/*

Copyright (C) 1996-2016 John W. Eaton

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 <cstdlib>

#include <algorithm>
#include <iostream>
#include <string>

#include "dir-ops.h"
#include "oct-env.h"
#include "file-stat.h"
#include "pathsearch.h"
#include "str-vec.h"

#include <defaults.h>
#include "defun.h"
#include "error.h"
#include "file-ops.h"
#include "errwarn.h"
#include "help.h"
#include "input.h"
#include "load-path.h"
#include "ovl.h"
#include "ov.h"
#include "parse.h"
#include "interpreter.h"
#include "unwind-prot.h"
#include "variables.h"
#include <version.h>

std::string Voctave_home;

std::string Vbin_dir;
std::string Vinfo_dir;
std::string Vdata_dir;
std::string Vlibexec_dir;
std::string Varch_lib_dir;
std::string Vlocal_arch_lib_dir;
std::string Vlocal_api_arch_lib_dir;
std::string Vlocal_ver_arch_lib_dir;

std::string Vlocal_ver_oct_file_dir;
std::string Vlocal_api_oct_file_dir;
std::string Vlocal_oct_file_dir;

std::string Vlocal_ver_fcn_file_dir;
std::string Vlocal_api_fcn_file_dir;
std::string Vlocal_fcn_file_dir;

std::string Voct_data_dir;
std::string Voct_etc_dir;
std::string Voct_locale_dir;

std::string Voct_file_dir;
std::string Vfcn_file_dir;

std::string Vimage_dir;

// The path that will be searched for programs that we execute.
// (--exec-path path)
static std::string VEXEC_PATH;

// Name of the editor to be invoked by the edit_history command.
std::string VEDITOR;

static std::string VIMAGE_PATH;

std::string Vlocal_site_defaults_file;
std::string Vsite_defaults_file;

std::string Vbuilt_in_docstrings_file;

std::string
subst_octave_home (const std::string& s)
{
  std::string retval;

  std::string prefix = OCTAVE_PREFIX;

  retval = s;

  if (Voctave_home != prefix)
    {
      size_t len = prefix.length ();

      if (s.substr (0, len) == prefix)
        retval.replace (0, len, Voctave_home);
    }

  if (octave::sys::file_ops::dir_sep_char () != '/')
    std::replace (retval.begin (), retval.end (), '/',
                  octave::sys::file_ops::dir_sep_char ());

  return retval;
}

static void
set_octave_home (void)
{
  std::string oh = octave::sys::env::getenv ("OCTAVE_HOME");

  Voctave_home = oh.empty () ? std::string (OCTAVE_PREFIX) : oh;
}

static void
set_default_info_dir (void)
{
  Vinfo_dir = subst_octave_home (OCTAVE_INFODIR);
}

static void
set_default_data_dir (void)
{
  Vdata_dir = subst_octave_home (OCTAVE_DATADIR);
}

static void
set_default_libexec_dir (void)
{
  Vlibexec_dir = subst_octave_home (OCTAVE_LIBEXECDIR);
}

static void
set_default_arch_lib_dir (void)
{
  Varch_lib_dir = subst_octave_home (OCTAVE_ARCHLIBDIR);
}

static void
set_default_local_arch_lib_dir (void)
{
  Vlocal_arch_lib_dir = subst_octave_home (OCTAVE_LOCALARCHLIBDIR);
}

static void
set_default_local_api_arch_lib_dir (void)
{
  Vlocal_api_arch_lib_dir = subst_octave_home (OCTAVE_LOCALAPIARCHLIBDIR);
}

static void
set_default_local_ver_arch_lib_dir (void)
{
  Vlocal_ver_arch_lib_dir = subst_octave_home (OCTAVE_LOCALVERARCHLIBDIR);
}

static void
set_default_local_ver_oct_file_dir (void)
{
  Vlocal_ver_oct_file_dir = subst_octave_home (OCTAVE_LOCALVEROCTFILEDIR);
}

static void
set_default_local_api_oct_file_dir (void)
{
  Vlocal_api_oct_file_dir = subst_octave_home (OCTAVE_LOCALAPIOCTFILEDIR);
}

