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

using System.Collections.Generic;
using System.Numerics;

namespace SixLabors.ImageSharp.Drawing {
  /// <summary>
  /// A shape made up of a single closed path made up of one of more <see cref="ILineSegment"/>s
  /// </summary>
  public class Polygon : Path
  {
      /// <summary>
      /// Initializes a new instance of the <see cref="Polygon"/> class.
      /// </summary>
      /// <param name="points">The collection of points; processed as a series of linear line segments.</param>
      public Polygon(PointF[] points)
          : this(new LinearLineSegment(points))
      {
      }

      /// <summary>
      /// Initializes a new instance of the <see cref="Polygon"/> class.
      /// </summary>
      /// <param name="segments">The segments.</param>
      public Polygon(params ILineSegment[] segments)
          : base(segments)
      {
      }

      /// <summary>
      /// Initializes a new instance of the <see cref="Polygon"/> class.
      /// </summary>
      /// <param name="segments">The segments.</param>
      public Polygon(IEnumerable<ILineSegment> segments)
          : base(segments)
      {
      }

      /// <summary>
      /// Initializes a new instance of the <see cref="Polygon" /> class.
      /// </summary>
      /// <param name="segment">The segment.</param>
      public Polygon(ILineSegment segment)
          : base(segment)
      {
      }

      /// <summary>
      /// Initializes a new instance of the <see cref="Polygon"/> class.
      /// </summary>
      /// <param name="path">The path.</param>
      internal Polygon(Path path)
          : base(path)
      {
      }

      /// <summary>
      /// Initializes a new instance of the <see cref="Polygon"/> class using the specified line segments.
      /// </summary>
      /// <remarks>
      /// If owned is set to <see langword="true"/>, modifications to the segments array after construction may affect
      /// the Polygon instance. If owned is <see langword="false"/>, the segments are copied to ensure the Polygon is not affected by
      /// external changes.
      /// </remarks>
      /// <param name="segments">An array of line segments that define the edges of the polygon. The order of segments determines the shape of
      /// the polygon.</param>
      /// <param name="owned">
      /// <see langword="true"/> to indicate that the Polygon instance takes ownership of the segments array;
      /// <see langword="false"/> to create a copy of the array.
      /// </param>
      internal Polygon(ILineSegment[] segments, bool owned)
          : base(owned ? segments : [.. segments])
      {
      }

      /// <inheritdoc />
      public override bool IsClosed => true;

      /// <inheritdoc />
      public override IPath Transform(Matrix4x4 matrix)
      {
          if (matrix.IsIdentity)
          {
              return this;
          }

          ILineSegment[] segments = new ILineSegment[this.LineSegments.Count];

          for (int i = 0; i < segments.Length; i++)
          {
              segments[i] = this.LineSegments[i].Transform(matrix);
          }

          return new Polygon(segments, true);
      }
  }
}