annotations/Azaion.Annotator/MainWindowEventHandler.cs

using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using Azaion.Annotator.DTO;
using LibVLCSharp.Shared;
using MediatR;
using Microsoft.Extensions.Logging;
using MediaPlayer = LibVLCSharp.Shared.MediaPlayer;

namespace Azaion.Annotator;

public class MainWindowEventHandler :
    INotificationHandler<KeyEvent>,
    INotificationHandler<AnnClassSelectedEvent>,
    INotificationHandler<PlaybackControlEvent>,
    INotificationHandler<VolumeChangedEvent>
{
    private readonly LibVLC _libVLC;
    private readonly MediaPlayer _mediaPlayer;
    private readonly MainWindow _mainWindow;
    private readonly FormState _formState;
    private readonly Config _config;
    private readonly IMediator _mediator;
    private readonly IGalleryManager _galleryManager;
    private readonly DatasetExplorer _datasetExplorer;
    private readonly ILogger<MainWindowEventHandler> _logger;

    private const int STEP = 20;
    private const int LARGE_STEP = 5000;
    private const int RESULT_WIDTH = 1280;

    private readonly Dictionary<Key, PlaybackControlEnum> _keysControlEnumDict = new()
    {
        { Key.Space, PlaybackControlEnum.Pause },
        { Key.Left, PlaybackControlEnum.PreviousFrame },
        { Key.Right, PlaybackControlEnum.NextFrame },
        { Key.Enter, PlaybackControlEnum.SaveAnnotations },
        { Key.Delete, PlaybackControlEnum.RemoveSelectedAnns },
        { Key.X, PlaybackControlEnum.RemoveAllAnns },
        { Key.PageUp, PlaybackControlEnum.Previous },
        { Key.PageDown, PlaybackControlEnum.Next },
    };

    public MainWindowEventHandler(LibVLC libVLC,
        MediaPlayer mediaPlayer,
        MainWindow mainWindow,
        FormState formState,
        Config config,
        IMediator mediator,
        IGalleryManager galleryManager,
        DatasetExplorer datasetExplorer,
        ILogger<MainWindowEventHandler> logger)
    {
        _libVLC = libVLC;
        _mediaPlayer = mediaPlayer;
        _mainWindow = mainWindow;
        _formState = formState;
        _config = config;
        _mediator = mediator;
        _galleryManager = galleryManager;
        _datasetExplorer = datasetExplorer;
        _logger = logger;
    }

    public async Task Handle(AnnClassSelectedEvent notification, CancellationToken cancellationToken)
    {
        SelectClass(notification.AnnotationClass);
        await Task.CompletedTask;
    }


    private void SelectClass(AnnotationClass annClass)
    {
        _mainWindow.Editor.CurrentAnnClass = annClass;
        foreach (var ann in _mainWindow.Editor.CurrentAnns.Where(x => x.IsSelected))
            ann.AnnotationClass = annClass;
        _mainWindow.LvClasses.SelectedIndex = annClass.Id;
    }

    public async Task Handle(KeyEvent notification, CancellationToken cancellationToken)
    {
        if (_formState.ActiveWindow != WindowsEnum.Main)
            return;

        var key = notification.Args.Key;
        var keyNumber = (int?)null;

        if ((int)key >= (int)Key.D1 && (int)key <= (int)Key.D9)
            keyNumber = key - Key.D1;
        if ((int)key >= (int)Key.NumPad1 && (int)key <= (int)Key.NumPad9)
            keyNumber = key - Key.NumPad1;
        if (keyNumber.HasValue)
            SelectClass((AnnotationClass)_mainWindow.LvClasses.Items[keyNumber.Value]);

        if (_keysControlEnumDict.TryGetValue(key, out var value))
            await ControlPlayback(value);

        if (key == Key.A)
            _mainWindow.AutoDetect(null!, null!);

        await VolumeControl(key);
    }

    private async Task VolumeControl(Key key)
    {
        switch (key)
        {
            case Key.VolumeMute when _mediaPlayer.Volume == 0:
                await ControlPlayback(PlaybackControlEnum.TurnOnVolume);
                break;
            case Key.VolumeMute:
                await ControlPlayback(PlaybackControlEnum.TurnOffVolume);
                break;
            case Key.Up:
            case Key.VolumeUp:
                var vUp = Math.Min(100, _mediaPlayer.Volume + 5);
                ChangeVolume(vUp);
                _mainWindow.Volume.Value = vUp;
                break;
            case Key.Down:
            case Key.VolumeDown:
                var vDown = Math.Max(0, _mediaPlayer.Volume - 5);
                ChangeVolume(vDown);
                _mainWindow.Volume.Value = vDown;
                break;
        }
    }

    public async Task Handle(PlaybackControlEvent notification, CancellationToken cancellationToken)
    {
        await ControlPlayback(notification.PlaybackControl);
        _mainWindow.VideoView.Focus();
    }

    private async Task ControlPlayback(PlaybackControlEnum controlEnum)
    {
        try
        {
            var isCtrlPressed = Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl);
            var step = isCtrlPressed ? LARGE_STEP : STEP;

            switch (controlEnum)
            {
                case PlaybackControlEnum.Play:
                    Play();
                    break;
                case PlaybackControlEnum.Pause:
                    _mediaPlayer.Pause();
                    if (!_mediaPlayer.IsPlaying)
                        _mainWindow.BlinkHelp(HelpTexts.HelpTextsDict[HelpTextEnum.AnnotationHelp]);
                    if (_formState.BackgroundShown)
                    {
                        _mainWindow.Editor.Background = new SolidColorBrush(Color.FromArgb(1, 0, 0, 0));
                        _formState.BackgroundShown = false;
                    }
                    break;
                case PlaybackControlEnum.Stop:
                    _mediaPlayer.Stop();
                    break;
                case PlaybackControlEnum.PreviousFrame:
                    _mainWindow.SeekTo(_mediaPlayer.Time - step);
                    break;
                case PlaybackControlEnum.NextFrame:
                    _mainWindow.SeekTo(_mediaPlayer.Time + step);
                    break;
                case PlaybackControlEnum.SaveAnnotations:
                    await SaveAnnotations();
                    break;
                case PlaybackControlEnum.RemoveSelectedAnns:

