using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.VisualBasic.FileIO;
using SearchOption = Microsoft.VisualBasic.FileIO.SearchOption;

namespace FNZCM.ConHost.Ver2
{
    internal static class Program2
    {
        //0. start http server
        //1. scan libraries and fill data struct
        //    libs
        //     albums
        //      Tracks(FLAC / AAC_*)
        //       Meta(title(artist) / duration)
        //       FSI ( size )

        // TODO: Generate thumbnail of BKS

        private static readonly ConcurrentDictionary<string, Library2> Libraries = new();
        private static readonly ConcurrentDictionary<string, string> PathMapping = new();
        private static readonly ConcurrentDictionary<string, MediaTag2> MediaTags = new();


        private static bool _isRunning;
        private static bool _isLoading;
        private static DateTime _lastRequestAccepted;


        private static void Main()
        {
            Console.WriteLine("Starting...");

            var tWorker = new Thread(Working);
            _isRunning = true;
            tWorker.Start();

            Task.Run(ScanLibrary);

            Console.WriteLine("Press ENTER to Stop.");
            Console.ReadLine();

            Console.WriteLine("Shutting down...");
            _isRunning = false;
            tWorker.Join();

            Console.WriteLine("Stopped.");

            Console.WriteLine();
            Console.Write("Press ENTER to Exit.");
            Console.ReadLine();
        }

        private static void ScanLibrary()
        {
            if (_isLoading) return;
            _isLoading = true;
            try
            {
                Console.WriteLine("Scanning libraries...");
                MediaTags.Clear();
                PathMapping.Clear();
                Libraries.Clear();
                foreach (var kvpLib in ConfigFile.Instance.Libraries)
                {
                    if (_isRunning == false) throw new OperationCanceledException();

                    Console.WriteLine($"Library {kvpLib.Key} - {kvpLib.Value}");

                    var libPath = kvpLib.Key.ToLower();
                    var lib = Libraries[libPath] = new Library2(kvpLib.Key);
                    var albDirArray = Directory.GetDirectories(kvpLib.Value);

                    foreach (var albDir in albDirArray)
                    {
                        if (_isRunning == false) throw new OperationCanceledException();

                        Console.WriteLine($" Album {albDir}");

                        var albName = Path.GetFileName(albDir);
                        var albPath = albName.ToLower();
                        var alb = lib.Albums[albPath] = new Album2(albName);

                        var coverFilePath = Path.Combine(albDir, "cover.jpg");
                        if (File.Exists(coverFilePath)) PathMapping[$"/cover/{libPath}/{albPath}/cover.jpg"] = coverFilePath;

                        var bkDir = Path.Combine(albDir, "bk");
                        if (Directory.Exists(bkDir))
                        {
                            var bkFiles = FileSystem.GetFiles(bkDir, SearchOption.SearchTopLevelOnly, ConfigFile.Instance.BkFilePattern);
                            foreach (var file in bkFiles)
                            {
                                var bkName = Path.GetFileName(file);
                                var bkPath = bkName.ToLower();
                                alb.Bks[bkPath] = bkName;

                                PathMapping[$"/bk/{libPath}/{albPath}/{bkPath}"] = file;
                            }
                        }

                        var mainTrackFiles = FileSystem.GetFiles(albDir, SearchOption.SearchTopLevelOnly, ConfigFile.Instance.MediaFilePattern);

                        foreach (var mainTrackFile in mainTrackFiles)
                        {
                            var trackName = Path.GetFileName(mainTrackFile);
                            var trackPath = trackName.ToLower();
                            alb.MainTracks[trackPath] = trackName;

                            PathMapping[$"/media/{libPath}/{albPath}/{trackPath}"] = mainTrackFile;
                        }

                        var aacTrackDirArray = Directory.GetDirectories(albDir, "AAC_Q*");
                        foreach (var aacTrackDir in aacTrackDirArray)
                        {
                            var aacTrackSetName = Path.GetFileName(aacTrackDir);
                            var aacTrackSetPath = aacTrackSetName.ToLower();
                            var aacTrackSet = alb.SubTracks[aacTrackSetPath] = new TrackSet(aacTrackSetName);