static void
set_default_local_oct_file_dir (void)
{
  Vlocal_oct_file_dir = subst_octave_home (OCTAVE_LOCALOCTFILEDIR);
}

static void
set_default_local_ver_fcn_file_dir (void)
{
  Vlocal_ver_fcn_file_dir = subst_octave_home (OCTAVE_LOCALVERFCNFILEDIR);
}

static void
set_default_local_api_fcn_file_dir (void)
{
  Vlocal_api_fcn_file_dir = subst_octave_home (OCTAVE_LOCALAPIFCNFILEDIR);
}

static void
set_default_local_fcn_file_dir (void)
{
  Vlocal_fcn_file_dir = subst_octave_home (OCTAVE_LOCALFCNFILEDIR);
}

static void
set_default_fcn_file_dir (void)
{
  Vfcn_file_dir = subst_octave_home (OCTAVE_FCNFILEDIR);
}

static void
set_default_image_dir (void)
{
  Vimage_dir = subst_octave_home (OCTAVE_IMAGEDIR);
}

static void
set_default_oct_data_dir (void)
{
  Voct_data_dir = subst_octave_home (OCTAVE_OCTDATADIR);
}

static void
set_default_oct_etc_dir (void)
{
  Voct_etc_dir = subst_octave_home (OCTAVE_OCTETCDIR);
}

static void
set_default_oct_locale_dir (void)
{
  Voct_locale_dir = subst_octave_home (OCTAVE_OCTLOCALEDIR);
}

static void
set_default_oct_file_dir (void)
{
  Voct_file_dir = subst_octave_home (OCTAVE_OCTFILEDIR);
}

static void
set_default_bin_dir (void)
{
  Vbin_dir = subst_octave_home (OCTAVE_BINDIR);
}

void
set_exec_path (const std::string& path_arg)
{
  std::string tpath = path_arg;

  if (tpath.empty ())
    tpath = octave::sys::env::getenv ("OCTAVE_EXEC_PATH");

  if (tpath.empty ())
    tpath = Vlocal_ver_arch_lib_dir + octave::directory_path::path_sep_str ()
            + Vlocal_api_arch_lib_dir + octave::directory_path::path_sep_str ()
            + Vlocal_arch_lib_dir + octave::directory_path::path_sep_str ()
            + Varch_lib_dir + octave::directory_path::path_sep_str ()
            + Vbin_dir;

  VEXEC_PATH = tpath;

  // FIXME: should we really be modifying PATH in the environment?
  // The way things are now, Octave will ignore directories set in the
  // PATH with calls like
  //
  //   setenv ("PATH", "/my/path");
  //
  // To fix this, I think Octave should be searching the combination of
  // PATH and EXEC_PATH for programs that it executes instead of setting
  // the PATH in the environment and relying on the shell to do the
  // searching.

  // This is static so that even if set_exec_path is called more than
  // once, shell_path is the original PATH from the environment,
  // before we start modifying it.
  static std::string shell_path = octave::sys::env::getenv ("PATH");

  if (! shell_path.empty ())
    tpath = shell_path + octave::directory_path::path_sep_str () + tpath;

  octave::sys::env::putenv ("PATH", tpath);
}

void
set_image_path (const std::string& path)
{
  VIMAGE_PATH = ".";

  std::string tpath = path;

  if (tpath.empty ())
    tpath = octave::sys::env::getenv ("OCTAVE_IMAGE_PATH");

  if (! tpath.empty ())
    VIMAGE_PATH += octave::directory_path::path_sep_str () + tpath;

  tpath = genpath (Vimage_dir, "");

  if (! tpath.empty ())
    VIMAGE_PATH += octave::directory_path::path_sep_str () + tpath;
}

static void
set_default_doc_cache_file (void)
{
  if (Vdoc_cache_file.empty ())
    {
      std::string def_file = subst_octave_home (OCTAVE_DOC_CACHE_FILE);

      std::string env_file = octave::sys::env::getenv ("OCTAVE_DOC_CACHE_FILE");

