using System.Collections.Generic;
using System.Linq;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using EmbyToolbox.Models;
using EmbyToolbox.Services;

namespace EmbyToolbox.ViewModels;

public interface ITrackPlanPreviewHost
{
    void RecalculatePlanPreview();
    void OnTrackDefaultEnabled(TrackSettingsRowViewModel row);
    void ValidateDefaultConflicts();
}

public sealed class TrackSettingsRowViewModel : INotifyPropertyChanged
{
    private readonly ITrackPlanPreviewHost _parent;
    private readonly TrackOverrideEntry _entry;
    private readonly MediaStreamInfo? _embeddedStream;
    private string _details;
    private TrackActionKind _action;
    private bool _hasDefaultConflict;

    public TrackSettingsRowViewModel(
        ITrackPlanPreviewHost parent,
        TrackOverrideEntry entry,
        int displayIndex,
        MediaStreamInfo? embedded,
        string? targetContainer)
    {
        _parent = parent;
        _entry = entry;
        _embeddedStream = embedded;
        _action = entry.Action;
        IndexDisplay = displayIndex;
        if (entry.Source == SourceKind.External)
        {
            SourceDisplay = "Внешняя";
            if (entry.StreamKind == MediaStreamKind.Subtitle)
            {
                entry.Language = "rus";
            }
            else if (string.IsNullOrEmpty(entry.Language))
            {
                entry.Language = "rus";
            }
        }
        else
        {
            SourceDisplay = "Встроенная";
        }

        TypeDisplay = entry.StreamKind switch
        {
            MediaStreamKind.Video => "Video",
            MediaStreamKind.Audio => "Audio",
            MediaStreamKind.Subtitle => "Subtitle",
            MediaStreamKind.Attachment => "Attachment",
            MediaStreamKind.Data => "Data",
            _ => "?"
        };

        Codec = entry.StreamKind == MediaStreamKind.Subtitle && embedded is not null && SubtitleCodecRules.IsTeletext(embedded.CodecName)
            ? "dvb_teletext"
            : embedded?.CodecName ?? (entry.Source == SourceKind.External
                ? (entry.StreamKind == MediaStreamKind.Attachment
                    ? "font"
                    : entry.StreamKind == MediaStreamKind.Audio && !string.IsNullOrWhiteSpace(entry.ExternalStreamCodec)
                        ? entry.ExternalStreamCodec
                        : (System.IO.Path.GetExtension(entry.ExternalPath ?? string.Empty) is { Length: > 0 } e ? e : "?"))
                : "?");

        _details = BuildDetails(entry, embedded, targetContainer);

        ValidActions = new List<TrackActionKind>(GetValidActions(entry));
        if (!ValidActions.Contains(_action) && ValidActions.Count > 0)
        {
            _action = ValidActions[0];
            _entry.Action = _action;
        }
    }

    public TrackOverrideEntry DataModel => _entry;

    public int IndexDisplay { get; }

    public string SourceDisplay { get; }
    public string TypeDisplay { get; }
    public string Codec { get; }
    public string Details => _details;

    /// <summary>Обновить подсказку Details при смене целевого контейнера (teletext + MKV).</summary>
    public void RefreshSubtitleDetails(string? targetContainer)
    {
        if (_entry is not { Source: SourceKind.Embedded, StreamKind: MediaStreamKind.Subtitle })
        {
            return;
        }

        var next = BuildDetails(_entry, _embeddedStream, targetContainer);
        if (_details == next)
        {
            return;
        }

        _details = next;
        OnPropertyChanged(nameof(Details));
    }

    /// <summary>Встроенная teletext-субдорожка для выделения строки (MKV copy не поддерживается).</summary>
    public bool IsTeletextSubtitle =>
        _entry.Source == SourceKind.Embedded
        && _entry.StreamKind == MediaStreamKind.Subtitle
        && SubtitleCodecRules.IsTeletext(_embeddedStream?.CodecName);
    public IList<TrackActionKind> ValidActions { get; }

    public TrackActionKind Action
    {
        get => _action;
        set
        {
            if (_action == value)
            {
                return;
            }

            _action = value;
            _entry.Action = value;
            if (value == TrackActionKind.Remove)
            {
                _entry.Default = false;
                OnPropertyChanged(nameof(Default));
            }

            OnPropertyChanged();
            OnPropertyChanged(nameof(IsAudioBitrateVisible));
            OnPropertyChanged(nameof(IsDefaultEnabled));
            _parent.ValidateDefaultConflicts();
            _parent.RecalculatePlanPreview();
        }
    }

    public string? Language
    {
        get => _entry.Language;
        set
        {
            if (_entry.Language == value)
            {
                return;
            }

