk",NULL);
  if (!is)
    {
    vtkGenericWarningMacro("unable to find interp struct");
    }
  return is;
}

VTKTCL_EXPORT int vtkTclInDelete(Tcl_Interp *interp)
{  
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);
  if (is)
    {
    return is->InDelete;
    }
  return 0;
}


// just another way into DeleteCommand
VTKTCL_EXPORT void vtkTclDeleteObjectFromHash(vtkObject *obj, 
                                              unsigned long vtkNotUsed(eventId), 
                                              void *cd, void *)
{
  vtkTclCommandArgStruct *as = (vtkTclCommandArgStruct *)cd;
  char temps[80];
  Tcl_HashEntry *entry;
  char *temp;
  vtkTclInterpStruct *is = vtkGetInterpStruct(as->Interp);
  
  // lookup the objects name
  sprintf(temps,"%p",obj);
  entry = Tcl_FindHashEntry(&is->PointerLookup,temps); 
  if (entry)
    {
    temp = (char *)(Tcl_GetHashValue(entry));
    if (temp)
      {
      Tcl_DeleteCommand(as->Interp,temp);
      }
    }
}

// we do no error checking in this.  We assume that if we were called
// then tcl must have been able to find the command function and object.
VTKTCL_EXPORT void vtkTclGenericDeleteObject(ClientData cd)
{
  char temps[80];
  Tcl_HashEntry *entry;
  int (*command)(ClientData, Tcl_Interp *,int, char *[]);
  char *args[2];
  char *temp;
  vtkObject *tobject;
  int error;
  vtkTclCommandArgStruct *as = (vtkTclCommandArgStruct *)cd;
  Tcl_Interp *interp = as->Interp;
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);

  /* set up the args */
  args[1] = (char *) "Delete";

  // lookup the objects name
  sprintf(temps,"%p",as->Pointer);
  entry = Tcl_FindHashEntry(&is->PointerLookup,temps); 
  if (!entry)
    {
    return;
    }

  temp = (char *)(Tcl_GetHashValue(entry));
  args[0] = temp;
  
  // first we clear the delete callback since we will
  // always remove this object from the hash regardless
  // of if it has really been freed.
  tobject = (vtkObject *)vtkTclGetPointerFromObject(temp,"vtkObject",
                                                    interp, error);
  tobject->RemoveObserver(as->Tag);
  as->Tag = 0;
  
  // get the command function and invoke the delete operation
  entry = Tcl_FindHashEntry(&is->CommandLookup,temp);
  command = (int (*)(ClientData,Tcl_Interp *,int,char *[]))
    Tcl_GetHashValue(entry);
  
  // do we need to delete the c++ obj
  if (strncmp(temp,"vtkTemp",7))
    {
    is->InDelete = 1;
    command(cd,interp,2,args);
    is->InDelete = 0;
    }

  // the actual C++ object may not be freed yet. So we 
  // force it to be free from the hash table.
  Tcl_DeleteHashEntry(entry);
  entry = Tcl_FindHashEntry(&is->PointerLookup,temps); 
  Tcl_DeleteHashEntry(entry);
  entry = Tcl_FindHashEntry(&is->InstanceLookup,temp);
  Tcl_DeleteHashEntry(entry);
  delete as;
  
  if (is->DebugOn)
    {
    vtkGenericWarningMacro("vtkTcl Attempting to free object named " << temp);
    }
  if (temp)
    {
    free(temp);
    }
}

int vtkCreateCommand(ClientData vtkNotUsed(cd), Tcl_Interp *interp, int argc, char *argv[])
{
  Tcl_HashEntry *entry;
  Tcl_HashSearch search;
  char * tmp;
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);
  
