using Nonemm.Core;

namespace Nonemm.Contests.Tests;

/// Contacts an hour, as the network status window and the score window show
/// them.
public class RatesTests
{
    private static readonly DateTime Now = new(2026, 5, 30, 12, 0, 0, DateTimeKind.Utc);

    private static readonly TimeSpan Off = TimeSpan.FromMinutes(30);

    private static Qso MinutesAgo(int minutes) =>
        TestLog.Contact("OM3XYZ") with { TimestampUtc = Now.AddMinutes(-minutes) };

    /// Ten contacts spread over the last ten minutes: the oldest of them was
    /// ten minutes ago, so the rate is ten in a sixth of an hour.
    [Fact]
    public void TheRateIsTheContactsOverTheTimeTheyTook()
    {
        List<Qso> log = [.. Enumerable.Range(1, 10).Select(MinutesAgo)];

        Assert.Equal(60, Rates.PerHour(log, 10, Now, Off));
    }

    /// Only the last `count` contacts count, whatever else is in the log.
    [Fact]
    public void OlderContactsThanTheWindowAreLeftOut()
    {
        List<Qso> log = [.. Enumerable.Range(1, 40).Select(MinutesAgo)];

        Assert.Equal(60, Rates.PerHour(log, 10, Now, Off));
    }

    /// A gap as long as the contest's minimum off time ends the count.
    [Fact]
    public void CountingStopsAtATimeOffGap()
    {
        List<Qso> log = [MinutesAgo(1), MinutesAgo(2), MinutesAgo(90), MinutesAgo(91)];

        // two contacts in the last two minutes, floored at a minute
        Assert.Equal(60, Rates.PerHour(log, 10, Now, Off));
    }

    /// Under ten contacts the span counts as at least a minute, so a burst does
    /// not read as thousands an hour.
    [Fact]
    public void AShortBurstIsFlooredAtAMinute()
    {
        List<Qso> log = [MinutesAgo(0), MinutesAgo(0), MinutesAgo(0)];

        Assert.Equal(180, Rates.PerHour(log, 10, Now, Off));
    }

    [Fact]
    public void AnEmptyLogIsNoRate() =>
        Assert.Equal(0, Rates.PerHour([], 10, Now, Off));

    /// A station that has worked nobody since the gap has no rate, even with a
    /// full log behind it.
    [Fact]
    public void NothingSinceTheGapIsNoRate()
    {
        List<Qso> log = [.. Enumerable.Range(60, 20).Select(MinutesAgo)];

        Assert.Equal(0, Rates.PerHour(log, 10, Now, Off));
    }
}