/// XML grep.
library;

import 'dart:io';

import 'package:args/args.dart' as args;
import 'package:xml/xml.dart';

final args.ArgParser argumentParser = args.ArgParser()
  ..addOption('tag', abbr: 't', help: 'Filter by tag name.', defaultsTo: '*')
  ..addOption(
    'namespace',
    abbr: 'n',
    help: 'Filter by namespace.',
    defaultsTo: '*',
  )
  ..addFlag('pretty', abbr: 'p', help: 'Pretty print matching results.');

void printUsage() {
  stdout.writeln('Usage: xml_grep [options] {files}');
  stdout.writeln();
  stdout.writeln(argumentParser.usage);
  exit(1);
}

void main(List<String> arguments) {
  final files = <File>[];
  final results = argumentParser.parse(arguments);
  final tag = results['tag'] as String;
  final namespace = results['namespace'] as String;
  final pretty = results['pretty'] as bool;

  for (final argument in results.rest) {
    final file = File(argument);
    if (file.existsSync()) {
      files.add(file);
    } else {
      stderr.writeln('File not found: $file');
      exit(2);
    }
  }
  if (files.isEmpty) {
    printUsage();
  }

  for (final file in files) {
    final document = XmlDocument.parse(file.readAsStringSync());
    final elements = document.findAllElements(tag, namespace: namespace);
    for (final element in elements) {
      stdout.writeln(element.toXmlString(pretty: pretty));
    }
  }
}