namespace Api.Data.Repositories;

public static class VectorSerializer
{
    public static byte[] ToBytes(float[] vector)
    {
        var bytes = new byte[vector.Length * sizeof(float)];
        Buffer.BlockCopy(vector, 0, bytes, 0, bytes.Length);
        return bytes;
    }

    public static float[] FromBytes(byte[] bytes)
    {
        var vector = new float[bytes.Length / sizeof(float)];
        Buffer.BlockCopy(bytes, 0, vector, 0, bytes.Length);
        return vector;
    }

    public static double CosineSimilarity(float[] a, float[] b)
    {
        if (a.Length == 0 || a.Length != b.Length) return 0;
        double dot = 0, magA = 0, magB = 0;
        for (var i = 0; i < a.Length; i++)
        {
            dot += a[i] * b[i];
            magA += a[i] * a[i];
            magB += b[i] * b[i];
        }
        return magA == 0 || magB == 0 ? 0 : dot / (Math.Sqrt(magA) * Math.Sqrt(magB));
    }
}