using System;

using System.IO;

using System.Linq;

using Maroontress.Cui;

​

public class Program

{

    public static void Main()

    {

        ParseArgs(["--count=abc"]);

    }

​

    private const int DefaultCount = 3;

​

    private static int Count { get; set; } = DefaultCount;

​

    private static void PrintUsage(OptionSchema schema, TextWriter output)

    {

        var usage = new[]

        {

            "usage: command [Options...] [--] Arguments...",

            "",

            "Options are:",

        };

        var messages = usage.Concat(schema.GetHelpMessage());

        foreach (var m in messages)

        {

            output.WriteLine(m);

        }

    }

​

    private static void ParseCount(RequiredArgumentOption o)

    {

        var v = o.ArgumentValue;

        if (!int.TryParse(v, out var num) || num < 0)

        {

            var n = o.ArgumentName;

            throw new OptionParsingException(

                o, $"option '{o}': the value '{v}' is invalid for {n}");

        }

        Count = num;

    }

​

    public static void ParseArgs(string[] args)

    {

        var schema = Options.NewSchema()

            .Add(

                "count",

                'c',

                "NUM",

                "Specifies the count",

                ParseCount)

            .Add("help", 'h', "Show help and exit");

        try

        {

            var setting = schema.Parse(args);

            var options = setting.Options;

            var arguments = setting.Arguments;

            foreach (var o in options)

            {

                if (o.Name is "help")

                {

                    PrintUsage(schema, Console.Out);

                    Environment.Exit(0);

                }

            }

            Console.WriteLine($"Count: {Count}");

        }

        catch (OptionParsingException e)

        {

            var output = Console.Error;

            output.WriteLine(e.Message);

            PrintUsage(schema, output);

            Environment.Exit(1);

        }

    }

}