Splitter-UI/Controls/TimelinePreviewSlider.cs

@@ -1,957 +0,0 @@
-using System.Collections.ObjectModel;
-using System.Collections.Specialized;
-using System.ComponentModel;
-using System.Globalization;
-using Avalonia;
-using Avalonia.Controls;
-using Avalonia.Input;
-using Avalonia.Media;
-using Avalonia.Media.Imaging;
-using Avalonia.Threading;
-using Point = Avalonia.Point;
-
-namespace Splitter_UI.Controls;
-
-public class TimelinePreviewSlider : Control, IDisposable
-{
-    // Public properties
-    public static readonly StyledProperty<JobViewModel?> ViewModelProperty =
-            AvaloniaProperty.Register<TimelinePreviewSlider, JobViewModel?>(nameof(ViewModel));
-
-    public JobViewModel? ViewModel
-    {
-        get => GetValue(ViewModelProperty);
-        set => SetValue(ViewModelProperty, value);
-    }
-
-    private double PixelsPerSecond
-    {
-        get
-        {
-            var vm = ViewModel;
-            if (vm == null || vm.DurationSeconds <= 0 || Bounds.Width <= 0)
-                return 10000; // fallback value
-
-            // Full control width maps to full video duration
-            return Bounds.Width / vm.DurationSeconds;
-        }
-    }
-
-    public static readonly StyledProperty<IBrush?> SegmentFillProperty =
-            AvaloniaProperty.Register<TimelinePreviewSlider, IBrush?>(nameof(SegmentFill), Brushes.DimGray);
-
-    public IBrush? SegmentFill
-    {
-        get => GetValue(SegmentFillProperty);
-        set => SetValue(SegmentFillProperty, value);
-    }
-
-    public static readonly StyledProperty<IBrush?> MarkerStrokeProperty =
-            AvaloniaProperty.Register<TimelinePreviewSlider, IBrush?>(nameof(MarkerStroke), Brushes.White);
-
-    public IBrush? MarkerStroke
-    {
-        get => GetValue(MarkerStrokeProperty);
-        set => SetValue(MarkerStrokeProperty, value);
-    }
-
-    // Visual constants
-    private const double _timelineHeight         = 80;
-    private const double _markerLineHeight       = 36;
-    private const double _markerLineWidth        = 2;
-    private const double _markerTriangleSize     = 8;
-    private const double _segmentBarHeight       = 40;
-    private const int    _maxPreviewCacheItems   = 128;
-
-    // Internal state
-    private readonly LruCache<string, Bitmap> _previewCache = new(_maxPreviewCacheItems);
-    private readonly Dictionary<string, CancellationTokenSource> _previewLoadCts = new();
-    private readonly object _cacheLock = new();
-
-    private IDisposable?  _segmentsSubscription;
-    private bool          _isInternalSliderUpdate;
-    private JobViewModel? _currentVm;
-
-    // Interaction state
-    private bool         _isPointerCaptured;
-    private Point        _lastPointerPoint;
-    private DragMode     _dragMode           = DragMode.None;
-    private int          _activeSegmentIndex = -1;
-    private bool         _isSplitModifierActive;
-
-    // Throttle invalidation during drag
-    private DateTime _lastInvalidate = DateTime.MinValue;
-    private readonly TimeSpan _invalidateThrottle = TimeSpan.FromMilliseconds(16); // ~60Hz
-
-    public TimelinePreviewSlider()
-    {
-        Focusable    = true;
-        Height       = _timelineHeight;
-        ClipToBounds = true;
-
-        // Use property change override instead of GetObservable.Subscribe to avoid IObserver compile issues.
-        PointerPressed     += OnPointerPressed;
-        PointerMoved       += OnPointerMoved;
-        PointerReleased    += OnPointerReleased;
-        PointerCaptureLost += OnPointerCaptureLost;
-        KeyDown            += OnKeyDown;
-        KeyUp              += OnKeyUp;
-    }
-
-    // Override to detect ViewModel property changes
-    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
-    {
-        base.OnPropertyChanged(change);
-
-        if (change.Property == ViewModelProperty)
-        {
-            OnViewModelChanged((JobViewModel?)change.NewValue);
-        }
-    }
-
-    private void OnViewModelChanged(JobViewModel? vm)
-    {
-        UnsubscribeFromViewModel();
-        _previewCache.Clear();
-        CancelAllPreviewLoads();
-
-        if (vm != null)
-        {
-            _segmentsSubscription = SubscribeToSegments(vm.Segments);
-            vm.PropertyChanged += OnVmPropertyChanged;
-        }
-
-        InvalidateVisual();
-    }
-
-
-    private void OnVmPropertyChanged(object? sender, PropertyChangedEventArgs e)
-    {
-        if (e.PropertyName == nameof(JobViewModel.SliderLiveValue))
-        {
-            if (_isInternalSliderUpdate)
-                return;
-
-            InvalidateVisual();
-        }
-    }
-
-    private IDisposable SubscribeToSegments(ObservableCollection<Segment> segments)
-    {
-        NotifyCollectionChangedEventHandler handler = (s, e) =>
-        {
-            Dispatcher.UIThread.Post(() => {
-                InvalidateVisual();
-            }, DispatcherPriority.Background);
-        };
-        segments.CollectionChanged += handler;