  if (argc < 2)
    {
    return TCL_OK;
    }

  if (!strcmp(argv[1],"DeleteAllObjects"))
    {
    for (entry = Tcl_FirstHashEntry(&is->PointerLookup,&search); 
         entry != NULL;
         entry = Tcl_FirstHashEntry(&is->PointerLookup,&search))
      {
      tmp = strdup((char *)Tcl_GetHashValue(entry));
      if (tmp)
        {
        Tcl_DeleteCommand(interp,tmp);
        }
      if (tmp)
        {
        free(tmp);
        }
      }
    return TCL_OK;
    }
  if (!strcmp(argv[1],"ListAllInstances"))
    {
    for (entry = Tcl_FirstHashEntry(&is->InstanceLookup,&search); 
         entry != NULL; entry = Tcl_NextHashEntry(&search))
      {
      Tcl_AppendResult(interp,
                       (char *)Tcl_GetHashKey(&is->InstanceLookup,entry),NULL);
      Tcl_AppendResult(interp,"\n",NULL);
      }
    return TCL_OK;
    }
  if (!strcmp(argv[1],"DebugOn"))
    {
    is->DebugOn = 1;
    return TCL_OK;
    }
  if (!strcmp(argv[1],"DebugOff"))
    {
    is->DebugOn = 0;
    return TCL_OK;
    }
  if (!strcmp(argv[1],"DeleteExistingObjectOnNewOn"))
    {
    is->DeleteExistingObjectOnNew = 1;
    return TCL_OK;
    }
  if (!strcmp(argv[1],"DeleteExistingObjectOnNewOff"))
    {
    is->DeleteExistingObjectOnNew = 0;
    return TCL_OK;
    }
  if (!strcmp("ListMethods",argv[1]))
    {
    Tcl_AppendResult(interp,"Methods for vtkCommand:\n",NULL);
    Tcl_AppendResult(interp,"  DebugOn\n",NULL);
    Tcl_AppendResult(interp,"  DebugOff\n",NULL);
    Tcl_AppendResult(interp,"  DeleteAllObjects\n",NULL);
    Tcl_AppendResult(interp,"  ListAllInstances\n",NULL);
    Tcl_AppendResult(interp,"  DeleteExistingObjectOnNewOn\n",NULL);
    Tcl_AppendResult(interp,"  DeleteExistingObjectOnNewOff\n",NULL);
    return TCL_OK;
    }

  Tcl_AppendResult(interp,"invalid method for vtkCommand\n",NULL);
  return TCL_ERROR;
}

VTKTCL_EXPORT void
vtkTclUpdateCommand(Tcl_Interp *interp, char *name,  vtkObject *temp)
{
  Tcl_CmdProc *command = NULL;

  // check to see if we can find the command function based on class name
  Tcl_CmdInfo cinf;
  char *tstr = strdup(temp->GetClassName());
  if (Tcl_GetCommandInfo(interp,tstr,&cinf))
    {
    if (cinf.clientData)
      {
      vtkTclCommandStruct *cs = (vtkTclCommandStruct *)cinf.clientData;
      command = (Tcl_CmdProc *)cs->CommandFunction;
      }
    }
  if (tstr)
    {
    free(tstr);
    }

  // if not found then just return
  if (!command)
    {
    return;
    }
  
  // is the current command the same
  Tcl_CmdInfo cinfo;
  Tcl_GetCommandInfo(interp, name, &cinfo);
  cinfo.proc = command;
  Tcl_SetCommandInfo(interp, name, &cinfo);

  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);
  Tcl_HashEntry *entry = Tcl_FindHashEntry(&is->CommandLookup,name);
  Tcl_SetHashValue(entry,(ClientData)command);
}


VTKTCL_EXPORT void
vtkTclGetObjectFromPointer(Tcl_Interp *interp, void *temp1,
                           const char *targetType)
{
  int (*command)(ClientData, Tcl_Interp *,int, char *[]) = 0;
  int is_new;
  vtkObject *temp = (vtkObject *)temp1;
  char temps[80];
  char name[80];
  Tcl_HashEntry *entry;
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);

  /* if it is NULL then return empty string */
  if (!temp)
    {
    Tcl_ResetResult(interp);
    return;
    }
  