                            foreach (var file in Directory.GetFiles(aacTrackDir))
                            {
                                var aacTrackName = Path.GetFileName(file);
                                var aacTrackPath = aacTrackName.ToLower();
                                aacTrackSet.Tracks[aacTrackPath] = aacTrackName;

                                PathMapping[$"/media/{libPath}/{albPath}/{aacTrackSetPath}/{aacTrackPath}"] = file;
                            }
                        }
                    }
                }

                Console.WriteLine("Looking tags...");
                Parallel.ForEach(PathMapping.Keys.Where(p => p.StartsWith("/media/")), k => GetTag(k));
                Console.WriteLine("Looking tags...Done");

            }
            catch (Exception e)
            {
                Console.WriteLine($"Load error: {e}");
            }

            _isLoading = false;
        }

        private static void Working()
        {
            var listener = new HttpListener();
            listener.Prefixes.Add(ConfigFile.Instance.ListenPrefix);
            listener.Start();

            var upTime = DateTime.Now;

            Console.WriteLine($"HTTP Server started, listening on {ConfigFile.Instance.ListenPrefix}");

            listener.BeginGetContext(ContextGet, listener);

            _lastRequestAccepted = DateTime.Now;
            while (_isRunning)
            {
                var timeSpan = DateTime.Now - _lastRequestAccepted;
                var up = DateTime.Now - upTime;
                Console.Title =
                    "FNZCM"
                    + $" UP {up.Days:00}D {up.Hours:00}H {up.Minutes:00}M {up.Seconds:00}S {up.Milliseconds:000}"
                    + $" / "
                    + $" LA {timeSpan.Days:00}D {timeSpan.Hours:00}H {timeSpan.Minutes:00}M {timeSpan.Seconds:00}S {timeSpan.Milliseconds:000}"
                ;

                Thread.Sleep(1000);
            }

            listener.Close();

            Thread.Sleep(1000);
        }

        private static void ContextGet(IAsyncResult ar)
        {
            var listener = (HttpListener)ar.AsyncState;
            HttpListenerContext context;

            try
            {
                // ReSharper disable once PossibleNullReferenceException
                context = listener.EndGetContext(ar);
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                return;
            }

            if (_isRunning) listener.BeginGetContext(ContextGet, listener);
            ProcessRequest(context);
        }

        private static void ProcessRequest(HttpListenerContext context)
        {
            _lastRequestAccepted = DateTime.Now;

            var request = context.Request;
            Console.WriteLine($"Request from {request.RemoteEndPoint} {request.HttpMethod} {request.RawUrl}");

            // GET / show all libraries

            // foo=library bar=album
            // GET /list/foo/ show all album and cover with name, provide m3u path
            // GET /list/foo/bar/bk/ list all picture as grid
            // GET /list/foo/bar/tracks/ list all tracks as text list
            // GET /list/foo/bar/playlist.m3u8 auto gen

            // GET /list/foo/bar/aac_q1.00/playlist.m3u8 auto gen

            // media streaming HTTP Partial RANGE SUPPORT
            // GET /cover/foo/bar/cover.jpg
            // GET /media/foo/bar/01.%20foobar.flac
            // GET /bk/foo/bar/foobar.jpg

            // GET /media/foo/aac_q1.00/01.%20foobar.m4a

            try
            {
                // ReSharper disable once PossibleNullReferenceException
                var requestPath = request.Url.LocalPath.ToLower();
                var pathParts = (IReadOnlyList<string>)requestPath.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries);

                if (requestPath == "/scan/")
                {
                    Task.Run(ScanLibrary);
                    context.Response.Redirect("/");
                }
                else if (requestPath == "/")
                {
                    var sb = new StringBuilder();
                    sb.Append("<!DOCTYPE html><html lang=\"zh-cn\"><meta charset=\"UTF-8\">");
                    sb.Append($"<title> Libraries - {ConfigFile.Instance.Title} </title>");
                    sb.Append("<body bgColor=skyBlue style=font-size:3vh>");

                    if (_isLoading) sb.Append("<h2 style=position:fixed;right:0px;top:0px;margin:0>Still Loading...</h2>");

                    sb.Append($"<h1>{ConfigFile.Instance.Title}</h1>");
                    sb.Append("<h1>Libraries</h1>");

