using SafelyYou.Data;

namespace SafelyYouTests;

public class HeartBeatHistoriesUptimeTests
{
    private static readonly DeviceId Device = new("device-1");
    private static readonly DateTimeOffset T0 = new(2024, 1, 1, 12, 0, 0, TimeSpan.Zero);

    [Test]
    public void Uptime_UnknownDevice_ReturnsZero()
    {
        var histories = new HeartBeatHistories();

        Assert.That(histories.Uptime(Device), Is.EqualTo(0));
    }

    [Test]
    public void Uptime_SingleHeartbeat_ReturnsZero()
    {
        var histories = new HeartBeatHistories();
        histories.Add(Device, T0);

        // first == last => TotalMinutes is 0, guarded to return 0
        Assert.That(histories.Uptime(Device), Is.EqualTo(0));
    }

    [Test]
    public void Uptime_TwoHeartbeatsOneMinuteApart_ReturnsTwoHundred()
    {
        var histories = new HeartBeatHistories();
        histories.Add(Device, T0);
        histories.Add(Device, T0.AddMinutes(1));

        // (2 beats / 1 minute) * 100
        Assert.That(histories.Uptime(Device), Is.EqualTo(200).Within(0.001));
    }

    [Test]
    public void Uptime_TwoHeartbeatsOverTwoMinutes_ReturnsOneHundred()
    {
        var histories = new HeartBeatHistories();
        histories.Add(Device, T0);
        histories.Add(Device, T0.AddMinutes(2));

        // (2 beats / 2 minutes) * 100
        Assert.That(histories.Uptime(Device), Is.EqualTo(100).Within(0.001));
    }

    [Test]
    public void Uptime_ThreeHeartbeatsOverTwoMinutes_ReturnsOneHundredFifty()
    {
        var histories = new HeartBeatHistories();
        histories.Add(Device, T0);
        histories.Add(Device, T0.AddMinutes(1));
        histories.Add(Device, T0.AddMinutes(2));

        // (3 beats / 2 minutes) * 100
        Assert.That(histories.Uptime(Device), Is.EqualTo(150).Within(0.001));
    }

    [Test]
    public void Uptime_IsPerDevice()
    {
        var other = new DeviceId("device-2");
        var histories = new HeartBeatHistories();
        histories.Add(Device, T0);
        histories.Add(Device, T0.AddMinutes(1));
        histories.Add(other, T0);

        Assert.Multiple(() =>
        {
            Assert.That(histories.Uptime(Device), Is.EqualTo(200).Within(0.001));
            Assert.That(histories.Uptime(other), Is.EqualTo(0));
        });
    }

    [Test]
    public void Uptime_OutOfSequenceHeartbeat_DoesNotAffectCalculation()
    {
        var histories = new HeartBeatHistories();
        histories.Add(Device, T0.AddMinutes(1));
        histories.Add(Device, T0); // rejected
        histories.Add(Device, T0.AddMinutes(3));

        // still 2 beats over 2 minutes
        Assert.That(histories.Uptime(Device), Is.EqualTo(100).Within(0.001));
    }
}