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

  Program:   Visualization Toolkit
  Module:    vtkPythonAppInit.cxx

  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.

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

/* Minimal main program -- everything is loaded from the library */

#include "vtkPython.h"
#include "vtkPythonCompatibility.h"

#ifdef VTK_COMPILED_USING_MPI
# include <mpi.h>
# include "vtkMPIController.h"
#endif // VTK_COMPILED_USING_MPI

#include "vtkVersion.h"
#include "vtkPythonAppInitConfigure.h"

#include "vtkpythonmodules.h"

// Include the instantiators, this will be an empty file when instantiators
// are not turned on. It will contain all wrapped modules otherwise.
// Commenting out for now, as in my tests it made things slower.
//#include "vtkInstantiators.h"

#include <sys/stat.h>

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

#ifdef VTK_COMPILED_USING_MPI
class vtkMPICleanup {
public:
  vtkMPICleanup()
  {
      this->Controller = nullptr;
  }
  void Initialize(int* argc, char ***argv)
  {
      MPI_Init(argc, argv);
      this->Controller = vtkMPIController::New();
      this->Controller->Initialize(argc, argv, 1);
      vtkMultiProcessController::SetGlobalController(this->Controller);
  }
  void Cleanup()
  {
    if ( this->Controller )
    {
      this->Controller->Finalize();
      this->Controller->Delete();
      this->Controller = nullptr;
      vtkMultiProcessController::SetGlobalController(nullptr);
    }
  }
  ~vtkMPICleanup()
  {
    this->Cleanup();
  }

private:
  vtkMPIController *Controller;
};

static vtkMPICleanup VTKMPICleanup;
// AtExitCallback is needed to finalize the MPI controller if the python script
// calls sys.exit() directly.
static void AtExitCallback()
{
  VTKMPICleanup.Cleanup();
}
#endif // VTK_COMPILED_USING_MPI

extern "C" {
#ifdef VTK_PY3K
  PyAPI_FUNC(int) Py_Main(int, wchar_t **);
#else
  PyAPI_FUNC(int) Py_Main(int, char **);
#endif
}

#ifdef VTK_PY3K
#if defined(__APPLE__) && PY_VERSION_HEX < 0x03050000
extern "C" {
extern wchar_t*
_Py_DecodeUTF8_surrogateescape(const char *s, Py_ssize_t size);
}
#endif
#endif

static void vtkPythonAppInitEnableMSVCDebugHook();
static void vtkPythonAppInitPrependPath(const char* self_dir);
static void RemoveArgumentFromArgv(int &argc, char **&argv, int at);

/* The maximum length of a file name.  */
#if defined(PATH_MAX)
# define VTK_PYTHON_MAXPATH PATH_MAX
#elif defined(MAXPATHLEN)
# define VTK_PYTHON_MAXPATH MAXPATHLEN
#else
# define VTK_PYTHON_MAXPATH 16384
#endif

/* Python major.minor version string.  */
#define VTK_PYTHON_TO_STRING(x) VTK_PYTHON_TO_STRING0(x)
#define VTK_PYTHON_TO_STRING0(x) VTK_PYTHON_TO_STRING1(x)
#define VTK_PYTHON_TO_STRING1(x) #x
#define VTK_PYTHON_VERSION VTK_PYTHON_TO_STRING(PY_MAJOR_VERSION.PY_MINOR_VERSION)

int main(int argc, char **argv)
{
  vtkPythonAppInitEnableMSVCDebugHook();

#ifdef VTK_COMPILED_USING_MPI
  VTKMPICleanup.Initialize(&argc, &argv);
  Py_AtExit(::AtExitCallback);
#endif // VTK_COMPILED_USING_MPI

  int displayVersion = 0;
  if ( argc > 1 )
  {
    int cc;
    for ( cc = 1; cc < argc; cc ++ )
    {
      if ( strcmp(argv[cc], "-V") == 0 )
      {
        displayVersion = 1;
      }
      else
      if ( strcmp(argv[cc], "--enable-bt") == 0 )
      {
        RemoveArgumentFromArgv(argc, argv, cc);
        vtksys::SystemInformation::SetStackTraceOnError(1);
      }
    }
  }
  else
  {
    displayVersion = 1;
  }
  if ( displayVersion )
  {
    cout << vtkVersion::GetVTKSourceVersion() << endl;
  }

  // The following code will hack in the path for running VTK/Python
  // from the build tree. Do not try this at home. We are
  // professionals.

