using System;

using UnityEngine;

using NUnit.Framework;

using Framework.Navigation.Platformer;

namespace Framework.Navigation.Platformer {

  /// <summary>Unit tests for the ground class</summary>
  [TestFixture]
  internal class GroundTest {

    /// <summary>A default set of constraints to be used for unit tests</summary>
    public static Constraints DefaultConstraints = new Constraints() {
      MaximumJumpHeight = 5.0f,
      MaximumDropHeight = 10.0f,
      MaximumJumpDistance = 5.0f
    };

    /// <summary>
    ///   Verifies that the ground height determination clamps the X coordinate to
    ///   the left side of the ground
    /// </summary>
    [Test]
    public void GroundHeightClampsToLeftSide() {
      Ground test = makeGround(new Vector2(-10.0f, 2.5f), new Vector2(10.0f, 4.5f));
      Assert.AreEqual(test.Heights[0].y, test.GetGroundHeightAt(-20.0f));
    }

    /// <summary>
    ///   Verifies that the ground height determination clamps the X coordinate to
    ///   the right side of the ground
    /// </summary>
    [Test]
    public void GroundHeightClampsToRightSide() {
      Ground test = makeGround(new Vector2(-10.0f, 2.5f), new Vector2(10.0f, 4.5f));
      Assert.AreEqual(test.Heights[1].y, test.GetGroundHeightAt(20.0f));
    }

    /// <summary>
    ///   Verifies that the ground height determination linearly interpolates between
    ///   the provided samples
    /// </summary>
    [Test]
    public void GroundHeightIsInterpolatedLinearly() {
      Ground test = makeGround(new Vector2(-10.0f, 2.5f), new Vector2(10.0f, 4.5f));
      Assert.That(test.GetGroundHeightAt(0.0f), Is.EqualTo(3.5f).Within(32).Ulps);
    }

    /// <summary>Creates a new ground with the specified heights</summary>
    /// <param name="heights">Heights that will be used for the ground</param>
    /// <returns>The newly created ground</returns>
    private static Ground makeGround(params Vector2[] heights) {
      return new Ground() { Heights = heights };
    }

  }

} // namespace Framework.Navigation.Platformer