using System;
using Skeleton.Algebra.FieldStructures;

namespace Skeleton.Test;

public class CustomFieldStructureTest
{
    [CustomFieldStructure]
    public class CustomField : FieldStructure<int>
    {
        public override int Addition(int self, int other) => (self + other) % 7;
        public override int AdditionUnit => 0;
        public override int Multiplication(int self, int other) => (self * other) % 7;

        public override int MultiplicationUnit => 1;
        public override int AdditionInverse(int self) => (7 - self) % 7;

        public override int MultiplicationInverse(int self)
        {
            for(int i = 0; i <= 7; i++ )
                if ((i * self) % 7 == 1)
                    return i;
            throw new DivideByZeroException();
        }

        public override int Conj(int self) => self;

        public override bool IsEqualApprox(int self, int other, double? absTol = null, double? relTol = null) =>
            (self % 7) == (other % 7);

        public override string RawCSharpRepresentation(int x) => $"{x}";

        public override double MaxError(int a) => (Math.Abs(a) % 7);

        public override int SquareRoot(int a)
        {
            for (int i = 0; i <= 7; i++)
            {
                if ((i * i) % 7 == a)
                    return i;
            }
            throw new ArgumentException("negative number in sqrt");
        }
    }

    [Test]
    public static void CustomerFieldStructureShouldNotBeNullTest()
    {
        Assert.IsNotNull(FieldStructure<int>.Dispatch());
    }
}