-        return Disposable.Create(() => segments.CollectionChanged -= handler);
-    }
-
-    private void UnsubscribeFromViewModel()
-    {
-        if (_currentVm != null)
-            _currentVm.PropertyChanged -= OnVmPropertyChanged;
-
-        _currentVm = null;
-
-        _segmentsSubscription?.Dispose();
-        _segmentsSubscription = null;
-    }
-
-    private void CancelAllPreviewLoads()
-    {
-        lock (_cacheLock)
-        {
-            foreach (var cts in _previewLoadCts.Values)
-            {
-                try { cts.Cancel(); } catch { }
-            }
-            _previewLoadCts.Clear();
-        }
-    }
-
-    public override void Render(DrawingContext dc)
-    {
-        base.Render(dc);
-
-        var vm = ViewModel;
-        var bounds = new Rect(0, 0, Bounds.Width, Bounds.Height);
-
-        // Background
-        dc.FillRectangle(Brushes.Black, bounds);
-
-        DrawContinuousPreviewStrip(dc);
-        DrawGapOverlays(dc);
-        DrawOverlongSegmentOverlays(dc);
-
-        if (vm == null || vm.DurationSeconds <= 0 || vm.Segments.Count == 0)
-        {
-            // draw empty ruler
-            DrawRuler(dc, 0, vm?.DurationSeconds ?? 0);
-            return;
-        }
-
-        // Draw segments and previews
-        for (int i = 0; i < vm.Segments.Count; i++)
-        {
-            var seg = vm.Segments[i];
-            var segRect = SegmentRectFor(seg);
-            if (segRect.Width <= 0) continue;
-
-            // Segment background
-            var segBrush = new Pen(SegmentFill ?? Brushes.DimGray, 1);
-            var segRoundedRect = new Rect(segRect.X, segRect.Y + (Bounds.Height - _segmentBarHeight) / 2, segRect.Width, _segmentBarHeight);
-            var geom = new StreamGeometry();
-            using (var ctx = geom.Open())
-            {
-                ctx.BeginFigure(new Point(segRoundedRect.X, segRoundedRect.Y), true);
-                ctx.LineTo(     new Point(segRoundedRect.X + segRoundedRect.Width, segRoundedRect.Y));
-                ctx.LineTo(     new Point(segRoundedRect.X + segRoundedRect.Width, segRoundedRect.Y + segRoundedRect.Height));
-                ctx.LineTo(     new Point(segRoundedRect.X, segRoundedRect.Y + segRoundedRect.Height));
-                ctx.EndFigure(true);
-            }
-            dc.DrawGeometry(null, segBrush, geom);
-        }
-
-        // Draw markers on top
-        for (int i = 0; i < vm.Segments.Count; i++)
-        {
-            var seg = vm.Segments[i];
-            DrawMarker(dc, seg.Start, true);
-            DrawMarker(dc, seg.End, false);
-        }
-
-        // Draw current position indicator
-        DrawPositionIndicator(dc, vm.SliderLiveValue);
-
-        // Draw ruler
-        DrawRuler(dc, 0, vm.DurationSeconds);
-    }
-
-    private void DrawRuler(DrawingContext dc, double startSec, double endSec)
-    {
-        var height = Bounds.Height;
-        var y = height - 18;
-        var pen = new Pen(Brushes.Gray, 1);
-        dc.DrawLine(pen, new Point(0, y), new Point(Bounds.Width, y));
-
-        if (ViewModel == null || ViewModel.DurationSeconds <= 0) return;
-
-        var totalSec = ViewModel.DurationSeconds;
-        var approxTicks = Math.Max(2, (int)(Bounds.Width / 100));
-        var tickSec = Math.Max(1.0, totalSec / approxTicks);
-
-        for (double t = 0; t <= totalSec; t += tickSec)
-        {
-            var x = SecondsToPixel(t);
-            dc.DrawLine(pen, new Point(x, y), new Point(x, y - 6));
-            var text = FormatTime(t);
-            var textBrush = Brushes.LightGray; // or new SolidColorBrush(Color.Parse("#FFCCCCCC"));
-            var ft = new FormattedText(
-                text,
-                CultureInfo.CurrentUICulture,
-                FlowDirection.LeftToRight,
-                Typeface.Default,
-                12,
-                textBrush);
-
-            dc.DrawText(ft, new Point(x + 2, y - 18));
-        }
-    }
-
-    private void DrawContinuousPreviewStrip(DrawingContext dc)
-    {
-        var vm = ViewModel;
-        if (vm == null || vm.DurationSeconds <= 0)
-            return;
-
-        double stripY = (Bounds.Height - _segmentBarHeight) / 2;
-        double stripHeight = _segmentBarHeight;
-
-        double currentX = 0;
-        double endX = Bounds.Width;
-
-        var bmp = GetPreview(0);
-        var noPreviewAvailable = bmp == null;
-        if (bmp == null)
-        {
-            StartPreviewLoad(0);
-            return;
-        }
-
-        var previewScale = (double)stripHeight / bmp.PixelSize.Height;
-        var previewTileWidth = bmp.PixelSize.Width * previewScale;
-
-        using (dc.PushClip(new Rect(0, stripY, Bounds.Width, stripHeight)))
-        {
-            while (currentX < endX)
-            {
-                double posSec = PixelToSeconds(currentX);
-                if (posSec < 0) posSec = 0;
-                if (posSec > vm.DurationSeconds) posSec = vm.DurationSeconds;
-
-                bmp = GetPreview(posSec);
