using System;
using System.Globalization;

namespace Org.BouncyCastle.Utilities.Net;

public class IPAddress
{
	public static bool IsValid(string address)
	{
		if (!IsValidIPv4(address))
		{
			return IsValidIPv6(address);
		}
		return true;
	}

	public static bool IsValidWithNetMask(string address)
	{
		if (!IsValidIPv4WithNetmask(address))
		{
			return IsValidIPv6WithNetmask(address);
		}
		return true;
	}

	public static bool IsValidIPv4(string address)
	{
		try
		{
			return unsafeIsValidIPv4(address);
		}
		catch (FormatException)
		{
		}
		catch (OverflowException)
		{
		}
		return false;
	}

	private static bool unsafeIsValidIPv4(string address)
	{
		if (address.Length == 0)
		{
			return false;
		}
		int num = 0;
		string text = address + ".";
		int num2 = 0;
		int num3;
		while (num2 < text.Length && (num3 = text.IndexOf('.', num2)) > num2)
		{
			if (num == 4)
			{
				return false;
			}
			string s = text.Substring(num2, num3 - num2);
			int num4 = int.Parse(s);
			if (num4 < 0 || num4 > 255)
			{
				return false;
			}
			num2 = num3 + 1;
			num++;
		}
		return num == 4;
	}

	public static bool IsValidIPv4WithNetmask(string address)
	{
		int num = address.IndexOf('/');
		string text = address.Substring(num + 1);
		if (num > 0 && IsValidIPv4(address.Substring(0, num)))
		{
			if (!IsValidIPv4(text))
			{
				return IsMaskValue(text, 32);
			}
			return true;
		}
		return false;
	}

	public static bool IsValidIPv6WithNetmask(string address)
	{
		int num = address.IndexOf('/');
		string text = address.Substring(num + 1);
		if (num > 0)
		{
			if (IsValidIPv6(address.Substring(0, num)))
			{
				if (!IsValidIPv6(text))
				{
					return IsMaskValue(text, 128);
				}
				return true;
			}
			return false;
		}
		return false;
	}

	private static bool IsMaskValue(string component, int size)
	{
		int num = int.Parse(component);
		try
		{
			return num >= 0 && num <= size;
		}
		catch (FormatException)
		{
		}
		catch (OverflowException)
		{
		}
		return false;
	}

	public static bool IsValidIPv6(string address)
	{
		try
		{
			return unsafeIsValidIPv6(address);
		}
		catch (FormatException)
		{
		}
		catch (OverflowException)
		{
		}
		return false;
	}

	private static bool unsafeIsValidIPv6(string address)
	{
		if (address.Length == 0)
		{
			return false;
		}
		int num = 0;
		string text = address + ":";
		bool flag = false;
		int num2 = 0;
		int num3;
		while (num2 < text.Length && (num3 = text.IndexOf(':', num2)) >= num2)
		{
			if (num == 8)
			{
				return false;
			}
			if (num2 != num3)
			{
				string text2 = text.Substring(num2, num3 - num2);
				if (num3 == text.Length - 1 && text2.IndexOf('.') > 0)
				{
					if (!IsValidIPv4(text2))
					{
						return false;
					}
					num++;
				}
				else
				{
					string s = text.Substring(num2, num3 - num2);
					int num4 = int.Parse(s, NumberStyles.AllowHexSpecifier);
					if (num4 < 0 || num4 > 65535)
					{
						return false;
					}
				}
			}
			else
			{
				if (num3 != 1 && num3 != text.Length - 1 && flag)
				{
					return false;
				}
				flag = true;
			}
			num2 = num3 + 1;
			num++;
		}
		if (num != 8)
		{
			return flag;
		}
		return true;
	}
}