## Copyright (C) 2010 Martin Hepperle
##
## 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/>.

## -*- texinfo -*-
## @deftypefn  {Function File} {@var{btn} =} questdlg (@var{msg})
## @deftypefnx {Function File} {@var{btn} =} questdlg (@var{msg}, @var{title})
## @deftypefnx {Function File} {@var{btn} =} questdlg (@var{msg}, @var{title}, @var{default})
## @deftypefnx {Function File} {@var{btn} =} questdlg (@var{msg}, @var{title}, @var{btn1}, @var{btn2}, @var{default})
## @deftypefnx {Function File} {@var{btn} =} questdlg (@var{msg}, @var{title}, @var{btn1}, @var{btn2}, @var{btn3}, @var{default})
## Display @var{msg} using a question dialog box and return the caption
## of the activated button.
##
## The dialog may contain two or three buttons which will all close the dialog.
##
## The message may have multiple lines separated by newline characters
## ("\n"), or it may be a cellstr array with one element for each
## line.  The optional @var{title} (character string) can be used to
## decorate the dialog caption.
##
## The string @var{default} identifies the default button, 
## which is activated by pressing the @key{ENTER} key.
## It must match one of the strings given in @var{btn1}, @var{btn2}, or
## @var{btn3}.
##
## If only @var{msg} and @var{title} are specified, three buttons with
## the default captions "Yes", "No", and "Cancel" are used.
##
## If only two button captions, @var{btn1} and @var{btn2}, are specified 
## the dialog will have only these two buttons.
##
## @seealso{errordlg, helpdlg, inputdlg, listdlg, warndlg}
## @end deftypefn

function btn = questdlg (msg, title = "Question Dialog", varargin)

  if (nargin < 1 || nargin > 6)
    print_usage ();
  endif
  
  if (! ischar (msg))
    if (iscell (msg))
      msg = sprintf ("%s\n", msg{:});
      msg(end) = "";
    else
      error ("questdlg: MSG must be a character string or cellstr array");
    endif
  endif

  if (! ischar (title))
    error ("questdlg: TITLES must be a character string");
  endif

  options{1} = "Yes";      # button1
  options{2} = "No";       # button2
  options{3} = "Cancel";   # button3
  options{4} = "Yes";      # default

  defbtn_error_msg = "questdlg: DEFAULT must match one of the button options";

  switch (numel (varargin))
    case 0
      ## use default default

    case 1
      ## default button string
      options{4} = varargin{1};  # default
      if (! any (strcmp (options{4}, options(1:3))))
        error (defbtn_error_msg);
      end

    case 3
      ## two buttons and default button string
      options{1} = varargin{1};  # button1
      options{2} = "";           # not used, no middle button
      options{3} = varargin{2};  # button3
      options{4} = varargin{3};  # default
      if (! any (strcmp (options{4}, options([1 3]))))
        error (defbtn_error_msg);
      end

    case 4
      ## three buttons and default button string
      options{1} = varargin{1};  # button1
      options{2} = varargin{2};  # button2
      options{3} = varargin{3};  # button3
      options{4} = varargin{4};  # default
      if (! any (strcmp (options{4}, options(1:3))))
        error (defbtn_error_msg);
      end

    otherwise
      print_usage ();

  endswitch

  if (__octave_link_enabled__ ())
    btn = __octave_link_question_dialog__ (msg, title, options{1}, options{2},
                                           options{3}, options{4});
  elseif (__have_feature__ ("JAVA"))
    btn = javaMethod ("questdlg", "org.octave.JDialogBox", msg,
                      title, options);
  else
    error ("questdlg is not available in this version of Octave");
  endif

endfunction

%!demo
%!  disp('- test questdlg with two buttons');
%!  a = questdlg('Would you like some free money?',...
%!               '$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $',...
%!               'No', 'Cancel', 'Cancel');
%!  if strcmp (a, 'No')
%!    msgbox('Suit yourself.', 'Message Box');
%!  endif

%!demo
%!  disp('- test questdlg with message and title only.');
%!  a = 'No';
%!  c = 0;
%!  while (strcmp(a, 'No') || !c)
%!    a = questdlg('Close this Question Dialog?', 'Reductio Ad Absurdum');
%!    if strcmp(a, 'Yes')
%!      q = 'Are you sure?';
%!      while (strcmp(a, 'Yes') && !c)
%!        a = questdlg(q, 'Reductio Ad Absurdum');
%!        word = ' really';
%!        i = strfind(q, word);
%!        if isempty( i )
%!          i = strfind(q, ' sure');
%!          q = [q '!'];
%!        else
%!          word = [word ','];
%!        endif
%!        q = [q(1:i-1) word q(i:end)];
%!      endwhile
%!    endif
%!    if strcmp(a, 'Cancel')
%!      warndlg('Answer "Yes" or "No".', 'Warning Dialog');
%!      a = 'No';
%!      c = 1;
%!    endif
%!  endwhile
%!  msgbox('Whew!');

%!demo
%!  disp('- test questdlg with five inputs');
%!  ans = questdlg('Are you ready Steve?', 'Brian', 'No', 'Uh huh', 'Uh huh');
%!  if !strcmp (ans, 'No')
%!    ans = questdlg ('Andy?', 'Brian', 'No', 'Yeah', 'Yeah');
%!    if !strcmp (ans, 'No')
%!      ans = questdlg ('Mick?', 'Brian', 'No', 'Okay', 'Okay');
%!      if !strcmp (ans, 'No')
%!        ans = msgbox ("Well all right, fellas.    \n\n     Let''s GO!!!!!",...
%!                      'Ballroom Blitz', 'none');
%!      endif
%!    endif
%!  endif