function DownloadAdditionsForLinux(targetdirectory, flavor)
% DownloadAdditionsForLinux(targetdirectory [, flavor]);
%
% THIS FUNCTION DOES NO LONGER WORK, AS GITHUB HAS REMOVED THEIR
% SUBVERSION FRONTEND, WHICH IT CRITICALLY REQUIRES, FROM THEIR SERVICES
% PERMANENTLY AT 8TH JANUARY 2024.
%
% Due to the lack of financial support for Psychtoolbox by the vast
% majority of our non-paying users, we did not and currently do not have
% the funding to work on a good alternative solution for this.
%
% Try to manually download and install the Datapixx or Eyelink mex files,
% which this function would normally install for you. Other than that,
% see http://psychtoolbox.org/download.html#alternate-download for a
% workable, although way less convenient and advanced, download and
% installation method, via zip file download and execution of
% SetupPsychtoolbox(). Good luck!
%
% =========================================================================
%
% Install missing Matlab or Octave mex files for versions of the Psychtoolbox
% which are directly provided by some Linux distributions, e.g., Ubuntu 20.04
% and later.
%
% You *DO NOT NEED* this function if you downloaded Psychtoolbox from its
% home-site via DownloadPsychtoolbox(), or if you install Psychtoolbox from
% the NeuroDebian repository. If you installed from NeuroDebian, then for
% Matlab nothing extra needs to be done. For Octave, to add the Datapixx
% or Eyelink functions execute this in a terminal:
%
% sudo apt install octave-psychtoolbox-3-nonfree
%
% If you would call this function from within Octave, it will download only
% a few additional addon files for the Octave Psychtoolbox. Currently the
% only added files are the Eyelink mex files for SR-Research Eyelink
% Gazetrackers, and the Datapixx mex file for VPixx Inc. products.
%

% History:
% 29.09.2011  mk  Written.
% 30.11.2011  mk  Bugfix: Get from trunk, not beta.
%                 Bugfix: On Linux + Octave, get Datapixx.mex as well.
%
% 27.05.2012  mk  - Strip backwards compatibility support to Matlab pre-R2007a.
%                 - Strip support for 'stable' / 'unsupported' flavors et al.
%                 - Change location of SVN repository to our SVN frontend for GIT:
%                   https://github.com/Psychtoolbox-3/Psychtoolbox-3
%
% 16.04.2013  mk  - Rename to DownloadAdditionsForLinux. Make clear that
%                   this is no longer needed for NeuroDebian packages, but
%                   only for downloads from mainstream Ubuntu 12.10 &
%                   13.04.
%                 - Replace textread() by textscan() on R2012a and later.
%                 - Use javaclasspath.txt instead of classpath.txt on
%                   R2013a and later.
%

error('Function aborted due to currently unsupported update method. Read "help DownloadAdditionsForLinux".');

% Psychtoolbox package installed?
if ~exist('/usr/share/octave/site/m/psychtoolbox-3/', 'dir')
  fprintf('This system is missing a octave-psychtoolbox-3 installation.\n');
  fprintf('Install octave-psychtoolbox-3 first from your Linux distribution:\n');
  fprintf('sudo apt-get intall octave-psychtoolbox-3\n');
  fprintf('Then retry this script to get missing proprietary plugins or the Matlab bits.\n');
  error('Required octave-psychtoolbox-3 package missing!');
end

% Yes: Add its root path, so we find our M-Functions:
addpath(genpath('/usr/share/octave/site/m/psychtoolbox-3/'));
savepath;

% From here on we should have access to all Psychtoolbox-3 M-Files, but not
% yet to mex files -- those are what we wanna get from GitHub after all...

%
% Get svn revision number for this octave-psychtoolbox3 installation from the
% NeuroDebian repository:
v = PsychtoolboxVersion ;
rev = strfind (v, 'svn');
v = v(rev+3:end);
rev = sscanf (v, '%i');

% Try to extract the missing Matlab mex files and other proprietary
% stuff from the Psychtoolbox SVN repo. Get the files corresponding
% to the exact revision of the installation:
if ~exist('IsLinux') || ~IsLinux || isempty(strfind(PsychtoolboxVersion, 'Debian')) %#ok<*EXIST>
  fprintf('Not sure how you managed to get me to get up to here, but i am confused\n');
  fprintf('Anyway, this is not a correctly configured Linux system with psychtoolbox packages.\n');
  fprintf('Giving up!\n');
  error('This function is only supported on Linux with an already installed distribution Psychtoolbox package.');
end

if nargin < 1 || isempty(targetdirectory)
  error('Required "targetdirectory" parameter is missing. You must tell me where to install the additional files!');
end