                    sb.Append("<ul>");
                    foreach (var library in Libraries.OrderBy(p => p.Key))
                    {
                        sb.Append("<li>");
                        sb.Append($"<a href='/list/{library.Key.FuckVlcAndEscape()}/'>{library.Value.Name}</a>");
                        sb.Append("</li>");
                    }

                    sb.Append("</ul>");

                    sb.Append("<a href=/scan/> Scan Libraries</a>");

                    context.Response.WriteText(sb.ToString());
                }
                else if (pathParts.Count == 2 && pathParts[0] == "list")
                {
                    var libName = pathParts[1];
                    if (Libraries.TryGetValue(libName, out var l))
                    {
                        var sb = new StringBuilder();
                        sb.Append("<!DOCTYPE html><html lang=\"zh-cn\"><meta charset=\"UTF-8\">");
                        sb.Append($"<title> Albums of {l.Name} - {ConfigFile.Instance.Title} </title>");
                        sb.Append(
                            "<style>" +
                            "a:link{ text-decoration: none; }" +
                            "div.item{" +
                            " vertical-align:top;" +
                            " height:20vh;" +
                            " margin-bottom:1vh;" +
                            " padding:0.5vh;" +
                            " border:solid 1px;" +
                            " border-radius:0.5vh;" +
                            " font-size:1.5vh;" +
                            " overflow:scroll;" +
                            "}" +
                            "div.item::-webkit-scrollbar{" +
                            " display: none;" +
                            "}" +
                            "img.cover{" +
                            " float:left;" +
                            " background-size:cover;" +
                            " max-width:25vw;" +
                            " max-height:20vh" +
                            "}" +
                            "a.button{" +
                            " margin-left:4vw;" +
                            "}" +
                            "</style>");

                        sb.Append($"<body bgColor=skyBlue>");

                        if (_isLoading) sb.Append("<h2 style=position:fixed;right:0px;top:0px;margin:0>Still Loading...</h2>");

                        sb.Append($"<h1>Albums of {l.Name}</h1>");
                        sb.Append("<div><a href=/>Back to home</a></div>");

                        //Cover list
                        foreach (var a in l.Albums.OrderBy(p => p.Key))
                        {
                            sb.Append("<div class=item>");
                            sb.Append($"<img class=cover src=\"/cover/{libName}/{a.Key}/cover.jpg\" />");

                            sb.Append("<div style=text-align:right>");
                            sb.Append($"<a class=button href=\"/list/{libName}/{a.Key}/tracks/\">[TRACKERS]</a>");
                            if (a.Value.Bks?.Count > 0) sb.Append($"<a class=button href=\"/list/{libName}/{a.Key}/bk/\">[BK]</a>");
                            sb.Append("</div>");

                            sb.Append("<div style=text-align:right>");
                            var totalDur = a.Value.MainTracks.Sum(p => GetTag($"/media/{libName}/{a.Key}/{p.Key}", true)?.Duration ?? 0);
                            var totalLen = a.Value.MainTracks.Sum(p => GetTag($"/media/{libName}/{a.Key}/{p.Key}", true)?.Length ?? 0);
                            sb.Append($"<a class=button href=\"/list/{libName}/{a.Key.FuckVlcAndEscape()}/playlist.m3u8\">[M3U8({totalDur.FormatDuration()}){totalLen.FormatFileSize()}]</a>");
                            if (a.Value.SubTracks.Count > 0)
                            {
                                foreach (var subTrack in a.Value.SubTracks)
                                {
                                    totalDur = subTrack.Value.Tracks.Sum(p => GetTag($"/media/{libName}/{a.Key}/{subTrack.Key}/{p.Key}", true)?.Duration ?? 0);
                                    totalLen = subTrack.Value.Tracks.Sum(p => GetTag($"/media/{libName}/{a.Key}/{subTrack.Key}/{p.Key}", true)?.Length ?? 0);
                                    sb.Append($"<br/><a class=button href=\"/list/{libName}/{a.Key.FuckVlcAndEscape()}/{subTrack.Key.FuckVlcAndEscape()}/playlist.m3u8\">[{subTrack.Value.Name}({totalDur.FormatDuration()}){totalLen.FormatFileSize()}]</a>");
                                }
                            }
                            sb.Append("</div>");