-
-                if (bmp == null)
-                {
-                    StartPreviewLoad(posSec);
-
-                    // advance by estimated width
-                    currentX += previewTileWidth;
-                    continue;
-                }
-
-                // scale full frame to strip height
-                double scale = stripHeight / bmp.PixelSize.Height;
-                double tileWidth = bmp.PixelSize.Width * scale;
-
-                var src = new Rect(0, 0, bmp.PixelSize.Width, bmp.PixelSize.Height);
-                var dst = new Rect(currentX, stripY, tileWidth, stripHeight);
-
-                dc.DrawImage(bmp, src, dst);
-
-                currentX += tileWidth;
-            }
-        }
-    }
-
-    private void DrawGapOverlays(DrawingContext dc)
-    {
-        var vm = ViewModel;
-        if (vm == null || vm.Segments.Count == 0)
-            return;
-
-        double stripY = (Bounds.Height - _segmentBarHeight) / 2;
-        double stripHeight = _segmentBarHeight;
-
-        var gapBrush = new SolidColorBrush(Color.FromArgb(190, 80, 80, 80)); 
-
-        double lastEnd = 0;
-
-        for (int i = 0; i < vm.Segments.Count; i++)
-        {
-            var seg = vm.Segments[i];
-
-            if (seg.Start > lastEnd)
-            {
-                double gapLeft = SecondsToPixel(lastEnd);
-                double gapRight = SecondsToPixel(seg.Start);
-                double w = gapRight - gapLeft;
-
-                if (w > 0)
-                    dc.FillRectangle(gapBrush, new Rect(gapLeft, stripY, w, stripHeight));
-            }
-
-            lastEnd = seg.End;
-        }
-
-        // tail gap
-        if (lastEnd < vm.DurationSeconds)
-        {
-            double gapLeft = SecondsToPixel(lastEnd);
-            double gapRight = SecondsToPixel(vm.DurationSeconds);
-            double w = gapRight - gapLeft;
-
-            if (w > 0)
-                dc.FillRectangle(gapBrush, new Rect(gapLeft, stripY, w, stripHeight));
-        }
-    }
-
-    private void DrawOverlongSegmentOverlays(DrawingContext dc)
-    {
-        var vm = ViewModel;
-        if (vm == null || vm.Segments.Count == 0)
-            return;
-
-        if (vm.OverrideTargetDuration <= 0)
-            return;
-
-        double stripY = (Bounds.Height - _segmentBarHeight) / 2;
-        double stripHeight = _segmentBarHeight;
-
-        var overBrush = new SolidColorBrush(Color.FromArgb(128, 255, 0, 0)); // 50% red
-
-        foreach (var seg in vm.Segments)
-        {
-            double length = seg.End - seg.Start;
-            if (length <= vm.OverrideTargetDuration)
-                continue;
-
-            double left = SecondsToPixel(seg.Start);
-            double right = SecondsToPixel(seg.End);
-            double w = right - left;
-
-            if (w > 0)
-                dc.FillRectangle(overBrush, new Rect(left, stripY, w, stripHeight));
-        }
-    }
-
-    private Bitmap? GetPreview(double pos)
-    {
-        var key = PreviewCacheKey(pos);
-        lock (_cacheLock)
-        {
-            _previewCache.TryGet(key, out var bmp);
-            return bmp;
-        }
-    }
-
-    private void StartPreviewLoad(double pos)
-    {
-        var vm = ViewModel;
-        if (vm == null) 
-            return;
-
-        var key = PreviewCacheKey(pos);
-        lock (_cacheLock)
-        {
-            if (_previewLoadCts.ContainsKey(key) || _previewCache.ContainsKey(key))
-                return;
-
-            var cts = new CancellationTokenSource();
-            _previewLoadCts[key] = cts;
-
-            // Run an async loader on threadpool
-            Task.Run(async () =>
-            {
-                try
-                {
-                    // call host-provided async GetPreview
-                    var bmp = await vm.GetThumbnail(pos).ConfigureAwait(false);
-
-                    if (bmp != null && !cts.IsCancellationRequested)
-                    {
-                        lock (_cacheLock)
-                        {
-                            _previewCache.Add(key, bmp);
-                            _previewLoadCts.Remove(key);
-                        }
-
-                        // notify UI thread to redraw
-                        Dispatcher.UIThread.Post(InvalidateVisual, DispatcherPriority.Background);
-                    }
-                    else
-                    {
-                        lock (_cacheLock)
-                        {
-                            _previewLoadCts.Remove(key);
-                        }
-                    }
-                }
-                catch (OperationCanceledException)
-                {
-                    lock (_cacheLock) { _previewLoadCts.Remove(key); }
-                }
-                catch
-                {
-                    lock (_cacheLock) { _previewLoadCts.Remove(key); }
-                }
-            }, cts.Token);
-        }
-    }
-
-
-    private string PreviewCacheKey(double pos) => $"{pos:F3}";