% Strip trailing fileseperator, if any:
if targetdirectory(end) == filesep
    targetdirectory = targetdirectory(1:end-1);
end

% Build target revision string:
if ~isempty(rev)
    targetRevision = ['-r ' num2str(rev) ' '];
else
    % Fallback if revision could not be parsed. Leave -r out, so the latest
    % stuff is downloaded, and hope for the best:
    fprintf('Huh?!? Could not determine proper svn revision number of your installed Psychtoolbox.\n');
    fprintf('Will download the very latest code and hope this will work out ok. Cross your fingers!\n');
    targetRevision = ' ';
end

% Set flavor defaults and synonyms
if nargin < 2
    flavor = [];
end

if isempty(flavor)
    % Default flavor is trunk. Why? Because NeuroDebian sync's with
    % specific revisions of trunk, so the targetRevision number extracted
    % from octave-psychtoolbox-3's PsychtoolboxVersion() corresponds to a
    % stable point in trunk, not in beta. Therefore we need to fetch from
    % exactly the same revision of trunk to get the missing mex files
    % compatible with that revision of trunk - and thereby compatible
    % with the installed octave-psychtoolbox-3:
    flavor='trunk';
end

% Make sure that flavor is lower-case, unless its a 'Psychtoolbox-x.y.z'
% spec string which is longer than 10 characters and mixed case:
if length(flavor) < 10
    % One of the short flavor spec strings: lowercase'em:
    flavor = lower(flavor);
end

switch (flavor)
    % 'current' is a synonym for 'beta'.
    case 'beta'
    case 'current'
        flavor = 'beta';        

    case 'trunk'
        % This is our default. Possibly the only reasonable choice at all for
        % NeuroDebian.

    otherwise
        fprintf('\n\n\nHmm, requested flavor is the unusual flavor: %s\n',flavor);
        fprintf('Either you request something exotic, or you made a typo?\n');
        fprintf('We will see. If you get an error, this might be the first thing to check.\n');
        fprintf('Press any key to continue...\n');
        pause;
end

if ~strcmp(flavor, 'trunk')
    flavor = ['branches/' flavor];
end

% Check if this is Matlab of version prior to V 7.4:
if ~IsOctave
    v = ver('matlab');
    if ~isempty(v)
        v = v(1).Version; v = sscanf(v, '%i.%i.%i');
        if (v(1) < 7) || ((v(1) == 7) && (v(2) < 4))
            % Matlab version < 7.4 detected. This is no longer
            % supported by current PTB beta.
            fprintf('\n\n\nYou request download of Psychtoolbox V 3.0.10 or later.\n');
            fprintf('This is no longer available for your version of Matlab.\n');
            fprintf('Current versions only work on Matlab Version 7.4 or later.\n\n\n');
            error('Unsupported Matlab version detected. Only support V7.4 (R2007a) and later.');
        end
    end
end

fprintf('DownloadAdditionsForLinux(''%s'',''%s'')\n',targetdirectory, flavor);
fprintf('Requested flavor is: %s\n',flavor);
fprintf('Requested location for the additions folder is inside: %s\n',targetdirectory);
fprintf('\n');

% Search for Unix executable in path:
svnpath = which('svn.');

% Found one?
if ~isempty(svnpath)
    % Extract basepath and use it:
    svnpath=[fileparts(svnpath) filesep];
end

if ~isempty(svnpath)
    fprintf('Will use the svn client which is located in this folder: %s\n', svnpath);
end

% Do we have sufficient privileges to install at the requested location?
p='Psychtoolbox123test';
[success,m,mm]=mkdir(targetdirectory,p);
if success
    rmdir(fullfile(targetdirectory,p));
else
    fprintf('Write permission test in folder %s failed.\n', targetdirectory);
    if strcmp(m,'Permission denied')
            fprintf([
            'Sorry. You would need administrator privileges to install the \n'...
            'Psychtoolbox into the ''%s'' folder. Please rerun the script, choosing \n'...
            'a location where you have write permission, or ask a user with administrator \n'...
            'privileges to run this function for you.\n\n'],targetdirectory);
            error('Need administrator privileges for requested installation into folder: %s.',targetdirectory);
    else
        error(mm,m);
    end
end
fprintf('Good. Your privileges suffice for the requested installation into folder %s.\n\n',targetdirectory);

p=fullfile(targetdirectory,'PsychtoolboxAddons');

