using System;
using System.Collections.Generic;
using System.Net;
using System.Text;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography;
using System.Net.Security;
using System.Security;

namespace Intel.Management.Wsman
{
    class WsmanConnectionOptions : IWsmanConnectionOptions
    {
        private const string OID_LOCAL = "2.16.840.1.113741.1.2.2";
        private const string OID_REMOTE = "2.16.840.1.113741.1.2.1";

        public const int MAX_PWD_LENGTH = 32;
        public const int MIN_PWD_LENGTH = 8;
        public const int MAX_USERNAME_LENGTH = 32;
        private const int DEFAULT_TIME_OUT = 30000;

        private int _maxElements;
        private int _timeout;
        private int _maxConnections;
        private X509Certificate _clientCert;
        private InternetProtocolType _protocolType;
        private bool _useDmp;
        private bool _hidePassword;

        private bool _bVerifyCerts;
        private bool _acceptSelfSignedCertificate; 
        private string _proxyUser;
        private string _proxyAddress;
        private SecureString _proxyPassword;
        private string _serviceName;

        private ServerCertificateValidationCallback _serverCertificateValidationCallback;

        public WsmanConnectionOptions()
        {
            _timeout = DEFAULT_TIME_OUT; //default 30 second time for sleeping ME
            _maxElements=20;
            _clientCert = null;
            _proxyAddress = null;
            _proxyUser = null;
            _proxyPassword = null;
            _serviceName = null;
            _bVerifyCerts = true;
            _protocolType = InternetProtocolType.IPv4;
            _maxConnections = 20;
            _acceptSelfSignedCertificate = false;
        }

        public int MaxElements
        {
            get
            {
                return _maxElements;
            }
            set
            {
                _maxElements = value;
            }
        }

        public int Timeout
        {
            get
            {
                return _timeout;
            }
            set
            {
                _timeout = value;
            }
        }

        /// <summary>
        /// The certificate to use for establishing the connection.
        /// To set this property by providing a certificate name string only, use the SetClientCertificateByCertificateName function.
        /// </summary>
        public X509Certificate ClientCertificate
        {
            get
            {
                return _clientCert;
            }
            set
            {
                _clientCert = value;
            }
        }

        public string ProxyUser
        {
          
            get
            {
                return _proxyUser;
            }
            set
            {
                if (string.IsNullOrEmpty(value))
                    _proxyUser = "";
                else
                {
                    _proxyUser = value;
                    if (_proxyUser.Length > MAX_USERNAME_LENGTH)
                        throw new WsmanConnectionException("Username can contain up to 32 characters.");
                }
            }
        }

        public SecureString ProxyPassword
        {
            get
            {
                return _proxyPassword;
            }
            set
            {
                if (value == null || value.Length == 0)
                {
                    _proxyPassword?.Dispose();
                    _proxyPassword = value ?? new SecureString();
                    return;
                }
                if (value.Length < MIN_PWD_LENGTH || value.Length > MAX_PWD_LENGTH)
                    throw new WsmanConnectionException("Password can contain between 8 to 32 characters.");
                _proxyPassword?.Dispose();
                _proxyPassword = value;
            }
        }

        public string ProxyAddress
        {
            get
            {
                return _proxyAddress;
            }
            set
            {
                if (!Uri.IsWellFormedUriString(value, 0))
                    throw new WsmanConnectionException("Invalid argument - Address is not a valid uri");
                _proxyAddress = value;
            }
        }

        public string ServiceName
        {
            get
            {
                return _serviceName;
            }
            set
            {
                _serviceName = value;
            }
        }

        public bool VerifyCertificates
        {
            get
            {
                return _bVerifyCerts;;
            }
            set
            {
                _bVerifyCerts = value;
            }
        }

        public bool AcceptSelfSignedCertificate
        {
            get
            {
                return _acceptSelfSignedCertificate; ;
            }
            set
            {
                _acceptSelfSignedCertificate = value;
            }
        }

        public bool UseDigestMasterPassword
        {
            get
            {
                return _useDmp;
            }
            set
            {
                _useDmp = value;
            }
        }

        public IWebProxy Proxy
        {
            get
            {
                WebProxy result = null;
                if (_proxyAddress != null)
                {
                    result = new WebProxy(_proxyAddress, false);
                }
                if (result != null && _proxyUser != null && ProxyPassword != null)
                {
                    result.Credentials = new NetworkCredential(_proxyUser, ProxyPassword);
                }

                return result;
            }
        }

        public bool IsSetupCertificate(X509Certificate2 cert)
        {
            bool isSetupCert = false;
            // check the EnhacedKeyUsageExtention to see if its a AMTRemoteConfig Certificate
            foreach (X509Extension extention in cert.Extensions)
            {
                if (extention is X509EnhancedKeyUsageExtension)
                {
                    X509EnhancedKeyUsageExtension enhanced = (X509EnhancedKeyUsageExtension)extention;
                    foreach (Oid oid in enhanced.EnhancedKeyUsages)
                    {
                        if (oid.Value.Equals("2.16.840.1.113741.1.2.3"))
                        {
                            isSetupCert = true;
                        }
                    }