-
-    private Rect SegmentRectFor(Segment seg)
-    {
-        var left = SecondsToPixel(seg.Start);
-        var right = SecondsToPixel(seg.End);
-        var y = 0;
-        return new Rect(left, y, Math.Max(0, right - left), Bounds.Height);
-    }
-
-    private double SecondsToPixel(double seconds)
-    {
-        return seconds * PixelsPerSecond;
-    }
-
-    private double PixelToSeconds(double px)
-    {
-        return px / PixelsPerSecond;
-    }
-
-    private void DrawMarker(DrawingContext dc, double seconds, bool isStart)
-    {
-        var x = SecondsToPixel(seconds);
-        var top = (Bounds.Height - _segmentBarHeight) / 2 - _markerTriangleSize - 2;
-        var lineTop = top + _markerTriangleSize + 2;
-        var lineBottom = lineTop + _markerLineHeight;
-
-        double midY = top + _markerTriangleSize / 2.0;
-
-        var tri = new StreamGeometry();
-        using (var ctx = tri.Open())
-        {
-            if (isStart)
-            {
-                // segment is to the right -> triangle points right
-                var vTop = new Point(x, top);
-                var vBottom = new Point(x, top + _markerTriangleSize);
-                var point = new Point(x + _markerTriangleSize, midY);
-
-                ctx.BeginFigure(point, true);
-                ctx.LineTo(vBottom);
-                ctx.LineTo(vTop);
-                ctx.EndFigure(true);
-            }
-            else
-            {
-                // segment is to the left -> triangle points left
-                var vTop = new Point(x, top);
-                var vBottom = new Point(x, top + _markerTriangleSize);
-                var point = new Point(x - _markerTriangleSize, midY);
-
-                ctx.BeginFigure(point, true);
-                ctx.LineTo(vTop);
-                ctx.LineTo(vBottom);
-                ctx.EndFigure(true);
-            }
-        }
-
-        dc.DrawGeometry(MarkerStroke ?? Brushes.White, null, tri);
-
-        var pen = new Pen(MarkerStroke ?? Brushes.White, _markerLineWidth);
-        dc.DrawLine(pen, new Point(x, lineTop), new Point(x, lineBottom));
-    }
-
-    private void DrawPositionIndicator(DrawingContext dc, double seconds)
-    {
-        var x = SecondsToPixel(seconds);
-        var pen = new Pen(Brushes.Red, 1.5);
-        dc.DrawLine(pen, new Point(x, 0), new Point(x, Bounds.Height));
-    }
-
-    private string FormatTime(double seconds)
-    {
-        var ts = TimeSpan.FromSeconds(Math.Max(0, seconds));
-        if (ts.TotalHours >= 1)
-            return $"{(int)ts.TotalHours:D2}:{ts.Minutes:D2}:{ts.Seconds:D2}";
-        return $"{ts.Minutes:D2}:{ts.Seconds:D2}";
-    }
-
-    // Interaction
-
-    private void OnPointerPressed(object? sender, PointerPressedEventArgs e)
-    {
-        Focus();
-
-        var p = e.GetPosition(this);
-        _lastPointerPoint = p;
-        _isSplitModifierActive = e.KeyModifiers.HasFlag(KeyModifiers.Control);
-
-        var hit = HitTestAtPoint(p);
-        if (hit.Type == HitType.StartMarker)
-        {
-            BeginDrag(DragMode.DragStartMarker, hit.SegmentIndex, e);
-        }
-        else if (hit.Type == HitType.EndMarker)
-        {
-            BeginDrag(DragMode.DragEndMarker, hit.SegmentIndex, e);
-        }
-        else
-        {
-            // any other hit just moves playhead
-            SetPlayheadFromPoint(p);
-        }
-
-        if (_isSplitModifierActive && hit.Type == HitType.SegmentBody)
-        {
-            var sec = PixelToSeconds(p.X);
-            TrySplitSegmentAt(hit.SegmentIndex, sec);
-        }
-
-        e.Pointer.Capture(this);
-        _isPointerCaptured = true;
-        e.Handled = true;
-    }
-
-
-    private void OnPointerMoved(object? sender, PointerEventArgs e)
-    {
-        if (!_isPointerCaptured) return;
-        var p = e.GetPosition(this);
-
-        if (_dragMode == DragMode.None)
-        {
-            _lastPointerPoint = p;
-            return;
-        }
-
-        var vm = ViewModel;
-        if (vm == null) return;
-
-        var sec = PixelToSeconds(p.X);
-        sec = Math.Max(0, Math.Min(vm.DurationSeconds, sec));
-
-        switch (_dragMode)
-        {
-            case DragMode.DragStartMarker:
-                MoveSegmentStart(_activeSegmentIndex, sec);
-                break;
-            case DragMode.DragEndMarker:
-                MoveSegmentEnd(_activeSegmentIndex, sec);
-                break;
-        }
-
-        _isInternalSliderUpdate = true;
-        vm.SliderLiveValue = sec;
-        _isInternalSliderUpdate = false;
-
-        ThrottledInvalidate();
-        _lastPointerPoint = p;
-        e.Handled = true;
-    }
-
-
-    private void OnPointerReleased(object? sender, PointerReleasedEventArgs e)
-    {
-        if (_isPointerCaptured)
-        {
-            e.Pointer.Capture(null);
-            _isPointerCaptured = false;
-        }
-        _dragMode = DragMode.None;
-        _activeSegmentIndex = -1;
-        e.Handled = true;
