using Nonemm.Core;

namespace Nonemm.Contests.Tests;

/// The `…BandChange…` settings: what counts as a change, and over what stretch
/// of time the changes are counted.
public class BandChangeRulesTests
{
    private static readonly DateTime Start = new(2026, 5, 30, 12, 0, 0, DateTimeKind.Utc);

    private static Qso At(int minutes, double kilohertz, Mode? mode = null, int seconds = 0) =>
        TestLog.Contact("OM3XYZ", kilohertz, mode: mode) with
        {
            TimestampUtc = Start.AddMinutes(minutes).AddSeconds(seconds),
        };

    /// N1MM's fallback, which is the ten-minute rule: a multi-operator entry
    /// with one transmitter has to stay ten minutes on a band, and nothing caps
    /// how many times it may move.
    [Theory]
    [InlineData("MULTI-ONE", "ONE", 10)]
    [InlineData("MULTI-OP", "ONE", 10)]
    [InlineData("MULTI-TWO", "TWO", 10)]
    [InlineData("MULTI-OP", "TWO", 10)]
    [InlineData("MULTI-OP", "UNLIMITED", 0)]
    [InlineData("SINGLE-OP", "ONE", 0)]
    public void TheCategoryAloneSaysHowLongAStationStaysOnABand(
        string operatorCategory,
        string transmitters,
        int minutes)
    {
        BandChangeRules rules = BandChangeRules.ForCategory(new ContestEntry
        {
            OperatorCategory = operatorCategory,
            TransmitterCategory = transmitters,
        });

        Assert.Equal(TimeSpan.FromMinutes(minutes), rules.MinimumStay);
        Assert.False(rules.IsCounted);
    }

    /// A contest that says nothing about band changes still gets the rule for
    /// the category, which is what N1MM does.
    [Fact]
    public void AContestThatSaysNothingStillGetsTheTenMinuteRule()
    {
        Contest contest = new Rules.CqWorldWide(ModeCategory.Cw);

        BandChangeRules rules = contest.BandChangesFor(new ContestEntry
        {
            OperatorCategory = "MULTI-ONE",
            TransmitterCategory = "ONE",
        });

        Assert.True(rules.HasStayTimer);
        Assert.Equal(TimeSpan.FromMinutes(10), rules.MinimumStay);
    }

    [Fact]
    public void ASingleOperatorEntryHasNoBandChangeRule()
    {
        Contest contest = new Rules.CqWorldWide(ModeCategory.Cw);

        Assert.Equal(
            BandChangeRules.None,
            contest.BandChangesFor(new ContestEntry { OperatorCategory = "SINGLE-OP" }));
    }

    [Fact]
    public void EachMoveToAnotherBandIsOneChange() =>
        Assert.Equal(
            2,
            new BandChangeRules(8).CountedIn(
                [At(0, 14_025), At(5, 7_040), At(10, 7_045), At(15, 14_030)],
                Start.AddMinutes(20)));

    /// The count is per clock hour unless the file says otherwise, so a change
    /// made in the hour before does not count against this one.
    [Fact]
    public void ChangesMadeInAnEarlierHourAreNotCounted() =>
        Assert.Equal(
            1,
            new BandChangeRules(8).CountedIn(
                [At(0, 14_025), At(5, 7_040), At(65, 14_025)],
                Start.AddMinutes(70)));

    [Fact]
    public void CountingPerContestKeepsEveryChange() =>
        Assert.Equal(
            2,
            new BandChangeRules(8, PerContest: true).CountedIn(
                [At(0, 14_025), At(5, 7_040), At(65, 14_025)],
                Start.AddMinutes(70)));

    /// `CountBandChangesPerPeriod` counts the hour up to now rather than the
    /// clock hour.
    [Fact]
    public void CountingPerPeriodLooksBackAnHour() =>
        Assert.Equal(
            1,
            new BandChangeRules(8, PerPeriod: true).CountedIn(
                [At(0, 14_025), At(5, 7_040), At(65, 14_025)],
                Start.AddMinutes(70)));

    /// `CountBandOrModeChange` counts a move to another mode on the same band.
    [Fact]
    public void ModeChangesCountWhenTheContestSaysSo() =>
        Assert.Equal(
            1,
            new BandChangeRules(8, CountsModeChanges: true).CountedIn(
                [At(0, 14_025), At(5, 14_250, Modes.Usb)],
                Start.AddMinutes(10)));

    /// The stay runs from the minute after the contact that changed band, so a
    /// change at 12:05:40 with a ten-minute stay has five minutes left at
    /// 12:11. N1MM starts it the same way.
    [Fact]
    public void TheStayCountsDownFromTheMinuteAfterTheChange()
    {
        BandChangeRules rules = new(8, MinimumStay: TimeSpan.FromMinutes(10));

        Assert.Equal(
            TimeSpan.FromMinutes(5),
            rules.StayLeft([At(0, 14_025), At(5, 7_040, seconds: 40)], Start.AddMinutes(11)));
    }

    [Fact]
    public void TheStayIsUpOnceTheTimeHasPassed() =>
        Assert.Equal(
            TimeSpan.Zero,
            new BandChangeRules(8, MinimumStay: TimeSpan.FromMinutes(10)).StayLeft(
                [At(0, 14_025), At(5, 7_040)],
                Start.AddMinutes(30)));

    /// A log that has stayed on one band has nothing to count down.
    [Fact]
    public void NothingCountsDownUntilTheStationChangesBand() =>
        Assert.Equal(
            TimeSpan.Zero,
            new BandChangeRules(8, MinimumStay: TimeSpan.FromMinutes(10)).StayLeft(
                [At(0, 14_025), At(5, 14_030)],
                Start.AddMinutes(6)));

    [Fact]
    public void AContestThatAsksForNoStayHasNoTimer()
    {
        Assert.False(new BandChangeRules(8).HasStayTimer);
        Assert.True(new BandChangeRules(8, MinimumStay: TimeSpan.FromMinutes(10)).HasStayTimer);
    }

    [Fact]
    public void AContestWithNoLimitCountsNothing() => Assert.False(BandChangeRules.None.IsCounted);
}