using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace Futonizer.Models;

/// <summary>
/// Represents one track of a queued MKV file, as shown in the track table.
/// The <see cref="Copy"/> property is user-editable and drives which tracks
/// are passed to mkvmerge when stripping.
/// </summary>
public class TrackItem : INotifyPropertyChanged
{
    private bool _copy;

    public int Id { get; init; }
    public string Type { get; init; } = string.Empty;
    public string Codec { get; init; } = string.Empty;
    public string Language { get; init; } = string.Empty;
    public string Name { get; init; } = string.Empty;
    public bool ForcedDisplay { get; init; }

    /// <summary>
    /// True for the first track of each type group (video/audio/subtitles/
    /// chapters) in the track table, computed once when the list is built.
    /// Used to draw a divider line above the row in the UI.
    /// </summary>
    public bool IsGroupStart { get; set; }


    private bool _defaultTrack;

    /// <summary>
    /// Whether this track should be flagged as the default track of its type
    /// when stripped. For audio and subtitles this is kept in sync with
    /// <see cref="Copy"/> (selecting a track also makes it the default one
    /// of its type).
    /// </summary>
    public bool DefaultTrack
    {
        get => _defaultTrack;
        set
        {
            if (_defaultTrack == value) return;
            _defaultTrack = value;
            OnPropertyChanged();
        }
    }

    /// <summary>
    /// Text shown in the track table's Name column.
    /// </summary>
    public string DisplayName => Name;

    /// <summary>
    /// Video is always kept, and chapters (a synthetic pseudo-track, not a
    /// real mkvmerge track) are always kept too — neither is user-selectable,
    /// so their Copy checkbox is shown checked but disabled.
    /// </summary>
    public bool IsEditable => Type is "audio" or "subtitles";

    /// <summary>
    /// Chapters aren't a real track and have no track ID; show a dash
    /// instead of a meaningless number.
    /// </summary>
    public string IdDisplay => Type == "chapters" ? "—" : Id.ToString();


    public bool Copy
    {
        get => _copy;
        set
        {
            if (_copy == value) return;
            _copy = value;
            OnPropertyChanged();
        }
    }

    /// <summary>
    /// Key used to match a track's identity across different queued files
    /// when propagating an audio/subtitle selection. Matched on "Codec/Name"
    /// so tracks with the same name but a different codec are treated as
    /// distinct, even though only the name is shown in the table.
    /// </summary>
    public string PropagationKey => $"{Codec}/{Name}";

    public event PropertyChangedEventHandler? PropertyChanged;

    private void OnPropertyChanged([CallerMemberName] string? name = null)
        => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}