-    }
-
-    private void OnPointerCaptureLost(object? sender, PointerCaptureLostEventArgs e)
-    {
-        _isPointerCaptured = false;
-        _dragMode = DragMode.None;
-        _activeSegmentIndex = -1;
-    }
-
-    private void OnKeyDown(object? sender, KeyEventArgs e)
-    {
-        if (e.Key == Key.LeftCtrl || e.Key == Key.RightCtrl)
-        {
-            _isSplitModifierActive = true;
-            return;
-        }
-
-        if (e.Key == Key.Delete)
-        {
-            TryDeleteCurrentSegment();
-            e.Handled = true;
-            return;
-        }
-    }
-
-
-    private void OnKeyUp(object? sender, KeyEventArgs e)
-    {
-        if (e.Key == Key.LeftCtrl || e.Key == Key.RightCtrl) 
-            _isSplitModifierActive = false;
-    }
-
-    private void TryDeleteCurrentSegment()
-    {
-        var vm = ViewModel;
-        if (vm == null)
-            return;
-
-        double pos = vm.SliderLiveValue;
-
-        int idx = -1;
-        for (int i = 0; i < vm.Segments.Count; i++)
-        {
-            var s = vm.Segments[i];
-            if (pos >= s.Start && pos <= s.End)
-            {
-                idx = i;
-                break;
-            }
-        }
-
-        if (idx == -1)
-            return;
-
-        Dispatcher.UIThread.Post(() =>
-        {
-            if (idx >= 0 && idx < vm.Segments.Count)
-                vm.Segments.RemoveAt(idx);
-
-            if (vm.Segments.Count == 0)
-                vm.GenerateSegments();
-
-        }, DispatcherPriority.Background);
-    }
-
-
-    private void BeginDrag(DragMode mode, int segmentIndex, PointerPressedEventArgs e)
-    {
-        _dragMode = mode;
-        _activeSegmentIndex = segmentIndex;
-        _lastPointerPoint = e.GetPosition(this);
-    }
-
-    private void ThrottledInvalidate()
-    {
-        var now = DateTime.UtcNow;
-        if (now - _lastInvalidate > _invalidateThrottle)
-        {
-            _lastInvalidate = now;
-            InvalidateVisual();
-        }
-    }
-
-    private void SetPlayheadFromPoint(Point p)
-    {
-        var vm = ViewModel;
-        if (vm == null) 
-            return;
-
-        double sec = PixelToSeconds(p.X);
-        sec = Math.Max(0, Math.Min(vm.DurationSeconds, sec));
-
-        _isInternalSliderUpdate = true;
-        vm.SliderLiveValue = sec;
-        _isInternalSliderUpdate = false;
-
-        InvalidateVisual();
-    }
-
-    private void MoveSegmentStart(int index, double newStart)
-    {
-        var vm = ViewModel;
-        if (vm == null) return;
-        if (index < 0 || index >= vm.Segments.Count) return;
-
-        var seg = vm.Segments[index];
-        var min = index == 0 ? 0.0 : vm.Segments[index - 1].End;
-        var max = seg.End - 0.001;
-        var clamped = Math.Max(min, Math.Min(max, newStart));
-        if (Math.Abs(clamped - seg.Start) < 1e-6) return;
-
-        var newSeg = seg with { Start = clamped };
-        vm.Segments[index] = newSeg;
-    }
-
-    private void MoveSegmentEnd(int index, double newEnd)
-    {
-        var vm = ViewModel;
-        if (vm == null) return;
-        if (index < 0 || index >= vm.Segments.Count) return;
-
-        var seg = vm.Segments[index];
-        var min = seg.Start + 0.001;
-        var max = index == vm.Segments.Count - 1 ? vm.DurationSeconds : vm.Segments[index + 1].Start;
-        var clamped = Math.Max(min, Math.Min(max, newEnd));
-        if (Math.Abs(clamped - seg.End) < 1e-6) return;
-
-        var newSeg = seg with { End = clamped };
-        vm.Segments[index] = newSeg;
-    }
-
-    private void MoveSegmentByDelta(int index, double deltaSec)
-    {
-        var vm = ViewModel;
-        if (vm == null) return;
-        if (index < 0 || index >= vm.Segments.Count) return;
-
-        var seg = vm.Segments[index];
-        var leftLimit = index == 0 ? 0.0 : vm.Segments[index - 1].End;
-        var rightLimit = index == vm.Segments.Count - 1 ? vm.DurationSeconds : vm.Segments[index + 1].Start;
-
-        var newStart = seg.Start + deltaSec;
-        var newEnd = seg.End + deltaSec;
-
-        // clamp so segment stays within neighbors
-        var segLength = seg.End - seg.Start;
-        if (newStart < leftLimit)
-        {
-            newStart = leftLimit;
-            newEnd = newStart + segLength;
-        }
-        if (newEnd > rightLimit)
-        {
-            newEnd = rightLimit;
-            newStart = newEnd - segLength;
-        }
-
-        // apply
-        vm.Segments[index] = seg with { Start = newStart, End = newEnd };
-    }
-
-    private void TrySplitSegmentAt(int index, double sec)
-    {
-        var vm = ViewModel;
-        if (vm == null) return;
-        if (index < 0 || index >= vm.Segments.Count) return;
-
-        var seg = vm.Segments[index];
-        if (sec <= seg.Start + 0.001 || sec >= seg.End - 0.001) return;
-
-        var left = seg with { End = sec };
-        var right = seg with { Start = sec };
-        vm.Segments[index] = left;
