#if ENABLE_UNITTESTS

using System;

using UnityEngine;

using NUnit.Framework;

namespace Framework.Support {

  /// <summary>Unit tests for the utility methods</summary>
  [TestFixture]
  internal class IntersectorTest {

    /// <summary>
    ///   Verifies that the ground height determination clamps the X coordinate to
    ///   the left side of the ground
    /// </summary>
    [Test]
    public void PointIsNeverInZeroSizeEllipse() {
      Assert.IsFalse(
        Intersector.IsPointInEllipse(Vector2.zero, Vector2.zero, Vector2.zero)
      );
    }

    /// <summary>Verifies that points in tall ellipses are detected correctly</summary>
    /// <remarks>
    ///   Checks both X and Y offsets to catch when the extents are the wrong way around
    /// </remarks>
    [Test]
    public void PointInTallEllipseIsDetected() {
      Vector2 ellipseExtents = new Vector2(5.0f, 50.0f);

      Assert.IsTrue(
        Intersector.IsPointInEllipse(new Vector2(0.0f, 49.0f), Vector2.zero, ellipseExtents)
      );
      Assert.IsTrue(
        Intersector.IsPointInEllipse(new Vector2(0.0f, -49.0f), Vector2.zero, ellipseExtents)
      );

      Assert.IsFalse(
        Intersector.IsPointInEllipse(new Vector2(49.0f, 0.0f), Vector2.zero, ellipseExtents)
      );
      Assert.IsFalse(
        Intersector.IsPointInEllipse(new Vector2(-49.0f, 0.0f), Vector2.zero, ellipseExtents)
      );
    }

    /// <summary>Verifies that points in flat ellipses are detected correctly</summary>
    /// <remarks>
    ///   Checks both X and Y offsets to catch when the extents are the wrong way around
    /// </remarks>
    [Test]
    public void PointInFlatEllipseIsDetected() {
      Vector2 ellipseExtents = new Vector2(50.0f, 5.0f);

      Assert.IsTrue(
        Intersector.IsPointInEllipse(new Vector2(49.0f, 0.0f), Vector2.zero, ellipseExtents)
      );
      Assert.IsTrue(
        Intersector.IsPointInEllipse(new Vector2(-49.0f, 0.0f), Vector2.zero, ellipseExtents)
      );

      Assert.IsFalse(
        Intersector.IsPointInEllipse(new Vector2(0.0f, 49.0f), Vector2.zero, ellipseExtents)
      );
      Assert.IsFalse(
        Intersector.IsPointInEllipse(new Vector2(0.0f, -49.0f), Vector2.zero, ellipseExtents)
      );
    }

    /// <summary>
    ///   Verifies that the union between an ellipse and a line segment can be found
    /// </summary>
    [Test]
    public void LineSegmentEllipseUnionCanBeFound() {
      Vector2 ellipseExtents = new Vector2(5.0f, 50.0f);

      LineSegment2? union = Intersector.GetLineSegmentEllipseUnion(
        new LineSegment2(new Vector2(-10.0f, 0.0f), new Vector2(+10.0f, 0.0f)),
        Vector2.zero, ellipseExtents
      );

      Assert.IsTrue(union.HasValue);
      Assert.That(union.Value.From.x, Is.EqualTo(-5.0f).Within(32).Ulps);
      Assert.That(union.Value.To.x, Is.EqualTo(5.0f).Within(32).Ulps);
    }

    /// <summary>
    ///   Verifies that the union between a rectangle and a horizontal line segment can be found
    /// </summary>
    [Test]
    public void HorizontalLineSegmentRectangleUnionCanBeFound() {
      Vector2 rectangleMin = new Vector2(-5.0f, -10.0f);
      Vector2 rectangleMax = new Vector2(+5.0f, +10.0f);

      LineSegment2? union = Intersector.GetLineSegmentRectangleUnion(
        new LineSegment2(new Vector2(-10.0f, 0.0f), new Vector2(+10.0f, 0.0f)),
        rectangleMin, rectangleMax
      );

      Assert.IsTrue(union.HasValue);
      Assert.That(union.Value.From.x, Is.EqualTo(-5.0f).Within(32).Ulps);
      Assert.That(union.Value.To.x, Is.EqualTo(5.0f).Within(32).Ulps);
    }

    /// <summary>
    ///   Verifies that the union between a rectangle and a vertical line segment can be found
    /// </summary>
    [Test]
    public void VerticalLineSegmentRectangleUnionCanBeFound() {
      Vector2 rectangleMin = new Vector2(-5.0f, -10.0f);
      Vector2 rectangleMax = new Vector2(+5.0f, +10.0f);

      LineSegment2? union = Intersector.GetLineSegmentRectangleUnion(
        new LineSegment2(new Vector2(0.0f, -20.0f), new Vector2(0.0f, +20.0f)),
        rectangleMin, rectangleMax
      );

      Assert.IsTrue(union.HasValue);
      Assert.That(union.Value.From.y, Is.EqualTo(-10.0f).Within(32).Ulps);
      Assert.That(union.Value.To.y, Is.EqualTo(10.0f).Within(32).Ulps);
    }

    /// <summary>
    ///   Verifies that the union between a rectangle and a diagonal line segment can be found
    /// </summary>
    [Test]
    public void DiagonalLineSegmentRectangleUnionCanBeFound() {
      Vector2 rectangleMin = new Vector2(-5.0f, -5.0f);
      Vector2 rectangleMax = new Vector2(+5.0f, +5.0f);

      LineSegment2? union = Intersector.GetLineSegmentRectangleUnion(
        new LineSegment2(new Vector2(-10.0f, -10.0f), new Vector2(+10.0f, +10.0f)),
        rectangleMin, rectangleMax
      );

      Assert.IsTrue(union.HasValue);
      Assert.That(union.Value.From.x, Is.EqualTo(-5.0f).Within(32).Ulps);
      Assert.That(union.Value.From.y, Is.EqualTo(-5.0f).Within(32).Ulps);
      Assert.That(union.Value.To.x, Is.EqualTo(5.0f).Within(32).Ulps);
      Assert.That(union.Value.To.y, Is.EqualTo(5.0f).Within(32).Ulps);
    }

  }

} // namespace Framework.Support

#endif // ENABLE_UNITTESTS