using Avalonia.Interactivity;

namespace Avalonia.Controls
{
    /// <summary>
    /// Describes a change in scrolling state.
    /// </summary>
    public class ScrollChangedEventArgs : RoutedEventArgs
    {
        public ScrollChangedEventArgs(
            Vector extentDelta,
            Vector offsetDelta,
            Vector viewportDelta)
            : this(ScrollViewer.ScrollChangedEvent, extentDelta, offsetDelta, viewportDelta)
        {
        }

        public ScrollChangedEventArgs(
            RoutedEvent? routedEvent,
            Vector extentDelta,
            Vector offsetDelta,
            Vector viewportDelta)
            : base(routedEvent)
        {
            ExtentDelta = extentDelta;
            OffsetDelta = offsetDelta;
            ViewportDelta = viewportDelta;
        }

        /// <summary>
        /// Gets the change to the value of <see cref="ScrollViewer.Extent"/>.
        /// </summary>
        public Vector ExtentDelta { get; }

        /// <summary>
        /// Gets the change to the value of <see cref="ScrollViewer.Offset"/>.
        /// </summary>
        public Vector OffsetDelta { get; }

        /// <summary>
        /// Gets the change to the value of <see cref="ScrollViewer.Viewport"/>.
        /// </summary>
        public Vector ViewportDelta { get; }
    }
}