buildConfig method

C buildConfig(List<String> args)

Implementation

C buildConfig(List<String> args) {
  final parser = ArgParser(usageLineLength: 80)
    ..addOption(
      'yaml',
      abbr: 'y',
      defaultsTo: defaultYaml,
      help: 'YAML configuration file.',
    )
    ..addFlag('help', abbr: 'h', negatable: false, help: 'Show help.');
  addOptions(parser);

  final ArgResults results;
  try {
    results = parser.parse(args);
  } on ArgParserException catch (e) {
    throw ConfigUserException('${e.message}\n\n${parser.usage}');
  }

  if (results.flag('help')) {
    throw ConfigHelpException(parser.usage);
  }

  C? config;
  if ((results.option('yaml') ?? '').isNotEmpty) {
    final yaml = File(results['yaml'] as String).readAsStringSync();
    try {
      config = checkedYamlDecode(
        yaml,
        (m) => configFromJson(m!),
        allowNull: false,
      );
    } on ParsedYamlException catch (e) {
      throw ConfigUserException(e.formattedMessage ?? e.toString());
    }
  }

  final bool pickedAny;
  try {
    (:config, :pickedAny) = merge(config, results);
    if (config == null) {
      throw ConfigHelpException(parser.usage);
    }
  } on ArgumentError catch (e) {
    throw ConfigUserException('${e.toString()}\n\n${parser.usage}');
  }

  if (pickedAny) {
    JsonEncoder encoder = JsonEncoder.withIndent('  ');
    String asYaml = encoder.convert(toJson(config));
    stderr.writeln(
      'To make this configuration reusable, copy/paste the following into a YAML file:',
    );
    stderr.writeln(asYaml);
  }

  return config;
}