// OpenTween - Client of Twitter
// Copyright (c) 2015 takke (@takke) <http://takke.jp/>
// All rights reserved.
//
// This file is part of OpenTween.
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. If not, see <http://www.gnu.org/licenses/>, or write to
// the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
// Boston, MA 02110-1301, USA.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace OpenTween
{
    /// <summary>
    /// ツイート内の絵文字を img タグに書き換えるクラス
    /// </summary>
    public static class EmojiFormatter
    {
        public static string ReplaceEmojiToImg(string text)
        {
            // HTMLタグを壊さないように <...> の外側のみを置換する
            return Regex.Replace(text, @"^[^<]+$|^[^<]+(?:<)|(?:>)[^<]+(?:<)|(?:>)[^<]+$", m =>
            {
                return Regex.Replace(m.Value,
                    @"\ud83d[\udc68-\udc69](?:\ud83c[\udffb-\udfff])?\u200d(?:\u2695\ufe0f|\u2696\ufe0f|\u2708\ufe0f|\ud83c[\udf3e\udf73\udf93\udfa4\udfa8\udfeb\udfed]|\ud83d[\udcbb\udcbc\udd27\udd2c\ude80\ude92])|(?:\ud83c[\udfcb\udfcc]|\ud83d\udd75|\u26f9)(?:\ufe0f|\ud83c[\udffb-\udfff])\u200d[\u2640\u2642]\ufe0f|(?:\ud83c[\udfc3\udfc4\udfca]|\ud83d[\udc6e\udc71\udc73\udc77\udc81\udc82\udc86\udc87\ude45-\ude47\ude4b\ude4d\ude4e\udea3\udeb4-\udeb6]|\ud83e[\udd26\udd37-\udd39\udd3d\udd3e\uddd6-\udddd])(?:\ud83c[\udffb-\udfff])?\u200d[\u2640\u2642]\ufe0f|\ud83d\udc68\u200d\u2764\ufe0f\u200d\ud83d\udc8b\u200d\ud83d\udc68|\ud83d\udc68\u200d\ud83d\udc68\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc68\u200d\ud83d\udc68\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\ud83d\udc69\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc68\u200d\ud83d\udc69\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\u2764\ufe0f\u200d\ud83d\udc8b\u200d\ud83d[\udc68\udc69]|\ud83d\udc69\u200d\ud83d\udc69\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc69\u200d\ud83d\udc69\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\u2764\ufe0f\u200d\ud83d\udc68|\ud83d\udc68\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc68\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\ud83d\udc68\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\ud83d\udc69\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\u2764\ufe0f\u200d\ud83d[\udc68\udc69]|\ud83d\udc69\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc69\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\ud83d\udc69\u200d\ud83d[\udc66\udc67]|\ud83c\udff3\ufe0f\u200d\ud83c\udf08|\ud83c\udff4\u200d\u2620\ufe0f|\ud83d\udc41\u200d\ud83d\udde8|\ud83d\udc68\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\ud83d[\udc66\udc67]|\ud83d\udc6f\u200d\u2640\ufe0f|\ud83d\udc6f\u200d\u2642\ufe0f|\ud83e\udd3c\u200d\u2640\ufe0f|\ud83e\udd3c\u200d\u2642\ufe0f|\ud83e\uddde\u200d\u2640\ufe0f|\ud83e\uddde\u200d\u2642\ufe0f|\ud83e\udddf\u200d\u2640\ufe0f|\ud83e\udddf\u200d\u2642\ufe0f|(?:[\u0023\u002a\u0030-\u0039])\ufe0f?