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[0].Value;
        string username = match.Groups["name"].Captures.Count > 0 ? match.Groups["name"].Captures[0].Value : null;
        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");
    }
}