%'calc_field': defines fields (velocity, vort, div...) from civx data and calculate them  
%---------------------------------------------------------------------

%
% OUTPUT: 
% Scal: matlab vector representing the scalar values (length nbvec defined by var_read)  
            % if no input , Scal=list of programmed scalar names (to put in menus)
            % if only the sclar name is put as input, vec_A=type of scalar, which can be:
%                   'vel': scalar calculated solely from velocity components
%                   'der': needs spatial derivatives     
%                   'var': the scalar name directly corresponds to a field name in the netcdf files
% error: error flag
            % error = 0; OK
            % error = 1; the prescribed scalar cannot be read or calculated from available fields
% INPUT:
% ScalName: string representing the name of the scalar
% DataIn: structure representing the field, as defined in check_field_srtructure.m

% FUNCTION related
% varname_generator.m: determines the field names to read in the netcdf file, depending on the scalar

function [DataOut,errormsg]=calc_field(FieldName,DataIn)

%list of defined scalars to display in menus (in addition to 'ima_cor').
% a type is associated to each scalar: 
%              'discrete': related to the individual velocity vectors, not interpolated by patch
%              'vel': calculated from velocity components, continuous field (interpolated with velocity)              
%              'der': needs spatial derivatives     
%              'var': the scalar name corresponds to a field name in the netcdf files
% a specific variable name for civ1 and civ2 fields are also associated, if
% '' the scalar is calculated from other fields, as explicited below
%list_scal={title, type, civ1 var name,civ2 var name}
list_field={'velocity';...%image correlation corresponding to a vel vector
            'ima_cor';...%image correlation corresponding to a vel vector
           'norm_vel';...%norm of the velocity
           'vort';...%vorticity
           'div';...%divergence
           'strain';...%rate of strain
           'u';... %u velocity component
           'v';... %v velocity component
           'w';... %w velocity component
           'w_normal';... %w velocity component normal to the plane
          'error'}; %error associated to a vector (for stereo or patch)
errormsg=[]; %default error message
if ~exist('FieldName','var') 
    DataOut=list_field;% gives the list of possible fields in the absence of input
else
    if ~exist('DataIn','var')
        DataIn=[];
    end
    if ischar(FieldName)
        FieldName={FieldName};
    end
    if isfield(DataIn,'Z')&& isequal(size(DataIn.Z),size(DataIn.X))
        nbcoord=3;
    else
        nbcoord=2;
    end    
    DataOut=DataIn; %reporduce global attribute
    ListVarName={};
    ValueList={};
    RoleList={};
    units_cell={};
    for ilist=1:length(FieldName)  
        [VarName,Value,Role,units]=feval(FieldName{ilist},DataIn);%calculate field with appropriate function named FieldName{ilist}
        ListVarName=[ListVarName VarName];
        ValueList=[ValueList Value];
        RoleList=[RoleList Role];
        units_cell=[units_cell units];
    end   
       %erase previous data (except coordinates)
    for ivar=nbcoord+1:length(DataOut.ListVarName)
        VarName=DataOut.ListVarName{ivar};
        DataOut=rmfield(DataOut,VarName);
    end  
    DataOut.ListVarName=DataOut.ListVarName(1:nbcoord);
    if isfield(DataOut,'VarDimName')
        DataOut.VarDimName=DataOut.VarDimName(1:nbcoord);
    else
        errormsg='element .VarDimName missing in input data';
        return
    end
    DataOut.VarAttribute=DataOut.VarAttribute(1:nbcoord);
    %append new data
    DataOut.ListVarName=[DataOut.ListVarName ListVarName];
    for ivar=1:length(ListVarName)
        DataOut.VarDimName{nbcoord+ivar}=DataOut.VarDimName{1};      
        DataOut.VarAttribute{nbcoord+ivar}.Role=RoleList{ivar};  
        DataOut.VarAttribute{nbcoord+ivar}.units=units_cell{ivar};
        eval(['DataOut.' ListVarName{ivar} '=ValueList{ivar};'])
    end
end

%%%%%%%%%%%%% velocity fieldn%%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units_cell]=velocity(DataIn)
VarName={};
ValCell={};
Role={};
units_cell={};
if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
    units=[DataIn.CoordUnit '/' DataIn.TimeUnit];
else
    units='pixel';
end
if isfield(DataIn,'U')
    VarName=[VarName {'U'}];
    ValCell=[ValCell {DataIn.U}];
    Role=[Role {'vector_x'}];
    units_cell=[units_cell {units}];
end
if isfield(DataIn,'V')
    VarName=[VarName {'V'}];
    ValCell=[ValCell {DataIn.V}];
    Role=[Role {'vector_y'}];  
    units_cell=[units_cell {units}];
end
if isfield(DataIn,'W')
    VarName=[VarName {'W'}];
    ValCell=[ValCell {DataIn.W}];
    Role=[Role {'vector_z'}];
    units_cell=[units_cell {units}];
end
if isfield(DataIn,'F')
    VarName=[VarName {'F'}];
    ValCell=[ValCell {DataIn.F}];
    Role=[Role {'warnflag'}];
    units_cell=[units_cell {[]}];
end
if isfield(DataIn,'FF')
    VarName=[VarName,{'FF'}];
    ValCell=[ValCell {DataIn.FF}];
    Role=[Role {'errorflag'}];
    units_cell=[units_cell {[]}];
end

