harmonia/Harmonia.WinUI/ViewModels/PlaylistItemViewModel.cs

using CommunityToolkit.Mvvm.ComponentModel;
using Harmonia.Core.Playlists;
using System;
using System.Linq;

namespace Harmonia.WinUI.ViewModels;

public partial class PlaylistItemViewModel : ObservableObject
{
    public Playlist Playlist { get; private set; }

    private string _summary = string.Empty;
    public string Summary
    {
        get
        {
            return _summary;
        }
        set
        {
            SetProperty(ref _summary, value);
        }
    }

    public PlaylistItemViewModel(Playlist playlist)
    {
        Playlist = playlist;
        Playlist.PlaylistUpdated += OnPlaylistUpdated;
        UpdateMetaData();
    }

    public void Unsubscribe()
    {
        Playlist.PlaylistUpdated -= OnPlaylistUpdated;
    }

    private void OnPlaylistUpdated(object? sender, EventArgs e)
    {
        UpdateMetaData();
    }

    private void UpdateMetaData()
    {
        TimeSpan total = TimeSpan.FromSeconds(Playlist.Songs.Sum(s => s.Song.Length.TotalSeconds));
        Summary = $"{Playlist.Songs.Count} songs / {total:h\\:mm\\:ss}";
    }
}