/*

Copyright (C) 2008 Michael Goffioul

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#if defined (HAVE_CONFIG_H)
#include <config.h>
#endif

#include <string>
#include <map>
#include <iostream>
#include <algorithm>
#include <cstdlib>

#if defined (__WIN32__) && ! defined (_POSIX_VERSION)
#include <windows.h>
#endif

static bool initialized = false;
static std::map<std::string,std::string> vars;
static std::string OCTAVE_HOME, PREFIX;
static std::string usage_msg = "usage: octave-config [options]";
static std::string help_msg =
"\n"
"Options:\n"
"\n"
"  -h, -?, --help        Print this message.\n"
"\n"
"  --m-site-dir          Print the name of the directory where Octave\n"
"                        expects to find locally installed .m files.\n"
"\n"
"  --oct-site-dir        Print the name of the directory where Octave\n"
"                        expects to find locally installed .oct files.\n"
"\n"
"  -p VAR, --print VAR   Print the value of the given configuration\n"
"		        variable VAR.  Recognized variables are:\n"
"\n"
"			  API_VERSION	         LOCALAPIARCHLIBDIR\n"
"			  CANONICAL_HOST_TYPE	 LOCALAPIFCNFILEDIR\n"
"			  DEFAULT_PAGER	         LOCALAPIOCTFILEDIR\n"
"			  ARCHLIBDIR	         LOCALARCHLIBDIR\n"
"			  BINDIR	         LOCALFCNFILEDIR\n"
"			  DATADIR	         LOCALOCTFILEDIR\n"
"			  DATAROOTDIR	         LOCALSTARTUPFILEDIR\n"
"			  EXEC_PREFIX	         LOCALVERARCHLIBDIR\n"
"			  FCNFILEDIR		 LOCALVERFCNFILEDIR\n"
"			  LOCALVEROCTFILEDIR	 MAN1DIR\n"
"			  IMAGEDIR	         MANDIR\n"
"			  MAN1EXT	         OCTFILEDIR\n"
"			  INCLUDEDIR	         OCTINCLUDEDIR\n"
"			  INFODIR	         OCTLIBDIR\n"
"			  INFOFILE	         PREFIX\n"
"			  LIBDIR	         STARTUPFILEDIR\n"
"			  LIBEXECDIR		 VERSION\n"
"\n"
"  -v, --version         Print the Octave version number.\n"
"\n";

static std::string
substitute_prefix (const std::string& s, const std::string& prefix,
		   const std::string new_prefix)
{
  std::string retval = s;

  if (!prefix.empty () && new_prefix != prefix)
    {
      int len = prefix.length ();
      if (retval.find (prefix) == 0)
	retval.replace (0, len, new_prefix);
    }

#if defined (__WIN32__) && ! defined (_POSIX_VERSION)
  std::replace (retval.begin (), retval.end (), '/', '\\');
#endif

  return retval;
}

static void
initialize (void)
{
  if (initialized)
    return;

  initialized = true;

  const char *homestr = getenv ("OCTAVE_HOME");
  OCTAVE_HOME = (homestr ? homestr : "");
  PREFIX = %OCTAVE_PREFIX%;

#if defined (__WIN32__) && ! defined (_POSIX_VERSION)
  int n = 1024;

  std::string bin_dir (n, '\0');

  while (true)
    {
      int status = GetModuleFileName (0, &bin_dir[0], n);

      if (status < n)
	{
	  bin_dir.resize (status);
	  break;
	}
      else
	{
	  n *= 2;
	  bin_dir.resize (n);
	}
    }

  if (! bin_dir.empty ())
    {
      size_t pos = bin_dir.rfind ("\\bin\\");

      if (pos != std::string::npos)
	OCTAVE_HOME = bin_dir.substr (0, pos);
    }
#endif

