using FluentAssertions;
using FluentAssertions.Equivalency;

namespace LCU.API.Internal.DocumentLibTest;

public static class DateTimeComparison
{
    public static IEquivalencyStep Truncated { get; } = new TruncatedDateTimeStep();

    public static DateTime Truncate(this DateTime date) => date.AddTicks(-(date.Ticks % 10000));

    private class TruncatedDateTimeStep : IEquivalencyStep
    {
        public EquivalencyResult Handle
        (
            Comparands comparands,
            IEquivalencyValidationContext context,
            IEquivalencyValidator nestedValidator
        )
        {
            if (comparands.Subject is not DateTime subject || comparands.Expectation is not DateTime expectation)
                return EquivalencyResult.ContinueWithNext;

            subject.Truncate()
                .Should()
                .Be(expectation.Truncate(), context.Reason.FormattedMessage, context.Reason.Arguments);

            return EquivalencyResult.AssertionCompleted;
        }
    }
}