namespace Just.PreciseMath.Tests.SanityChecks;

public class DoubleDoubleArithmeticEqualityChecks
{
    public static IEnumerable<TheoryDataRow<double>> ReferenceCases => [1.0, 2.0, 3.0, 100.0, 0.1, 0.5, 0.333333333333333333, -1.0, 1553.0, 1.0e+10];

    [Theory]
    [MemberData(nameof(ReferenceCases))]
    public void AdditionShouldProduceIdenticalResults(double reference)
    {
        DoubleDouble testValue = DoubleDouble.E; // any value with full precision range used

        DoubleDouble ddxdd_Result = testValue + (new DoubleDouble(reference));
        DoubleDouble ddxd_Result = testValue + reference;
        DoubleDouble dxdd_Result = reference + testValue;

        ddxdd_Result.High.ShouldBe(ddxd_Result.High);
        ddxdd_Result.Low.ShouldBe(ddxd_Result.Low);
        ddxdd_Result.ShouldBe(ddxd_Result);

        ddxdd_Result.High.ShouldBe(dxdd_Result.High);
        ddxdd_Result.Low.ShouldBe(dxdd_Result.Low);
        ddxdd_Result.ShouldBe(dxdd_Result);

        ddxd_Result.High.ShouldBe(dxdd_Result.High);
        ddxd_Result.Low.ShouldBe(dxdd_Result.Low);
        ddxd_Result.ShouldBe(dxdd_Result);
    }

    [Theory]
    [MemberData(nameof(ReferenceCases))]
    public void SubtractionFromShouldProduceIdenticalResults(double reference)
    {
        DoubleDouble testValue = DoubleDouble.E; // any value with full precision range used

        DoubleDouble ddxdd_Result = testValue - (new DoubleDouble(reference));
        DoubleDouble ddxd_Result = testValue - reference;

        ddxdd_Result.High.ShouldBe(ddxd_Result.High);
        ddxdd_Result.Low.ShouldBe(ddxd_Result.Low);
        ddxdd_Result.ShouldBe(ddxd_Result);
    }

    [Theory]
    [MemberData(nameof(ReferenceCases))]
    public void SubtractionShouldProduceIdenticalResults(double reference)
    {
        DoubleDouble testValue = DoubleDouble.E; // any value with full precision range used

        DoubleDouble ddxdd_Result = (new DoubleDouble(reference)) - testValue;
        DoubleDouble dxdd_Result = reference - testValue;

        ddxdd_Result.High.ShouldBe(dxdd_Result.High);
        ddxdd_Result.Low.ShouldBe(dxdd_Result.Low);
        ddxdd_Result.ShouldBe(dxdd_Result);
    }

    [Theory]
    [MemberData(nameof(ReferenceCases))]
    public void MultiplicationShouldProduceIdenticalResults(double reference)
    {
        DoubleDouble testValue = DoubleDouble.E; // any value with full precision range used

        DoubleDouble ddxdd_Result = testValue * (new DoubleDouble(reference));
        DoubleDouble ddxd_Result = testValue * reference;
        DoubleDouble dxdd_Result = reference * testValue;

        ddxdd_Result.High.ShouldBe(ddxd_Result.High);
        ddxdd_Result.Low.ShouldBe(ddxd_Result.Low);
        ddxdd_Result.ShouldBe(ddxd_Result);

        ddxdd_Result.High.ShouldBe(dxdd_Result.High);
        ddxdd_Result.Low.ShouldBe(dxdd_Result.Low);
        ddxdd_Result.ShouldBe(dxdd_Result);

        ddxd_Result.High.ShouldBe(dxdd_Result.High);
        ddxd_Result.Low.ShouldBe(dxdd_Result.Low);
        ddxd_Result.ShouldBe(dxdd_Result);
    }

    [Theory]
    [MemberData(nameof(ReferenceCases))]
    public void DivisionShouldProduceIdenticalResults(double reference)
    {
        DoubleDouble testValue = DoubleDouble.E; // any value with full precision range used

        DoubleDouble ddxdd_Result = testValue / (new DoubleDouble(reference));
        DoubleDouble ddxd_Result = testValue / reference;

        ddxdd_Result.High.ShouldBe(ddxd_Result.High);
        ddxdd_Result.Low.ShouldBe(ddxd_Result.Low);
        ddxdd_Result.ShouldBe(ddxd_Result);
    }

    [Theory]
    [MemberData(nameof(ReferenceCases))]
    public void DivisionByShouldProduceIdenticalResults(double reference)
    {
        DoubleDouble testValue = DoubleDouble.E; // any value with full precision range used

        DoubleDouble ddxdd_Result = (new DoubleDouble(reference)) / testValue;
        DoubleDouble dxdd_Result = reference / testValue;

        ddxdd_Result.High.ShouldBe(dxdd_Result.High);
        ddxdd_Result.Low.ShouldBe(dxdd_Result.Low);
        ddxdd_Result.ShouldBe(dxdd_Result);
    }
}