function o = vertcat(varargin)

% Overloads vertcat method for dseries objects.
%
% INPUTS
%  o o1    dseries object.
%  o o2    dseries object.
%  o ...
%
% OUTPUTS
%  o o     dseries object.
%
% EXAMPLE 1
%  If o1, o2 and o3 are dseries objects containing the same variables over different samples, the following syntax:
%
%    o = [o1; o2; o3] ;
%
%  merges the samples.

% Copyright © 2013-2023 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 nargin==0
    o = dseries();
elseif nargin == 1
    o = copy(varargin{1});
elseif nargin>1
    o = copy(varargin{1});
    for i=2:nargin
        o = vertcat_(o, varargin{i});
    end
end

function d = vertcat_(b, c)
d = NaN;
if ~isequal(frequency(b), frequency(c))
    error('dseries::vertcat: Frequencies must be common!')
end
if ~isequal(vobs(b), vobs(c))
    error('dseries::vertcat: Number of variables must be common!')
end
reorder_variables_in_c = false;
if ~isequal(b.name, c.name)
    [t, idx] = ismember(b.name, c.name);
    if all(t)
        reorder_variables_in_c = true;
    else
        error('dseries::vertcat: Variables must be common!')
    end
end
d = b;
if reorder_variables_in_c
    d.data = [b.data; c.data(:,idx)];
else
    d.data = [b.data; c.data];
end
d.dates = [b.dates; c.dates];

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

%@test:1
% Define a data set.
A = [transpose(1:10),2*transpose(1:10)];
B = [transpose(1:10),2*transpose(1:10)];

% Define names
A_name = {'A1';'A2'};
B_name = {'A1';'A2'};

% Define expected results.
e.init = dates(1,1);
e.freq = 1;
e.name = {'A1';'A2'};
e.data = [A;B];

% Instantiate two time series objects.
ts1 = dseries(A,[],A_name,[]);
ts2 = dseries(B,[],B_name,[]);

% Call the tested method.
try
  ts3 = [ts1;ts2];
  t(1) = 1;
catch
  t(1) = 0;
end

% Check the results.
if t(1)
  t(2) = dassert(ts3.init,e.init);
  t(3) = dassert(ts3.freq,e.freq);
  t(4) = dassert(ts3.data,e.data);
  t(5) = dassert(ts3.name,e.name);
  t(6) = dassert(ts3.nobs,20);
end
T = all(t);
%@eof:1

%@test:2
% Define a data set.
A = [transpose(1:10),2*transpose(1:10)];
B = [transpose(1:10),2*transpose(1:10)];
C = [transpose(1:10),3*transpose(1:10)];

% Define names
A_name = {'A1';'A2'};
B_name = {'A1';'A2'};
C_name = {'A1';'A2'};

% Define expected results.
e.init = dates(1,1);
e.freq = 1;
e.name = {'A1';'A2'};
e.data = [A;B;C];

% Instantiate two time series objects.
ts1 = dseries(A,[],A_name,[]);
ts2 = dseries(B,[],B_name,[]);
ts3 = dseries(C,[],C_name,[]);

% Call the tested method.
try
  ts4 = [ts1; ts2; ts3];
  t(1) = 1;
catch
  t(1) = 0;
end


% Check the results.
if t(1)
  t(2) = dassert(ts4.init,e.init);
  t(3) = dassert(ts4.freq,e.freq);
  t(4) = dassert(ts4.data,e.data);
  t(5) = dassert(ts4.name,e.name);
  t(6) = dassert(ts4.nobs,30);
end
T = all(t);
%@eof:2

%@test:3
A = dseries([ones(5,1), 2*ones(5,1)],'1938Q4',{'A1', 'A2'});
B = dseries([2*ones(2,1), ones(2,1)],'1945Q3',{'A2', 'A1'});

try
   C = [A; B];
   t(1) = true;
catch
   t(1) = false;
end

% Check the results.
if t(1)
   t(2) = dassert(C.data,[ones(7,1), 2*ones(7,1)]);
end
T = all(t);
%@eof:3

%@test:4
A = dseries(ones(3, 1), '1990Q1');
B = dseries(2*ones(3, 1), '1990Q4');

try
   C = [A; B];
   t(1) = true;
catch
   t(1) = false;
end

% Check the results.
if t(1)
   t(2) = dassert(C.data, [ones(3,1); 2*ones(3,1)]);
   t(3) = dassert(A.data, ones(3,1));
   t(4) = dassert(B.data, 2*ones(3,1));
end
T = all(t);
%@eof:4
