import re


class IPAddress:
	"""
	A simple class encapsulating an ip-address. An IPAddress can be constructed by string, int and 4-element-list
	(e.g. [8, 8, 8, 8]). This is a leightweight class as it only contains string-to-ip-and-reverse-conversion
	and some convenience methods.
	"""
	
	# a number between 0 and 255, no leading zeros
	_IP_NUMBER_REGEXP = r"(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)"
	# 4 numbers between 0 and 255, joined together with dots
	IP_REGEXP = r"{0}\.{0}\.{0}\.{0}".format(_IP_NUMBER_REGEXP)
	
	def __init__(self, intlist):
		"""
		Construct an ipv4-address with a list of 4 integers, e.g. to construct the ip 10.0.0.0 pass [10, 0, 0, 0]
		"""
		if not isinstance(intlist, list) or not all(isinstance(n, int) for n in intlist):
			raise TypeError("The first constructor argument must be an list of ints")
		if not len(intlist) == 4 or not all(0 <= n <= 255 for n in intlist):
			raise ValueError("The integer list must contain 4 ints in range of 0 and 255, like an ip-address")
		
		# For easier calculations store the ip as integer, e.g. 10.0.0.0 is 0x0a000000
		self.ipnum = int.from_bytes(bytes(intlist), "big")
	
	@staticmethod
	def parse(ip: str):
		"""
		Parse an ip-address-string. If the string does not comply to the ipv4-format a ValueError is raised
		:param ip: A string-representation of an ip-address, e.g. "10.0.0.0"
		:return: IPAddress-object describing the ip-address
		"""
		match = re.match("^" + IPAddress.IP_REGEXP + "$", ip)
		if not match:
			raise ValueError("%s is no ipv4-address" % ip)
		
		# the matches we get are the numbers of the ip-address (match 0 is the whole ip-address)
		numbers = [int(match.group(i)) for i in range(1, 5)]
		return IPAddress(numbers)
	
	@staticmethod
	def from_int(numeric: int):
		if numeric not in range(1 << 32):
			raise ValueError("numeric value must be in uint-range")
		
		# to_bytes is the easiest way to split a 32-bit int into bytes
		return IPAddress(list(numeric.to_bytes(4, "big")))
	
	@staticmethod
	def is_ipv4(ip: str):
		"""
		Check if the supplied string is in ipv4-format
		"""
		
		match = re.match("^" + IPAddress.IP_REGEXP + "$", ip)
		return True if match else False

	def to_int(self):
		"""
		Convert the ip-address to a 32-bit uint, e.g. IPAddress.parse("10.0.0.255").to_int() returns 0x0a0000ff
		"""
		return self.ipnum
	
	def is_private(self):
		"""
		Returns a boolean indicating if the ip-address lies in the private ip-segments (see ReservedIPBlocks)
		"""
		return ReservedIPBlocks.is_private(self)
	
	def get_private_segment(self):
		"""
		Return the private ip-segment the ip-address belongs to (there are several)
		If this ip does not belong to a private ip-segment a ValueError is raised
		:return: IPAddressBlock
		"""
		return ReservedIPBlocks.get_private_segment(self)

	def is_localhost(self):
		"""
		Returns a boolean indicating if the ip-address lies in the localhost-segment
		"""
		return ReservedIPBlocks.is_localhost(self)
	
	def is_multicast(self):
		"""
		Returns a boolean indicating if the ip-address lies in the multicast-segment
		"""
		return ReservedIPBlocks.is_multicast(self)
	
	def is_reserved(self):
		"""
		Returns a boolean indicating if the ip-address lies in the reserved-segment
		"""
		return ReservedIPBlocks.is_reserved(self)
	
	def is_zero_conf(self):
		"""
		Returns a boolean indicating if the ip-address lies in the zeroconf-segment
		"""
		return ReservedIPBlocks.is_zero_conf(self)
	
	def _tuple(self):
		return tuple(self.ipnum.to_bytes(4, "big"))
	
	def __repr__(self):
		"""
		Following the python style guide, eval(repr(obj)) should equal obj
		"""
		return "IPAddress([%i, %i, %i, %i])" % self._tuple()
	
	def __str__(self):
		"""
		Return the ip-address described by this object in ipv4-format
		"""
		return "%i.%i.%i.%i" % self._tuple()
	
	def __hash__(self):
		return self.ipnum
	
	def __eq__(self, other):
		if other is None:
			return False
		
		return isinstance(other, IPAddress) and self.ipnum == other.ipnum
	
	def __lt__(self, other):
		if other is None:
			raise TypeError("Cannot compare to None")
		if not isinstance(other, IPAddress):
			raise NotImplemented # maybe other can compare to self
		
		return self.ipnum < other.ipnum
	
	def __int__(self):
		return self.ipnum

class IPAddressBlock:
	"""
	This class describes a block of IPv4-addresses, just as a string in CIDR-notation does.
	It can be seen as a range of ip-addresses. To check if a block contains a ip-address
	simply use "ip in ip_block"
	"""
	
