OpenQuery/Services/EmbeddingService.cs

using System.Numerics.Tensors;

namespace OpenQuery.Services;

public class EmbeddingService
{
    private readonly OpenRouterClient _client;
    private readonly string _embeddingModel;

    public EmbeddingService(OpenRouterClient client, string embeddingModel = "openai/text-embedding-3-small")
    {
        _client = client;
        _embeddingModel = embeddingModel;
    }

    public async Task<float[][]> GetEmbeddingsAsync(List<string> texts)
    {
        var results = new List<float[]>();
        const int batchSize = 300;
        
        for (var i = 0; i < texts.Count; i += batchSize)
        {
            if (texts.Count > batchSize)
                Console.WriteLine(
                    $"[Generating {Math.Ceiling(i / (double)batchSize)}/{Math.Ceiling(texts.Count / (double)batchSize)} batch of embeddings]");
            var batch = texts.Skip(i).Take(batchSize).ToList();
            var batchResults = await _client.EmbedAsync(_embeddingModel, batch);
            results.AddRange(batchResults);
        }
        
        return results.ToArray();
    }

    public static float CosineSimilarity(float[] vector1, float[] vector2)
    {
        return TensorPrimitives.CosineSimilarity(vector1, vector2);
    }
}