  /* return a pointer to a vtk Object */
  if (is->DebugOn)
    {
      vtkGenericWarningMacro("Looking up name for vtk pointer: " << temp);
    }

  /* first we must look up the pointer to see if it already exists */
  sprintf(temps,"%p",temp);
  if ((entry = Tcl_FindHashEntry(&is->PointerLookup,temps))) 
    {
    if (is->DebugOn)
      {
        vtkGenericWarningMacro("Found name: " 
                               << (char *)(Tcl_GetHashValue(entry)) 
                               << " for vtk pointer: " << temp);
      }
    
    /* while we are at it store the name since it is required anyhow */
    Tcl_SetResult(interp, (char *)(Tcl_GetHashValue(entry)), TCL_VOLATILE);
    return;
    }

  /* we must create a new name if it isn't NULL */
  sprintf(name,"vtkTemp%i",is->Number);
  is->Number++;
  
  if (is->DebugOn)
    {
      vtkGenericWarningMacro("Created name: " << name
                             << " for vtk pointer: " << temp);
    }

  // check to see if we can find the command function based on class name
  Tcl_CmdInfo cinf;
  char *tstr = strdup(temp->GetClassName());
  if (Tcl_GetCommandInfo(interp,tstr,&cinf))
    {
    if (cinf.clientData)
      {
      vtkTclCommandStruct *cs = (vtkTclCommandStruct *)cinf.clientData;
      command = cs->CommandFunction;
      }
    }
  // if the class command wasn;t found try the target return type command
  if (!command && targetType)
    {
    if (tstr)
      {
      free(tstr);
      }
    tstr = strdup(targetType);
    if (Tcl_GetCommandInfo(interp,tstr,&cinf))
      {
      if (cinf.clientData)
        {
        vtkTclCommandStruct *cs = (vtkTclCommandStruct *)cinf.clientData;
        command = cs->CommandFunction;
        }
      }
    }
  // if we still do not havbe a match then try vtkObject
  if (!command)
    {
    if (tstr)
      {
      free(tstr);
      }
    tstr = strdup("vtkObject");
    if (Tcl_GetCommandInfo(interp,tstr,&cinf))
      {
      if (cinf.clientData)
        {
        vtkTclCommandStruct *cs = (vtkTclCommandStruct *)cinf.clientData;
        command = cs->CommandFunction;
        }
      }
    }
  if (tstr)
    {
    free(tstr);
    }

  entry = Tcl_CreateHashEntry(&is->InstanceLookup,name,&is_new);
  Tcl_SetHashValue(entry,(ClientData)(temp));
  entry = Tcl_CreateHashEntry(&is->PointerLookup,temps,&is_new);
  Tcl_SetHashValue(entry,(ClientData)(strdup(name)));
  vtkTclCommandArgStruct *as = new vtkTclCommandArgStruct;
  as->Pointer = (void *)temp;
  as->Interp = interp;
  Tcl_CreateCommand(interp,name,
                    reinterpret_cast<vtkTclCommandType>(command),
                    (ClientData)(as),
                    (Tcl_CmdDeleteProc *)vtkTclGenericDeleteObject);
  entry = Tcl_CreateHashEntry(&is->CommandLookup,name,&is_new);
  Tcl_SetHashValue(entry,(ClientData)command);
  
  // setup the delete callback
  vtkCallbackCommand *cbc = vtkCallbackCommand::New();
  cbc->SetCallback(vtkTclDeleteObjectFromHash);
  cbc->SetClientData((void *)as);
  as->Tag = temp->AddObserver(vtkCommand::DeleteEvent, cbc);
  cbc->Delete();
  
  Tcl_SetResult(interp, (char *)name, TCL_VOLATILE);
}
      
VTKTCL_EXPORT void *vtkTclGetPointerFromObject(const char *name,
                                               const char *result_type,
                                               Tcl_Interp *interp, 
                                               int &error)
{
  Tcl_HashEntry *entry;
  ClientData temp;
  int (*command)(ClientData, Tcl_Interp *,int, char *[]);
  char *args[3];
  char temps[256];
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);

