buildConditional function

String buildConditional(Map<String, String> branches)

Implementation

String buildConditional(Map<String, String> branches) {
  if (branches.isEmpty) {
    throw ArgumentError.value(branches, 'branches', 'Must not be empty');
  }

  final conditions = branches.keys.toList();
  if (conditions.length == 1 && conditions.last.trim().isEmpty) {
    return branches[conditions.first]!;
  }

  final list = <String>[];
  String? elseBranch;
  for (var i = 0; i < conditions.length; i++) {
    final condition = conditions[i];
    final body = branches[condition]!;
    if (condition.trim().isEmpty) {
      if (i != conditions.length - 1) {
        throw ArgumentError(
            'A branch without a condition must be the last branch');
      }

      if (conditions.length < 2) {
        throw ArgumentError(
            'A conditional with an empty condition must contain at least 2 branches');
      }

      elseBranch = body;
      continue;
    }

    final sb = StringBuffer();
    sb.writeln('($condition) {');
    sb.writeln(body);
    sb.write('}');
    list.add(sb.toString());
  }

  final sb = StringBuffer();
  sb.write('if ');
  sb.write(list.join(' else if '));
  if (elseBranch != null) {
    sb.writeln(' else {');
    sb.writeln(elseBranch);
    sb.write('}');
  }

  return sb.toString();
}