% std_saveindvar - save independent variables of a STUDY
%
% Usage:
%   std_saveindvar(STUDY, indvars, filename);
%   std_saveindvar(STUDY, indvars, filename, session, group);
%
% Input:
%   STUDY - EEGLAB STUDY structure
%   indvars - [cell] cell array of independent variables
%   filename - [string] file name to save variables in
%   session  - [array of value] list of session, first save all the
%              variable for the first session in the list etc...
%   group    - [array of string] list of group, first save all the
%              variable for the first group in the list etc...
%
% Authors: A. Delorme, CERCO/CNRS and SCCN/UCSD, 2022-

% Copyright (C) Arnaud Delorme, SCCN, INC, UCSD, 2010, arno@ucsd.edu
%
% This file is part of EEGLAB, see http://www.eeglab.org
% for the documentation and details.
%
% Redistribution and use in source and binary forms, with or without
% modification, are permitted provided that the following conditions are met:
%
% 1. Redistributions of source code must retain the above copyright notice,
% this list of conditions and the following disclaimer.
%
% 2. Redistributions in binary form must reproduce the above copyright notice,
% this list of conditions and the following disclaimer in the documentation
% and/or other materials provided with the distribution.
%
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
% THE POSSIBILITY OF SUCH DAMAGE.

function std_saveindvar(STUDY, indvars, filename, sessions, groups, interaction_sess, interaction_group)

if nargin < 1
    help std_saveindvar;
    return;
end

if nargin < 4
    sessions = [];
    interaction_sess = false;
end
if nargin < 5
    groups = {};
    interaction_group = false;
end

if length(sessions) > 1 && length(groups) > 1
    error('Cannot process groups and session - code untested');
end

fid = fopen(filename, 'w');
if fid == -1
    error('Cannot open file for writing');
end
for iGroup = 1:max(1, length(groups))
    for iSess = 1:max(1, length(sessions))
        for iSubj = 1:length(STUDY.subject)
            for iVar  = 1:length(indvars)
                indS = strmatch(STUDY.subject{iSubj}, {STUDY.datasetinfo.subject}, 'exact');
                
                % sessions
                if ~isempty(sessions)
                    indSess = find([STUDY.datasetinfo.session] == sessions(iSess));
                    indS = intersect(indS, indSess);
                end
                
                % groups
                if ~isempty(groups)
                    indGp = strmatch(groups{iGroup}, {STUDY.datasetinfo.group}, 'exact');
                    indS = intersect(indS, indGp);
                end
                
                if ~isempty(indS)
                    allVals = [ STUDY.datasetinfo(indS).(indvars{iVar})];
                    if isempty(allVals), allVals = NaN; end
                    if length(unique(allVals)) > 1
                        fprintf('Warning: more than 1 value for "%s" for subject %s, taking the average\n', indvars{iVar}, STUDY.subject{iSubj});
                        allVals = mean(allVals);
                    end
                else
                    allVals = NaN;
                    fprintf('Warning: no value for "%s" subject %s (session:%d,group:%d), using NaN\n', indvars{iVar}, STUDY.subject{iSubj}, iSess, iGroup);
                end
                
                % interactions
                interVal11 = compute_interaction(allVals, sessions, iSess , interaction_sess);
                interVal12 = compute_interaction(allVals, groups  , iGroup, interaction_group);
                vals = [  allVals(1) interVal11 interVal12 ];
                fprintf(fid, '%s', sprintf('%f\t',vals) );
            end
            fprintf(fid, '\n');
        end
    end
end
fclose(fid);

function interVal = compute_interaction(allVals, var, iVar, interaction_var)

interVal = [];
if interaction_var
    if length(var) > 2
        error('Cannot compute interaction with more than 2 sessions');
    end
    if iVar == 1
        interVal = -allVals;
    else
        interVal = allVals;
    end
end