      Vdoc_cache_file = env_file.empty () ? def_file : env_file;
    }
}

static void
set_default_texi_macros_file (void)
{
  if (Vtexi_macros_file.empty ())
    {
      std::string def_file = subst_octave_home (OCTAVE_TEXI_MACROS_FILE);

      std::string env_file = octave::sys::env::getenv ("OCTAVE_TEXI_MACROS_FILE");

      Vtexi_macros_file = env_file.empty () ? def_file : env_file;
    }
}

static void
set_default_info_file (void)
{
  if (Vinfo_file.empty ())
    {
      std::string std_info_file = subst_octave_home (OCTAVE_INFOFILE);

      std::string oct_info_file = octave::sys::env::getenv ("OCTAVE_INFO_FILE");

      Vinfo_file = oct_info_file.empty () ? std_info_file : oct_info_file;
    }
}

static void
set_default_info_prog (void)
{
  if (Vinfo_program.empty ())
    {
      std::string oct_info_prog = octave::sys::env::getenv ("OCTAVE_INFO_PROGRAM");

      if (oct_info_prog.empty ())
        Vinfo_program = "info";
      else
        Vinfo_program = std::string (oct_info_prog);
    }
}

static void
set_default_editor (void)
{
  VEDITOR = "emacs";

  std::string env_editor = octave::sys::env::getenv ("EDITOR");

  if (! env_editor.empty ())
    VEDITOR = env_editor;
}

static void
set_local_site_defaults_file (void)
{
  std::string lsf = octave::sys::env::getenv ("OCTAVE_SITE_INITFILE");

  if (lsf.empty ())
    {
      Vlocal_site_defaults_file
        = subst_octave_home (OCTAVE_LOCALSTARTUPFILEDIR);
      Vlocal_site_defaults_file.append ("/octaverc");
    }
  else
    Vlocal_site_defaults_file = lsf;
}

static void
set_site_defaults_file (void)
{
  std::string sf = octave::sys::env::getenv ("OCTAVE_VERSION_INITFILE");

  if (sf.empty ())
    {
      Vsite_defaults_file = subst_octave_home (OCTAVE_STARTUPFILEDIR);
      Vsite_defaults_file.append ("/octaverc");
    }
  else
    Vsite_defaults_file = sf;
}

static void
set_built_in_docstrings_file (void)
{
  if (Vbuilt_in_docstrings_file.empty ())
    {
      std::string df = octave::sys::env::getenv ("OCTAVE_BUILT_IN_DOCSTRINGS_FILE");

      if (df.empty ())
        Vbuilt_in_docstrings_file
          = Voct_etc_dir + octave::sys::file_ops::dir_sep_str () + "built-in-docstrings";
      else
        Vbuilt_in_docstrings_file = df;
    }
}

void
install_defaults (void)
{
  // OCTAVE_HOME must be set first!

  set_octave_home ();

  set_default_info_dir ();

  set_default_data_dir ();

  set_default_libexec_dir ();

  set_default_arch_lib_dir ();

  set_default_local_ver_arch_lib_dir ();
  set_default_local_api_arch_lib_dir ();
  set_default_local_arch_lib_dir ();

  set_default_local_ver_oct_file_dir ();
  set_default_local_api_oct_file_dir ();
  set_default_local_oct_file_dir ();

  set_default_local_ver_fcn_file_dir ();
  set_default_local_api_fcn_file_dir ();
  set_default_local_fcn_file_dir ();

  set_default_oct_data_dir ();
  set_default_oct_etc_dir ();
  set_default_oct_locale_dir ();

  set_default_fcn_file_dir ();
  set_default_oct_file_dir ();

  set_default_image_dir ();

  set_default_bin_dir ();

  set_exec_path ();

  set_image_path ();

  set_default_doc_cache_file ();

  set_default_texi_macros_file ();

  set_default_info_file ();

  set_default_info_prog ();

  set_default_editor ();

  set_local_site_defaults_file ();

  set_site_defaults_file ();

  set_built_in_docstrings_file ();
}

DEFUN (EDITOR, args, nargout,
       doc: /* -*- texinfo -*-
@deftypefn  {} {@var{val} =} EDITOR ()
@deftypefnx {} {@var{old_val} =} EDITOR (@var{new_val})
@deftypefnx {} {} EDITOR (@var{new_val}, "local")
Query or set the internal variable that specifies the default text editor.

