// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using System.Diagnostics.CodeAnalysis;
using SixLabors.ImageSharp.Memory;
using SixLabors.ImageSharp.PixelFormats;

namespace SixLabors.ImageSharp.Drawing.Processing.Backends {
  /// <summary>
  /// Canvas frame backed by a <see cref="NativeSurface"/>.
  /// </summary>
  /// <typeparam name="TPixel">The pixel format.</typeparam>
  public sealed class NativeCanvasFrame<TPixel> : ICanvasFrame<TPixel>
      where TPixel : unmanaged, IPixel<TPixel>
  {
      private readonly NativeSurface surface;

      /// <summary>
      /// Initializes a new instance of the <see cref="NativeCanvasFrame{TPixel}"/> class.
      /// </summary>
      /// <param name="bounds">The frame bounds.</param>
      /// <param name="surface">The native surface backing this frame.</param>
      public NativeCanvasFrame(Rectangle bounds, NativeSurface surface)
      {
          Guard.NotNull(surface, nameof(surface));
          Guard.MustBeGreaterThan(bounds.Width, 0, nameof(bounds));
          Guard.MustBeGreaterThan(bounds.Height, 0, nameof(bounds));

          this.Bounds = bounds;
          this.surface = surface;
      }

      /// <inheritdoc />
      public Rectangle Bounds { get; }

      /// <inheritdoc />
      public bool TryGetCpuRegion(out Buffer2DRegion<TPixel> region)
      {
          region = default;
          return false;
      }

      /// <inheritdoc />
      public bool TryGetNativeSurface([NotNullWhen(true)] out NativeSurface? surface)
      {
          surface = this.surface;
          return true;
      }
  }
}