  /* check for empty string, empty string is the same as passing NULL */
  if (name[0] == '\0')
    {
    return NULL;
    }
  
  // object names cannot start with a number
  if ((name[0] >= '0')&&(name[0] <= '9'))
    {
    error = 1;
    return NULL;
    }

  if ((entry = Tcl_FindHashEntry(&is->InstanceLookup,name)))
    {
    temp = (ClientData)Tcl_GetHashValue(entry);
    }
  else
    {
    sprintf(temps,"vtk bad argument, could not find object named %s\n", name);
    Tcl_AppendResult(interp,temps,NULL);
    error = 1;
    return NULL;
    }

  /* now handle the typecasting, get the command proc */
  if ((entry = Tcl_FindHashEntry(&is->CommandLookup,name)))
    {
    command = (int (*)(ClientData,Tcl_Interp *,int,char *[]))Tcl_GetHashValue(entry);
    }
  else
    {
    sprintf(temps,"vtk bad argument, could not find command process for %s.\n", name);
    Tcl_AppendResult(interp,temps,NULL);
    error = 1;
    return NULL;
    }

  /* set up the args */
  args[0] = (char *) "DoTypecasting";
  args[1] = strdup(result_type);
  args[2] = NULL;
  vtkTclCommandArgStruct foo;
  foo.Pointer = temp;
  foo.Interp = interp;
  if (command((ClientData)&foo,(Tcl_Interp *)NULL,3,args) == TCL_OK)
    {
    free (args[1]);
    return (void *)(args[2]);
    }
  else
    {
    Tcl_Interp *i;
    i = Tcl_CreateInterp();
    // provide more diagnostic info
    args[0] = (char *) "Dummy";
    free (args[1]);
    args[1] = (char *) "GetClassName";
    args[2] = NULL;
    command((ClientData)&foo,i,2,args);

    sprintf(temps,"vtk bad argument, type conversion failed for object %s.\nCould not type convert %s which is of type %s, to type %s.\n", name, name, i->result, result_type);
    Tcl_AppendResult(interp,temps,NULL);
    error = 1;
    Tcl_DeleteInterp(i);
    return NULL;
    }

}

VTKTCL_EXPORT void vtkTclVoidFunc(void *arg)
{
  int res;

  vtkTclVoidFuncArg *arg2;

  arg2 = (vtkTclVoidFuncArg *)arg;

#if TCL_MAJOR_VERSION == 8 && TCL_MINOR_VERSION <= 2
  res = Tcl_GlobalEval(arg2->interp, arg2->command);
#else
  res = Tcl_EvalEx(arg2->interp, arg2->command, -1, TCL_EVAL_GLOBAL);
#endif

  if (res == TCL_ERROR)
    {
    if (Tcl_GetVar(arg2->interp,(char *) "errorInfo",0))
      {
      vtkGenericWarningMacro("Error returned from vtk/tcl callback:\n" <<
                             arg2->command << endl <<
                             Tcl_GetVar(arg2->interp,(char *) "errorInfo",0) <<
                             " at line number " << arg2->interp->errorLine);
      }
    else
      {
      vtkGenericWarningMacro("Error returned from vtk/tcl callback:\n" <<
                             arg2->command << endl <<
                             " at line number " << arg2->interp->errorLine);
      }
    }
}

VTKTCL_EXPORT void vtkTclVoidFuncArgDelete(void *arg)
{
  vtkTclVoidFuncArg *arg2;

  arg2 = (vtkTclVoidFuncArg *)arg;
  
  // free the string and then structure
  delete [] arg2->command;
  delete arg2;
}

VTKTCL_EXPORT void vtkTclListInstances(Tcl_Interp *interp, ClientData arg)
{
  Tcl_HashSearch srch;
  Tcl_HashEntry *entry;
  int first = 1;
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);

