using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Azimuth;
using Azimuth.DenseLinearAlgebra;
using Azimuth.Approximation;

namespace Azimuth.UnitTests.Approximation
{
    public class MonomialBasisTests : UnitTestSharp.TestFixture
    {
        public class ShiftTests : UnitTestSharp.TestFixture
        {
            public void ZeroShift()
            {
                DenseVector coefficients = new Scalar[]
                {
                    6, 11, 6, 1,
                };

                MonomialBasis.ShiftPolynomialDomain(ref coefficients, 0);

                DenseVector expected = new Scalar[]
                {
                    6, 11, 6, 1,
                };

                CheckEqual(expected, coefficients);
            }

            public void Basic()
            {
                DenseVector coefficients = new Scalar[]
                {
                    6, 11, 6, 1,
                };

                MonomialBasis.ShiftPolynomialDomain(ref coefficients, -1);

                DenseVector expected = new Scalar[]
                {
                    0, 2, 3, 1,
                };

                CheckEqual(expected, coefficients);
            }
        }

        public class ScaleTests : UnitTestSharp.TestFixture
        {
            public void Basic()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1,
                };

                MonomialBasis.ScalePolynomialDomain(ref coefficients, 2.0);

                DenseVector expected = new Scalar[]
                {
                    1, 2, 4, 8,
                };

                CheckEqual(expected, coefficients);
            }
        }

        public class EvaluateTests : UnitTestSharp.TestFixture
        {
            public void Reasonable()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1, 1,
                };

                var abscissa = 1.24;

                CheckEqual(14.6152778997760, MonomialBasis.Evaluate(coefficients, abscissa));
            }

            public void Reasonable_Negative()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1, 1,
                };

                var abscissa = -1.24;

                CheckEqual(2.45877977497600, MonomialBasis.Evaluate(coefficients, abscissa));
            }

            public void Reasonable_Sub()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2,
                };

                var abscissa = 1.24;

                CheckEqual(14.6152778997760, MonomialBasis.Evaluate(coefficients, abscissa, 7));
            }

            public void NegativeRunLength()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2,
                };

                var abscissa = 1.24;

                CheckThrow(typeof(Exception));
                MonomialBasis.Evaluate(coefficients, abscissa, -1);
            }

            public void RunLengthTooHigh()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                var abscissa = 1.24;

                CheckThrow(typeof(Exception));
                MonomialBasis.Evaluate(coefficients, abscissa, 7);
            }

            public void ZeroRunLength()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                var abscissa = 1.24;

                CheckEqual(0, MonomialBasis.Evaluate(coefficients, abscissa, 0));
            }
        }

        public class DerivativeTests : UnitTestSharp.TestFixture
        {
            public void Basic()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                DenseVector expected = new Scalar[]
                {
                    1, 2, 3, 4, 5, 0,
                };

                MonomialBasis.Derivative(ref coefficients);                

                CheckEqual(expected, coefficients);
            }

            public void SubLength()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                DenseVector expected = new Scalar[]
                {
                    1, 2, 3, 0, 1, 1,
                };

                MonomialBasis.Derivative(ref coefficients, 4);

                CheckEqual(expected, coefficients);
            }

            public void RunLengthTooHigh()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                CheckThrow(typeof(IndexOutOfRangeException));
                MonomialBasis.Derivative(ref coefficients, 7);
            }

            public void NegativeRunLength()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                CheckThrow(typeof(Exception));
                MonomialBasis.Derivative(ref coefficients, -1);
            }

            public void ZeroRunLength()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                DenseVector expected = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                MonomialBasis.Derivative(ref coefficients, 0);

                CheckEqual(expected, coefficients);
            }

            public void OneRunLength()
            {
                DenseVector coefficients = new Scalar[]
                {
                    1, 1, 1, 1, 1, 1,
                };

                DenseVector expected = new Scalar[]
                {
                    0, 1, 1, 1, 1, 1,
                };

                MonomialBasis.Derivative(ref coefficients, 1);

                CheckEqual(expected, coefficients);
            }
        }
    }
}