using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Threading.Tasks;
using System.Xml;

namespace NcGamesWebView.Extensions
{
    public static class Encryption
    {
        public static void FromXmlFile(this RSA rsa, string xmlFilePath)
        {
            RSAParameters parameters = new RSAParameters();

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(File.ReadAllText(xmlFilePath));

            if (xmlDoc.DocumentElement.Name.Equals("RSAKeyValue"))
            {
                foreach (XmlNode node in xmlDoc.DocumentElement.ChildNodes)
                {
                    switch (node.Name)
                    {
                        case "Modulus": parameters.Modulus = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "Exponent": parameters.Exponent = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "P": parameters.P = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "Q": parameters.Q = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "DP": parameters.DP = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "DQ": parameters.DQ = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "InverseQ": parameters.InverseQ = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                        case "D": parameters.D = (string.IsNullOrEmpty(node.InnerText) ? null : Convert.FromBase64String(node.InnerText)); break;
                    }
                }
            }
            else
            {
                throw new Exception("Invalid XML RSA key.");
            }

            rsa.ImportParameters(parameters);
        }

        public static void ToXmlFile(this RSA rsa, bool includePrivateParameters, string xmlFilePath)
        {
            RSAParameters parameters = rsa.ExportParameters(includePrivateParameters);

            File.WriteAllText(xmlFilePath,
                string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent><P>{2}</P><Q>{3}</Q><DP>{4}</DP><DQ>{5}</DQ><InverseQ>{6}</InverseQ><D>{7}</D></RSAKeyValue>",
                  parameters.Modulus != null ? Convert.ToBase64String(parameters.Modulus) : null,
                  parameters.Exponent != null ? Convert.ToBase64String(parameters.Exponent) : null,
                  parameters.P != null ? Convert.ToBase64String(parameters.P) : null,
                  parameters.Q != null ? Convert.ToBase64String(parameters.Q) : null,
                  parameters.DP != null ? Convert.ToBase64String(parameters.DP) : null,
                  parameters.DQ != null ? Convert.ToBase64String(parameters.DQ) : null,
                  parameters.InverseQ != null ? Convert.ToBase64String(parameters.InverseQ) : null,
                  parameters.D != null ? Convert.ToBase64String(parameters.D) : null)
                  );
        }
    }
}