% Create quoted version of 'p'ath, so blanks in path are handled properly:
pt = strcat('"',p,'"');

% What do we need from Berlios?
delpattern = [];

if ~IsOctave
  % The Matlab mex files:
  if IsLinux(1)
    sourcefolder = 'PsychBasic/';
    delpattern = '*.mexglx';
  else
    sourcefolder = 'PsychBasic/';
    delpattern = '*.mexa64';
  end
  
  % Build final checkout command string:
  checkoutcommand = [svnpath 'svn export --force -N ' targetRevision ' https://github.com/Psychtoolbox-3/Psychtoolbox-3/' flavor '/Psychtoolbox/' sourcefolder ' ' pt];
else
  % Additional Octave mex files:
  % Get Eyelink:
  if IsLinux(1)
    sourcefolder = ['PsychBasic/Octave3LinuxFiles64/Eyelink.mex'];
  else
    sourcefolder = ['PsychBasic/Octave3LinuxFiles/Eyelink.mex'];
  end

  if exist([targetdirectory '/PsychtoolboxAddons/'], 'dir')
    system(['rm -r ' targetdirectory '/PsychtoolboxAddons/']);
  end
  [success,m,mm]=mkdir(targetdirectory, 'PsychtoolboxAddons/'); %#ok<*NASGU,*ASGLU>
  pt = strcat('"',p,'/Eyelink.mex"');

  % Build final checkout command string:
  checkoutcommand = [svnpath 'svn export --force -N ' targetRevision ' https://github.com/Psychtoolbox-3/Psychtoolbox-3/' flavor '/Psychtoolbox/' sourcefolder ' ' pt];
  checkoutcommand = [checkoutcommand ' ; '];

  % Get Datapixx:
  if IsLinux(1)
    sourcefolder = ['PsychBasic/Octave3LinuxFiles64/Datapixx.mex']; %#ok<*NBRAK>
  else
    sourcefolder = ['PsychBasic/Octave3LinuxFiles/Datapixx.mex'];
  end

  pt = strcat('"',p,'/Datapixx.mex"');

  % Build final checkout command string:
  checkoutcommand = [checkoutcommand ' ' svnpath 'svn export --force -N ' targetRevision ' https://github.com/Psychtoolbox-3/Psychtoolbox-3/' flavor '/Psychtoolbox/' sourcefolder ' ' pt];
  checkoutcommand = [checkoutcommand ' ; '];
end

fprintf('The following EXPORT command asks the Subversion client to \ndownload the few additional bits of Psychtoolbox:\n');
fprintf('%s\n',checkoutcommand);
fprintf('Downloading. It''s a few megabytes, which can take a bit of time. \nAlas there may be no output to this window to indicate progress until the download is complete. \nPlease be patient ...\n');
fprintf('If you see some message asking something like "accept certificate (p)ermanently, (t)emporarily? etc."\n');
fprintf('then please press the p key on your keyboard, possibly followed by pressing the ENTER key.\n\n');
err = system(checkoutcommand);
result = 'For reason, see output above.';

if err
    fprintf('Sorry, the download command "EXPORT" failed with error code %d: \n',err);
    fprintf('%s\n',result);
    fprintf('The download failure might be due to temporary network or server problems. You may want to try again in a\n');
    fprintf('few minutes. It could also be that the subversion client was not (properly) installed.\n');
    error('Download failed.');
end
fprintf('Download succeeded!\n\n');

if ~IsOctave
  % Remove all m-files and unrelated mex files:
  pt = strcat('',p,'/*.m');
  system(['rm ' pt ]);
  system(['rm ' p '/*.mexmac']);
  system(['rm ' p '/*.mexmaci']);
  if ~isempty(delpattern)
    system(['rm ' p '/' delpattern]);
  end
end