                            sb.Append($"<div>{a.Value.Name}</div>");
                            sb.Append("</div>");
                        }

                        context.Response.ContentType = "text/html";
                        context.Response.ContentEncoding = Encoding.UTF8;
                        context.Response.WriteText(sb.ToString());
                    }
                    else
                    {
                        context.Response.StatusCode = 404;
                        //context.Response.Redirect("https://www.youtube.com/watch?v=dQw4w9WgXcQ");
                    }
                }
                else if (pathParts.Count == 4 && pathParts[0] == "list" && pathParts[3] == "tracks")
                {
                    var libName = pathParts[1];
                    var albPath = pathParts[2];

                    if (Libraries.TryGetValue(libName, out var l) && l.Albums.TryGetValue(albPath, out var alb))
                    {
                        var sb = new StringBuilder();
                        sb.Append("<!DOCTYPE html><html lang=\"zh-cn\"><meta charset=\"UTF-8\">");
                        sb.Append($"<body bgColor=skyBlue style=font-size:2vh>");

                        if (_isLoading) sb.Append("<h2 style=position:fixed;right:0px;top:0px;margin:0>Still Loading...</h2>");

                        sb.Append($"<h2>Tracks of</h2><h1>{alb.Name}</h1>");
                        sb.Append($"<div><a href='/list/{libName.FuckVlcAndEscape()}/'>Back to library</a></div>");


                        var durTotal = 0;
                        var sizeTotal = 0L;

                        var sbm = new StringBuilder();
                        foreach (var kvpTrack in alb.MainTracks.OrderBy(p => p.Key))
                        {
                            sbm.Append($"<li>");
                            sbm.Append($"<a href=\"/media/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/{kvpTrack.Key.FuckVlcAndEscape()}\" >{kvpTrack.Value}</a>");

                            var tag = GetTag($"/media/{libName}/{albPath}/{kvpTrack.Key}");
                            durTotal += tag.Duration;
                            sizeTotal += tag.Length;
                            sbm.Append($" ({tag.Duration.FormatDuration()}) {tag.Length.FormatFileSize()}");

                            sbm.Append($"</li>");
                        }

                        sb.Append($"<h2>Main ({durTotal.FormatDuration()}) {sizeTotal.FormatFileSize()}</h2>");
                        sb.Append(sbm);

                        foreach (var kvpSubSet in alb.SubTracks.OrderBy(p => p.Key))
                        {
                            durTotal = 0;
                            sizeTotal = 0L;

                            sbm.Clear();
                            foreach (var kvpTrack in kvpSubSet.Value.Tracks.OrderBy(p => p.Key))
                            {
                                sbm.Append($"<li>");
                                sbm.Append($"<a href=\"/media/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/{kvpSubSet.Key.FuckVlcAndEscape()}/{kvpTrack.Key.FuckVlcAndEscape()}\" >{kvpTrack.Value}</a>");

                                var tag = GetTag($"/media/{libName}/{albPath}/{kvpSubSet.Key}/{kvpTrack.Key}");
                                durTotal += tag.Duration;
                                sizeTotal += tag.Length;
                                sbm.Append($" ({tag.Duration.FormatDuration()}) {tag.Length.FormatFileSize()}");

                                sbm.Append($"</li>");
                            }

                            sb.Append($"<h2>{kvpSubSet.Value.Name} ({durTotal.FormatDuration()}) {sizeTotal.FormatFileSize()}</h2>");
                            sb.Append(sbm);

                        }

                        context.Response.ContentType = "text/html";
                        context.Response.ContentEncoding = Encoding.UTF8;
                        context.Response.WriteText(sb.ToString());
                    }
                    else
                    {
                        context.Response.StatusCode = 404;
                        //context.Response.Redirect("https://www.youtube.com/watch?v=dQw4w9WgXcQ");
                    }
                }
                else if (pathParts.Count == 4 && pathParts[0] == "list" && pathParts[3] == "bk")
                {
                    var libName = pathParts[1];
                    var albPath = pathParts[2];

                    if (Libraries.TryGetValue(libName, out var lib) && lib.Albums.TryGetValue(albPath, out var alb))
                    {
                        var sb = new StringBuilder();
                        sb.Append("<!DOCTYPE html><html lang=\"zh-cn\"><meta charset=\"UTF-8\">");
                        sb.Append($"<body bgColor=skyBlue style=font-size:2vh>");

