using System;
using System.IO;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Xml;
using System.Xml.Serialization;
using Kreta.EESZTInterface.STS.Saml20;
using Kreta.Resources;

namespace Kreta.EESZTInterface.STS
{
    public class SamlRequest
    {
        private readonly X509Certificate2 sslCert;

        private bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        {
            return true;
        }

        public SamlRequest(X509Certificate2 sslCerrtificate)
        {
            sslCert = sslCerrtificate;
        }

        public string GetX509Saml(string interfaceUrl, X509Certificate2 stsCert, X509Certificate2 userCert)
        {
            var rst = CreateSoap.CreateX509Soap(stsCert, userCert);
            rst = DoRequest.GetSoapSamlResponse($"{interfaceUrl}/STS_x509", sslCert, rst);
            rst = DecryptFromRSTResponse(rst, stsCert, userCert);

            return XmlToString(GetSamlFromRSTR(rst));
        }

        private string XmlToString(XmlDocument xmlDoc)
        {
            if (xmlDoc.FirstChild is XmlDeclaration)
            {
                xmlDoc.RemoveChild(xmlDoc.FirstChild);
            }

            return xmlDoc.OuterXml;
        }

        private XmlDocument GetSamlFromRSTR(XmlDocument rstResponse)
        {
            var actionElement = XmlHelper.GetElement("Action", Namespaces.addressingNs, rstResponse.DocumentElement);
            if (!actionElement.InnerText.ToLower().Equals(STSValues.finalActionValue.ToLower()))
                throw new Exception(EESZTInterfaceResource.NemMegfeleloActionErtek);

            var deserializer = new XmlSerializer(typeof(AssertionType));
            AssertionType assetion;
            var body = XmlHelper.GetElement("Body", Namespaces.soap12Ns, rstResponse.DocumentElement);
            var assertionElement = XmlHelper.GetElement("Assertion", Namespaces.samlNs, body);
            if (assertionElement == null)
                throw new Exception(EESZTInterfaceResource.AssertionElementNemTalalhato);
            var saml = new XmlDocument
            {
                PreserveWhitespace = true
            };
            saml.LoadXml(assertionElement.OuterXml);

            using (TextReader xmlreader = new StringReader(assertionElement.OuterXml))
            {
                try
                {
                    assetion = (AssertionType)deserializer.Deserialize(xmlreader);
                }
                catch (Exception ex)
                {
                    throw new Exception(EESZTInterfaceResource.AssertionElementNemMegfelelo, ex);
                }
            }

            X509DataType x509dt;
            X509Certificate2 samlCert = null;

            foreach (var item in assetion.Signature.KeyInfo.Items)
            {
                if (item.GetType().Equals(typeof(X509DataType)))
                {
                    x509dt = (X509DataType)item;
                    for (int i1 = 0; i1 < x509dt.ItemsElementName.Length; i1++)
                    {
                        if (x509dt.ItemsElementName[i1].Equals(ItemsChoiceType.X509Certificate))
                        {
                            samlCert = new X509Certificate2((byte[])x509dt.Items[i1]);
                            break;
                        }
                    }
                }

                if (samlCert != null)
                {
                    break;
                }
            }

            if (samlCert == null)
                throw new Exception(EESZTInterfaceResource.SamlTanusitvanyNemTalalhato);
            var samlXml = new XmlDocument
            {
                PreserveWhitespace = true
            };
            samlXml.LoadXml(assertionElement.OuterXml);
            var valid = SignHelper.CheckSignature(samlXml, samlCert);

            if (valid)
            {
                return saml;
            }

            throw new Exception(EESZTInterfaceResource.SamlAlairasaErvenytelen);

        }
        private XmlDocument DecryptFromRSTResponse(XmlDocument rstResponse, X509Certificate2 stsCert, X509Certificate2 userCert)
        {
            rstResponse = EncryptHelper.DecryptMessageAll(rstResponse, userCert);

            if (SignHelper.CheckSignature(rstResponse, stsCert))
            {
                return rstResponse;
            }

            throw new Exception(EESZTInterfaceResource.RSTRalairasaErvenytelen);
        }

    }
}