// (c) Copyright Ascensio System SIA 2010-2022
//
// This program is a free software product.
// You can redistribute it and/or modify it under the terms
// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
// Foundation. In accordance with Section 7(a) of the GNU AGPL its Section 15 shall be amended
// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
// any third-party rights.
//
// This program is distributed WITHOUT ANY WARRANTY, without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For details, see
// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
//
// You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia, EU, LV-1021.
//
// The  interactive user interfaces in modified source and object code versions of the Program must
// display Appropriate Legal Notices, as required under Section 5 of the GNU AGPL version 3.
//
// Pursuant to Section 7(b) of the License you must retain the original Product logo when
// distributing the program. Pursuant to Section 7(e) we decline to grant you any rights under
// trademark law for use of our trademarks.
//
// All the Product's GUI elements, including illustrations and icon sets, as well as technical writing
// content are licensed under the terms of the Creative Commons Attribution-ShareAlike 4.0
// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode

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;
    }
}