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

namespace DigitalData.Core.Security.Config
{
    public class RSAFactoryParams : IJsonOnDeserialized
    {
        public int KeySizeInBits { get; init; } = 2048;

        public string PbePassword { internal get; init; } = Secrets.PBE_PASSWORD;

        public PbeEncryptionAlgorithm PbeEncryptionAlgorithm { get; init; } = PbeEncryptionAlgorithm.Aes256Cbc;

        public HashAlgorithmName PbeHashAlgorithm { get; init; } = HashAlgorithmName.SHA256;

        // 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; } = 100_000;

        public string EncryptedPrivateKeyPemLabel { get; init; } = "ENCRYPTED PRIVATE KEY";

        private PbeParameters? _pbeParameters;

        [JsonIgnore]
        public PbeParameters PbeParameters => _pbeParameters!;

        /// <summary>
        /// Provides a thread-safe initialization mechanism using Lazy initialization.
        /// </summary>
        private readonly Lazy<bool> _lazyInitializer;

        public bool IsInitialized => _lazyInitializer.IsValueCreated;

        public RSAFactoryParams()
        {
            _lazyInitializer = new(() =>
            {
                AfterCreate?.Invoke();
                return true;
            });

            AfterCreate += () => _pbeParameters = new PbeParameters(PbeEncryptionAlgorithm, PbeHashAlgorithm, PbeIterationCount);
        }

        protected event Action AfterCreate;

        public void Init() => _ = _lazyInitializer.Value;
        
        public void OnDeserialized() => Init();
    }
}