namespace Nonemm.Recorder.Tests;

public class SampleRingTests
{
    [Fact]
    public void Samples_come_out_in_the_order_they_went_in_across_the_wrap()
    {
        SampleRing ring = new(5);
        ring.Write([1, 2, 3, 4]);
        Span<float> first = stackalloc float[3];
        ring.Read(first);
        ring.Write([5, 6, 7]);

        Span<float> all = stackalloc float[5];
        int got = ring.Read(all);

        Assert.Equal(4, got);
        Assert.Equal([4f, 5f, 6f, 7f], all[..4].ToArray());
    }

    [Fact]
    public void A_full_ring_drops_the_oldest_samples()
    {
        SampleRing ring = new(4);
        ring.Write([1, 2, 3]);
        ring.Write([4, 5, 6]);

        Span<float> all = stackalloc float[4];
        ring.Read(all);

        Assert.Equal([3f, 4f, 5f, 6f], all.ToArray());
    }

    [Fact]
    public void Trim_keeps_the_newest_samples()
    {
        SampleRing ring = new(8);
        ring.Write([1, 2, 3, 4, 5]);
        ring.TrimTo(2);

        Span<float> all = stackalloc float[2];
        ring.Read(all);

        Assert.Equal([4f, 5f], all.ToArray());
    }
}