unison/Handlers/ShuffleHandler.cs

using MpcNET.Commands.Database;
using MpcNET.Commands.Queue;
using MpcNET.Tags;
using MpcNET.Types;
using MpcNET.Types.Filters;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace unison
{
    class ShuffleHandler
    {
        private MPDHandler _mpd;
        public List<string> _songList { get; }
        public int AddedSongs = 0;

        public ShuffleHandler()
        {
            _songList = new();
            _mpd = (MPDHandler)Application.Current.Properties["mpd"];
        }

        private bool IsOnMainThread()
        {
            return Application.Current.Dispatcher.Thread == System.Threading.Thread.CurrentThread;
        }

        public async Task GetSongsFromFilter(List<IFilter> filter)
        {
            Debug.WriteLine("[GetSongsFromFilterBefore] is on main thread => " + IsOnMainThread());
            await Task.Run(async() =>
            {
                Debug.WriteLine("[GetSongsFromFilterAfter] is on main thread => " + IsOnMainThread());

                _songList.Clear();
                int song = _mpd.GetStats().Songs;

                IEnumerable<IMpdFile> response = await _mpd.SafelySendCommandAsync(new SearchCommand(filter, 0, song + 1));

                Debug.WriteLine("got response => " + response.Count());

                foreach (IMpdFile file in response)
                {
                    _songList.Add(file.Path);
                    Debug.WriteLine(file.Path);
                }
            });
        }

        public async Task AddToQueueRandom(int SongNumber)
        {
            Debug.WriteLine("Add To Queue Random");

            await Task.Run(async () =>
            {
                int AddedSongs = 0;

                Debug.WriteLine("song to add => " + SongNumber);
                for (int i = 0; i < SongNumber; i++)
                {
                    // generate random number
                    int song = new Random().Next(0, _mpd.GetStats().Songs - 1);
                    Debug.WriteLine("song " + song + " - song total " + _mpd.GetStats().Songs);
                    IEnumerable<IMpdFile> Response = await _mpd.SafelySendCommandAsync(new SearchCommand(new FilterTag(MpdTags.Title, "", FilterOperator.Contains), song, song + 1));

                    Debug.WriteLine("got response");

                    await Task.Delay(1);
                    if (Response.Count() > 0)
                    {
                        string filePath = Response.First().Path;
                        _mpd.AddSong(filePath);
                        Debug.WriteLine("song path => " + filePath);

                        if (i == 0)
                        {
                            if (!_mpd.IsPlaying())
                                _mpd.Play(0);
                        }

                        AddedSongs++;
                    }
                }
            });

            Debug.WriteLine("Add To Queue Random - finished");
        }

        public async Task AddToQueueFilter(int SongNumber)
        {
            Debug.WriteLine("Add To Queue Filter");

            await Task.Run(async () =>
            {
                int AddedSongs = 0;

                Debug.WriteLine("song to add => " + SongNumber);
                // more requested songs than available => add everything
                if (SongNumber > _songList.Count)
                {
                    foreach (string path in _songList)
                    {
                        await Task.Delay(1);
                        _mpd.AddSong(path);
                        Debug.WriteLine("song path => " + path);
                        AddedSongs++;
                    }
                }
                // more available songs than requested =>
                // we add unique indexes until we reach the requested amount
                else
                {
                    HashSet<int> SongIndex = new();
                    Debug.WriteLine("while - before");
                    while (SongIndex.Count < SongNumber)
                    {
                        int MaxIndex = new Random().Next(0, _songList.Count - 1);
                        SongIndex.Add(MaxIndex);
                    }

                    foreach (int index in SongIndex)
                        _mpd.AddSong(_songList[index]);
                    Debug.WriteLine("while - after");
                }
            });

            Debug.WriteLine("Add To Queue Filter - finished");
        }
    }
}