  // iteratively search hash table for command function
  entry = Tcl_FirstHashEntry(&is->CommandLookup, &srch);
  if (!entry) 
    {
    Tcl_ResetResult(interp);
    return;
    }
  while (entry)
    {
    if (Tcl_GetHashValue(entry) == arg)
      {
      if (first)
        {
        first = 0;
        Tcl_AppendResult(interp,Tcl_GetHashKey(&is->CommandLookup,entry),NULL);
        }
      else
        {
        Tcl_AppendResult(interp, " ", Tcl_GetHashKey(&is->CommandLookup,entry), 
                         NULL);
        }
      }
    entry = Tcl_NextHashEntry(&srch);
    }
}

  
int vtkTclNewInstanceCommand(ClientData cd, Tcl_Interp *interp,
                             int argc, char *argv[])
{
  int (*command)(ClientData, Tcl_Interp *,int, char *[]);
  Tcl_HashEntry *entry;
  int is_new;
  char temps[80];
  char name[80];
  vtkTclCommandStruct *cs = (vtkTclCommandStruct *)cd;
  Tcl_CmdInfo cinf;
  vtkTclInterpStruct *is = vtkGetInterpStruct(interp);

  if (argc != 2)
    {
    Tcl_SetResult(interp, (char *) "vtk object creation requires one argument, a name, or the special New keyword to instantiate a new name.", TCL_VOLATILE);
    return TCL_ERROR;
    }

  if ((argv[1][0] >= '0')&&(argv[1][0] <= '9'))
    { 
    Tcl_SetResult(interp, argv[1], TCL_VOLATILE);
    Tcl_AppendResult(interp, ": vtk object cannot start with a numeric.", NULL);
    return TCL_ERROR;
    }
  
  if (Tcl_FindHashEntry(&is->InstanceLookup,argv[1]))
    { 
    if (is->DeleteExistingObjectOnNew)
      {
      Tcl_DeleteCommand(interp, argv[1]);
      }
    else
      {
      Tcl_SetResult(interp, argv[1], TCL_VOLATILE);
      Tcl_AppendResult(interp,
                       ": a vtk object with that name already exists.",
                       NULL);
      return TCL_ERROR;
      }
    }

  // Make sure we are not clobbering a built in command
  if (Tcl_GetCommandInfo(interp,argv[1],&cinf))
    {
    Tcl_SetResult(interp, argv[1], TCL_VOLATILE);
    Tcl_AppendResult(interp,
                     ": a tcl/tk command with that name already exists.",
                     NULL);
    return TCL_ERROR;
    }

  ClientData temp;
  if (!strcmp("ListInstances",argv[1]))
    {
    vtkTclListInstances(interp,(ClientData) cs->CommandFunction);
    return TCL_OK;
    }

  if (!strcmp("New",argv[1]))
    {
    sprintf(name,"vtkObj%i",is->Number);
    is->Number++;
    argv[1] = name;
    }

  temp = cs->NewCommand();

  entry = Tcl_CreateHashEntry(&is->InstanceLookup,argv[1],&is_new);
  Tcl_SetHashValue(entry,temp);
  sprintf(temps,"%p",(void *)temp);
  entry = Tcl_CreateHashEntry(&is->PointerLookup,temps,&is_new);
  Tcl_SetHashValue(entry,(ClientData)(strdup(argv[1])));
  
