function [freq, init, data, varlist, tex, ops, tags] = load_mat_file_data(file)

% Loads data in a matlab/octave mat-file.
%
% INPUTS
% - file            string, name of the matlab/octave mat file (with path)
%                   or structure
%
% OUTPUTS
% - freq        integer scalar equal to 1, 4, 12 or 52 (for annual, quaterly, monthly or weekly frequencies).
% - init        dates object, initial date in the dataset.
% - data        matrix of doubles, the data.
% - varlist     cell of strings, names of the variables.
%
% REMARKS
% The frequency and initial date can be specified with variables FREQ__ and INIT__ in the matlab/octave binary file. FREQ__ must
% be a scalar integer and INIT__ a string like '1938M11', '1945Q3', '1973W3' or '2009A'. If these variables are not specified
% default values for freq and init are 1 and dates(1,1).

% Copyright © 2012-2023 Dynare Team
%
% This file is part of Dynare.
%
% Dynare 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.
%
% Dynare 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 Dynare.  If not, see <https://www.gnu.org/licenses/>.

if ~isstruct(file)
    datafile = load(file);
else
    datafile=file;
end


if isfield(datafile,'INIT__')
    if isdate(datafile.INIT__)
        init = dates(datafile.INIT__);
        datafile = rmfield(datafile, 'INIT__');
    else
        error('load_mat_file_data: INIT__ cannot be interpreted as a date.')
    end
else
    init = dates(1,1);
end

if isfield(datafile,'FREQ__')
    freq = datafile.FREQ__;
    datafile = rmfield(datafile, 'FREQ__');
else
    freq = init.freq;
end

if ~isequal(freq,init.freq)
    error('load_mat_file_data: INIT__ and FREQ__ are not consistent!')
end

if isfield(datafile,'NAMES__')
    varlist = datafile.NAMES__;
    datafile = rmfield(datafile, 'NAMES__');
else
    varlist = [];
end

if isfield(datafile,'TEX__')
    tex = datafile.TEX__;
    datafile = rmfield(datafile, 'TEX__');
else
    tex = [];
end

if isfield(datafile,'OPS__')
    ops = datafile.OPS__;
    datafile = rmfield(datafile, 'OPS__');
else
    ops = [];
end

if isfield(datafile,'TAGS__')
    tags = datafile.TAGS__;
    datafile = rmfield(datafile, 'TAGS__');
else
    tags = struct();
end

if isfield(datafile,'DATA__')
    data = datafile.DATA__;
    datafile = rmfield(datafile, 'DATA__');
else
    % Previously to dynare 4.6 variables were stored as vectors of
    % common length in the mat file. This part of the code deals
    % with mat files generated by these older versions of Dynare.
    data = [];
    if isempty(varlist)
        varlist = fieldnames(datafile);
    end
    for i=1:length(varlist)
        try
            tmp = datafile.(varlist{i});
            if isvector(tmp)
                data = [data,  tmp(:)];
            else
                error('load_mat_file:: All the variables must be vectors (%s is not a vector)!', varlist{i})
            end
        catch
            error('load_mat_file:: All the vectors (variables) in %s must have the same number of rows (observations)!', inputname(1))
        end
    end
end

if isempty(ops)
    ops = cell(length(varlist), 1);
end

return % --*-- Unit tests --*--

%@test:1
% Create a data mat-file
FREQ__ = 12;
INIT__ = '1938M11';
NAMES__ = {'hagop'; 'bedros'};
TEX__ = NAMES__;
OPS__ = {'grandad(hagop)'; 'dad(bedros)'};
TAGS__ = struct();
TAGS__.gender = {'M'; 'M'};
hagop  = [1; 2; 3; 4; 5];
bedros = [2; 3; 4; 5; 6];
save('datafile_for_test.mat');

% Try to read the data mat-file
t = zeros(10,1);
try
    [freq, init, data, varlist, tex, ops, tags] = load_mat_file_data('datafile_for_test');
    t(1) = 1;
catch exception
    t = t(1);
    T = all(t);
    LOG = getReport(exception,'extended');
    return
end

delete('datafile_for_test.mat');

% Check the results.
t(2) = dassert(freq,12);
t(3) = dassert(isa(init,'dates'),true);
t(4) = dassert(init.freq,12);
t(5) = dassert(init.time,1938*12+11);
t(6) = dassert(varlist,{'hagop';'bedros'});
t(7) = dassert(tex,{'hagop';'bedros'});
t(8) = dassert(ops,{'grandad(hagop)';'dad(bedros)'});
t(8) = dassert(tags.gender,{'M';'M'});
t(9) = dassert(data(:,1),[1;2;3;4;5]);
t(10) = dassert(data(:,2),[2;3;4;5;6]);
T = all(t);
%@eof:1

%@test:2
% Create a data mat-file
FREQ__ = 12;
INIT__ = '1938M11';
NAMES__ = {'hagop'; 'bedros'};
TEX__ = NAMES__;
OPS__ = {'grandad(hagop)'; 'dad(bedros)'};
hagop  = [1, 2, 3, 4, 5];
bedros = [2, 3, 4, 5, 6];
save('datafile_for_test.mat');

% Try to read the data mat-file
t = zeros(10,1);
try
    [freq, init, data, varlist, tex, ops, tags] = load_mat_file_data('datafile_for_test');
    t(1) = 1;
catch exception
    t = t(1);
    T = all(t);
    LOG = getReport(exception,'extended');
    return
end

delete('datafile_for_test.mat');

% Check the results.
t(2) = dassert(freq,12);
t(3) = dassert(isa(init,'dates'),true);
t(4) = dassert(init.freq,12);
t(5) = dassert(init.time,1938*12+11);
t(6) = dassert(varlist,{'hagop';'bedros'});
t(7) = dassert(tex,{'hagop';'bedros'});
t(8) = dassert(ops,{'grandad(hagop)';'dad(bedros)'});
t(9) = dassert(data(:,1),[1;2;3;4;5]);
t(10) = dassert(data(:,2),[2;3;4;5;6]);
T = all(t);
%@eof:2
