using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UnitTestSharp;
using Azimuth.ODE;

namespace Azimuth.UnitTests.ODE
{
	public class IntegratorsTests : TestFixture
	{
		public void TODO()
		{
			TODO("Test out cold and warm start integrators.");
		}

		public class IntegrationTypes : TestFixture
		{
			public void SUVAT_Test()
			{
				Scalar pos = 0;
				Scalar vel = 1;
				Scalar accel = -2;
				Integrators<Scalar>.SUVAT(2.0, ref pos, vel, accel);

				CheckEqual(-2, pos);
			}

			public void ExplicitEuler_Test()
			{
				Scalar pos = 0;
				Scalar vel = 10;

				Integrators<Scalar>.ExplicitEuler(2.0, ref pos, vel);

				CheckEqual(20, pos);
			}

			public void Verlet_Test()
			{
				Scalar pos = 1;
				Scalar oPos = -10;

				Scalar accel = 5;

				Integrators<Scalar>.Verlet(2.0, ref pos, oPos, accel);

				CheckEqual(2 + 10 + 20, pos);
			}

			public void TrapezoidMethod_Test()
			{
				Scalar pos = 0;
				Scalar vel = -5;
				Scalar velNew = 15;

				Integrators<Scalar>.TrapezoidMethod(2.0, ref pos, vel, velNew);

				CheckEqual(10, pos);
			}

			public void BeemansAlgorithmForPosition_Test()
			{
				Scalar pos = 0;
				Scalar vel = 2;
				Scalar accel = 3;
				Scalar oldAccel = 5;
				
				Integrators<Scalar>.BeemansAlgorithmForPosition(2.0, ref pos, vel, accel, oldAccel);

				CheckEqual(26.0 / 3.0, pos);
			}

			public void BeemansAlgorithmForVelocityExplicit_Test()
			{
				Scalar pos = 0;
				Scalar vel = 3;
				Scalar oldVel = -5;
				
				Integrators<Scalar>.BeemansAlgorithmForVelocityExplicit(2.0, ref pos, vel, oldVel);

				CheckEqual(26.0 / 3.0, pos);
			}

			public void BeemansAlgorithmForVelocityImplicit_Test()
			{
				Scalar pos = 1;
				Scalar vel = 3;
				Scalar oldVel = -5;
				Scalar newVel = 7;
				
				Integrators<Scalar>.BeemansAlgorithmForVelocityImplicit(2.0, ref pos, vel, oldVel, newVel);

				CheckEqual(37.0 / 3.0, pos);
			}
		}
	}
}