-        vm.Segments.Insert(index + 1, right);
-        InvalidateVisual();
-    }
-
-    private HitResult HitTestAtPoint(Point p)
-    {
-        var vm = ViewModel;
-        if (vm == null)
-            return new HitResult(HitType.None, -1);
-
-        double topRegion = Bounds.Height / 4.0;
-
-        for (int i = 0; i < vm.Segments.Count; i++)
-        {
-            var seg = vm.Segments[i];
-            double startX = SecondsToPixel(seg.Start);
-            double endX   = SecondsToPixel(seg.End);
-
-            // marker hit only in top 1/4
-            if (p.Y >= 0 && p.Y <= topRegion)
-            {
-                // start marker triangle footprint: [startX .. startX + size]
-                if (p.X >= startX && p.X <= startX + _markerTriangleSize)
-                    return new HitResult(HitType.StartMarker, i);
-
-                // end marker triangle footprint: [endX - size .. endX]
-                if (p.X >= endX - _markerTriangleSize && p.X <= endX)
-                    return new HitResult(HitType.EndMarker, i);
-            }
-
-            // segment body (no drag, only click/split)
-            if (p.X >= startX && p.X <= endX && p.Y >= 0 && p.Y <= Bounds.Height)
-                return new HitResult(HitType.SegmentBody, i);
-        }
-
-        return new HitResult(HitType.Gap, -1);
-    }
-
-    // IDisposable
-    public void Dispose()
-    {
-        UnsubscribeFromViewModel();
-        CancelAllPreviewLoads();
-        _previewCache.Clear();
-    }
-
-    // Helpers and small types
-
-    private enum DragMode
-    {
-        None,
-        DragStartMarker,
-        DragEndMarker
-    }
-
-    private enum HitType
-    {
-        None,
-        StartMarker,
-        EndMarker,
-        SegmentBody,
-        Gap
-    }
-
-    private readonly struct HitResult
-    {
-        public HitType Type { get; }
-        public int SegmentIndex { get; }
-        public HitResult(HitType type, int idx) { Type = type; SegmentIndex = idx; }
-    }
-
-    // Simple LRU cache for Bitmaps
-    private class LruCache<TKey, TValue> where TKey : notnull where TValue : class
-    {
-        private readonly int _capacity;
-        private readonly Dictionary<TKey, LinkedListNode<(TKey key, TValue value)>> _map;
-        private readonly LinkedList<(TKey key, TValue value)> _list;
-        private readonly object _sync = new();
-
-        public LruCache(int capacity)
-        {
-            _capacity = Math.Max(1, capacity);
-            _map = new Dictionary<TKey, LinkedListNode<(TKey, TValue)>>();
-            _list = new LinkedList<(TKey, TValue)>();
-        }
-
-        public bool TryGet(TKey key, out TValue? value)
-        {
-            lock (_sync)
-            {
-                if (_map.TryGetValue(key, out var node))
-                {
-                    value = node.Value.value;
-                    _list.Remove(node);
-                    _list.AddFirst(node);
-                    return true;
-                }
-                value = null;
-                return false;
-            }
-        }
-
-        public void Add(TKey key, TValue value)
-        {
-            lock (_sync)
-            {
-                if (_map.TryGetValue(key, out var node))
-                {
-                    _list.Remove(node);
-                    _map.Remove(key);
-                }
-
-                var newNode = new LinkedListNode<(TKey, TValue)>((key, value));
-                _list.AddFirst(newNode);
-                _map[key] = newNode;
-
-                if (_map.Count > _capacity)
-                {
-                    var last = _list.Last!;
-                    _map.Remove(last.Value.key);
-                    _list.RemoveLast();
-                    if (last.Value.value is IDisposable d)
-                    {
-                        try { d.Dispose(); } catch { }
-                    }
-                }
-            }
-        }
-
-        public bool ContainsKey(TKey key)
-        {
-            lock (_sync) return _map.ContainsKey(key);
-        }
-
-        public void Clear()
-        {
-            lock (_sync)
-            {
-                foreach (var node in _list)
-                {
-                    if (node.value is IDisposable d)
-                    {
-                        try { d.Dispose(); } catch { }
-                    }
-                }
-                _map.Clear();
-                _list.Clear();
-            }
-        }
-    }
-
-    // Disposable helper
-    private static class Disposable
-    {
-        public static IDisposable Create(Action dispose)
-        {
-            return new AnonymousDisposable(dispose);
-        }
-
-        private sealed class AnonymousDisposable : IDisposable
-        {
-            private Action? _dispose;
-            public AnonymousDisposable(Action dispose) { _dispose = dispose; }
-            public void Dispose() { var d = Interlocked.Exchange(ref _dispose, null); d?.Invoke(); }
-        }
-    }
-}

