using Wiki.Core.Ports;

namespace Wiki.Contracts;

/// <summary>Every <see cref="IEmbeddingModel"/> adapter derives from this. The adapter under test may talk to a fake server.</summary>
public abstract class EmbeddingModelContract
{
    protected abstract Task<IEmbeddingModel> CreateModelAsync();

    [Fact]
    public async Task VectorsHaveTheDeclaredDimensionAndUnitLength()
    {
        var model = await CreateModelAsync();
        var vectors = await model.EmbedAsync(["alpha", "beta"], CancellationToken.None);
        Assert.Equal(2, vectors.Count);
        foreach (var v in vectors)
        {
            Assert.Equal(model.Dimension, v.Length);
            var norm = MathF.Sqrt(v.Sum(x => x * x));
            Assert.InRange(norm, 0.99f, 1.01f);
        }
    }

    [Fact]
    public async Task SameTextSameVectorAndOrderPreserved()
    {
        var model = await CreateModelAsync();
        var once = await model.EmbedAsync(["one", "two", "three"], CancellationToken.None);
        var again = await model.EmbedAsync(["three", "one"], CancellationToken.None);
        Assert.Equal(once[2], again[0]);
        Assert.Equal(once[0], again[1]);
    }

    [Fact]
    public async Task EmptyBatchIsEmpty()
    {
        var model = await CreateModelAsync();
        Assert.Empty(await model.EmbedAsync([], CancellationToken.None));
    }

    [Fact]
    public async Task ModelIdIsSet()
    {
        var model = await CreateModelAsync();
        Assert.False(string.IsNullOrWhiteSpace(model.ModelId));
        var health = await model.CheckAsync(CancellationToken.None);
        Assert.True(health.Ok, health.Detail);
    }
}