karmabot/JetKarmaBot/Commands/CommandString.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace JetKarmaBot.Commands
{
    public class CommandString
    {
        public CommandString(string command, params string[] parameters)
        {
            Command = command;
            Parameters = parameters;
        }

        public string Command { get; }
        public string UserName { get; set; } = null;
        public string[] Parameters { get; }

        public static readonly char[] WS_CHARS = new[] { ' ', '\r', '\n', '\n' };

        public static bool TryParse(string s, out CommandString result)
        {
            result = null;
            if (string.IsNullOrWhiteSpace(s) || s[0] != '/')
                return false;

            string[] words = s.Split(WS_CHARS, StringSplitOptions.RemoveEmptyEntries);

            if (!words.Any())
                return false;

            var cmdRegex = new Regex(@"/(?<cmd>\w+)(@(?<name>\w+))?");
            var match = cmdRegex.Match(words.First());
            if (!match.Success)
                return false;

            string cmd = match.Groups["cmd"].Captures.First().Value;
            string username = match.Groups["name"].Captures.FirstOrDefault()?.Value;
            string[] parameters = words.Skip(1).ToArray();

            result = new CommandString(cmd, parameters) { UserName = username};
            return true;
        }

        public static CommandString Parse(string s)
        {
            if (TryParse(s, out var c)) return c;
            throw new ArgumentException($"\"{s}\" is not a command");
        }
    }
}