#!/usr/bin/env python3
# -*- encoding: utf-8 -*-

#####################################################################
# (c) 2010-2011 by Sven Velt and team(ix) GmbH, Nuernberg, Germany  #
#                  sv@teamix.net                                    #
# (c) 2016- by Sven Velt, Germany                                   #
#              sven-mymonplugins@velt.biz                           #
#                                                                   #
# This file is part of "velt.biz - My Monitoring Plugins"           #
# a fork of "team(ix) Monitoring Plugins" in 2015                   #
# URL: https://gogs.velt.biz/velt.biz/MyMonPlugins/                 #
#                                                                   #
# This file is free software: you can redistribute it and/or modify #
# it under the terms of the GNU General Public License as published #
# by the Free Software Foundation, either version 2 of the License, #
# or (at your option) any later version.                            #
#                                                                   #
# This file is distributed in the hope that it will be useful, but  #
# WITHOUT ANY WARRANTY; without even the implied warranty of        #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the      #
# GNU General Public License for more details.                      #
#                                                                   #
# You should have received a copy of the GNU General Public License #
# along with this file. If not, see <http://www.gnu.org/licenses/>. #
#####################################################################

from .monitoringplugin import MonitoringPlugin

import os

class SNMPMonitoringPlugin(MonitoringPlugin):

	def __init__(self, *args, **kwargs):
		# Same as "MonitoringPlugin.__init__(*args, **kwargs)" but a little bit more flexible
		#super(MonitoringPlugin, self).__init__(*args, **kwargs)
		MonitoringPlugin.__init__(self, *args, **kwargs)

		self.add_cmdlineoption('-H', '', 'host', 'Host to check', default='127.0.0.1')
		self.add_cmdlineoption('-P', '', 'snmpversion', 'SNMP protocol version', metavar='1', default='1')
		self.add_cmdlineoption('-C', '', 'snmpauth', 'SNMP v1/v2c community OR SNMP v3 quadruple', metavar='public', default='public')
		self.add_cmdlineoption('', '--snmpcmdlinepath', 'snmpcmdlinepath', 'Path to "snmpget" and "snmpwalk"', metavar='/usr/bin/', default='/usr/bin')
		# FIXME
		self.add_cmdlineoption('', '--nonetsnmp', 'nonetsnmp', 'Do not use NET-SNMP python bindings', action='store_true')
		# self.__optparser.add_option('', '--nonetsnmp', dest='nonetsnmp',  help='Do not use NET-SNMP python bindings', action='store_true')

		self.__SNMP_Cache = {}

		self.__use_netsnmp = False
		self.__prepared_snmp = False


	def prepare_snmp(self):
		if not self._cmdlineoptions_parsed:
			self.parse_cmdlineoptions()

		if not self.options.nonetsnmp:
			try:
				import netsnmp
				self.__use_netsnmp = True
			except ImportError:
				pass

		if self.__use_netsnmp:
			self.verbose(1, 'Using NET-SNMP Python bindings')

			self.SNMPGET_wrapper = self.__SNMPGET_netsnmp
			self.SNMPWALK_wrapper = self.__SNMPWALK_netsnmp

			if self.options.snmpversion == '2c':
				self.options.snmpversion = '2'

		else:
			self.verbose(1, 'Using NET-SNMP command line tools')

			self.SNMPGET_wrapper = self.__SNMPGET_cmdline
			self.SNMPWALK_wrapper = self.__SNMPWALK_cmdline

