antiantiswearingbot/AntiAntiSwearingBot/Unbleeper.cs

using System.Text.RegularExpressions;

namespace AntiAntiSwearingBot;

public class Unbleeper
{
    SearchDictionary Dict { get; }
    UnbleeperSettings Cfg { get; }

    public Unbleeper(SearchDictionary dict, UnbleeperSettings cfg)
    {
        Dict = dict;
        Cfg = cfg;
        BleepedSwearsRegex = new Regex("^" + Cfg.BleepedSwearsRegex + "$", RegexOptions.Compiled);
    }

    Regex BleepedSwearsRegex { get; }

    static readonly char[] WORD_SEPARATORS = { ' ', '\t', '\r', '\n', '.', ',', '!', '?', ';', ':', '-', '—' };

    public string UnbleepSwears(string text)
    {
        if (string.IsNullOrWhiteSpace(text))
            return null;

        text = text.Trim();

        if (text.StartsWith('/')) // is chat command
            return null;

        var words = text.Split(WORD_SEPARATORS, StringSplitOptions.RemoveEmptyEntries);
        var candidates = words
            .Where(w =>
                !Language.IsTelegramMention(w)
                && !Language.IsEmailPart(w)
                && Language.HasNonWordChars(w)
                && !Language.IsHashTag(w)
                && (Language.HasWordChars(w) || w.Length >= Cfg.MinAmbiguousWordLength)
                && w.Length >= Cfg.MinWordLength
                && BleepedSwearsRegex.IsMatch(w)
                )
            .ToArray();

        if (candidates.Any())
        {
            var response = new StringBuilder();
            for (int i = 0; i < candidates.Length; ++i)
            {
                var m = Dict.Match(candidates[i]);
                response.AppendLine(new string('*', i + 1) + m.Word + new string('?', m.Distance));
            }
            return response.ToString();
        }
        else
            return null;
    }
}