from servicebase import ServiceBase
import socket


class ServiceDelegate(ServiceBase) :

	def get_arguments(cls) :
		"""Returns an array of information used to construct an argumentparser argument."""
		return [ '-vm', '--vm', 'store_true', "Return DNS resolution about the subject (dns)" ]

	def startup(self) :
		self.resolver = dns.resolver.Resolver()
		if 'resolver' in self._config :
			self.resolver.nameservers.append(self._config['resolver'])

	def lookup(self,subject) :

		# Note : hostname lookups always use system resolver.
		try :
			subjecttuple = socket.gethostbyname_ex(subject)
		# Can't make an IP of the subject
		except ValueError :
			try :
				# Lookup with system
				subjecttuple = socket.gethostbyname_ex(subject)
			except socket.gaierror :
				# Not a valid host or IP
				self._error.append("Unable to resolve " + subject)
				subjecttuple = [subject,[],['']]
		# Can't make IPv4 out of it
		except socket.gaierror :
			self._error.append("Unable to resolve " + subject)
			subjecttuple = [subject,[],['']]
		# Get additional records
		return_dict = {}
		mx = self.get_records(subjecttuple[0],'MX')
		ns = self.get_records(subjecttuple[0],'NS')
		txt = self.get_records(subjecttuple[0],'TXT')
		mx.sort()
		ns.sort()
		txt.sort()
		if mx and len(mx) > 0 :
			return_dict.update({'mx':mx})
		if ns and len(ns) > 0 :
			return_dict.update({'ns':ns})
		if txt and len(txt) > 0 :
			return_dict.update({'txt':txt})
		# Write final dictionary
		if len(subjecttuple[2]) > 0 and subjecttuple[2][0] != '':
			return_dict['addresses'] = list(subjecttuple[2])
		if subjecttuple[0] and subjecttuple[0] != '' :
			return_dict['name'] = subjecttuple[0]
		if len(subjecttuple[1]) > 0 :
			return_dict['aliases'] = list(subjecttuple[1])
		return return_dict


	def get_records(self,subject,recordtype) :
		recs = []
		try :
			results = self.resolver.query(subject,recordtype)
			for result in results :
				recs.append(result.to_text())
			return recs
		except Exception as exception :
			return  recs