using System;

using System.Net;

using System.Net.Sockets;

using System.Text.RegularExpressions;

namespace PoshLTM

{

    public struct F5Address

    {

        public static F5Address Any = IPAddress.Any;

        public IPAddress IPAddress;

        public int? RouteDomain;



        public F5Address(string address)

        {

            RouteDomain = null;

            IPAddress = null;

            string hostname = address;

            // Extract a RouteDomain, if applicable

            if (Regex.IsMatch(address,"%[0-9]+$"))

            {

                hostname = address.Split('%')[0];

                RouteDomain = int.Parse(address.Split('%')[1]);

            }

            // IPv4 Addresses always start with a number, server names can not

            if (Regex.IsMatch(hostname,"^[0-9]"))

            {

                IPAddress = IPAddress.Parse(hostname);

            }

            else if (address == "any6")

            {

                IPAddress = IPAddress.Any;

            }

            else

            {

                // Resolve hostname

                // IPv6 Addresses do not always start with a number, but resolve nicely

                foreach (IPAddress IPA in Dns.GetHostAddresses(hostname))

                {

                    // This avoids (but does not prevent) getting no address at all

                    IPAddress = IPA;

                    // This applies a bias in favor of IPv4 or IPv6 addresses that are NOT LinkLocal which often have a physical NIC ScopeId, not to be confused with a RouteDomain

                    if (IPA.AddressFamily == AddressFamily.InterNetwork || (IPA.AddressFamily == AddressFamily.InterNetworkV6 && !IPA.IsIPv6LinkLocal))

                    {

                        break;

                    }

                }

            }

        }



        #region Override Equals



        // https://msdn.microsoft.com/ru-ru/library/ms173147(v=vs.80).aspx

        public override bool Equals(Object obj)

        {

            // If parameter is null return false.

            if (obj == null)

            {

                return false;

            }

            if (obj is F5Address)

            {

                return this.Equals((F5Address)obj);

            }

            if (obj is IPAddress)

            {

                var f5address = new F5Address(((IPAddress)obj).ToString());

                return this.Equals(f5address);

            }

            if (obj is string)

            {

                var f5address = new F5Address((string)obj);

                return this.Equals(f5address);

            }

            return false;

        }



        public bool Equals(F5Address other)

        {

            return IPAddress.Equals(other.IPAddress) && RouteDomain.Equals(other.RouteDomain);

        }



        // Required to override Equals

        public override int GetHashCode()

        {

            return this.ToString().GetHashCode();

        }



        #endregion



        // This differs from Equals: it will match on IP alone if no RouteDomain criteria is specified.

        public bool IsMatch(string address)

        {

            // Built-in matching for the default (Any) filter

            if (this.Equals(Any)) {

                return true;

            }

            if (RouteDomain.HasValue)

            {

                return this.ToString() == address;

            }

            else

            {

                F5Address f5address = new F5Address(address);

                return IPAddress.ToString() == f5address.IPAddress.ToString();

            }

        }



        public override string ToString()

        {

            return String.Format("{0}{1:\\%0}", IPAddress, RouteDomain);

        }



        public static implicit operator F5Address(IPAddress value)

        {

            return new F5Address(value.ToString());

        }

        public static implicit operator F5Address(string value)

        {

            return new F5Address(value);

        }

        public static implicit operator IPAddress(F5Address value)

        {

            return value.IPAddress;

        }

        public static implicit operator string(F5Address value)

        {

            return String.Format("{0}{1:\\%0}", value.IPAddress, value.RouteDomain);

        }

        public static bool IsMatch(F5Address filter, string address)

        {

            return filter.IsMatch(address);

        }

        public static bool IsMatch(F5Address[] filter, string address)

        {

            foreach(F5Address f in filter)

            {

                if (f.IsMatch(address))

                {

                    return true;

                }

            }

            return false;

        }

    }

}