using MrGameEng.Core;
using Xunit;

namespace MrGameEng.Core.Tests;

public class GameClockTests
{
    [Fact]
    public void Advance_SingleFrame_UpdatesDeltaTotalAndFrameCount()
    {
        var clock = new GameClock();

        clock.Advance(0.016f);

        Assert.Equal(0.016f, clock.DeltaTime);
        Assert.Equal(0.016f, clock.UnscaledDeltaTime);
        Assert.Equal(0.016, clock.TotalTime, 3);
        Assert.Equal(1, clock.FrameCount);
    }

    [Fact]
    public void Advance_WithTimeScale_ScalesDeltaButNotUnscaled()
    {
        var clock = new GameClock { TimeScale = 0.5f };

        clock.Advance(0.02f);

        Assert.Equal(0.01f, clock.DeltaTime, 3);
        Assert.Equal(0.02f, clock.UnscaledDeltaTime, 3);
        Assert.Equal(0.01, clock.TotalTime, 3);
        Assert.Equal(0.02, clock.UnscaledTotalTime, 3);
    }

    [Fact]
    public void TimeScale_Zero_PausesScaledTime()
    {
        var clock = new GameClock { TimeScale = 0f };

        clock.Advance(0.016f);

        Assert.Equal(0f, clock.DeltaTime);
        Assert.Equal(0.0, clock.TotalTime);
        Assert.Equal(0.016, clock.UnscaledTotalTime, 3);
    }

    [Fact]
    public void TimeScale_Negative_ClampsToZero()
    {
        var clock = new GameClock { TimeScale = -1f };

        Assert.Equal(0f, clock.TimeScale);
    }
}