                }
            }
            // check to see of the subject says its an Setup Certificate
            if (!isSetupCert && cert.Subject.IndexOf("Intel(R) Client Setup Certificate") > 0)
            {
                isSetupCert = true;
            }

            return isSetupCert;
        }

        public bool HidePassword 
        {
            get { return _hidePassword; }
            set { _hidePassword = value; }
        }

        public InternetProtocolType InternetProtocol
        {
            get { return _protocolType; }
            set { _protocolType = value; }
        }

        public int MaxConnections
        {
            get { return _maxConnections; }
            set { _maxConnections = value; }
        }

        public ServerCertificateValidationCallback ServerCertificateValidationCallback
        {
            get
            {
                return _serverCertificateValidationCallback;
            }
            set
            {
                _serverCertificateValidationCallback = value;
            }
        }

        ///<summary>
        /// Sets the client certificate to be used in the connection by giving the certificate name.
        ///</summary>
        ///<param name="clientCert">The certificate name.</param>
        public void SetClientCertificateByCertificateName(string clientCert)
        {
            if (!string.IsNullOrEmpty(clientCert))
            {
                X509CertificateCollection collection = GetCertFromStore(clientCert);
                ClientCertificate = collection.Count > 0 ? collection[0] : null;
            }
        }

        //return a specific certificate from the cert store.
        private static X509CertificateCollection GetCertFromStore(string clientCert)
        {
            X509CertificateCollection certificatesCollection = new X509CertificateCollection();

            // Open CurrentUser cert store
            X509EnhancedKeyUsageExtension ex;
            using (X509Store currentUserStore = new X509Store(StoreName.My, StoreLocation.CurrentUser))
            {
                currentUserStore.Open(OpenFlags.ReadOnly);

                foreach (X509Certificate2 certificate in currentUserStore.Certificates)
                {
                    if (certificate.Subject.Contains(clientCert))
                    {
                        // Checking that the Enhanced Key Usage in the certificate is the one for AMT
                        foreach (X509Extension extension in certificate.Extensions)
                        {
                            ex = extension as X509EnhancedKeyUsageExtension;
                            if (ex != null)
                            {
                                foreach (Oid OID in ex.EnhancedKeyUsages)
                                {
                                    if (OID.Value == OID_REMOTE || OID.Value == OID_LOCAL)
                                        certificatesCollection.Add(certificate);
                                }
                            }
                        }
                    }
                }
            }

            // Open LocalMachine cert store
            using (X509Store localMachineStore = new X509Store(StoreName.My, StoreLocation.LocalMachine))
            {
                localMachineStore.Open(OpenFlags.ReadOnly);

                foreach (X509Certificate2 certificate in localMachineStore.Certificates)
                {
                    if (certificate.Subject.Contains(clientCert))
                    {
                        // Checking that the Enhanced Key Usage in the certificate is the one for AMT
                        foreach (X509Extension extension in certificate.Extensions)
                        {
                            ex = extension as X509EnhancedKeyUsageExtension;
                            if (ex != null)
                            {
                                foreach (Oid OID in ex.EnhancedKeyUsages)
                                {
                                    if (OID.Value == OID_REMOTE || OID.Value == OID_LOCAL)
                                        certificatesCollection.Add(certificate);
                                }
                            }
                        }
                    }
                }
            }
            return certificatesCollection;
        }

        #region IDisposable Implementation

        private bool _disposed = false;

        /// <summary>
        /// Implement IDisposable method 
        /// </summary>
        /// <param name="disposing"></param>
        protected virtual void Dispose(bool disposing)
        {
            if (_disposed)
                return;
            if (disposing)
            {
                ProxyPassword?.Dispose();
            }

            _disposed = true;
        }
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
        ~WsmanConnectionOptions()
        {
            Dispose(false);
        }

        #endregion

    } //end WsmanConnectionOptions





}//end namspace