MusicController.cs

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Media;

namespace AudioResumeTest
{
    public interface IMusicController
    {
        bool Enabled { get; set; }
        bool IsPlaying { get; }
        bool IsSuspended { get; }

        float Volume { get; set; }
        bool IsMuted { get; set; }
        bool IsRepeating { get; set; }

        void Play(Song song);
        void Stop();
        void Suspend();
        void Resume();

        void Update(GameTime gameTime);
    }

    public class MusicController : IMusicController
    {
        private Song _currentSong = null;
        private TimeSpan _currentPosition = TimeSpan.Zero;
        private TimeSpan _savedPosition = TimeSpan.Zero;
        private IMusicPlayer _player = null;

        public MusicController(IMusicPlayer player)
        {
            _player = player ?? throw new ArgumentNullException();
        }

        public bool IsPlaying { get; private set; } = false;
        public bool IsSuspended { get; private set; } = false;

        public bool Enabled
        {
            get { return _enabled; }
            set
            {
                if (value != _enabled)
                {
                    _enabled = value;

                    if (_enabled == false && this.IsPlaying)
                    {
                        var currentSong = _currentSong;
                        this.Stop();
                        _currentSong = currentSong;
                    }
                    else if (_enabled == true && _currentSong != null)
                    {
                        this.Play(_currentSong);
                    }
                }
            }
        }
        private bool _enabled = true;

        public float Volume
        {
            get { return _player.Volume; }
            set { _player.Volume = value; }
        }

        public bool IsMuted
        {
            get { return _player.IsMuted; }
            set { _player.IsMuted = value; }
        }

        public bool IsRepeating
        {
            get { return _player.IsRepeating; }
            set { _player.IsRepeating = value; }
        }

        public void Play(Song s)
        {
            if (this.Enabled == false)
            {
                _currentSong = s;
                return;
            }

            _player.Play(s);

            this.IsPlaying = true;
            _savedPosition = TimeSpan.Zero;
            _currentSong = s;
        }

        public void Suspend()
        {
            if (this.IsSuspended == false)
            {
                _player.Stop();
                _savedPosition = _currentPosition;
                this.IsPlaying = false;
                this.IsSuspended = true;
            }
        }

        public void Resume()
        {
            if (this.IsSuspended == true)
            {
                if (this.Enabled == true)
                {
                    _player.Play(_currentSong, _savedPosition);
                    _savedPosition = TimeSpan.Zero;
                    this.IsPlaying = true;
                }

                this.IsSuspended = false;
            }
        }

        public void Stop()
        {
            _player.Stop();
            _savedPosition = TimeSpan.Zero;
            this.IsPlaying = false;
            _currentSong = null;
        }

        public void Update(GameTime gameTime)
        {
            if (this.IsPlaying)
                _currentPosition = _player.PlayPosition;
            else
                _currentPosition = TimeSpan.Zero;
        }
    }
}