// Copyright (C) 2008 Soren Hauberg
//
// This program 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.
//
// This program 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 this program; if not, see <http://www.gnu.org/licenses/>.

#include <octave/oct.h>

extern std::string raw_help (const std::string& nm, bool &symbol_found);

static bool
looks_like_html (const std::string &msg)
{
  const size_t p1 = msg.find ('\n');
  std::string t = msg.substr (0, p1);
  const size_t p2 = t.find ("<html"); // XXX: this comparison should be case-insensitive

  return (p2 != NPOS);
}

static bool
looks_like_texinfo (const std::string& msg, size_t& p1)
{
  p1 = msg.find ('\n');

  std::string t = msg.substr (0, p1);

  if (p1 == NPOS)
    p1 = 0;

  size_t p2 = t.find ("-*- texinfo -*-");

  return (p2 != NPOS);
}

DEFUN_DLD(get_help_text, args, , 
"-*- texinfo -*-\n\
@deftypefn {Loadable Function} address@hidden, @var{format}] =} get_help_text (@var{name})\n\
Returns the help text of a given function.\n\
\n\
This function returns the raw help text @var{text} and an indication of its\n\
format for the function @var{name}. The format indication @var{format} is a string\n\
that can be either @t{\"texinfo\"}, @t{\"html\"}, or @t{\"plain text\"}.\n\
\n\
To convert the help text to other formats, use the @code{makeinfo} function.\n\
\n\
@seealso{makeinfo}\n\
@end deftypefn\n\
")
{
  octave_value_list retval;
  if (args.length () != 1)
    {
      print_usage ();
      return retval;
    }
  
  const std::string name = args (0).string_value ();
  if (error_state)
    {
      error ("get_help_text: invalid input");
      return retval;
    }
    
  bool symbol_found = false;
  std::string text = raw_help (name, symbol_found);
  
  std::string format = "Not found";
  if (symbol_found)
    {
      size_t idx = -1;
      if (looks_like_texinfo (text, idx))
        {
          format = "texinfo";
          text.erase (0, idx);
        }
      else if (looks_like_html (text))
        {
          format = "html";
        }
      else
        {
          format = "plain text";
        }
    }
  
  retval.append (octave_value (text));
  retval.append (octave_value (format));
  return retval;
}