% A table-based interface for editing structure field. The input structure
% is displayed as fieldname-value pairs in an editable table and the  
% modified values are returned as an output structure.

function OutS = tabledlg(varargin)
    p = inputParser();
    
    % Input structure which fields are displayed by default
    addOptional(p, 'InS', struct(), @(x)assert(isstruct(x), ...
        'Input argument must be structure'));
    
    % Figure name to display
    addParameter(p, 'Name', '', @ischar);
    
    % Structure fields to be kept unchanged
    addParameter(p, 'hidden_fields', {}, @iscellstr)
    
    parse(p, varargin{:});
    
    InS = p.Results.InS;
    
    % Remove hidden fields from the display and store them in a separate
    % structure
    hidden_fn = p.Results.hidden_fields;
    UnchangedS = struct();
    for i = 1:length(hidden_fn)
        if isfield(InS, hidden_fn{i})
            UnchangedS.(hidden_fn{i}) = InS.(hidden_fn{i});
            InS = rmfield(InS, hidden_fn{i});
        end
    end
    
    % Selected table row number is updated by callbacks
    sel_row = [];
    
    % Output structure is only assigned when 'Continue' button is pushed
    OutS = [];
    
    % Define geometry
    tbl_w = 262;
    tbl_h = 204;
    
    btn_w = 56;
    btn_h = 22;
    
    sps = 10; % space between elements
    
    fig_w = tbl_w+btn_w+2*sps;
    fig_h = tbl_h;
    R = groot();
    
    % Display the figure window in the center of the screen
    fig_x = R.ScreenSize(3)/2-fig_w/2;
    fig_y = R.ScreenSize(4)/2-fig_h/2;
    
    F = figure('MenuBar',   'none', ...
        'Name',             p.Results.Name, ...
        'NumberTitle',      'off', ...
        'Resize',           'off', ...
        'Position',         [fig_x,fig_y,fig_w,fig_h]);
    
    % Define buttons
    uicontrol(F, ...
        'Style',        'pushbutton', ...
        'String',       'Add',...
        'Position',     [tbl_w+sps, 2*sps+btn_h, btn_w, btn_h], ...
        'Callback',     @addButtonCallback);
    
    uicontrol(F, ...
        'Style',        'pushbutton', ...
        'String',       'Delete',...
        'Position',     [tbl_w+sps, sps+(sps+btn_h)*2, btn_w, btn_h], ...
        'Callback',     @deleteButtonCallback);
    
    uicontrol(F, ...
        'Style',        'pushbutton', ...
        'String',       'Continue',...
        'Position',     [tbl_w+sps, sps, btn_w, btn_h], ...
        'Callback',     @continueButtonCallback);
    
    % Define the table to dispaly
    data = [fieldnames(InS), cellfun(@(x)var2str(x), ...
        struct2cell(InS), 'UniformOutput', false)];
    
    T = uitable(F, ...
        'Data',                     data, ...
        'ColumnWidth',              {tbl_w/2, tbl_w/2-1}, ...
        'ColumnName',               {'parameter', 'value'}, ...
        'RowName',                  {}, ...
        'Position',                 [0 0 tbl_w tbl_h], ...
        'ColumnEditable',           true, ...
        'CellSelectionCallback',    @selectionCallback, ...
        'CellEditCallback',         @editCallback);
    
    % Wait until the figure f is deleted
    uiwait(F);
    
    
    %% Callbacks
    
    function selectionCallback(~, EventData)
        if ~isempty(EventData.Indices)
            sel_row = EventData.Indices(1);
        end
    end
    
    % Table edited, makes sure that the first column only contains valid 
    % and unique Matlab variable names, which is necessary to convert the
    % table content to structure
    function editCallback(~, EventData)
        row = EventData.Indices(1);
        col = EventData.Indices(2);
        if col == 1
            [newval, mod] = matlab.lang.makeValidName(T.Data{row, 1});
            if mod
                warning(['Parameter name must be a valid Matlab ' ...
                    'variable name']);
            end
            [newval, mod] = matlab.lang.makeUniqueStrings(newval, ...
                [T.Data(1:row-1, 1); T.Data(row+1:end, 1)]);
            if mod
                warning('Parameter name must be unique');
            end
            T.Data{row, 1} = newval;
        end
    end

    function continueButtonCallback(~,~)
        [nrows, ~] = size(T.Data);
        
        OutS = UnchangedS;
        for j = 1:nrows
            
            % Try converting values to numbers
            OutS.(T.Data{j,1}) = str2doubleHedged(T.Data{j,2});
        end
        delete(F);
    end
    
    % Add new entry
    function addButtonCallback(~, ~)
        
        % Generate dummy parameter name 
        parname = matlab.lang.makeUniqueStrings('par', T.Data(:,1));
        T.Data = [T.Data;{parname, ''}];
    end

    % Delete selected entry
    function deleteButtonCallback(~, ~)
        if ~isempty(sel_row)
            T.Data(sel_row,:) = [];
            sel_row = [];
        end
    end
end