SoundPreviewAction

using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Microsoft.Xaml.Interactivity;

namespace Anheledir.Utilities
{
    public class SoundPreviewAction : DependencyObject, IAction
    {
        public static readonly DependencyProperty SourceProperty = DependencyProperty.Register("Source", typeof (string), typeof (SoundPreviewAction), new PropertyMetadata(null));

        public static readonly DependencyProperty VolumeProperty = DependencyProperty.Register("Volume", typeof (double), typeof (SoundPreviewAction), new PropertyMetadata(0.5));

        public static readonly DependencyProperty PlayContentProperty = DependencyProperty.Register("PlayContent", typeof (object), typeof (SoundPreviewAction), new PropertyMetadata (new SymbolIcon(Symbol.Play)));

        public static readonly DependencyProperty StopContentProperty = DependencyProperty.Register("StopContent", typeof (object), typeof (SoundPreviewAction), new PropertyMetadata(new SymbolIcon(Symbol.Stop)));

        // The MediaElement will only be played when it is part of the visual tree, so we use a non-visible popup as a parent-element
        private Popup _helperElement;

        static SoundPreviewAction()
        {
        }

        private static MediaElement CurrentlyPlaying { get; set; }
        private static Button CurrentlyPlayingButton { get; set; }

        /// <summary>
        ///     This is the sound file that should be played on button click
        /// </summary>
        public string Source
        {
            get { return (string) GetValue(SourceProperty); }
            set { SetValue(SourceProperty, value); }
        }

        /// <summary>
        ///     You can set the volume of the sound between 0.0 and 1.0, default is 0.5 (50%)
        /// </summary>
        public double Volume
        {
            get { return (double) GetValue(VolumeProperty); }
            set { SetValue(VolumeProperty, value); }
        }

        /// <summary>
        ///     This content will be displayed while no sound is played, e.g. a Play-Button
        /// </summary>
        public object PlayContent
        {
            get { return GetValue(PlayContentProperty); }
            set { SetValue(PlayContentProperty, value); }
        }

        /// <summary>
        ///     This content will be displayed while the sound is playing, e.g. a Stop-Button
        /// </summary>
        public object StopContent
        {
            get { return GetValue(StopContentProperty); }
            set { SetValue(StopContentProperty, value); }
        }

        public object Execute(object sender, object parameter)
        {
            if (string.IsNullOrWhiteSpace(Source))
            {
                return false;
            }

            Uri sourceUri;
            if (!Uri.TryCreate(Source, UriKind.Absolute, out sourceUri))
            {
                if (!Uri.TryCreate(string.Concat("ms-appx:///{0}", Source), UriKind.Absolute, out sourceUri))
                {
                    return false;
                }
            }

            if (CurrentlyPlaying != null)
            {
                // There was already a sound playing, so stop it
                CurrentlyPlaying.Stop();

                if (CurrentlyPlayingButton != null)
                {
                    // We set the content of the previously playing sound-button back to the PlayContent
                    CurrentlyPlayingButton.Content = PlayContent;
                }

                if (CurrentlyPlaying.Source == sourceUri)
                {
                    // In case we stopped the currently playing sound without starting another, we cancel execution at this point
                    CurrentlyPlaying = null;
                    return false;
                }
            }

            _helperElement = new Popup();
            CurrentlyPlaying = new MediaElement();
            _helperElement.Child = CurrentlyPlaying;
            CurrentlyPlaying.Visibility = Visibility.Collapsed;
            CurrentlyPlaying.Source = sourceUri;
            CurrentlyPlaying.Volume = Volume;
            CurrentlyPlaying.MediaEnded += MediaElement_MediaEnded;
            CurrentlyPlaying.MediaFailed += MediaElement_MediaFailed;
            CurrentlyPlayingButton = sender as Button;
            if (CurrentlyPlayingButton != null)
            {
                CurrentlyPlayingButton.Content = StopContent;
            }
            _helperElement.IsOpen = true;
            return true;
        }

        private void MediaElement_MediaFailed(object sender, ExceptionRoutedEventArgs e)
        {
            if (CurrentlyPlayingButton != null)
            {
                CurrentlyPlayingButton.Content = PlayContent;
                CurrentlyPlayingButton = null;
                CurrentlyPlaying = null;
            }

            if (_helperElement != null)
            {
                _helperElement.IsOpen = false;
                _helperElement.Child = null;
                _helperElement = null;
            }
        }

        private void MediaElement_MediaEnded(object sender, RoutedEventArgs e)
        {
            if (CurrentlyPlayingButton != null)
            {
                CurrentlyPlayingButton.Content = PlayContent;
                CurrentlyPlayingButton = null;
                CurrentlyPlaying = null;
            }

            if (_helperElement != null)
            {
                _helperElement.IsOpen = false;
                _helperElement.Child = null;
                _helperElement = null;
            }
        }
    }
}