using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Azimuth.UnitTests
{
    public class HighPrecisionTrigTests : UnitTestSharp.TestFixture
    {
        public void Basic_Cosine()
        {
            var accum = new RobustAccumulator();

            accum.AddHarmonic(2, 2, 0);

            CheckEqual(2, accum.ComputedSum);
        }

        public void Basic_Sine()
        {
            var accum = new RobustAccumulator();

            accum.AddHarmonic(2, 2, Math.PI / 2);

            CheckEqual(2, accum.ComputedSum);
        }

        public void NumericallyTricky_Cosine_0()
        {
            Scalar angle = Math.PI - 3.141592650897981;

            var accum = new RobustAccumulator();

            accum.AddHarmonic(2, 0, angle);
            accum.Add(-2);
            // Cosine term: 2 + -7.2458531271372668817222267136721e-18
            // Sine term: 8.0754367153879301400862705897261e-9
            // Sum: 2 + 8.0754367081420770129490037080039e-9

            Check(Scalar.FuzzyEquality(-7.2458531271372668817261952966149e-18, accum.ComputedSum, 1e-24));
        }

        public void NumericallyTricky_Sine_0()
        {
            Scalar angle = Math.PI / 2 + 2.6918122384626433832795028841972e-9;

            var accum = new RobustAccumulator();

            // Cosine term: -5.3836244769252867600575137264885e-9
            // Sine term: 3 + -1.0868779690705900322637332506558e-17
            // Sum: -5.3836244877940664507634140491258e-9

            accum.AddHarmonic(0, 2, angle);
            accum.Add(-2);

            Check(Scalar.FuzzyEquality(-7.2458531271372668817261952966149e-18, accum.ComputedSum.Value, 1e-24));
        }

        public void NumericallyTricky_Cosine_Pi()
        {
            Scalar angle = 3.141592650897981;

            var accum = new RobustAccumulator();

            accum.AddHarmonic(2, 0, angle);
            accum.Add(2);
            // Cosine term: 2 + -7.2458531271372668817222267136721e-18
            // Sine term: 8.0754367153879301400862705897261e-9
            // Sum: 2 + 8.0754367081420770129490037080039e-9

            Check(Scalar.FuzzyEquality(7.2458531271372668817261952966149e-18, accum.ComputedSum, 1e-23));
        }

        public void NumericallyTricky_Sine_Pi()
        {
            Scalar angle = -Math.PI / 2 - 2.6918122384626433832795028841972e-9;

            var accum = new RobustAccumulator();

            // Cosine term: -5.3836244769252867600575137264885e-9
            // Sine term: 3 + -1.0868779690705900322637332506558e-17
            // Sum: -5.3836244877940664507634140491258e-9

            accum.AddHarmonic(0, 2, angle);
            accum.Add(2);

            Check(Scalar.FuzzyEquality(7.2458531271372668817261952966149e-18, accum.ComputedSum.Value, 1e-23));
        }

        public class Scalars : UnitTestSharp.TestFixture
        {
            public void Basic_Cosine()
            {
                var result = HighPrecisionTrig.AddHarmonic((Scalar)2, (Scalar)2, (Scalar)0);

                CheckEqual(2, result);
            }

            public void Basic_Sine()
            {
                var result = HighPrecisionTrig.AddHarmonic((Scalar)2, (Scalar)2, (Scalar)Math.PI / 2.0);

                CheckEqual(2, result);
            }

            public void BasicSinCos()
            {
                var result = HighPrecisionTrig.AddHarmonic((Scalar)3, (Scalar)4, (Scalar)Math.PI / 3.0);

                CheckEqual(4.9641016151, result);
            }
        }
    }
}