% Add Psychtoolbox to MATLAB / OCTAVE path
fprintf('Now adding the new Psychtoolbox add-on folder (and all its subfolders) to your MATLAB / OCTAVE path.\n');
pp=genpath(p);
addpath(pp);
err=savepath;

if err
    fprintf('SAVEPATH failed. Psychtoolbox is now already installed and configured for use on your Computer,\n');
    fprintf('but i could not save the updated MATLAB / OCTAVE path, probably due to insufficient permissions.\n');
    fprintf('You will either need to fix this manually via use of the path-browser (Menu: File -> Set Path),\n');
    fprintf('or by manual invocation of the savepath command (See help savepath). The third option is, of course,\n');
    fprintf('to add the path to the Psychtoolbox folder and all of its subfolders whenever you restart MATLAB / OCTAVE.\n\n\n');
else 
    fprintf('Success.\n\n');
end

% On Matlab?
if ~IsOctave
    % Try to setup Matlab static Java class path:
    PsychJavaTrouble(1);
end

% Some goodbye, copyright and getting started blurb...
fprintf('GENERAL LICENSING CONDITIONS AND TERMS OF USE:\n');
fprintf('----------------------------------------------\n\n');
fprintf('Almost all of the material contained in the Psychtoolbox-3 distribution\n');
fprintf('is free-software and/or open-source software under a OSI (http://www.opensource.org/)\n');
fprintf('approved license. Most material is covered by the MIT license or a MIT compatible license.\n\n');

fprintf('A few internal libraries and components are covered by other free software\n');
fprintf('licenses which we understand to be compatible with the MIT license, e.g., the GNU LGPL\n');
fprintf('license, or BSD and Apache-2.0 licenses, or they are in the public domain.\n\n');
fprintf('3rd-party components which are freely useable and redistributable for non-commercial\n');
fprintf('research use, due to the authors permissions, but are not neccessarily free / open-source\n')
fprintf('software, can be found in the "PsychContributed" subfolder of the Psychtoolbox distribution,\n');
fprintf('accompanied by their respective licenses.\n\n');

fprintf('A few components are licensed under the GNU GPL v2 license with a special linking\n');
fprintf('exception for use with Mathworks proprietary Matlab application. A very few components,\n');
fprintf('e.g., the PsychCV() function are currently covered by the standard GPL v2 license and\n');
fprintf('cannot be used with Matlab. These are only available for use with GNU/Octave.\n\n');

fprintf('Please read the license text and copyright info in the Psychtoolbox file\n');
fprintf('License.txt carefully before you use or redistribute Psychtoolbox-3.\n');
fprintf('Use of Psychtoolbox-3 components implies that you have read, understood and accepted\n');
fprintf('the licensing conditions.\n\n');
fprintf('However, in a nutshell, if you just use Psychtoolbox for your research, our licenses\n');
fprintf('don''t restrict you in any practically relevant way. Commercial users, developers or\n');
fprintf('redistributors should make sure they understood the licenses for the components they use.\n');
fprintf('If in doubt, contact one of the Psychtoolbox developers, or the original authors of the\n');
fprintf('components you want to use, modify, merge or redistribute with other software.\n\n');
fprintf('Your standard Psychtoolbox distribution comes without the source code for\n');
fprintf('the binary plugins (the MEX files). If you want to access the corresponding\n');
fprintf('source code, please type "help UseTheSource" for specific download instructions.\n\n');
fprintf('BEGINNERS READ THIS:\n');
fprintf('--------------------\n\n');
fprintf('If you are new to the Psychtoolbox, you might try this: \nhelp Psychtoolbox\n\n');
fprintf('Psychtoolbox website:\n');
fprintf('web http://www.psychtoolbox.org -browser\n');
fprintf('\n');
fprintf('Please make sure that you have a look at the PDF file Psychtoolbox3-Slides.pdf\n');
fprintf('in the Psychtoolbox/PsychDocumentation subfolder for an overview of differences\n');
fprintf('between Psychtoolbox-2 and Psychtoolbox-3 and proper use of basic features. That\n');
fprintf('folder contains various additional helpful information for use of Psychtoolbox.\n\n');
fprintf('\n');
fprintf('Please also familiarize yourself with the demos contained in the PsychDemos subfolder\n');
fprintf('and its subfolders. They show best practices for many common tasks and are generally\n');
fprintf('well documented.\n');

fprintf('\nEnjoy!\n\n');

end