                    _mainWindow.Editor.RemoveSelectedAnns();
                    break;
                case PlaybackControlEnum.RemoveAllAnns:
                    _mainWindow.Editor.RemoveAllAnns();
                    break;
                case PlaybackControlEnum.TurnOnVolume:
                    _mainWindow.TurnOnVolumeBtn.Visibility = Visibility.Collapsed;
                    _mainWindow.TurnOffVolumeBtn.Visibility = Visibility.Visible;
                    _mediaPlayer.Volume = _formState.CurrentVolume;
                    break;
                case PlaybackControlEnum.TurnOffVolume:
                    _mainWindow.TurnOffVolumeBtn.Visibility = Visibility.Collapsed;
                    _mainWindow.TurnOnVolumeBtn.Visibility = Visibility.Visible;
                    _formState.CurrentVolume = _mediaPlayer.Volume;
                    _mediaPlayer.Volume = 0;
                    break;
                case PlaybackControlEnum.Previous:
                    NextMedia(isPrevious: true);
                    break;
                case PlaybackControlEnum.Next:
                    NextMedia();
                    break;
                case PlaybackControlEnum.None:
                    break;
                default:
                    throw new ArgumentOutOfRangeException(nameof(controlEnum), controlEnum, null);
            }
        }
        catch (Exception e)
        {
            _logger.LogError(e, e.Message);
            throw;
        }
    }

    private void NextMedia(bool isPrevious = false)
    {
        var increment = isPrevious ? -1 : 1;
        var check = isPrevious ? -1 : _mainWindow.LvFiles.Items.Count;
        if (_mainWindow.LvFiles.SelectedIndex + increment == check)
            return;

        _mainWindow.LvFiles.SelectedIndex += increment;
        Play();
    }

    public async Task Handle(VolumeChangedEvent notification, CancellationToken cancellationToken)
    {
        ChangeVolume(notification.Volume);
        await Task.CompletedTask;
    }

    private void ChangeVolume(int volume)
    {
        _formState.CurrentVolume = volume;
        _mediaPlayer.Volume = volume;
    }

    private void Play()
    {
        if (_mainWindow.LvFiles.SelectedItem == null)
            return;
        var mediaInfo = (MediaFileInfo)_mainWindow.LvFiles.SelectedItem;

        _formState.CurrentMedia = mediaInfo;
        _mediaPlayer.Stop();
        _mainWindow.Title = $"Azaion Annotator - {mediaInfo.Name}";
        _mainWindow.BlinkHelp(HelpTexts.HelpTextsDict[HelpTextEnum.PauseForAnnotations]);
        _mediaPlayer.Play(new Media(_libVLC, mediaInfo.Path));
    }

    private async Task SaveAnnotations()
    {
        if (_formState.CurrentMedia == null)
            return;

        var time = TimeSpan.FromMilliseconds(_mediaPlayer.Time);
        var fName = _formState.GetTimeName(time);

        var currentAnns = _mainWindow.Editor.CurrentAnns
            .Select(x => new YoloLabel(x.Info, _mainWindow.Editor.RenderSize, _formState.BackgroundShown ? _mainWindow.Editor.RenderSize : _formState.CurrentVideoSize))
            .ToList();

        await YoloLabel.WriteToFile(currentAnns, Path.Combine(_config.LabelsDirectory, $"{fName}.txt"));
        await _mainWindow.AddAnnotations(time, currentAnns);

        _formState.CurrentMedia.HasAnnotations = _mainWindow.Annotations.Count != 0;
        _mainWindow.LvFiles.Items.Refresh();

        var isVideo = _formState.CurrentMedia.MediaType == MediaTypes.Video;
        var destinationPath = Path.Combine(_config.ImagesDirectory, $"{fName}{(isVideo ? ".jpg" : Path.GetExtension(_formState.CurrentMedia.Path))}");

        _mainWindow.Editor.RemoveAllAnns();
        if (isVideo)
        {
            if (_formState.BackgroundShown)
            {
                //no need to save image, it's already there, just remove background
                _mainWindow.Editor.Background = new SolidColorBrush(Color.FromArgb(1, 0, 0, 0));
                _formState.BackgroundShown = false;
            }
            else
            {
                var resultHeight = (uint)Math.Round(RESULT_WIDTH / _formState.CurrentVideoSize.Width * _formState.CurrentVideoSize.Height);
                _mediaPlayer.TakeSnapshot(0, destinationPath, RESULT_WIDTH, resultHeight);
            }
            
            _mediaPlayer.Play();
        }
        else
        {
            File.Copy(_formState.CurrentMedia.Path, destinationPath, overwrite: true);
            NextMedia();
        }

        var thumbnailDto = await _galleryManager.CreateThumbnail(destinationPath);
        if (thumbnailDto != null)
            _datasetExplorer.AddThumbnail(thumbnailDto, currentAnns.Select(x => x.ClassNumber));
    }
}