                        if (_isLoading) sb.Append("<h2 style=position:fixed;right:0px;top:0px;margin:0>Still Loading...</h2>");

                        sb.Append($"<h2>BK of </h2><h1>{alb.Name}</h1>");
                        sb.Append($"<div><a href='/list/{libName.FuckVlcAndEscape()}/'>Back to library</a></div>");

                        foreach (var albBk in alb.Bks.OrderBy(p => p.Key))
                        {
                            //TODO: auto gen thumbnail 512x512 jpg 80 
                            sb.Append($"<img src='/bk/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/{albBk.Key.FuckVlcAndEscape()}' style=max-width:24vw;max-height:24vw;margin-right:1vw;margin-bottom:1vh; />");
                        }

                        context.Response.ContentType = "text/html";
                        context.Response.ContentEncoding = Encoding.UTF8;
                        context.Response.WriteText(sb.ToString());
                    }
                    else
                    {
                        context.Response.StatusCode = 404;
                        //context.Response.Redirect("https://www.youtube.com/watch?v=dQw4w9WgXcQ");
                    }
                }
                else if (pathParts.Count == 4 && pathParts[0] == "list" && pathParts[3] == "playlist.m3u8")
                {
                    var libName = pathParts[1];
                    var albPath = pathParts[2];

                    if (Libraries.TryGetValue(libName, out var lib) && lib.Albums.TryGetValue(albPath, out var alb))
                    {
                        // ReSharper disable once BitwiseOperatorOnEnumWithoutFlags
                        var prefix = $"{request.Url.GetLeftPart(UriPartial.Scheme | UriPartial.Authority)}";

                        var sb = new StringBuilder();

                        sb.AppendLine("#EXTM3U");
                        foreach (var track in alb.MainTracks.OrderBy(p => p.Key))
                        {
                            var mediaTag = GetTag($"/media/{libName}/{albPath}/{track.Key}");
                            if (mediaTag != null)
                            {
                                var coverPath = $"/cover/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/cover.jpg";
                                sb.AppendLine($"#EXTINF:{mediaTag.Duration} tvg-logo=\"{prefix + coverPath}\",{mediaTag.Title}");
                            }

                            var mediaPath = $"/media/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/{track.Key.FuckVlcAndEscape()}";
                            sb.AppendLine(prefix + mediaPath);
                        }

                        context.Response.ContentType = "audio/mpegurl";
                        context.Response.ContentEncoding = Encoding.UTF8;
                        context.Response.WriteText(sb.ToString());
                    }
                    else
                    {
                        context.Response.StatusCode = 404;
                        //context.Response.Redirect("https://www.youtube.com/watch?v=dQw4w9WgXcQ");
                    }
                }
                else if (pathParts.Count == 5 && pathParts[0] == "list" && pathParts[4] == "playlist.m3u8")
                {
                    var libName = pathParts[1];
                    var albPath = pathParts[2];
                    var subSetPath = pathParts[3];

                    if (Libraries.TryGetValue(libName, out var lib) && lib.Albums.TryGetValue(albPath, out var alb))
                    {
                        // ReSharper disable once BitwiseOperatorOnEnumWithoutFlags
                        var prefix = $"{request.Url.GetLeftPart(UriPartial.Scheme | UriPartial.Authority)}";

                        if (false == alb.SubTracks.TryGetValue(subSetPath, out var trackSet))
                        {
                            context.Response.StatusCode = 404;
                        }
                        else
                        {
                            var sb = new StringBuilder();

                            sb.AppendLine("#EXTM3U");
                            foreach (var track in trackSet.Tracks.OrderBy(p => p.Key))
                            {
                                var mediaTag = GetTag($"/media/{libName}/{albPath}/{subSetPath}/{track.Key}");
                                if (mediaTag != null)
                                {
                                    var coverPath = $"/cover/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/cover.jpg";
                                    sb.AppendLine($"#EXTINF:{mediaTag.Duration} tvg-logo=\"{prefix + coverPath}\",{mediaTag.Title}");
                                }