\u20e3|(?:(?:\ud83c[\udfcb\udfcc]|\ud83d[\udd74\udd75\udd90]|[\u261d\u26f7\u26f9\u270c\u270d])(?:\ufe0f|(?!\ufe0e))|\ud83c[\udf85\udfc2-\udfc4\udfc7\udfca]|\ud83d[\udc42\udc43\udc46-\udc50\udc66-\udc69\udc6e\udc70-\udc78\udc7c\udc81-\udc83\udc85-\udc87\udcaa\udd7a\udd95\udd96\ude45-\ude47\ude4b-\ude4f\udea3\udeb4-\udeb6\udec0\udecc]|\ud83e[\udd18-\udd1c\udd1e\udd1f\udd26\udd30-\udd39\udd3d\udd3e\uddd1-\udddd]|[\u270a\u270b])(?:\ud83c[\udffb-\udfff]|)|\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc65\udb40\udc6e\udb40\udc67\udb40\udc7f|\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc73\udb40\udc63\udb40\udc74\udb40\udc7f|\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc77\udb40\udc6c\udb40\udc73\udb40\udc7f|\ud83c\udde6\ud83c[\udde8-\uddec\uddee\uddf1\uddf2\uddf4\uddf6-\uddfa\uddfc\uddfd\uddff]|\ud83c\udde7\ud83c[\udde6\udde7\udde9-\uddef\uddf1-\uddf4\uddf6-\uddf9\uddfb\uddfc\uddfe\uddff]|\ud83c\udde8\ud83c[\udde6\udde8\udde9\uddeb-\uddee\uddf0-\uddf5\uddf7\uddfa-\uddff]|\ud83c\udde9\ud83c[\uddea\uddec\uddef\uddf0\uddf2\uddf4\uddff]|\ud83c\uddea\ud83c[\udde6\udde8\uddea\uddec\udded\uddf7-\uddfa]|\ud83c\uddeb\ud83c[\uddee-\uddf0\uddf2\uddf4\uddf7]|\ud83c\uddec\ud83c[\udde6\udde7\udde9-\uddee\uddf1-\uddf3\uddf5-\uddfa\uddfc\uddfe]|\ud83c\udded\ud83c[\uddf0\uddf2\uddf3\uddf7\uddf9\uddfa]|\ud83c\uddee\ud83c[\udde8-\uddea\uddf1-\uddf4\uddf6-\uddf9]|\ud83c\uddef\ud83c[\uddea\uddf2\uddf4\uddf5]|\ud83c\uddf0\ud83c[\uddea\uddec-\uddee\uddf2\uddf3\uddf5\uddf7\uddfc\uddfe\uddff]|\ud83c\uddf1\ud83c[\udde6-\udde8\uddee\uddf0\uddf7-\uddfb\uddfe]|\ud83c\uddf2\ud83c[\udde6\udde8-\udded\uddf0-\uddff]|\ud83c\uddf3\ud83c[\udde6\udde8\uddea-\uddec\uddee\uddf1\uddf4\uddf5\uddf7\uddfa\uddff]|\ud83c\uddf4\ud83c\uddf2|\ud83c\uddf5\ud83c[\udde6\uddea-\udded\uddf0-\uddf3\uddf7-\uddf9\uddfc\uddfe]|\ud83c\uddf6\ud83c\udde6|\ud83c\uddf7\ud83c[\uddea\uddf4\uddf8\uddfa\uddfc]|\ud83c\uddf8\ud83c[\udde6-\uddea\uddec-\uddf4\uddf7-\uddf9\uddfb\uddfd-\uddff]|\ud83c\uddf9\ud83c[\udde6\udde8\udde9\uddeb-\udded\uddef-\uddf4\uddf7\uddf9\uddfb\uddfc\uddff]|\ud83c\uddfa\ud83c[\udde6\uddec\uddf2\uddf3\uddf8\uddfe\uddff]|\ud83c\uddfb\ud83c[\udde6\udde8\uddea\uddec\uddee\uddf3\uddfa]|\ud83c\uddfc\ud83c[\uddeb\uddf8]|\ud83c\uddfd\ud83c\uddf0|\ud83c\uddfe\ud83c[\uddea\uddf9]|\ud83c\uddff\ud83c[\udde6\uddf2\uddfc]|\ud800\udc00|\ud83c[\udccf\udd8e\udd91-\udd9a\udde6-\uddff\ude01\ude32-\ude36\ude38-\ude3a\ude50\ude51\udf00-\udf20\udf2d-\udf