import 'dart:io';

class ReadData {
  static const prefix = 'lib/data/';

  static Future<List<T>> readFile<T>(String classString, {bool test}) async {
    var fileName = prefix + classString.toLowerCase() + (test ?? false ? 'test' : '') + '.data';
    var file = File(fileName);
    var contents = <T>[];

    // print('open file "$fileName"');
    if (await file.exists()) {
      var contentStrings = await File(fileName).readAsLines();
      if (T == num) {
        contents = contentStrings.map(num.parse).toList() as List<T>;
      } else if (T == String) {
        contents = contentStrings as List<T>;
      }
    } else {
      print('File "$fileName" not found.');
    }
    return contents;
  }
}