                                var mediaPath = $"/media/{libName.FuckVlcAndEscape()}/{albPath.FuckVlcAndEscape()}/{subSetPath.FuckVlcAndEscape()}/{track.Key.FuckVlcAndEscape()}";
                                sb.AppendLine(prefix + mediaPath);
                            }

                            context.Response.ContentType = "audio/mpegurl";
                            context.Response.ContentEncoding = Encoding.UTF8;
                            context.Response.WriteText(sb.ToString());
                        }
                    }
                    else
                    {
                        context.Response.StatusCode = 404;
                        //context.Response.Redirect("https://www.youtube.com/watch?v=dQw4w9WgXcQ");
                    }
                }
                else if (PathMapping.TryGetValue(requestPath, out var realPath))
                {
                    var range = request.Headers.GetValues("Range");

                    FileStream fs = null;
                    try
                    {
                        fs = File.OpenRead(realPath);

                        if (range is { Length: > 0 })
                        {
                            var rngParts = range[0].Split(new[] { "bytes=", "-" }, StringSplitOptions.RemoveEmptyEntries);
                            if (rngParts.Length >= 1 && long.TryParse(rngParts[0], out var start))
                            {
                                fs.Position = start;
                                context.Response.StatusCode = 206;
                                context.Response.Headers.Add("Accept-Ranges", "bytes");
                                context.Response.Headers.Add("Content-Range", $"bytes {start}-{fs.Length - 1}/{fs.Length}");
                                context.Response.ContentLength64 = fs.Length - start;
                                context.Response.ContentType = "video/mp4";
                                fs.CopyTo(context.Response.OutputStream);
                            }
                        }
                        else
                        {
                            context.Response.ContentType = "video/mp4";
                            context.Response.ContentLength64 = fs.Length;
                            fs.CopyTo(context.Response.OutputStream);
                        }
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine(e);
                    }
                    finally
                    {
                        fs?.Close();
                    }
                }
                else
                {
                    context.Response.StatusCode = 404;
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);

                try
                {
                    context.Response.StatusCode = 500;
                }
                catch (Exception exception)
                {
                    Console.WriteLine(exception);
                }
            }
            finally
            {
                try
                {
                    context.Response.Close();
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
            }
        }

        private static string FormatDuration(this int second)
        {
            var sbd = new StringBuilder();
            var ts = TimeSpan.FromSeconds(second);
            if (ts.TotalHours > 1) sbd.Append($"{ts.TotalHours:00}:");
            sbd.Append($"{ts.Minutes:00}:{ts.Seconds:00}");
            return sbd.ToString();
        }

        private static string FormatFileSize(this long length)
        {
            string[] sizes = { "B", "KB", "MB", "GB", "TB" };
            double len = length;
            int order = 0;
            while (len >= 1024 && order < sizes.Length - 1)
            {
                order++;
                len = len / 1024;
            }

            // Adjust the format string to your preferences. For example "{0:0.#}{1}" would
            // show a single decimal place, and no space.
            string result = String.Format("{0:0.##} {1}", len, sizes[order]);
            return result;
        }

        private static void WriteText(this HttpListenerResponse response, string content)
        {
            var bytes = Encoding.UTF8.GetBytes(content);
            response.OutputStream.Write(bytes);
        }

        private static string FuckVlcAndEscape(this string input)
        {
            if (input == null) return null;
            return input
                .Replace("[", "%5B")
                .Replace("]", "%5D")
                .Replace("'", "%27")
                ;
        }

        private static MediaTag2 GetTag(string internalPath, bool peek = false)
        {
            if (peek)
            {
                if (MediaTags.TryGetValue(internalPath, out var mediaTag))
                {
                    return mediaTag;
                }

                return null;
            }
            else
            {
                if (false == MediaTags.TryGetValue(internalPath, out var mediaTag) && PathMapping.TryGetValue(internalPath, out var mediaFilePath))
                {
                    var fi = new FileInfo(mediaFilePath);
                    using var tagLib = TagLib.File.Create(mediaFilePath);
                    mediaTag = MediaTags[internalPath] = new MediaTag2(
                        $"{string.Join(";", tagLib.Tag.Performers)} - {tagLib.Tag.Title}",
                        (int)tagLib.Properties.Duration.TotalSeconds,
                        fi.Length
                    );
                }

                return mediaTag;
            }


        }
    }
}