using System.Threading;
using Xunit;

namespace MECF.Framework.Common.SicMath.Tests
{
    public class TimeDomainArithmeticMeanFilterTests
    {
        private IFilter _filterUnderTest;


        [Fact()]
        public void FilterEmptyBufferTest()
        {
            _filterUnderTest = new TimeDomainArithmeticMeanFilter(3);
            var output = _filterUnderTest.Filter();
            Assert.True(double.IsNaN(output), "The output is not double.NaN");
        }

        [Fact()]
        public void FilterZeroFilterDurationTest()
        {
            _filterUnderTest = new TimeDomainArithmeticMeanFilter(0);
            _filterUnderTest.Feed(1);
            _filterUnderTest.Feed(2);
            _filterUnderTest.Feed(3);
            var output = _filterUnderTest.Filter();
            Assert.True(output == 3, $"The output {output} is not last value.");
        }

        [Fact()]
        public void FilterNormalTest()
        {
            _filterUnderTest = new TimeDomainArithmeticMeanFilter(3);
            _filterUnderTest.Feed(1);
            _filterUnderTest.Feed(2);
            _filterUnderTest.Feed(3);
            var output = _filterUnderTest.Filter();
            Assert.True(output == 2, $"The output {output} is not 2.");
        }

        [Fact()]
        public void FilterIfContainDoubleNaNTest()
        {
            _filterUnderTest = new TimeDomainArithmeticMeanFilter(3);
            _filterUnderTest.Feed(1);
            _filterUnderTest.Feed(double.NaN);
            _filterUnderTest.Feed(3);
            var output = _filterUnderTest.Filter();
            Assert.True(output == 2, $"The output {output} is not 2.");
        }

        [Fact()]
        public void FilterNormalWithFirstElementShouldBeRemovedTest()
        {
            _filterUnderTest = new TimeDomainArithmeticMeanFilter(1);
            _filterUnderTest.Feed(1);
            Thread.Sleep(1200);
            _filterUnderTest.Feed(2);
            _filterUnderTest.Feed(3);
            var output = _filterUnderTest.Filter();
            Assert.True(output == 2.5, $"The output {output} is not 2.5");
        }
    }
}