The default value is taken from the environment variable @w{@env{EDITOR}}
when Octave starts.  If the environment variable is not initialized,
@w{@env{EDITOR}} will be set to @qcode{"emacs"}.

When called from inside a function with the @qcode{"local"} option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.

@seealso{edit, edit_history}
@end deftypefn */)
{
  return SET_NONEMPTY_INTERNAL_STRING_VARIABLE (EDITOR);
}

/*
%!test
%! orig_val = EDITOR ();
%! old_val = EDITOR ("X");
%! assert (orig_val, old_val);
%! assert (EDITOR (), "X");
%! EDITOR (orig_val);
%! assert (EDITOR (), orig_val);

%!error (EDITOR (1, 2))
*/

DEFUN (EXEC_PATH, args, nargout,
       doc: /* -*- texinfo -*-
@deftypefn  {} {@var{val} =} EXEC_PATH ()
@deftypefnx {} {@var{old_val} =} EXEC_PATH (@var{new_val})
@deftypefnx {} {} EXEC_PATH (@var{new_val}, "local")
Query or set the internal variable that specifies a colon separated
list of directories to append to the shell PATH when executing external
programs.

The initial value of is taken from the environment variable
@w{@env{OCTAVE_EXEC_PATH}}, but that value can be overridden by the command
line argument @option{--exec-path PATH}.

When called from inside a function with the @qcode{"local"} option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.

@seealso{IMAGE_PATH, OCTAVE_HOME}
@end deftypefn */)
{
  octave_value retval = SET_NONEMPTY_INTERNAL_STRING_VARIABLE (EXEC_PATH);

  if (args.length () > 0)
    set_exec_path (VEXEC_PATH);

  return retval;
}

/*
%!test
%! orig_val = EXEC_PATH ();
%! old_val = EXEC_PATH ("X");
%! assert (orig_val, old_val);
%! assert (EXEC_PATH (), "X");
%! EXEC_PATH (orig_val);
%! assert (EXEC_PATH (), orig_val);

%!error (EXEC_PATH (1, 2))
*/

DEFUN (IMAGE_PATH, args, nargout,
       doc: /* -*- texinfo -*-
@deftypefn  {} {@var{val} =} IMAGE_PATH ()
@deftypefnx {} {@var{old_val} =} IMAGE_PATH (@var{new_val})
@deftypefnx {} {} IMAGE_PATH (@var{new_val}, "local")
Query or set the internal variable that specifies a colon separated
list of directories in which to search for image files.

When called from inside a function with the @qcode{"local"} option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.

@seealso{EXEC_PATH, OCTAVE_HOME}
@end deftypefn */)
{
  return SET_NONEMPTY_INTERNAL_STRING_VARIABLE (IMAGE_PATH);
}

/*
%!test
%! orig_val = IMAGE_PATH ();
%! old_val = IMAGE_PATH ("X");
%! assert (orig_val, old_val);
%! assert (IMAGE_PATH (), "X");
%! IMAGE_PATH (orig_val);
%! assert (IMAGE_PATH (), orig_val);

%!error (IMAGE_PATH (1, 2))
*/

DEFUN (OCTAVE_HOME, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} OCTAVE_HOME ()
Return the name of the top-level Octave installation directory.
@seealso{EXEC_PATH, IMAGE_PATH}
@end deftypefn */)
{
  if (args.length () != 0)
    print_usage ();

  return ovl (Voctave_home);
}

/*
%!assert (ischar (OCTAVE_HOME ()))
%!error OCTAVE_HOME (1)
*/

DEFUNX ("OCTAVE_VERSION", FOCTAVE_VERSION, args, ,
        doc: /* -*- texinfo -*-
@deftypefn {} {} OCTAVE_VERSION ()
Return the version number of Octave as a string.
@seealso{ver, version}
@end deftypefn */)
{
  if (args.length () != 0)
    print_usage ();

  return ovl (OCTAVE_VERSION);
}

/*
%!assert (ischar (OCTAVE_VERSION ()))
%!error OCTAVE_VERSION (1)
*/

