progressPercent<T> static method

Future<T> progressPercent<T>(String message, Future<T> action(CappProgressReporter reporter), { int width = 30, CappColors color = CappColors.success, })

progressPercent is used to show a progress widget of an action that can report its own percentage of completion (e.g. downloading or uploading a file), together with a message that can be updated at any moment during the action.

Unlike progress, which only shows an indeterminate spinner/bar, the action here receives a CappProgressReporter that it can call to update the percentage (reporter.update(percent: ...)) and/or the message shown above the bar (reporter.update(message: ...)) while it runs.

The message is the initial text shown above the progress bar. The width is the number of characters used to draw the bar. The color is the color of the filled part of the bar (defaults to CappColors.success, i.e. green).

Implementation

static Future<T> progressPercent<T>(
  String message,
  Future<T> Function(CappProgressReporter reporter) action, {
  int width = 30,
  CappColors color = CappColors.success,
}) async {
  var reporter = CappProgressReporter(message);
  bool isLoading = true;
  var colorCode = _progressColorCode(color);

  String buildBar(double percent, int width) {
    var filled = (percent / 100 * width).round().clamp(0, width);
    const reset = '\x1B[0m';
    var filledPart = '█' * filled;
    if (colorCode.isNotEmpty) filledPart = '$colorCode$filledPart$reset';
    return '$filledPart${'░' * (width - filled)}';
  }

  Future<void> render() async {
    var isFirst = true;
    while (isLoading) {
      if (!isFirst) Cout.write('\x1B[1A');
      isFirst = false;
      var bar = buildBar(reporter.percent, width);
      Cout.write('\r\x1B[2K${reporter.message}\n');
      Cout.write(
        '\r\x1B[2K[$bar] ${reporter.percent.toStringAsFixed(0)}%\n',
      );
      await Future.delayed(Duration(milliseconds: 80));
    }
  }

  var renderFuture = render();

  try {
    var result = await action(reporter);
    return result;
  } finally {
    isLoading = false;
    await renderFuture;
    Cout.write('\x1B[1A');
    Cout.write('\r\x1B[2K${reporter.message}\n');
    Cout.write('\r\x1B[2K[${buildBar(100, width)}] 100%\tDone!\n');
  }
}