			# Building command lines
			self.__CMDLINE_get = os.path.join(self.options.snmpcmdlinepath, 'snmpget') + ' -OqevtU '
			self.__CMDLINE_walk = os.path.join(self.options.snmpcmdlinepath, 'snmpwalk') + ' -OqevtU '

			if self.options.snmpversion in [1, 2, '1', '2', '2c']:
				if self.options.snmpversion in [2, '2']:
					self.options.snmpversion = '2c'
				self.__CMDLINE_get += ' -v' + str(self.options.snmpversion) + ' -c' + self.options.snmpauth + ' '
				self.__CMDLINE_walk += ' -v' + str(self.options.snmpversion) + ' -c' + self.options.snmpauth + ' '
			elif options.snmpversion == [3, '3']:
				# FIXME: Better error handling
				try:
					snmpauth = self.options.snmpauth.split(':')
					self.__CMDLINE_get += ' -v3 -l' + snmpauth[0] + ' -u' + snmpauth[1] + ' -a' + snmpauth[2] + ' -A' + snmpauth[3] + ' '
					self.__CMDLINE_walk += ' -v3 -l' + snmpauth[0] + ' -u' + snmpauth[1] + ' -a' + snmpauth[2] + ' -A' + snmpauth[3] + ' '
				except:
					self.back2nagios(3, 'Could not build SNMPv3 command line, need "SecLevel:SecName:AuthProtocol:AuthKey"')
			else:
				self.back2nagios(3, 'Unknown SNMP version "' + str(self.options.snmpversion) + '"')

			self.__CMDLINE_get += ' ' + self.options.host + ' %s 2>/dev/null'
			self.__CMDLINE_walk += ' ' + self.options.host + ' %s 2>/dev/null'

			self.verbose(3, 'Using commandline: ' + self.__CMDLINE_get)
			self.verbose(3, 'Using commandline: ' + self.__CMDLINE_walk)

			# Test if snmp(get|walk) are executable
			for fpath in [self.__CMDLINE_get, self.__CMDLINE_walk,]:
				fpath = fpath.split(' ',1)[0]
				if not( os.path.exists(fpath) and os.path.isfile(fpath) and os.access(fpath, os.X_OK) ):
					self.back2nagios(3, 'Could not execute "%s"' % fpath)

		self.__prepared_snmp = True


	def find_index_for_value(self, list_indexes, list_values, wanted):
		self.verbose(2, 'Look for "' + str(wanted) + '"')

		index = None

		if len(list_indexes) != len(list_values):
			self.verbose(1, 'Length of index and value lists do not match!')
			return None

		try:
			index = list_values.index(wanted)
			index = list_indexes[index]
		except ValueError:
			pass

		if index:
			self.verbose(2, 'Found "' + str(wanted) +'" with index "' + str(index) + '"')
		else:
			self.verbose(2, 'Nothing found!')

		return index


	def find_in_table(self, oid_index, oid_values, wanted):
		self.verbose(2, 'Look for "' + str(wanted) + '" in "' + str(oid_values) +'"')

		index = None
		indexes = list(self.SNMPWALK(oid_index))
		values = list(self.SNMPWALK(oid_values))

		if len(indexes) != len(values):
			self.back2nagios(3, 'Different data from 2 SNMP Walks!')

		return self.find_index_for_value(indexes, values, wanted)


	def SNMPGET(self, baseoid, idx=None, exitonerror=True):
		if type(baseoid) in (list, tuple):
			if idx not in ['', None]:
				idx = '.' + str(idx)
			else:
				idx = ''

			if self.options.snmpversion in [1, '1']:
				value_low = int(self.SNMPGET_wrapper(baseoid[1] +  idx, exitonerror=exitonerror))
				if value_low < 0:
					value_low += 2 ** 32

				value_hi = int(self.SNMPGET_wrapper(baseoid[2] + idx, exitonerror=exitonerror))
				if value_hi < 0:
					value_hi += 2 ** 32

				return value_hi * 2 ** 32 + value_low

			elif self.options.snmpversion in [2, 3, '2', '2c', '3']:
				return int(self.SNMPGET_wrapper(baseoid[0] + idx, exitonerror=exitonerror))

		elif type(baseoid) in (str, ) and idx != None:
			return self.SNMPGET_wrapper(baseoid + '.' + str(idx), exitonerror=exitonerror)
		else:
			return self.SNMPGET_wrapper(baseoid, exitonerror=exitonerror)


