## Copyright (C) 2013-2019 Vytautas Jančauskas
##
## 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
## <https://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn  {} {@var{player} =} audioplayer (@var{y}, @var{fs})
## @deftypefnx {} {@var{player} =} audioplayer (@var{y}, @var{fs}, @var{nbits})
## @deftypefnx {} {@var{player} =} audioplayer (@var{y}, @var{fs}, @var{nbits}, @var{id})
## @deftypefnx {} {@var{player} =} audioplayer (@var{recorder})
## @deftypefnx {} {@var{player} =} audioplayer (@var{recorder}, @var{id})
## Create an audioplayer object that will play back data @var{y} at sample
## rate @var{fs}.
##
## The optional arguments @var{nbits}, and @var{id} specify the bit depth and
## player device id, respectively.  Device IDs may be found using the
## audiodevinfo function.  Given an audioplayer object, use the data from the
## object to initialize the player.
##
## The signal @var{y} can be a vector or a two-dimensional array.
##
## The following example will create an audioplayer object that will play
## back one second of white noise at 44100 sample rate using 8 bits per
## sample.
##
## @example
## @group
## y = 0.25 * randn (2, 44100);
## player = audioplayer (y, 44100, 8);
## play (player);
## @end group
## @end example
## @end deftypefn

## FIXME: callbacks don't work properly, apparently because portaudio
## will execute the callbacks in a separate thread, and calling Octave
## functions in a separate thread which is likely to cause trouble with
## all of Octave's global data...
##
## @deftypefnx {} {@var{player} =} audioplayer (@var{function}, @dots{})
##
## Given a function handle, use that function to process the audio.
#
## The following example will create and register a callback that generates
## a sine wave on both channels.
##
## @example
## @group
## function [ sound, status ] = callback_sine (frames)
##   global lphase = 0.0;
##   global rphase = 0.0;
##   incl = 440.0 / 44100.0;
##   incr = 443.0 / 44100.0;
##   nl = incl * frames;
##   nr = incr * frames;
##   left = sin (2.0 * pi * [lphase:incl:lphase+nl]);
##   right = sin (2.0 * pi * [rphase:incr:rphase+nr]);
##   sound = [left', right'];
##   status = 0;
##   lphase = lphase + nl;
##   rphase = rphase + nr;
## endfunction
## player = audioplayer (@@callback_sine, 44100);
## play (player);
## # play for as long as you want
## stop (player);
## @end group

function player = audioplayer (varargin)

  if (nargin < 1 || nargin > 4
      || (nargin < 2 && ! (is_function_handle (varargin{1})
                           || ischar (varargin{1}))))
    print_usage ();
  endif

  if (isa (varargin{1}, "audiorecorder"))
    if (nargin == 1)
      player = getplayer (varargin{1});
    elseif (nargin == 2)
      recorder = varargin{1};
      data = getaudiodata (recorder);
      player = audioplayer (data, get (recorder, "SampleRate"),
                            get (recorder, "BitsPerSample"), varargin{2});
    else
      print_usage ();
    endif
  else
    if (ischar (varargin{1}))
      varargin{1} = str2func (varargin{1});
    endif
    player.player = __player_audioplayer__ (varargin{:});
    player = class (player, "audioplayer");
  endif

endfunction


%!demo
%! fs = 44100;
%! audio = 0.25 * randn (2, 2*fs);
%! player = audioplayer (audio, fs);
%! play (player);
%! pause (1);
%! pause (player);
%! pause (1);
%! resume (player);
%! pause (1);
%! stop (player);

## Tests of audioplayer must not actually play anything.

%!testif HAVE_PORTAUDIO; audiodevinfo (0) > 0
%! mono = 0.25 * randn (1, 44100);
%! stereo = 0.25 * randn (2, 44100);
%! fs = 44100;
%! player1 = audioplayer (mono, fs);
%! player2 = audioplayer (stereo, fs);
%! assert (player1.NumberOfChannels, 1);
%! assert (player2.NumberOfChannels, 2);
%! assert (player1.SampleRate, 44100);
%! assert (player2.SampleRate, 44100);
%! assert (player1.TotalSamples, 44100);
%! assert (player2.TotalSamples, 44100);

%!testif HAVE_PORTAUDIO; audiodevinfo (0) > 0
%! audio = 0.25 * randn (2, 44100);
%! fs = 44100;
%! player = audioplayer (audio, fs);
%! set (player, {"SampleRate", "Tag", "UserData"}, {8000, "tag", [1, 2; 3, 4]});
%! assert (player.SampleRate, 8000);
%! assert (player.Tag, "tag");
%! assert (player.UserData, [1, 2; 3, 4]);

%!testif HAVE_PORTAUDIO; audiodevinfo (0) > 0
%! audio = 0.25 * randn (2, 44100);
%! fs = 44100;
%! player = audioplayer (audio, fs);
%! settable = set (player);
%! settable.SampleRate = 8000;
%! settable.Tag = "tag";
%! settable.UserData = [1, 2; 3, 4];
%! set (player, settable);
%! assert (player.SampleRate, 8000);
%! assert (player.Tag, "tag");
%! assert (player.UserData, [1, 2; 3, 4]);

%!testif HAVE_PORTAUDIO; audiodevinfo (0) > 0
%! audio = 0.25 * randn (2, 44100);
%! fs = 44100;
%! player = audioplayer (audio, fs);
%! player.SampleRate = 8000;
%! player.Tag = "tag";
%! player.UserData = [1, 2; 3, 4];
%! properties = get (player, {"SampleRate", "Tag", "UserData"});
%! assert (properties, {8000, "tag", [1, 2; 3, 4]});

#%!function [sound, status] = callback (samples)
#%!  sound = rand (samples, 2) - 0.5;
#%!  status = 0;
#%!endfunction

#%!testif HAVE_PORTAUDIO
#%! player = audioplayer (@callback, 44100);
#%! play (player);
#%! pause (2);
#%! stop (player);
#%! assert (1);

#%!testif HAVE_PORTAUDIO
#%! player = audioplayer ("callback", 44100, 16);
#%! play (player);
#%! pause (2);
#%! stop (player);
#%! assert (1);