Splitter-UI/Services/ThumbnailService.cs

@@ -7,11 +7,11 @@ namespace Splitter_UI.Services;
 
 public sealed class ThumbnailService : IThumbnailService
 {
-    public const int ThumbWidth  = 160;
+    private const int _thumbWidth  = 160;
-    public const int ThumbHeight = 90;
+    private const int _thumbHeight = 90;
 
-    private readonly byte [] _bgrBuffer  = new byte[ThumbWidth * ThumbHeight * 3];
+    private readonly byte [] _bgrBuffer  = new byte[_thumbWidth * _thumbHeight * 3];
-    private readonly byte [] _bgraBuffer = new byte[ThumbWidth * ThumbHeight * 4];
+    private readonly byte [] _bgraBuffer = new byte[_thumbWidth * _thumbHeight * 4];
 
     public SemaphoreSlim _lock = new(1,1);
 
@@ -49,15 +49,15 @@ public sealed class ThumbnailService : IThumbnailService
         int? height = null,
         int? rotateDegree = null)
     {
-        width  ??= ThumbWidth;
+        width  ??= _thumbWidth;
-        height ??= ThumbHeight;
+        height ??= _thumbHeight;
         skip   ??= TimeSpan.Zero;
 
         // buffer for BGR24 → 3 bytes per pixel
 
         var canUseStaticBuffers =
-            width.Value == ThumbWidth &&
+            width.Value == _thumbWidth &&
-            height.Value == ThumbHeight;
+            height.Value == _thumbHeight;
 
         var bgrBuffer  = canUseStaticBuffers ? _bgrBuffer  : new byte[width.Value * height.Value * 3];
         var bgraBuffer = canUseStaticBuffers ? _bgraBuffer : new byte[width.Value * height.Value * 4];

Splitter-UI/ViewModels/JobViewModel.cs

@@ -8,8 +8,6 @@ using CommunityToolkit.Mvvm.Input;
 
 namespace Splitter_UI.ViewModels;
 