35\udf37-\udf7c\udf7e-\udf84\udf86-\udf93\udfa0-\udfc1\udfc5\udfc6\udfc8\udfc9\udfcf-\udfd3\udfe0-\udff0\udff4\udff8-\udfff]|\ud83d[\udc00-\udc3e\udc40\udc44\udc45\udc51-\udc65\udc6a-\udc6d\udc6f\udc79-\udc7b\udc7d-\udc80\udc84\udc88-\udca9\udcab-\udcfc\udcff-\udd3d\udd4b-\udd4e\udd50-\udd67\udda4\uddfb-\ude44\ude48-\ude4a\ude80-\udea2\udea4-\udeb3\udeb7-\udebf\udec1-\udec5\uded0-\uded2\udeeb\udeec\udef4-\udef8]|\ud83e[\udd10-\udd17\udd1d\udd20-\udd25\udd27-\udd2f\udd3a\udd3c\udd40-\udd45\udd47-\udd4c\udd50-\udd6b\udd80-\udd97\uddc0\uddd0\uddde-\udde6]|[\u23e9-\u23ec\u23f0\u23f3\u2640\u2642\u2695\u26ce\u2705\u2728\u274c\u274e\u2753-\u2755\u2795-\u2797\u27b0\u27bf\ue50a]|(?:\ud83c[\udc04\udd70\udd71\udd7e\udd7f\ude02\ude1a\ude2f\ude37\udf21\udf24-\udf2c\udf36\udf7d\udf96\udf97\udf99-\udf9b\udf9e\udf9f\udfcd\udfce\udfd4-\udfdf\udff3\udff5\udff7]|\ud83d[\udc3f\udc41\udcfd\udd49\udd4a\udd6f\udd70\udd73\udd76-\udd79\udd87\udd8a-\udd8d\udda5\udda8\uddb1\uddb2\uddbc\uddc2-\uddc4\uddd1-\uddd3\udddc-\uddde\udde1\udde3\udde8\uddef\uddf3\uddfa\udecb\udecd-\udecf\udee0-\udee5\udee9\udef0\udef3]|[\u00a9\u00ae\u203c\u2049\u2122\u2139\u2194-\u2199\u21a9\u21aa\u231a\u231b\u2328\u23cf\u23ed-\u23ef\u23f1\u23f2\u23f8-\u23fa\u24c2\u25aa\u25ab\u25b6\u25c0\u25fb-\u25fe\u2600-\u2604\u260e\u2611\u2614\u2615\u2618\u2620\u2622\u2623\u2626\u262a\u262e\u262f\u2638-\u263a\u2648-\u2653\u2660\u2663\u2665\u2666\u2668\u267b\u267f\u2692-\u2694\u2696\u2697\u2699\u269b\u269c\u26a0\u26a1\u26aa\u26ab\u26b0\u26b1\u26bd\u26be\u26c4\u26c5\u26c8\u26cf\u26d1\u26d3\u26d4\u26e9\u26ea\u26f0-\u26f5\u26f8\u26fa\u26fd\u2702\u2708\u2709\u270f\u2712\u2714\u2716\u271d\u2721\u2733\u2734\u2744\u2747\u2757\u2763\u2764\u27a1\u2934\u2935\u2b05-\u2b07\u2b1b\u2b1c\u2b50\u2b55\u3030\u303d\u3297\u3299])(?:\ufe0f|(?!\ufe0e))",
                    ReplaceEmojiEntity);
            });
        }

        private static string ReplaceEmojiEntity(System.Text.RegularExpressions.Match m)
        {
            string input = m.Value;
            string codes = "";

            // 異字体セレクタ U+FE0F (emoji style) は除去する (ZWJ を含まない場合のみ)
            if (!input.Contains('\u200D'))
                input = input.Replace("\uFE0F", "");

            for (var i = 0; i < input.Length; i += char.IsSurrogatePair(input, i) ? 2 : 1)
            {
                var codepoint = char.ConvertToUtf32(input, i);

                if (i > 0)
                {
                    codes += "-";
                }

                codes += string.Format("{0:x}", codepoint);
            }

            return "<img class=\"emoji\" src=\"https://twemoji.maxcdn.com/2/72x72/" + codes + ".png\" alt=\"" + input + "\" />";
        }
    }
}