%%%%%%%%%%%%% ima cor%%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=ima_cor(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'C')
    VarName{1}='C';
    ValCell{1}=DataIn.C;
    Role={'ancillary'};
    units={[]};
end

%%%%%%%%%%%%% norm_vec %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=norm_vel(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'U') && isfield(DataIn,'V')
    VarName{1}='norm_vel';
     ValCell{1}=DataIn.U.*DataIn.U+ DataIn.V.*DataIn.V;
     if isfield(DataIn,'W') && isequal(size(DataIn.W),size(DataIn.U))
         ValCell{1}=ValCell{1}+DataIn.W.*DataIn.W;
     end
     ValCell{1}=sqrt(ValCell{1});
     Role{1}='scalar';
     if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
        units={[DataIn.CoordUnit '/' DataIn.TimeUnit]};
     else
        units={'pixel'};
     end
end  



%%%%%%%%%%%%% vorticity%%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=vort(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'DjUi')
    VarName{1}='vort';
    ValCell{1}=DataIn.DjUi(:,1,2)-DataIn.DjUi(:,2,1);  %vorticity
    siz=size(ValCell{1});
    ValCell{1}=reshape(ValCell{1},siz(1),1);
    Role{1}='scalar';
    if isfield(DataIn,'TimeUnit')
        units={[DataIn.TimeUnit '-1']};
    else
        units={[]};
    end
end  

%%%%%%%%%%%%% divergence%%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=div(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'DjUi')
    VarName{1}='div';
    ValCell{1}=DataIn.DjUi(:,1,1)+DataIn.DjUi(:,2,2); %DUDX+DVDY
    siz=size(ValCell{1});
    ValCell{1}=reshape(ValCell{1},siz(1),1);
    Role{1}='scalar';
    if isfield(DataIn,'TimeUnit')
        units={[DataIn.TimeUnit '-1']};
    else
        units={[]};
    end
end  

%%%%%%%%%%%%% strain %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=strain(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'DjUi')
   VarName{1}='strain'; 
   ValCell{1}=DataIn.DjUi(:,1,2)+DataIn.DjUi(:,2,1);%DVDX+DUDY
   siz=size(ValCell{1});    
   ValCell{1}=reshape(ValCell{1},siz(1),1); 
   if isfield(DataIn,'TimeUnit')
        units={[DataIn.TimeUnit '-1']};
   else
        units={[]};
   end
end  

%%%%%%%%%%%%% u %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=u(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'U')
    VarName{1}='U';
    ValCell{1}=DataIn.U;
    Role{1}='scalar';
    if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
        units={[DataIn.CoordUnit '/' DataIn.TimeUnit]};
    else
        units={'pixel'};
    end
end

%%%%%%%%%%%%% v %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=v(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'V')
    VarName{1}='V';
    ValCell{1}=DataIn.V;
    Role{1}='scalar';
    if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
        units={[DataIn.CoordUnit '/' DataIn.TimeUnit]};
    else
        units={'pixel'};
    end
end

%%%%%%%%%%%%% w %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=w(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'W')
    VarName{1}='W';
    ValCell{1}=DataIn.W;
    Role{1}='scalar';%will remain unchanged by projection
    if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
        units={[DataIn.CoordUnit '/' DataIn.TimeUnit]};
    else
        units={'pixel'};
    end
end

%%%%%%%%%%%%% w_normal %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=w_normal(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'W')
    VarName{1}='W';
    ValCell{1}=DataIn.W;
    Role{1}='vector_z';%will behave like a vector component  by projection 
    if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
        units={[DataIn.CoordUnit '/' DataIn.TimeUnit]};
    else
        units={'pixel'};
    end
end

%%%%%%%%%%%%% error %%%%%%%%%%%%%%%%%%%%
function [VarName,ValCell,Role,units]=error(DataIn)
VarName={};
ValCell={};
Role={};
units={};
if isfield(DataIn,'E')
    VarName{1}='E';
    ValCell{1}=DataIn.E;
    Role{1}='ancillary'; %TODO CHECK units in actual fields
    if isfield(DataIn,'CoordUnit') && isfield(DataIn,'TimeUnit')
        units={[DataIn.CoordUnit '/' DataIn.TimeUnit]};
    else
        units={'pixel'};
    end
end