DigitalData.Core/DigitalData.Core.Security/Cryptographer/RSACryptographer.cs

using DigitalData.Core.Abstractions.Security;
using System.Security.Cryptography;
using System.Text.Json.Serialization;

namespace DigitalData.Core.Security.Cryptographer
{
    public class RSACryptographer : IRSACryptographer, IJsonOnDeserialized
    {
        private string? _pem;

        private string? _pemPath;

        public virtual string Pem
        {
            get => _pem!;
            init
            {
                ValidatePemInit();
                _pem = value;
            }
        }

        public string? PemPath
        {
            get => _pemPath;
            init
            {
                _pemPath = value;
                if (value is null)
                    return;
                ValidatePemInit();
                _pem = File.ReadAllText(value);
            }
        }

        public RSAEncryptionPadding Padding { get; init; } = RSAEncryptionPadding.OaepSHA256;

        protected virtual RSA RSA { get; } = RSA.Create();

        public string Issuer { get; init; } = string.Empty;

        public string Audience { get; init; } = string.Empty;

        internal RSACryptographer() { }

        public void OnDeserialized()
        {
            if (Pem is null)
                throw new InvalidOperationException($"Pem must be initialized. Issuer: {Issuer} and Audience: {Audience}");
        }

        private void ValidatePemInit()
        {
            if (_pem is not null)
                throw new InvalidOperationException($"Pem can only be initilized once. Remove one of the Pem or Pem file initilizations. Issuer: {Issuer} and Audience: {Audience}");
        }
    }
}