using AvParser.Core.Collecting;
using AvParser.Core.Collecting.Sources;
using AvParser.UI.Localization;
using ReactiveUI;

namespace AvParser.UI.ViewModels;

/// <summary>A media source paired with its translated name and description.</summary>
/// <remarks>
/// The domain knows nothing about languages, so <see cref="IMediaSource"/> carries English text.
/// This looks the id up as <c>Source.{id}.Name</c> and falls back to what the source itself says —
/// which is what user-added sources always do, since their name is data the user typed, not a resx
/// key. Disposable because the catalog rebuilds these on every edit, and each one holds a
/// language-changed subscription that would otherwise leak.
/// </remarks>
public sealed class MediaSourceViewModel : ReactiveObject, IDisposable
{
    private bool _isSelected;

    /// <summary>Wraps a source.</summary>
    public MediaSourceViewModel(IMediaSource source)
    {
        Source = source ?? throw new ArgumentNullException(nameof(source));
        Localizer.Instance.LanguageChanged += OnLanguageChanged;
    }

    /// <summary>Whether the next run includes this source.</summary>
    /// <remarks>
    /// Ticking is what a run acts on; the list's highlight only says which source the editor,
    /// the delete button and the purge button are aimed at. Keeping the two apart is what lets a
    /// run cover five sources while the user edits a sixth.
    /// </remarks>
    public bool IsSelected
    {
        get => _isSelected;
        set => this.RaiseAndSetIfChanged(ref _isSelected, value);
    }

    /// <summary>The source itself.</summary>
    public IMediaSource Source { get; }

    /// <summary>The config behind the source, when it is a pattern source (they all are today).</summary>
    public PatternSourceConfig? Config => (Source as PatternMediaSource)?.Config;

    /// <summary>Stable identifier.</summary>
    public string Id => Source.Id;

    /// <summary>Translated name, or the source's own when untranslated.</summary>
    public string Name => Localizer.Instance.GetOrDefault($"Source.{Id}.Name", Source.DisplayName);

    /// <summary>Translated description, or the source's own when untranslated.</summary>
    public string Description => Localizer.Instance.GetOrDefault($"Source.{Id}.Description", Source.Description);

    /// <summary>Whether this source goes to the network at all.</summary>
    public bool RequiresNetwork => Source.RequiresNetwork;

    /// <summary>
    /// Whether this source may run from the user's own address when no proxy is live.
    /// </summary>
    /// <remarks>
    /// Anything that is not a configured pattern source answers <see langword="false"/>: the safe
    /// end, since a source with nowhere to say otherwise has not said otherwise.
    /// </remarks>
    public bool AllowsDirectConnection => Config?.AllowDirectConnection ?? false;

    /// <summary>Whether a run including this source is gated on a live proxy.</summary>
    public bool NeedsProxy => RequiresNetwork && !AllowsDirectConnection;

    /// <inheritdoc />
    public override string ToString() => Name;

    /// <inheritdoc />
    public void Dispose() => Localizer.Instance.LanguageChanged -= OnLanguageChanged;

    private void OnLanguageChanged(object? sender, EventArgs e)
    {
        this.RaisePropertyChanged(nameof(Name));
        this.RaisePropertyChanged(nameof(Description));
    }
}