import "dart:convert";
import "dart:io";

import "package:args/command_runner.dart";

class Day1Command extends Command {
  // The [name] and [description] properties must be defined by every
  // subclass.
  @override
  final name = "day1";

  @override
  final description = "Run Advent of Code 2025 Day 1";

  Day1Command() {
    // we can add command specific arguments here.
    // [argParser] is automatically created by the parent class.
  }

  // [run] may also return a Future.
  @override
  void run() {
    // [argResults] is set before [run()] is called and contains the flags/options
    // passed to this command.
    print(argResults!.rest);

    if (argResults!.rest.length != 1) {
      print(
        "Expected 1 positional arguments, found ${argResults!.rest.length}",
      );
    }
    var fileName = argResults!.rest[0];

    var inputFile = File(fileName);
    var openFile = inputFile.openRead();

    openFile
        .transform(utf8.decoder)
        .transform(LineSplitter())
        .listen(
          (String line) {
            print('$line: ${line.length} bytes');
          },
          onDone: () {
            print('File is now closed.');
          },
          onError: (e) {
            print(e.toString());
          },
        );
  }
}