#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;
}