function TableLabViewIss = importLabViewIssfile(filenameOrFolder, dataLines)
%IMPORTFILE Import data from a text file or folder
%  TableLabViewIss = IMPORTFILE(FILENAME) reads data from text
%  file FILENAME and returns the data as a table.
%
%  TableLabViewIss = IMPORTFILE(FOLDER) reads all .txt files from
%  FOLDER, merges them into a single table (sorted by datetime).
%
%  TableLabViewIss = IMPORTFILE(FILE, DATALINES) reads data
%  for the specified row interval(s) of text file FILENAME.
%
%  Example (single file):
%  TableLabViewIss = importLabViewIssfile("/Users/bartels-rausch/Desktop/17-12-2025_09-14datafile.txt", [2, Inf]);
%
%  Example (folder):
%  TableLabViewIss = importLabViewIssfile("/Users/bartels-rausch/Desktop/DataFolder");
%
%  See also READTABLE.

%% Input handling

% If dataLines is not specified, define defaults
if nargin < 2
    dataLines = [2, Inf];
end

%% Check if input is a file or folder
if isfolder(filenameOrFolder)
    % Process all .txt files in the folder
    folderPath = filenameOrFolder;
    fileList = dir(fullfile(folderPath, '*.txt'));
    
    if isempty(fileList)
        error('No .txt files found in folder: %s', folderPath);
    end
    
    fprintf('Found %d .txt files in folder. Processing...\n', length(fileList));
    
    % Initialize empty table
    TableLabViewIss = table();
    
    % Loop through each file
    for i = 1:length(fileList)
        filepath = fullfile(folderPath, fileList(i).name);
        fprintf('  [%d/%d] Processing: %s\n', i, length(fileList), fileList(i).name);
        
        % Import this file
        tbl_temp = importSingleFile(filepath, dataLines);
        
        % Append to main table
        if isempty(TableLabViewIss)
            TableLabViewIss = tbl_temp;
        else
            TableLabViewIss = [TableLabViewIss; tbl_temp];
        end
    end
    
    % Sort by datetime
    [~, sortIdx] = sort(TableLabViewIss.datetime);
    TableLabViewIss = TableLabViewIss(sortIdx, :);
    
    fprintf('Merged %d files into single table with %d rows.\n', length(fileList), height(TableLabViewIss));
    
else
    % Process single file
    TableLabViewIss = importSingleFile(filenameOrFolder, dataLines);
end

end

%% Helper function to import a single file
function tbl = importSingleFile(filename, dataLines)
% Import options setup
opts = delimitedTextImportOptions("NumVariables", 10);

% Specify range and delimiter
opts.DataLines = dataLines;
opts.Delimiter = "\t";

% Specify column names and types
opts.VariableNames = ["date_DD_MM_JJJJ_", "time_hh_mm_ss_", "pressure_cell_hPa_", "temperature__C_", "x_mm_", "y_mm_", "z_mm_", "Tsealing__C_", "flowCryo_l_min_", "pOut_hPa_"];
opts.VariableTypes = ["datetime", "duration", "double", "double", "double", "double", "double", "double", "double", "double"];

% Specify file level properties
opts.ExtraColumnsRule = "ignore";
opts.EmptyLineRule = "read";

% Specify variable properties
opts = setvaropts(opts, "date_DD_MM_JJJJ_", "InputFormat", "dd.MM.yyyy");
opts = setvaropts(opts, "time_hh_mm_ss_", "InputFormat", "hh:mm:ss.S");

% Import the data as regular table
tbl = readtable(filename, opts);

% Merge date + time into a single datetime column
tbl.datetime = tbl.date_DD_MM_JJJJ_ + tbl.time_hh_mm_ss_;

% Set the datetime display format to show date and time
tbl.datetime.Format = 'dd.MM.yyyy HH:mm:ss.SSS';

% Remove the original date and time columns
tbl(:, ["date_DD_MM_JJJJ_", "time_hh_mm_ss_"]) = [];

% Move datetime to be the first column
tbl = movevars(tbl, "datetime", "Before", 1);

end