Off-Season International Round 1 Matching algorithm

import 'dart:io';
import 'dart:math';
import 'package:csv/csv.dart';
import 'dart:convert';

class TeamObject {
  TeamObject(
      {this.teamName,
      this.coachName,
      this.race,
      this.redditName,
      this.region,
      this.timezone,
      this.previousDiv});

  final String teamName;
  final String coachName;
  final String race;
  final String timezone;
  final String redditName;
  final String region;
  final String previousDiv;

  List<String> produceCSVSequence() {
    return [redditName, coachName, teamName, timezone, region];
  }

  bool isSingleSeasonTeam() {
    return previousDiv.contains("5") || previousDiv.isEmpty;
  }
}

List<List<String>> randomMatchesForTeams(List<TeamObject> teams) {
  var matches = List<List<String>>();
  var rng = Random();
  while (teams.length > 1) {
    var firstTeam = teams.removeAt(rng.nextInt(teams.length));
    var secondTeam = teams.removeAt(rng.nextInt(teams.length));
    print(
        "Match $matchNumber : ${firstTeam.teamName} vs ${secondTeam.teamName} | ${firstTeam.race} vs ${secondTeam.race}"
    );

    matches.add(["OSI"] +
        ["${matchNumber++}"] +
        firstTeam.produceCSVSequence() +
        ["VS"] +
        secondTeam.produceCSVSequence().reversed.toList());
    sleep(Duration(seconds: 1));
  }

  if (teams.length == 1) {
    print(
        "One team left remaining ${teams[0].teamName} coached by ${teams[0].coachName}");
  }

  return matches;
}

int matchNumber = 1;

main(List<String> arguments) async {
  if (arguments.length != 2) {
    print("Usage: osi_matchmaker coachlist.csv matchups.csv");
    return;
  }

  var fileName = arguments[0];
  final input = File(fileName).openRead();

  var teams = await input
      .transform(utf8.decoder)
      .transform(CsvToListConverter(eol: "\n"))
      .where((value) => value[0] != "team name")
      .toList()
      .then((values) {
    return values.map((value) {
      return TeamObject(
        teamName: value[0],
        coachName: value[5],
        race: value[1],
        timezone: value[2],
        redditName: value[3],
        region: value[7],
        previousDiv: value[8],
      );
    }).toList();
  });

  var singleSeasonTeams =
      teams.where((team) => team.isSingleSeasonTeam()).toList();

  var multiSeasonTeams =
      teams.where((team) => !team.isSingleSeasonTeam()).toList();

  print("Single Season Team Match ups");
  var allMatches = randomMatchesForTeams(singleSeasonTeams);

  print("Multiseason team match ups");
  allMatches += randomMatchesForTeams(multiSeasonTeams);

  var matchesCsv = ListToCsvConverter().convert(allMatches);
  var newFileName = arguments[1];
  var output = File(newFileName).openWrite();
  output.write(matchesCsv);
  await output.close();
}