namespace Textile.Blocks;

public class CodeBlockModifier : BlockModifier
{
    public override string ModifyLine(string line)
    {
        // Replace "@...@" zones with "<code>" tags.
        var me = new MatchEvaluator(CodeFormatMatchEvaluator);
        line = Regex.Replace(line,
                                @"(?<before>^|([\s\([{]))" +    // before
                                "@" +
                                @"(\|(?<lang>\w+)\|)?" +        // lang
                                "(?<code>[^@]+)" +              // code
                                "@" +
                                @"(?<after>$|([\]}])|(?=" + Globals.PunctuationPattern + @"{1,2}|\s|$))",  // after
                            me);
        // Encode the contents of the "<code>" tags so that we don't
        // generate formatting out of it.
        line = NoTextileEncoder.EncodeNoTextileZones(line,
                                @"(?<=(^|\s)<code(" + Globals.HtmlAttributesPattern + @")>)",
                                @"(?=</code>)");
        return line;
    }

    public override string Conclude(string line)
    {
        // Recode everything except "<" and ">";
        line = NoTextileEncoder.DecodeNoTextileZones(line,
                                @"(?<=(^|\s)<code(" + Globals.HtmlAttributesPattern + @")>)",
                                @"(?=</code>)",
                                new string[] { "<", ">" });
        return line;
    }

    public string CodeFormatMatchEvaluator(Match m)
    {
        var res = m.Groups["before"].Value + "<code";
        if (m.Groups["lang"].Length > 0)
            res += " language=\"" + m.Groups["lang"].Value + "\"";
        res += ">" + m.Groups["code"].Value + "</code>" + m.Groups["after"].Value;
        return res;
    }
}