	def SNMPWALK(self, baseoid, exitonerror=True):
		return self.SNMPWALK_wrapper(baseoid, exitonerror=exitonerror)


	def __SNMPGET_netsnmp(self, oid, exitonerror=True):
		if not self.__prepared_snmp:
			self.prepare_snmp()

		if oid in self.__SNMP_Cache:
			self.verbose(2, "%40s -> (CACHED) %s" % (oid, self.__SNMP_Cache[oid]))
			return self.__SNMP_Cache[oid]

		result = netsnmp.snmpget(oid, Version=int(self.options.snmpversion), DestHost=self.options.host, Community=self.options.snmpauth)[0]

		if not result:
			if exitonerror:
				self.back2nagios(3, 'Timeout or no answer from "%s" looking for "%s"' % (self.options.host, oid))
			else:
				return None

		self.__SNMP_Cache[oid] = result

		self.verbose(2, "%40s -> %s" % (oid, result))
		return result


	def __SNMPWALK_netsnmp(self, oid, exitonerror=True):
		if not self.__prepared_snmp:
			self.prepare_snmp()

		if oid in self.__SNMP_Cache:
			self.verbose(2, "%40s -> (CACHED) %s" % (oid, self.__SNMP_Cache[oid]))
			return self.__SNMP_Cache[oid]

		result = netsnmp.snmpwalk(oid, Version=int(self.options.snmpversion), DestHost=self.options.host, Community=self.options.snmpauth)

		if not result:
			if exitonerror:
				self.back2nagios(3, 'Timeout or no answer from "%s" looking for "%s"' % (self.options.host, oid))
			else:
				return None

		self.__SNMP_Cache[oid] = result

		self.verbose(2, "%40s -> %s" %  (oid, result))
		return result


	def __SNMPGET_cmdline(self, oid, exitonerror=True):
		if not self.__prepared_snmp:
			self.prepare_snmp()

		cmdline = self.__CMDLINE_get % oid
		self.verbose(2, cmdline)

		if oid in self.__SNMP_Cache:
			self.verbose(2, "(CACHED) %s" % (self.__SNMP_Cache[oid]))
			return self.__SNMP_Cache[oid]

		cmd = os.popen(cmdline)
		out = cmd.readline().rstrip().replace('"','')
		retcode = cmd.close()

		if retcode:
			if not exitonerror:
				return None
			if retcode == 256:
				self.back2nagios(3, 'Timeout - no SNMP answer from "' + self.options.host + '"')
			elif retcode ==512:
				self.back2nagios(3, 'OID "' + oid + '" not found')
			else:
				self.back2nagios(3, 'Unknown error code "' + str(retcode) + '" from command line utils')

		self.__SNMP_Cache[oid] = out

		self.verbose(1, out)
		return out


	def __SNMPWALK_cmdline(self, oid, exitonerror=True):
		if not self.__prepared_snmp:
			self.prepare_snmp()

		cmdline = self.__CMDLINE_walk % oid
		self.verbose(2, cmdline)

		if oid in self.__SNMP_Cache:
			self.verbose(2, "(CACHED) %s" % (self.__SNMP_Cache[oid]))
			return self.__SNMP_Cache[oid]

		cmd = os.popen(cmdline)
		out = cmd.readlines()
		retcode = cmd.close()

		if retcode:
			if not exitonerror:
				return None
			if retcode == 256:
				self.back2nagios(3, 'Timeout - no SNMP answer from "' + self.options.host + '"')
			elif retcode ==512:
				self.back2nagios(3, 'OID "' + oid + '" not found')
			else:
				self.back2nagios(3, 'Unknown error code "' + str(retcode) + '" from command line utils')

		for line in range(0,len(out)):
			out[line] = out[line].rstrip().replace('"','')

		self.__SNMP_Cache[oid] = out

		self.verbose(1, str(out))
		return out