///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2016 - License: GNU GPLv3      //
//  Please see: http://www.gnu.org/licenses/gpl.html for legal details,  //
//  rights of fair usage, the disclaimer and warranty conditions.        //
///////////////////////////////////////////////////////////////////////////

using System;
using System.Net;

namespace wasSharpNET.Network
{
    /// <summary>
    ///     IPAddress extensions.
    /// </summary>
    /// <remarks>https://blogs.msdn.microsoft.com/knom/2008/12/31/ip-address-calculations-with-c-subnetmasks-networks/</remarks>
    public static class IPAddressExtensions
    {
        public static IPAddress GetBroadcastAddress(this IPAddress address, IPAddress subnetMask)
        {
            var ipAdressBytes = address.GetAddressBytes();
            var subnetMaskBytes = subnetMask.GetAddressBytes();

            if (ipAdressBytes.Length != subnetMaskBytes.Length)
                throw new ArgumentException("Lengths of IP address and subnet mask do not match.");

            var broadcastAddress = new byte[ipAdressBytes.Length];
            for (var i = 0; i < broadcastAddress.Length; i++)
                broadcastAddress[i] = (byte) (ipAdressBytes[i] | (subnetMaskBytes[i] ^ 255));
            return new IPAddress(broadcastAddress);
        }

        public static IPAddress GetNetworkAddress(this IPAddress address, IPAddress subnetMask)
        {
            var ipAdressBytes = address.GetAddressBytes();
            var subnetMaskBytes = subnetMask.GetAddressBytes();

            if (ipAdressBytes.Length != subnetMaskBytes.Length)
                throw new ArgumentException("Lengths of IP address and subnet mask do not match.");

            var broadcastAddress = new byte[ipAdressBytes.Length];
            for (var i = 0; i < broadcastAddress.Length; i++)
                broadcastAddress[i] = (byte) (ipAdressBytes[i] & subnetMaskBytes[i]);
            return new IPAddress(broadcastAddress);
        }

        public static bool IsInSameSubnet(this IPAddress address2, IPAddress address, IPAddress subnetMask)
        {
            var network1 = address.GetNetworkAddress(subnetMask);
            var network2 = address2.GetNetworkAddress(subnetMask);

            return network1.Equals(network2);
        }
    }
}