	# this regex describes CIDR-notation (an ip-address plus "/XX", whereas XX is a number between 1 and 32)
	CIDR_REGEXP = IPAddress.IP_REGEXP + r"(\/(3[0-2]|[12]?\d)|)?"
	
	def __init__(self, ip, netmask = 32):
		"""
		Construct a ip-block given a ip-address and a netmask. Given an ip and a netmask,
		the constructed ip-block will describe the range ip/netmask (e.g. 127.0.0.1/8)
		:param ip: An ip-address, represented as IPAddress, string or 4-element-list
		"""
		if isinstance(ip, str):
			ip = IPAddress.parse(ip)
		elif isinstance(ip, list):
			ip = IPAddress(ip)
		
		if not 1 <= netmask <= 32:
			raise ValueError("netmask must lie between 1 and 32")
		
		# clear the unnecessary bits in the base-ip, e.g. this will convert 10.0.0.255/24 to 10.0.0.0/24 which are equivalent
		self.ipnum = ip.to_int() & self._bitmask(netmask)
		self.netmask = netmask

	@staticmethod
	def parse(cidr: str):
		"""
		Parse a string in cidr-notation and return a IPAddressBlock describing the ip-segment
		If the string is not in cidr-notation a ValueError is raised
		"""
		
		match = re.match("^" + IPAddressBlock.CIDR_REGEXP + "$", cidr)
		if not match:
			raise ValueError("%s is no valid cidr-notation" % cidr)
		
		ip = [int(match.group(i)) for i in range(1, 5)]
		suffix = 32 if not match.group(6) else int(match.group(6))
		
		return IPAddressBlock(ip, suffix)
	
	def block_size(self):
		"""
		Return the size of the ip-address-block. E.g. the size of someip/24 is 256
		"""
		return 2 ** (32 - self.netmask)
	
	def first_address(self):
		"""
		Return the first ip-address of the ip-block
		"""
		return IPAddress.from_int(self.ipnum)

	def last_address(self):
		"""
		Return the last ip-address of the ip-block
		"""
		return IPAddress.from_int(self.ipnum + self.block_size() - 1)

	def _bitmask(self, netmask):
		ones = lambda x: (1 << x) - 1
		
		return ones(32) ^ ones(32 - netmask)
	
	def __repr__(self):
		"""
		Conforming to python style-guide, eval(repr(obj)) equals obj
		"""
		return "IPAddressBlock(%s, %i)" % (repr(IPAddress.from_int(self.ipnum)), self.netmask)
	
	def __str__(self):
		"""
		Return a string in cidr-notation
		"""
		return str(IPAddress.from_int(self.ipnum)) + "/" + str(self.netmask)
	
	def __contains__(self, ip):
		return (ip.to_int() & self._bitmask(self.netmask)) == self.ipnum

class ReservedIPBlocks:
	"""
	To avoid magic values and save developers some research this class contains several constants
	describing special network-segments and some is_-methods to check if an ip is in the specified segment.
	"""
	
 	# a list of ip-addresses that can be used in private networks
	PRIVATE_IP_SEGMENTS = [
		IPAddressBlock.parse(block)
		for block in
		("10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16")
	]
	
	LOCALHOST_SEGMENT = IPAddressBlock.parse("127.0.0.0/8")
	
	MULTICAST_SEGMENT = IPAddressBlock.parse("224.0.0.0/4")
	RESERVED_SEGMENT = IPAddressBlock.parse("240.0.0.0/4")
	
	ZERO_CONF_SEGMENT = IPAddressBlock.parse("169.254.0.0/16")
	
	@staticmethod
	def is_private(ip):
		return any(ip in block for block in ReservedIPBlocks.PRIVATE_IP_SEGMENTS)
	
	@staticmethod
	def get_private_segment(ip):
		if not ReservedIPBlocks.is_private(ip):
			raise ValueError("%s is not part of a private IP segment" % ip)

		for block in ReservedIPBlocks.PRIVATE_IP_SEGMENTS:
			if ip in block:
				return block

	@staticmethod
	def is_localhost(ip):
		return ip in ReservedIPBlocks.LOCALHOST_SEGMENT
	
	@staticmethod
	def is_multicast(ip):
		return ip in ReservedIPBlocks.MULTICAST_SEGMENT
	
	@staticmethod
	def is_reserved(ip):
		return ip in ReservedIPBlocks.RESERVED_SEGMENT
	
	@staticmethod
	def is_zero_conf(ip):
		return ip in ReservedIPBlocks.ZERO_CONF_SEGMENT