  // check to see if we can find the command function based on class name
  char *tstr = strdup(((vtkObject *)temp)->GetClassName());
  if (Tcl_GetCommandInfo(interp,tstr,&cinf))
    {
    if (cinf.clientData)
      {
      vtkTclCommandStruct *cs2 = (vtkTclCommandStruct *)cinf.clientData;
      command = cs2->CommandFunction;
      }
    else
      {
      command = cs->CommandFunction;
      }
    }
  else
    {
    command = cs->CommandFunction;
    }
  if (tstr)
    {
    free(tstr);
    }

  vtkTclCommandArgStruct *as = new vtkTclCommandArgStruct;
  as->Pointer = (void *)temp;
  as->Interp = interp;
  Tcl_CreateCommand(interp,argv[1],
                    reinterpret_cast<vtkTclCommandType>(command),
                    (ClientData)as,
                    (Tcl_CmdDeleteProc *)vtkTclGenericDeleteObject);
  entry = Tcl_CreateHashEntry(&is->CommandLookup,argv[1],&is_new);
  Tcl_SetHashValue(entry,(ClientData)(cs->CommandFunction));
  
  // setup the delete callback
  vtkCallbackCommand *cbc = vtkCallbackCommand::New();
  cbc->SetCallback(vtkTclDeleteObjectFromHash);
  cbc->SetClientData((void *)as);
  as->Tag = ((vtkObject *)temp)->AddObserver(vtkCommand::DeleteEvent, cbc);
  cbc->Delete();

  Tcl_SetResult(interp, argv[1], TCL_VOLATILE);
  return TCL_OK;
}

void vtkTclDeleteCommandStruct(ClientData cd)
{
  vtkTclCommandStruct *cs = (vtkTclCommandStruct *)cd;
  delete cs;
}

void vtkTclCreateNew(Tcl_Interp *interp, const char *cname,
                     ClientData (*NewCommand)(),
                     int (*CommandFunction)(ClientData cd,
                                            Tcl_Interp *interp,
                                            int argc, char *argv[]))
{
  vtkTclCommandStruct *cs = new vtkTclCommandStruct;
  cs->NewCommand = NewCommand;
  cs->CommandFunction = CommandFunction;
  Tcl_CreateCommand(interp,(char *) cname,
                    reinterpret_cast<vtkTclCommandType>(
                      vtkTclNewInstanceCommand),
                   (ClientData *)cs,
                   (Tcl_CmdDeleteProc *)vtkTclDeleteCommandStruct);
}


vtkTclCommand::vtkTclCommand()
{ 
  this->Interp = NULL; 
  this->StringCommand = NULL;
}

vtkTclCommand::~vtkTclCommand() 
{ 
  if(this->StringCommand) { delete [] this->StringCommand; }
}

void vtkTclCommand::SetStringCommand(const char *arg)
{
  if(this->StringCommand) { delete [] this->StringCommand; }
  this->StringCommand = new char[strlen(arg)+1];
  strcpy(this->StringCommand, arg);
}
  
void vtkTclCommand::Execute(vtkObject *, unsigned long, void *)
{
  int res;
#if TCL_MAJOR_VERSION == 8 && TCL_MINOR_VERSION <= 2
  res = Tcl_GlobalEval(this->Interp, this->StringCommand);
#else
  res = Tcl_EvalEx(this->Interp, this->StringCommand, -1, TCL_EVAL_GLOBAL);
#endif  

  if (res == TCL_ERROR)
    {
    if (Tcl_GetVar(this->Interp,(char *) "errorInfo",0))
      {
      vtkGenericWarningMacro("Error returned from vtk/tcl callback:\n" <<
                             this->StringCommand << endl <<
                             Tcl_GetVar(this->Interp,(char *) "errorInfo",0) <<
                             " at line number " << this->Interp->errorLine);
      }
    else
      {
      vtkGenericWarningMacro("Error returned from vtk/tcl callback:\n" <<
                             this->StringCommand << endl <<
                             " at line number " << 
                             this->Interp->errorLine);
      }
    }
  else if (res == -1)
    {
    this->AbortFlagOn();
    } 
}

void vtkTclApplicationInitExecutable(int vtkNotUsed(argc),
                                     const char* const argv[])
{
  vtkstd::string av0 = vtksys::SystemTools::CollapseFullPath(argv[0]);
  Tcl_FindExecutable(av0.c_str());
}

