// OpenTween - Client of Twitter
// Copyright (c) 2007-2011 kiri_feather (@kiri_feather) <kiri.feather@gmail.com>
//           (c) 2008-2011 Moz (@syo68k)
//           (c) 2008-2011 takeshik (@takeshik) <http://www.takeshik.org/>
//           (c) 2010-2011 anis774 (@anis774) <http://d.hatena.ne.jp/anis774/>
//           (c) 2010-2011 fantasticswallow (@f_swallow) <http://twitter.com/f_swallow>
//           (c) 2012      kim_upsilon (@kim_upsilon) <https://upsilo.net/~upsilon/>
// 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.Threading;
using System.Threading.Tasks;
using System.Xml;
using System.Text.RegularExpressions;

namespace OpenTween.Thumbnail.Services
{
    class Youtube : IThumbnailService
    {
        public static readonly Regex UrlPatternRegex =
            new Regex(@"^https?://(?:(www\.youtube\.com)|(youtu\.be))/(watch\?v=)?(?<videoid>([\w\-]+))");

        public override Task<ThumbnailInfo> GetThumbnailInfoAsync(string url, PostClass post, CancellationToken token)
        {
            return Task.Run(() =>
            {
                var match = Youtube.UrlPatternRegex.Match(url);
                if (!match.Success)
                    return null;

                var videoId = match.Groups["videoid"].Value;
                var imgUrl = "http://i.ytimg.com/vi/" + videoId + "/default.jpg";

                // 参考
                // http://code.google.com/intl/ja/apis/youtube/2.0/developers_guide_protocol_video_entries.html
                // デベロッパー ガイド: Data API プロトコル - 単独の動画情報の取得 - YouTube の API とツール - Google Code
                // http://code.google.com/intl/ja/apis/youtube/2.0/developers_guide_protocol_understanding_video_feeds.html#Understanding_Feeds_and_Entries
                // デベロッパー ガイド: Data API プロトコル - 動画のフィードとエントリについて - YouTube の API とツール - Google Code
                var videourl = (new HttpVarious()).GetRedirectTo(url);
                var mc = Regex.Match(videourl, @"^http://(?:(www\.youtube\.com)|(youtu\.be))/(watch\?v=)?(?<videoid>([\w\-]+))", RegexOptions.IgnoreCase);
                if (videourl.StartsWith("http://www.youtube.com/index?ytsession="))
                {
                    videourl = url;
                    mc = Regex.Match(videourl, @"^http://(?:(www\.youtube\.com)|(youtu\.be))/(watch\?v=)?(?<videoid>([\w\-]+))", RegexOptions.IgnoreCase);
                }
                if (mc.Success)
                {
                    var apiurl = "http://gdata.youtube.com/feeds/api/videos/" + mc.Groups["videoid"].Value;
                    var src = "";
                    if ((new HttpVarious()).GetData(apiurl, null, out src, 5000))
                    {
                        var sb = new StringBuilder();
                        var xdoc = new XmlDocument();
                        try
                        {
                            xdoc.LoadXml(src);
                            var nsmgr = new XmlNamespaceManager(xdoc.NameTable);
                            nsmgr.AddNamespace("root", "http://www.w3.org/2005/Atom");
                            nsmgr.AddNamespace("app", "http://purl.org/atom/app#");
                            nsmgr.AddNamespace("media", "http://search.yahoo.com/mrss/");

                            var xentryNode = xdoc.DocumentElement.SelectSingleNode("/root:entry/media:group", nsmgr);
                            var xentry = (XmlElement)xentryNode;
                            var tmp = "";
                            try
                            {
                                tmp = xentry["media:title"].InnerText;
                                if (!string.IsNullOrEmpty(tmp))
                                {
                                    sb.Append(Properties.Resources.YouTubeInfoText1);
                                    sb.Append(tmp);
                                    sb.AppendLine();
                                }
                            }
                            catch (Exception)
                            {
                            }

                            try
                            {
                                var sec = 0;
                                if (int.TryParse(xentry["yt:duration"].Attributes["seconds"].Value, out sec))
                                {
                                    sb.Append(Properties.Resources.YouTubeInfoText2);
                                    sb.AppendFormat("{0:d}:{1:d2}", sec / 60, sec % 60);
                                    sb.AppendLine();
                                }
                            }
                            catch (Exception)
                            {
                            }

                            try
                            {
                                var tmpdate = new DateTime();
                                xentry = (XmlElement)xdoc.DocumentElement.SelectSingleNode("/root:entry", nsmgr);
                                if (DateTime.TryParse(xentry["published"].InnerText, out tmpdate))
                                {
                                    sb.Append(Properties.Resources.YouTubeInfoText3);
                                    sb.Append(tmpdate);
                                    sb.AppendLine();
                                }
                            }
                            catch (Exception)
                            {
                            }

                            try
                            {
                                var count = 0;
                                xentry = (XmlElement)xdoc.DocumentElement.SelectSingleNode("/root:entry", nsmgr);
                                tmp = xentry["yt:statistics"].Attributes["viewCount"].Value;
                                if (int.TryParse(tmp, out count))
                                {
                                    sb.Append(Properties.Resources.YouTubeInfoText4);
                                    sb.Append(tmp);
                                    sb.AppendLine();
                                }
                            }
                            catch (Exception)
                            {
                            }

                            try
                            {
                                xentry = (XmlElement)xdoc.DocumentElement.SelectSingleNode("/root:entry/app:control", nsmgr);
                                if (xentry != null)
                                {
                                    sb.Append(xentry["yt:state"].Attributes["name"].Value);
                                    sb.Append(":");
                                    sb.Append(xentry["yt:state"].InnerText);
                                    sb.AppendLine();
                                }
                            }
                            catch (Exception)
                            {
                            }

                            //mc = Regex.Match(videourl, @"^http://www\.youtube\.com/watch\?v=([\w\-]+)", RegexOptions.IgnoreCase)
                            //if (mc.Success)
                            //{
                            // imgurl = mc.Result("http://i.ytimg.com/vi/${1}/default.jpg");
                            //}
                            //mc = Regex.Match(videourl, @"^http://youtu\.be/([\w\-]+)", RegexOptions.IgnoreCase)
                            //if (mc.Success)
                            //{
                            // imgurl = mc.Result("http://i.ytimg.com/vi/${1}/default.jpg");
                            //}

                        }
                        catch (Exception)
                        {

                        }

                        return new ThumbnailInfo
                        {
                            ImageUrl = url,
                            ThumbnailUrl = imgUrl,
                            TooltipText = sb.ToString().Trim(),
                        };
                    }

                }
                return null;
            }, token);
        }
    }
}
