using System.Security.Cryptography;
using IdentityShroud.Core.Contracts;
using IdentityShroud.Core.Messages;
using IdentityShroud.Core.Model;
using IdentityShroud.Core.Security;
using Microsoft.AspNetCore.WebUtilities;

namespace IdentityShroud.Api.Mappers;

public class KeyMapper(IEncryptionService encryptionService)
{
    public JsonWebKey KeyToJsonWebKey(Key key)
    {
        using var rsa = RsaHelper.LoadFromPkcs8(key.GetPrivateKey(encryptionService));
        RSAParameters parameters = rsa.ExportParameters(includePrivateParameters: false);
        
        return new JsonWebKey()
        {
            KeyType = rsa.SignatureAlgorithm,
            KeyId = key.Id.ToString(),
            Use = "sig",
            Exponent = WebEncoders.Base64UrlEncode(parameters.Exponent!),
            Modulus = WebEncoders.Base64UrlEncode(parameters.Modulus!),
        };
    }

    public JsonWebKeySet KeyListToJsonWebKeySet(IEnumerable<Key> keys)
    {
        return new JsonWebKeySet()
        {
            Keys = keys.Select(e => KeyToJsonWebKey(e)).ToList(),
        };
    }
}