using System.Net;
using System.Net.Sockets;

namespace PrivaPub.Infrastructure.Http
{
	public static class IpRangeGuard
	{
		static readonly IPNetwork[] BlockedV4 =
		{
			IPNetwork.Parse("0.0.0.0/8"),
			IPNetwork.Parse("10.0.0.0/8"),
			IPNetwork.Parse("100.64.0.0/10"),
			IPNetwork.Parse("127.0.0.0/8"),
			IPNetwork.Parse("169.254.0.0/16"),
			IPNetwork.Parse("172.16.0.0/12"),
			IPNetwork.Parse("192.0.0.0/24"),
			IPNetwork.Parse("192.0.2.0/24"),
			IPNetwork.Parse("192.88.99.0/24"),
			IPNetwork.Parse("192.168.0.0/16"),
			IPNetwork.Parse("198.18.0.0/15"),
			IPNetwork.Parse("198.51.100.0/24"),
			IPNetwork.Parse("203.0.113.0/24"),
			IPNetwork.Parse("224.0.0.0/4"),
			IPNetwork.Parse("240.0.0.0/4")
		};

		static readonly IPNetwork GlobalUnicastV6 = IPNetwork.Parse("2000::/3");

		static readonly IPNetwork[] BlockedV6 =
		{
			IPNetwork.Parse("2001::/32"),//Teredo
			IPNetwork.Parse("2001:2::/48"),
			IPNetwork.Parse("2001:10::/28"),
			IPNetwork.Parse("2001:20::/28"),
			IPNetwork.Parse("2001:db8::/32"),
			IPNetwork.Parse("2002::/16"),//6to4
			IPNetwork.Parse("3fff::/20")
		};

		public static bool IsPublic(IPAddress address)
		{
			if (address == default)
				return false;
			if (address.IsIPv4MappedToIPv6)
				address = address.MapToIPv4();

			return address.AddressFamily switch
			{
				AddressFamily.InterNetwork => !BlockedV4.Any(range => range.Contains(address)),
				AddressFamily.InterNetworkV6 => GlobalUnicastV6.Contains(address) && !BlockedV6.Any(range => range.Contains(address)),
				_ => false
			};
		}
	}
}