-public record Segment(double Start, double End);
-
 public partial class JobViewModel : ObservableObject
 {
     private SingleJob Job { get; }
@@ -72,8 +70,6 @@ public partial class JobViewModel : ObservableObject
     public ObservableCollection<ParameterEntry> ParametersList { get; }
         = new();
 
-    public ObservableCollection<Segment> Segments { get; } = new();
-
     public string CropText
     {
         get => Job.Crop is { } c ? $"{c.width},{c.height}" : "";
@@ -315,8 +311,6 @@ public partial class JobViewModel : ObservableObject
         {
             if (e.PropertyName == nameof(Probe))
             {
-                if (Segments.Count == 0)
-                    GenerateSegments();
                 OnPropertyChanged(nameof(DurationSeconds));
             }
         };
@@ -332,21 +326,6 @@ public partial class JobViewModel : ObservableObject
         _debounceTimer.Tick += DebounceTimerTick;
     }
 
-    public void GenerateSegments()
-    {
-        Segments.Clear();
-        if (Probe == null || Probe.Duration <= 0)
-            return;
-        var duration = SegmentDuration;
-        var segments = (int)Math.Ceiling(Probe.Duration / duration);
-        for (int i = 0; i < segments; i++)
-        {
-            var start = i * duration;
-            var end   = Math.Min(start + duration, Probe.Duration);
-            Segments.Add(new Segment(start, end));
-        }
-    }
-
     public void CopyFrom(JobViewModel src)
     {
         Job.CopyFrom(src.Job);
@@ -462,48 +441,26 @@ public partial class JobViewModel : ObservableObject
 
     private void StepForward()
     {
-        if (Segments.Count <= 1)
+        if (DurationSeconds <= 0)
             return;
 
-        var current = GetCurrentSegment();
+        var duration = SegmentDuration;
-        if ( current < 0 || current >= Segments.Count - 1 )
+        var segment = Math.Round(SliderLiveValue / duration, MidpointRounding.ToZero)+1;
-            return;
 
-        SliderLiveValue = Segments[current + 1].Start;
+        SliderLiveValue = Math.Min(DurationSeconds - duration, segment * duration);
+        // trigger seek in your playback pipeline here
     }
 
     private void StepBackward()
     {
-        if (Segments.Count <= 0)
+        if (DurationSeconds <= 0)
             return;
 
-        var current = GetCurrentSegment();
+        var duration = SegmentDuration;
-        if (current <= 0)
+        var segment = Math.Max(0, Math.Round(SliderLiveValue / duration, MidpointRounding.ToZero)-1);
-        {
-            SliderLiveValue = 0;
-            return;
-        }
 
-        if (SliderLiveValue > Segments[current].Start)
+        SliderLiveValue = segment * duration;
-            SliderLiveValue = Segments[current].Start;
+        // trigger seek in your playback pipeline here
-        else
-            SliderLiveValue = Segments[current - 1].Start;
-    }
-
-    private int GetCurrentSegment()
-    {
-        double pos = SliderLiveValue;
-
-        for (int i = 0; i < Segments.Count; i++)
-        {
-            var s = Segments[i];
-            if (pos < s.Start)
-                return i - 1;
-            if (pos == s.Start)
-                return i;
-        }
-
-        return -1;
     }
 
     partial void OnSliderLiveValueChanged(double value)
@@ -526,15 +483,4 @@ public partial class JobViewModel : ObservableObject
         Task.Run(CreatePreview);
     }
 
-    public async Task<Avalonia.Media.Imaging.Bitmap?> GetThumbnail(double positionSec)
-    {
-        if (Probe == null)
-            return null;
-
-        var pos = TimeSpan.FromSeconds(positionSec);
-        var frame = await _thumbnails.CreateThumbnailAsync(Job.InputFile, Probe, pos, ThumbnailService.ThumbWidth, ThumbnailService.ThumbHeight, Job.Rotate).ConfigureAwait(false);
-        //frame.Save($"c:\\temp\\thmb-{positionSec:N4}.png");
-        return frame;
-    }
-
 }

Splitter-UI/Views/PreviewPane.axaml

@@ -42,17 +42,13 @@
                     Maximum="{Binding Selected.DurationSeconds}"
                     Value="{Binding Selected.SliderLiveValue, Mode=TwoWay}"
                     Margin="5,0,5,0" />
-
+-->
                 <controls:PreviewSlider Grid.Column="1"
                     Minimum="0"
                     Maximum="{Binding Selected.DurationSeconds}"
                     Value="{Binding Selected.SliderLiveValue, Mode=TwoWay}"
                     SegmentDuration="{Binding Selected.SegmentDuration}"
                     Margin="5,0,5,0" />
--->
-                <controls:TimelinePreviewSlider Grid.Column="1"
-                    ViewModel="{Binding Selected}"
-                    Margin="5,0,5,0" />
 
                 <Button Grid.Column="2"
                         HorizontalAlignment="Right"