  // Set the program name, so that we can ask python to provide us
  // full path.  We need to collapse the path name to aid relative
  // path computation for the VTK python module installation.
  std::string av0 = vtksys::SystemTools::CollapseFullPath(argv[0]);
#ifdef VTK_PY3K
  wchar_t *argv0;
#if PY_VERSION_HEX >= 0x03050000
  argv0 = Py_DecodeLocale(av0.c_str(), nullptr);
#elif defined(__APPLE__)
  argv0 = _Py_DecodeUTF8_surrogateescape(av0.data(), av0.length());
#else
  argv0 = _Py_char2wchar(av0.c_str(), nullptr);
#endif
  if (argv0 == 0)
  {
    fprintf(stderr, "Fatal vtkpython error: "
                    "unable to decode the program name\n");
    return 1;
  }
#else /* VTK < PY3K */
  static char argv0[VTK_PYTHON_MAXPATH];
  strcpy(argv0, av0.c_str());
#endif
  Py_SetProgramName(argv0);

  // This function is generated, and will register any static Python modules for VTK
  // This needs to be done *before* Py_Initialize().
  CMakeLoadAllPythonModules();

  // Initialize interpreter.
  Py_Initialize();

  // Initialize python thread support. This function should first be
  // called from the main thread, after Py_Initialize.
#ifndef VTK_NO_PYTHON_THREADS
  PyEval_InitThreads();
#endif

  // Compute the directory containing this executable.  The python
  // sys.executable variable contains the full path to the interpreter
  // executable.
  char tmpExe[] = "executable";
  PyObject *executable = PySys_GetObject(tmpExe);
#ifdef VTK_PY3K
  executable = PyUnicode_EncodeFSDefault(executable);
#endif
  const char *exe_str = PyBytes_AsString(executable);
  if (exe_str)
  {
    // Use the executable location to try to set sys.path to include
    // the VTK python modules.
    std::string self_dir = vtksys::SystemTools::GetFilenamePath(exe_str);
    vtkPythonAppInitPrependPath(self_dir.c_str());
  }
#ifdef VTK_PY3K
  Py_DECREF(executable);
#endif

  // Ok, all done, now enter python main.
#ifdef VTK_PY3K
  // Need two copies of args, because programs might modify the first
  wchar_t **argvWide = new wchar_t *[argc];
  wchar_t **argvWide2 = new wchar_t *[argc];
  for (int i = 0; i < argc; i++)
  {
#if PY_VERSION_HEX >= 0x03050000
    argvWide[i] = Py_DecodeLocale(argv[i], nullptr);
#elif defined(__APPLE__)
    argvWide[i] = _Py_DecodeUTF8_surrogateescape(argv[i], strlen(argv[i]));
#else
    argvWide[i] = _Py_char2wchar(argv[i], nullptr);
#endif
    argvWide2[i] = argvWide[i];
    if (argvWide[i] == 0)
    {
      fprintf(stderr, "Fatal vtkpython error: "
                      "unable to decode the command line argument #%i\n",
                      i + 1);
      for (int k = 0; k < i; k++)
      {
        PyMem_Free(argvWide2[i]);
      }
      PyMem_Free(argv0);
      delete [] argvWide;
      delete [] argvWide2;
      return 1;
    }
  }
  int res = Py_Main(argc, argvWide);
  PyMem_Free(argv0);
  for (int i = 0; i < argc; i++)
  {
    PyMem_Free(argvWide2[i]);
  }
  delete [] argvWide;
  delete [] argvWide2;
  return res;
#else
  return Py_Main(argc, argv);
#endif
}

// For a DEBUG build on MSVC, add a hook to prevent error dialogs when
// being run from DART.
#if defined(_MSC_VER) && defined(_DEBUG)
# include <crtdbg.h>
static int vtkPythonAppInitDebugReport(int, char* message, int*)
{
  fprintf(stderr, message);
  exit(1);
}
void vtkPythonAppInitEnableMSVCDebugHook()
{
  if(getenv("DART_TEST_FROM_DART") ||
    getenv("DASHBOARD_TEST_FROM_CTEST"))
  {
    _CrtSetReportHook(vtkPythonAppInitDebugReport);
  }
}
#else
void vtkPythonAppInitEnableMSVCDebugHook()
{
}
#endif

//----------------------------------------------------------------------------
static void vtkPythonAppInitPrependPythonPath(const char* dir)
{
  // Convert slashes for this platform.
  std::string out_dir = dir;
#if defined(_WIN32) && !defined(__CYGWIN__)
  for(std::string::size_type i = 0; i < out_dir.length(); ++i)
  {
    if(out_dir[i] == '/')
    {
      out_dir[i] = '\\';
    }
  }
#endif

  // Append the path to the python sys.path object.
  char tmpPath[] = "path";
  PyObject* path = PySys_GetObject(tmpPath);
  PyObject* newpath;
  newpath = PyString_FromString(out_dir.c_str());
  PyList_Insert(path, 0, newpath);
  Py_DECREF(newpath);
}

