function [sheets,vakken,success] = getSheetCombination(file, OPT, theSheets)
%GETSHEETCOMBINATION  define the sheets to be used for the volume computation.
%
%   With OPT, the function is told what computation is asked for. This function first
%   searches what compartments must be used an then selects the appropriate 
%   sheets fro the given sheets collection (theSheets found in the Excell file).
%
%   Syntax:
%   [sheets,vakken,success] = getSheetCombination(OPT, theSheets)
%
%   Input:
%   file      = the name of the excell file
%   OPT       = options used to inform what computation is asked for
%   theSheets = the sheets in the excell database
%
%   Output:
%   sheets  = the sheets to be used in the combination
%   vakken  = a structure that gives the numbers of the compartments to be
%             used: Rvaksas and Heakon
%   success = is the search sucessfull
%
%   Example
%
%   See also 

%% Copyright notice
%   --------------------------------------------------------------------
%   Copyright (C) 2010 <COMPANY>
%       Lou Verhage
%
%       <lou.verhage@deltares.nl>	
%
%       <ADDRESS>
%
%   This library is free software: you can redistribute it and/or
%   modify it under the terms of the GNU Lesser General Public
%   License as published by the Free Software Foundation, either
%   version 2.1 of the License, or (at your option) any later version.
%
%   This library 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
%   Lesser General Public License for more details.
%
%   You should have received a copy of the GNU Lesser General Public
%   License along with this library. If not, see <http://www.gnu.org/licenses/>.
%   --------------------------------------------------------------------

% This tool is part of <a href="http://OpenEarth.nl">OpenEarthTools</a>.
% OpenEarthTools is an online collaboration to share and manage data and 
% programming tools in an open source, version controlled environment.
% Sign up to recieve regular updates of this function, and to contribute 
% your own tools.

%% Version <http://svnbook.red-bean.com/en/1.5/svn.advanced.props.special.keywords.html>
% Created: 06 Sep 2010
% Created with Matlab version: 7.8.0.347 (R2009a)

% $Id: $
% $Date: $
% $Author: $
% $Revision: $
% $HeadURL: $
% $Keywords: $

%% Initialize
success = true;
sheets  = [];
vakken.Heakon  = [];
vakken.Rvaksas = [];

%get the indelings information
[dummy1,dummy2,indeling] = xlsread(file,'indeling rekenvakken');

% check the selection type and related selections
switch (lower(OPT.selection))
    case 'macrocel'
        if isempty(OPT.set)
            errordlg(sprintf('For selection: %s \n "set" must be given with a macrocel number.',OPT.selection),'!!Selection error!!','modal');
            success = false;
        end
        switch (lower(OPT.trenchtype))
            case {'all','flood','ebb','','trenches'}
                [Rvaksas,Heakon,success] = getVakken(indeling,lower(OPT.selection),lower(OPT.trenchtype),OPT.set);
            otherwise
                errordlg(sprintf('Wrong selection for macrocell: %s \n Allowed: flood, ebb, trenches, all or "empty".',OPT.trenchtype),'!!Selection error!!','modal');
                success = false;
        end
    case {'heakon','compartments'}
        if isempty(OPT.set)
            errordlg(sprintf('For selection: %s \n "set" must be given to select compartments.',OPT.selection),'!!Selection error!!','modal');
            success = false;
        else
            [Rvaksas,Heakon,success] = getVakken(indeling,lower(OPT.selection),OPT.set);
        end
    otherwise
        errordlg(sprintf('Wrong selection: %s \n Allowed: macrocell, heakon, compartments.',OPT.selection),'!!Selection error!!','modal');
        success = false;
end

if ~success
    return
end
%% select the sheets for the computation (and set vakken that are used)

vakken.Rvaksas = Rvaksas;
vakken.Heakon  = Heakon;

sheets         = setSheets(Rvaksas,Heakon);