using System.Reflection;
using System.Security.Cryptography;
using System.Text.Json.Serialization;

namespace DigitalData.Core.Security.Config
{
    public class RSAFactoryParams
    {
        public int KeySizeInBits { get; init; } = Default.KeySizeInBits;

        public string PbePassword { internal get; init; } = Default.PbePassword;

        public PbeEncryptionAlgorithm PbeEncryptionAlgorithm { get; init; } = Default.PbeEncryptionAlgorithm;

        public HashAlgorithmName PbeHashAlgorithm { get; init; } = Default.PbeHashAlgorithm;

        // TODO: add as json converter to IConfigurIConfiguration.Config
        public string PbeHashAlgorithmName
        {
            get => PbeHashAlgorithm.ToString();
            init => PbeHashAlgorithm = (typeof(HashAlgorithmName).GetProperty(value, BindingFlags.Public | BindingFlags.Static)?.GetValue(null) is HashAlgorithmName hashAlgorithmName)
                ? hashAlgorithmName
                : new(value);            
        }

        public int PbeIterationCount { get; init; } = Default.PbeIterationCount;

        public string EncryptedPrivateKeyPemLabel { get; init; } = Default.EncryptedPrivateKeyPemLabel;

        private readonly Lazy<PbeParameters> _lazyPbeParameters;

        [JsonIgnore]
        public PbeParameters PbeParameters => _lazyPbeParameters.Value;

        public RSAFactoryParams()
        {
            _lazyPbeParameters = new(() => new PbeParameters(PbeEncryptionAlgorithm, PbeHashAlgorithm, PbeIterationCount));
        }

        public static class Default
        {
            public static readonly int KeySizeInBits = 2048;

            public static readonly string PbePassword = Secrets.PBE_PASSWORD;

            public static readonly PbeEncryptionAlgorithm PbeEncryptionAlgorithm = PbeEncryptionAlgorithm.Aes256Cbc;

            public static readonly HashAlgorithmName PbeHashAlgorithm = HashAlgorithmName.SHA256;

            public static readonly int PbeIterationCount = 100_000;

            public static readonly string EncryptedPrivateKeyPemLabel = "ENCRYPTED PRIVATE KEY";

            public static readonly PbeParameters PbeParameters = new(PbeEncryptionAlgorithm, PbeHashAlgorithm, PbeIterationCount);
        }
    }
}