//----------------------------------------------------------------------------
static void vtkPythonAppInitPrependPath(const char* self_dir)
{
  // Try to put the VTK python module location in sys.path.
  const char* build_dirs[] = {
    "/../Wrapping/Python",
    "/../VTK/Wrapping/Python",
    nullptr
  };

  int found_vtk = 0;
  for (const char** build_dir = build_dirs; *build_dir && !found_vtk; ++build_dir)
  {
    std::string package_dir = self_dir;
#if defined(CMAKE_INTDIR)
    package_dir += "/..";
#endif
    package_dir += (*build_dir);
    package_dir = vtksys::SystemTools::CollapseFullPath(package_dir.c_str());

    // We try to locate the directory containing vtk python module files.
    std::string vtk_module_dir = package_dir + "/vtk";
    if(vtksys::SystemTools::FileIsDirectory(vtk_module_dir.c_str()))
    {
      // This executable is running from the build tree.  Prepend the
      // library directory and package directory to the search path.
      vtkPythonAppInitPrependPythonPath(package_dir.c_str());
      vtkPythonAppInitPrependPythonPath(VTK_PYTHON_LIBRARY_DIR);
      found_vtk = 1;
    }
  }

  if (!found_vtk)
  {
    // This executable is running from an install tree.  Check for
    // possible VTK python module locations.  See
    // http://python.org/doc/2.4.1/inst/alt-install-windows.html for
    // information about possible install locations.  If the user
    // changes the prefix to something other than VTK's prefix or
    // python's native prefix then he/she will have to get the
    // packages in sys.path himself/herself.
    const char* inst_dirs[] = {
      "/lib/python" VTK_PYTHON_VERSION "/site-packages/vtk", // UNIX --prefix
      "/python" VTK_PYTHON_VERSION "/site-packages/vtk", // UNIX + Forwarding exe --prefix
      "/../Library/Python/" VTK_PYTHON_VERSION "/site-packages/vtk", // Apple + Forwarding exe
      "/lib/python/vtk", // UNIX --home
      "/Lib/site-packages/vtk", "/Lib/vtk", // Windows
      "/site-packages/vtk", "/vtk", // Windows
      nullptr
    };
    std::string prefix = vtksys::SystemTools::GetFilenamePath(self_dir);
    for(const char** dir = inst_dirs; *dir; ++dir)
    {
      std::string package_dir = prefix;
      package_dir += *dir;
      package_dir = vtksys::SystemTools::CollapseFullPath(package_dir.c_str());
      if(vtksys::SystemTools::FileIsDirectory(package_dir.c_str()))
      {
        // We found the modules.  Add the location to sys.path, but
        // without the "/vtk" suffix.
        std::string path_dir =
          vtksys::SystemTools::GetFilenamePath(package_dir);
        vtkPythonAppInitPrependPythonPath(path_dir.c_str());
        break;
      }
    }

    // This executable does not actually link to the python wrapper
    // libraries, though it probably should now that the stub-modules
    // are separated from them.  Since it does not we have to make
    // sure the wrapper libraries can be found by the dynamic loader
    // when the stub-modules are loaded.  On UNIX this executable must
    // be running in an environment where the main VTK libraries (to
    // which this executable does link) have been found, so the
    // wrapper libraries will also be found.  On Windows this
    // executable may have simply found its .dll files next to itself
    // so the wrapper libraries may not be found when the wrapper
    // modules are loaded.  Solve this problem by adding this
    // executable's location to the system PATH variable.  Note that
    // this need only be done for an installed VTK because in the
    // build tree the wrapper modules are in the same directory as the
    // wrapper libraries.
#if defined(_WIN32)
    static char system_path[(VTK_PYTHON_MAXPATH+1)*10] = "PATH=";
    strcat(system_path, self_dir);
    if(char* oldpath = getenv("PATH"))
    {
      strcat(system_path, ";");
      strcat(system_path, oldpath);
    }
    putenv(system_path);
#endif
  }

  // Try to put the VTK python module location in sys.path.
  const char* site_build_dirs[] = {
    "/../lib/site-packages",
    nullptr
  };

  int found_site = 0;
  for (const char** site_build_dir = site_build_dirs; *site_build_dir && !found_site; ++site_build_dir)
  {
    std::string package_dir = self_dir;
#if defined(CMAKE_INTDIR)
    package_dir += "/..";
#endif
    package_dir += (*site_build_dir);
    package_dir = vtksys::SystemTools::CollapseFullPath(package_dir.c_str());

    // We try to locate the directory containing vtk python module files.
    if(vtksys::SystemTools::FileIsDirectory(package_dir.c_str()))
    {
      // This executable is running from the build tree.  Prepend the
      // library directory and package directory to the search path.
      vtkPythonAppInitPrependPythonPath(package_dir.c_str());
      vtkPythonAppInitPrependPythonPath(VTK_PYTHON_LIBRARY_DIR);
      found_site = 1;
    }
  }
}

//----------------------------------------------------------------------------
static void RemoveArgumentFromArgv(int &argc, char **&argv, int at)
{
  int ii=at+1;
  while (ii<argc)
  {
    argv[ii-1]=argv[ii];
    ii+=1;
  }
  argc-=1;
}