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

using System.Collections.Generic;

namespace SixLabors.ImageSharp.Drawing.Processing {
  /// <summary>
  /// Immutable drawing state snapshot used by <see cref="DrawingCanvas{TPixel}"/>.
  /// </summary>
  internal sealed class DrawingCanvasState
  {
      /// <summary>
      /// Initializes a new instance of the <see cref="DrawingCanvasState"/> class.
      /// </summary>
      /// <param name="options">Drawing options for this state.</param>
      /// <param name="clipPaths">Clip paths for this state.</param>
      /// <param name="targetBounds">Absolute target bounds used for commands recorded in this state.</param>
      /// <param name="destinationOffset">Absolute destination offset for paths recorded in local canvas coordinates.</param>
      public DrawingCanvasState(
          DrawingOptions options,
          IReadOnlyList<IPath> clipPaths,
          Rectangle targetBounds,
          Point destinationOffset)
      {
          this.Options = options;
          this.ClipPaths = clipPaths;
          this.TargetBounds = targetBounds;
          this.DestinationOffset = destinationOffset;
      }

      /// <summary>
      /// Gets drawing options associated with this state.
      /// </summary>
      /// <remarks>
      /// This is the original <see cref="DrawingOptions"/> reference supplied to the state.
      /// It is not deep-cloned.
      /// </remarks>
      public DrawingOptions Options { get; }

      /// <summary>
      /// Gets clip paths associated with this state.
      /// </summary>
      public IReadOnlyList<IPath> ClipPaths { get; }

      /// <summary>
      /// Gets the absolute target bounds used for commands recorded in this state.
      /// </summary>
      public Rectangle TargetBounds { get; }

      /// <summary>
      /// Gets the absolute destination offset for paths recorded in local canvas coordinates.
      /// </summary>
      public Point DestinationOffset { get; }

      /// <summary>
      /// Gets a value indicating whether this state represents a compositing layer.
      /// </summary>
      public bool IsLayer { get; init; }

      /// <summary>
      /// Gets the layer compositing options when this state represents a compositing layer.
      /// </summary>
      public GraphicsOptions? LayerOptions { get; init; }
  }
}