// We need two internal Tcl functions.  They usually are declared in
// tclIntDecls.h, but UNIX builds do not have access to VTK's
// tkInternals include path.  Since the signature has not changed for
// years (at least since 8.2), let's just prototype them.
EXTERN Tcl_Obj* TclGetLibraryPath _ANSI_ARGS_((void));
EXTERN void TclSetLibraryPath _ANSI_ARGS_((Tcl_Obj * pathPtr));

void vtkTclApplicationInitTclTk(Tcl_Interp* interp,
                                const char* const relative_dirs[])
{
  /*
    Tcl/Tk requires support files to work (set of tcl files).
    When an app is linked against Tcl/Tk shared libraries, the path to
    the libraries is used by Tcl/Tk to search for its support files.
    For example, on Windows, if bin/tcl84.dll is the shared lib, support
    files will be searched in bin/../lib/tcl8.4, which is where they are
    usually installed.
    If an app is linked against Tcl/Tk *static* libraries, there is no
    way for Tcl/Tk to find its support files. In that case, it will
    use the TCL_LIBRARY and TK_LIBRARY environment variable (those should
    point to the support files dir, ex: c:/tcl/lib/tcl8.4, c:/tk/lib/tcl8.4).

    The above code will also make Tcl/Tk search inside VTK's build/install
    directory, more precisely inside a TclTk/lib sub dir.
    ex: [path to vtk.exe]/TclTk/lib/tcl8.4, [path to vtk.exe]/TclTk/lib/tk8.4
    Support files are copied to that location when
    VTK_TCL_TK_COPY_SUPPORT_LIBRARY is ON.
  */

  int has_tcllibpath_env = getenv("TCL_LIBRARY") ? 1 : 0;
  int has_tklibpath_env = getenv("TK_LIBRARY") ? 1 : 0;
  vtkstd::string selfdir;
  if(!has_tcllibpath_env || !has_tklibpath_env)
    {
    const char* nameofexec = Tcl_GetNameOfExecutable();
    if(nameofexec && vtksys::SystemTools::FileExists(nameofexec))
      {
      vtkstd::string name = nameofexec;
      vtksys::SystemTools::ConvertToUnixSlashes(name);
      selfdir = vtksys::SystemTools::GetFilenamePath(name);
      }
    }
  if(selfdir.length() > 0)
    {
    if(!has_tcllibpath_env)
      {
      vtkstd::string tdir;
      for(const char* const* p = relative_dirs; *p; ++p)
        {
        tdir = selfdir;
        tdir += "/";
        tdir += *p;
        tdir += "/tcl" TCL_VERSION;
        tdir = vtksys::SystemTools::CollapseFullPath(tdir.c_str());
        if(vtksys::SystemTools::FileExists(tdir.c_str()) &&
           vtksys::SystemTools::FileIsDirectory(tdir.c_str()))
          {
          // Set the tcl_library Tcl variable.
          char tcl_library[1024];
          strcpy(tcl_library, tdir.c_str());
          Tcl_SetVar(interp, "tcl_library", tcl_library,
                     TCL_GLOBAL_ONLY | TCL_LEAVE_ERR_MSG);
          break;
          }
        }
      }
    if(!has_tklibpath_env)
      {
      vtkstd::string tdir;
      for(const char* const* p = relative_dirs; *p; ++p)
        {
        tdir = selfdir;
        tdir += "/";
        tdir += *p;
        tdir += "/tk" TCL_VERSION;
        tdir = vtksys::SystemTools::CollapseFullPath(tdir.c_str());
        if(vtksys::SystemTools::FileExists(tdir.c_str()) &&
           vtksys::SystemTools::FileIsDirectory(tdir.c_str()))
          {
          // Set the tk_library Tcl variable.
          char tk_library[1024];
          strcpy(tk_library, tdir.c_str());
          Tcl_SetVar(interp, "tk_library", tk_library,
                     TCL_GLOBAL_ONLY | TCL_LEAVE_ERR_MSG);
          break;
          }
        }
      }
    }
}