            _entry.Language = value;
            OnPropertyChanged();
            _parent.RecalculatePlanPreview();
        }
    }

    public string? Title
    {
        get => _entry.Title;
        set
        {
            if (_entry.Title == value)
            {
                return;
            }

            _entry.Title = value;
            OnPropertyChanged();
            _parent.RecalculatePlanPreview();
        }
    }

    public bool? Default
    {
        get => _entry.Default;
        set
        {
            if (_entry.Default == value)
            {
                return;
            }

            _entry.Default = value;
            OnPropertyChanged();
            if (value is true)
            {
                _parent.OnTrackDefaultEnabled(this);
            }

            _parent.ValidateDefaultConflicts();
            _parent.RecalculatePlanPreview();
        }
    }

    public bool IsDefaultEnabled =>
        (_entry.StreamKind is MediaStreamKind.Audio or MediaStreamKind.Subtitle) && _action != TrackActionKind.Remove;

    public bool HasDefaultConflict
    {
        get => _hasDefaultConflict;
        set
        {
            if (_hasDefaultConflict == value)
            {
                return;
            }

            _hasDefaultConflict = value;
            OnPropertyChanged();
        }
    }

    public string? AudioBitrateKbps
    {
        get => _entry.AudioBitrateKbps;
        set
        {
            if (_entry.AudioBitrateKbps == value)
            {
                return;
            }

            _entry.AudioBitrateKbps = value;
            OnPropertyChanged();
            _parent.RecalculatePlanPreview();
        }
    }

    public bool IsAudioBitrateVisible =>
        _entry.StreamKind == MediaStreamKind.Audio
        && ((_entry.Source == SourceKind.Embedded && _action == TrackActionKind.Convert)
            || (_entry.Source == SourceKind.External && _action == TrackActionKind.Add
                && !string.IsNullOrWhiteSpace(_entry.AudioBitrateKbps)));

    public event PropertyChangedEventHandler? PropertyChanged;

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

    private static string FormatBps(long? bps) =>
        bps is { } b ? $"{(b + 500) / 1000} kbps" : "?";

    private static string BuildDetails(TrackOverrideEntry entry, MediaStreamInfo? embedded, string? targetContainer)
    {
        if (entry.Source == SourceKind.External)
        {
            if (!string.IsNullOrWhiteSpace(entry.ExternalStreamDetails))
            {
                return entry.ExternalStreamDetails;
            }

            return entry.ExternalPath ?? string.Empty;
        }

        if (embedded is { Kind: MediaStreamKind.Subtitle } sub)
        {
            if (SubtitleCodecRules.IsTeletext(sub.CodecName) && SubtitleCodecRules.TargetsMkv(targetContainer))
            {
                return "unsupported for MKV copy";
            }

            return sub.SubtitleFormat ?? sub.CodecName;
        }

        return embedded switch
        {
            { Kind: MediaStreamKind.Video } v =>
                $"{v.Width?.ToString() ?? "?"}x{v.Height?.ToString() ?? "?"}; {(v.FrameRate is { } fr ? fr.ToString("0.###", System.Globalization.CultureInfo.InvariantCulture) : "?")} fps; {v.PixelFormat ?? "?"}",
            { Kind: MediaStreamKind.Audio } a => $"{a.Channels} ch; {a.SampleRateHz} Hz; {FormatBps(a.BitRateBps)}",
            _ => string.Empty
        };
    }

    private static IReadOnlyList<TrackActionKind> GetValidActions(TrackOverrideEntry e)
    {
        if (e.Source == SourceKind.External)
        {
            return [TrackActionKind.Add, TrackActionKind.Remove];
        }

        if (e.StreamKind is MediaStreamKind.Data)
        {
            return [TrackActionKind.Remove, TrackActionKind.Keep];
        }

        if (e.StreamKind is MediaStreamKind.Attachment)
        {
            return [TrackActionKind.Remove, TrackActionKind.Keep];
        }

        if (e.StreamKind is MediaStreamKind.Video)
        {
            return [TrackActionKind.Keep, TrackActionKind.Convert, TrackActionKind.Remove];
        }

        if (e.StreamKind is MediaStreamKind.Subtitle)
        {
            return [TrackActionKind.Keep, TrackActionKind.Convert, TrackActionKind.Remove];
        }

        if (e.StreamKind is MediaStreamKind.Audio)
        {
            return [TrackActionKind.Keep, TrackActionKind.Convert, TrackActionKind.Remove];
        }

        return [TrackActionKind.Keep, TrackActionKind.Remove];
    }
}