using Nonemm.Core;

namespace Nonemm.Spotting.Tests;

public class BandmapSliceTests
{
    private static Frequency Khz(double kilohertz) => Frequency.FromHertz((long)(kilohertz * 1000));

    [Fact]
    public void ACentredSliceHasTheReceiverInTheMiddleEvenPastTheBandEdge()
    {
        (Frequency low, Frequency high) = BandmapSlice.Choose(
            Bands.Band20M, Khz(14_348), 20_000, centred: true, previousLow: null);

        Assert.Equal(Khz(14_338), low);
        Assert.Equal(Khz(14_358), high);
    }

    [Fact]
    public void ASliceThatDoesNotFollowKeepsItsPlaceWhileTheReceiverIsInside()
    {
        (Frequency low, _) = BandmapSlice.Choose(
            Bands.Band20M, Khz(14_025), 20_000, centred: false, previousLow: Khz(14_010));

        Assert.Equal(Khz(14_010), low);
    }

    [Fact]
    public void ASliceThatDoesNotFollowMovesWhenTheReceiverLeaves()
    {
        (Frequency low, _) = BandmapSlice.Choose(
            Bands.Band20M, Khz(14_100), 20_000, centred: false, previousLow: Khz(14_010));

        Assert.Equal(Khz(14_090), low);
    }

    [Fact]
    public void AMovedSliceStaysInsideTheBand()
    {
        (Frequency low, _) = BandmapSlice.Choose(
            Bands.Band20M, Bands.Band20M.Low, 20_000, centred: false, previousLow: null);

        Assert.Equal(Bands.Band20M.Low, low);
    }

    [Fact]
    public void ASpanOfZeroShowsTheWholeBand()
    {
        (Frequency low, Frequency high) = BandmapSlice.Choose(
            Bands.Band20M, Khz(14_025), 0, centred: true, previousLow: null);

        Assert.Equal(Bands.Band20M.Low, low);
        Assert.Equal(Bands.Band20M.High, high);
    }

    [Fact]
    public void ZoomingKeepsTheFrequencyUnderThePointerAtTheSameHeight()
    {
        // the pointer is a quarter of the way down a 40 kHz slice
        Frequency low = BandmapSlice.Zoom(Khz(14_000), 40_000, 20_000, Khz(14_010));

        Assert.Equal(Khz(14_005), low);
    }

    private static readonly BandSegments Segments = new(
        Bands.Band20M, CwHigh: Khz(14_150), DigitalLow: Khz(14_070), DigitalHigh: Khz(14_099));

    [Theory]
    [InlineData(14_025, 14_000, 14_150)]
    [InlineData(14_080, 14_070, 14_099)]
    [InlineData(14_250, 14_150, 14_350)]
    public void ThePartOfTheBandIsTheOneTheReceiverIsIn(double receiver, double low, double high)
    {
        (Frequency from, Frequency to) = BandmapSlice.Part(Bands.Band20M, Segments, Khz(receiver));

        Assert.Equal((Khz(low), Khz(high)), (from, to));
    }

    [Fact]
    public void ABandWithoutBoundariesShowsTheWholeBandAsAPart()
    {
        (Frequency from, Frequency to) = BandmapSlice.Part(Bands.Band20M, null, Khz(14_025));

        Assert.Equal((Bands.Band20M.Low, Bands.Band20M.High), (from, to));
    }

    [Fact]
    public void ThePartIsStretchedToIncludeAReceiverOutsideTheBand()
    {
        (_, Frequency to) = BandmapSlice.Part(Bands.Band20M, Segments, Khz(14_360));

        Assert.Equal(Khz(14_360), to);
    }
}