  vars["API_VERSION"] = %OCTAVE_API_VERSION%;
  vars["CANONICAL_HOST_TYPE"] = %OCTAVE_CANONICAL_HOST_TYPE%;
  vars["DEFAULT_PAGER"] = %OCTAVE_DEFAULT_PAGER%;
  vars["ARCHLIBDIR"] = substitute_prefix (%OCTAVE_ARCHLIBDIR%, PREFIX, OCTAVE_HOME);
  vars["BINDIR"] = substitute_prefix (%OCTAVE_BINDIR%, PREFIX, OCTAVE_HOME);
  vars["DATADIR"] =substitute_prefix (%OCTAVE_DATADIR%, PREFIX, OCTAVE_HOME);
  vars["DATAROOTDIR"] =substitute_prefix (%OCTAVE_DATAROOTDIR%, PREFIX, OCTAVE_HOME);
  vars["EXEC_PREFIX"] =substitute_prefix (%OCTAVE_EXEC_PREFIX%, PREFIX, OCTAVE_HOME);
  vars["FCNFILEDIR"] =substitute_prefix (%OCTAVE_FCNFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["IMAGEDIR"] =substitute_prefix (%OCTAVE_IMAGEDIR%, PREFIX, OCTAVE_HOME);
  vars["INCLUDEDIR"] =substitute_prefix (%OCTAVE_INCLUDEDIR%, PREFIX, OCTAVE_HOME);
  vars["INFODIR"] =substitute_prefix (%OCTAVE_INFODIR%, PREFIX, OCTAVE_HOME);
  vars["INFOFILE"] =substitute_prefix (%OCTAVE_INFOFILE%, PREFIX, OCTAVE_HOME);
  vars["LIBDIR"] =substitute_prefix (%OCTAVE_LIBDIR%, PREFIX, OCTAVE_HOME);
  vars["LIBEXECDIR"] =substitute_prefix (%OCTAVE_LIBEXECDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALAPIARCHLIBDIR"] =substitute_prefix (%OCTAVE_LOCALAPIARCHLIBDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALAPIFCNFILEDIR"] =substitute_prefix (%OCTAVE_LOCALAPIFCNFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALAPIOCTFILEDIR"] =substitute_prefix (%OCTAVE_LOCALAPIOCTFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALARCHLIBDIR"] =substitute_prefix (%OCTAVE_LOCALARCHLIBDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALFCNFILEDIR"] =substitute_prefix (%OCTAVE_LOCALFCNFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALOCTFILEDIR"] =substitute_prefix (%OCTAVE_LOCALOCTFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALSTARTUPFILEDIR"] =substitute_prefix (%OCTAVE_LOCALSTARTUPFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALVERARCHLIBDIR"] =substitute_prefix (%OCTAVE_LOCALVERARCHLIBDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALVERFCNFILEDIR"] =substitute_prefix (%OCTAVE_LOCALVERFCNFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["LOCALVEROCTFILEDIR"] =substitute_prefix (%OCTAVE_LOCALVEROCTFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["MAN1DIR"] =substitute_prefix (%OCTAVE_MAN1DIR%, PREFIX, OCTAVE_HOME);
  vars["MAN1EXT"] = %OCTAVE_MAN1EXT%;
  vars["MANDIR"] =substitute_prefix (%OCTAVE_MANDIR%, PREFIX, OCTAVE_HOME);
  vars["OCTFILEDIR"] =substitute_prefix (%OCTAVE_OCTFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["OCTINCLUDEDIR"] =substitute_prefix (%OCTAVE_OCTINCLUDEDIR%, PREFIX, OCTAVE_HOME);
  vars["OCTLIBDIR"] =substitute_prefix (%OCTAVE_OCTLIBDIR%, PREFIX, OCTAVE_HOME);
  vars["PREFIX"] = (OCTAVE_HOME.empty() ? PREFIX : OCTAVE_HOME);
  vars["STARTUPFILEDIR"] =substitute_prefix (%OCTAVE_STARTUPFILEDIR%, PREFIX, OCTAVE_HOME);
  vars["VERSION"] = %OCTAVE_VERSION%;
}

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

  if (argc == 1)
    {
      std::cout << usage_msg << std::endl;
      return 1;
    }

  for (int i = 1; i < argc; i++)
    {
      std::string arg (argv[i]);

      if (arg == "-h" || arg == "-?" || arg == "--help")
	{
	  std::cout << usage_msg << std::endl;
	  std::cout << help_msg;
	  return 0;
	}
      else if (arg == "--m-site-dir")
	std::cout << vars["LOCALVERFCNFILEDIR"] << std::endl;
      else if (arg == "--oct-site-dir")
	std::cout << vars["LOCALVEROCTFILEDIR"] << std::endl;
      else if (arg == "-v" || arg == "--version")
	std::cout << vars["VERSION"] << std::endl;
      else if (arg == "-p" || arg == "--print")
	{
	  if (i < argc-1)
	    {
	      arg = argv[++i];
	      std::cout << vars[arg] << std::endl;
	    }
	  else
	    {
	      std::cerr << "octave-config: " << arg
			<< " options requires argument" << std::endl;
	      return 1;
	    }
	}
      else
	{
	  std::cerr << "octave-config: unrecognized argument " << arg << std::endl;
	  return 1;
	}
    }
  
  return 0;
}