using Nonemm.Core;

namespace Nonemm.Spotting.Tests;

public class BandmapLayoutTests
{
    private const double LabelHeight = 10;

    private static readonly DateTime Now = new(2026, 5, 30, 12, 0, 0, DateTimeKind.Utc);

    /// 14000 to 14100 kHz over 100 pixels, so one pixel is one kilohertz.
    private static BandmapScale Scale() =>
        new(Frequency.FromKilohertz(14_000), Frequency.FromKilohertz(14_100), 100);

    private static Spot At(double kilohertz, string call = "DL1ABC") =>
        new(Callsign.Parse(call), Frequency.FromKilohertz(kilohertz), Now, SpotSource.Cluster);

    [Fact]
    public void ALabelSitsCentredOnItsFrequency()
    {
        IReadOnlyList<BandmapLabel> placed = BandmapLayout.Place([At(14_050)], Scale(), LabelHeight);

        Assert.Equal(50, placed[0].MarkY);
        Assert.Equal(45, placed[0].LabelY);
    }

    [Fact]
    public void LabelsComeOutInFrequencyOrder()
    {
        IReadOnlyList<BandmapLabel> placed = BandmapLayout.Place(
            [At(14_080, "JA1XYZ"), At(14_010, "DL1ABC")],
            Scale(),
            LabelHeight);

        Assert.Equal(["DL1ABC", "JA1XYZ"], placed.Select(l => l.Spot.Call.Text));
    }

    /// Two stations a hundred hertz apart would have their text on top of each
    /// other, so the lower one moves down and its leader line does the work.
    [Fact]
    public void ALabelThatWouldCoverTheOneAboveIsPushedDown()
    {
        IReadOnlyList<BandmapLabel> placed = BandmapLayout.Place(
            [At(14_050, "DL1ABC"), At(14_050.1, "JA1XYZ")],
            Scale(),
            LabelHeight);

        Assert.Equal(45, placed[0].LabelY);
        Assert.Equal(55.5, placed[1].LabelY);
        // the leader still points at where the station really is
        Assert.Equal(50.1, placed[1].MarkY, 3);
    }

    [Fact]
    public void ALabelWithRoomKeepsItsOwnPlace()
    {
        IReadOnlyList<BandmapLabel> placed = BandmapLayout.Place(
            [At(14_010, "DL1ABC"), At(14_090, "JA1XYZ")],
            Scale(),
            LabelHeight);

        Assert.Equal(5, placed[0].LabelY);
        Assert.Equal(85, placed[1].LabelY);
    }

    [Fact]
    public void AStationOutsideTheSliceIsNotDrawn() =>
        Assert.Empty(BandmapLayout.Place([At(14_200)], Scale(), LabelHeight));

    [Fact]
    public void TheTicksStartAtTheFirstRoundFrequencyInTheSlice()
    {
        IReadOnlyList<Frequency> ticks = BandmapLayout.Ticks(
            new BandmapScale(Frequency.FromKilohertz(14_003), Frequency.FromKilohertz(14_012), 100),
            Frequency.FromKilohertz(5));

        Assert.Equal([14_005_000, 14_010_000], ticks.Select(t => t.Hertz));
    }

    [Fact]
    public void TheScaleTurnsPixelsBackIntoFrequencies() =>
        Assert.Equal(14_050_000, Scale().At(50).Hertz);

    [Fact]
    public void AReceiverBarIsAsWideAsTheModeItIsIn()
    {
        VfoMarker vfo = VfoMarker.Centred(
            Frequency.FromKilohertz(14_025),
            Frequency.FromHertz(500),
            VfoRole.Receive);

        Assert.Equal(14_024_750, vfo.Low.Hertz);
        Assert.Equal(14_025_250, vfo.High.Hertz);
    }
}