#!/usr/bin/env python
# -*- coding: utf-8 -*-

from pysnmp.hlapi import *
from pysnmp.smi.builder import MibBuilder
from pysnmp.smi.view import MibViewController

import importlib
import itertools
import mock
import random
import unittest

_mbuilder = MibBuilder()
_mvc = MibViewController(_mbuilder)

#import data

# received packages
# pvid: dot1qPvid
#
# tx packets:
# dot1qVlanStaticEgressPorts
# dot1qVlanStaticUntaggedPorts
#
# vlans:
# dot1qVlanCurrentTable
#	lists ALL vlans, including baked in ones
#
# note that even though an snmpwalk of dot1qVlanStaticEgressPorts
# skips over other vlans (only shows statics), the other vlans (1,2,3)
# are still accessible via that oid
#
# LLDP:
# 1.0.8802.1.1.2.1.4.1.1 aka LLDP-MIB, lldpRemTable

class SwitchConfig(object):
	def __init__(self, host, community, vlanconf):
		self._host = host
		self._community = community
		self._vlanconf = vlanconf

	@property
	def host(self):
		return self._host

	@property
	def community(self):
		return self._community

	@property
	def vlanconf(self):
		return self._vlanconf

def _octstrtobits(os):
	num = 1
	for i in str(os):
		num = (num << 8) | ord(i)

	return bin(num)[3:]

def _intstobits(*ints):
	v = 0
	for i in ints:
		v |= 1 << i

	r = list(bin(v)[2:-1])
	r.reverse()

	return ''.join(r)

import vlanmang

def checkchanges(module):
	mod = importlib.import_module(module)
	mods = [ i for i in mod.__dict__.itervalues() if isinstance(i, vlanmang.SwitchConfig) ]

	res = []

	for i in mods:
		vlans = i.vlanconf.keys()
		switch = SNMPSwitch(i.host, i.community)
		portmapping = switch.getportmapping()
		invportmap = { y: x for x, y in portmapping.iteritems() }
		lufun = invportmap.__getitem__

		# get complete set of ports
		portlist = getportlist(i.vlanconf, lufun)

		ports = set(portmapping.iterkeys())

		# make sure switch agrees w/ them all
		if ports != portlist:
			raise ValueError('missing or extra ports found: %s' %
			    `ports.symmetric_difference(portlist)`)

		# compare pvid
		pvidmap = getpvidmapping(i.vlanconf, lufun)
		switchpvid = switch.getpvid()

		res.extend(('setpvid', idx, vlan, switchpvid[idx]) for idx, vlan in
		    pvidmap.iteritems() if switchpvid[idx] != vlan)

		# compare egress & untagged
		switchegress = switch.getegress(*vlans)
		egress = getegress(i.vlanconf, lufun)
		switchuntagged = switch.getuntagged(*vlans)
		untagged = getuntagged(i.vlanconf, lufun)
		for i in vlans:
			if switchegress[i] != egress[i]:
				res.append(('setegress', i, egress[i], switchegress[i]))
			if switchuntagged[i] != untagged[i]:
				res.append(('setuntagged', i, untagged[i], switchuntagged[i]))

	return res

def getidxs(lst, lookupfun):
	return [ lookupfun(i) if isinstance(i, str) else i for i in lst ]

def getpvidmapping(data, lookupfun):
	'''Return a mapping from vlan based table to a port: vlan
	dictionary.'''

	res = []
	for id in data:
		for i in data[id].get('u', []):
			if isinstance(i, str):
				i = lookupfun(i)
			res.append((i, id))

	return dict(res)

def getegress(data, lookupfun):
	r = {}
	for id in data:
		r[id] = _intstobits(*(getidxs(data[id].get('u', []),
		    lookupfun) + getidxs(data[id].get('t', []), lookupfun)))

	return r

def getuntagged(data, lookupfun):
	r = {}
	for id in data:
		r[id] = _intstobits(*getidxs(data[id].get('u', []), lookupfun))

	return r

def getportlist(data, lookupfun):
	'''Return a set of all the ports indexes in data.'''

	res = set()

	for id in data:
		res.update(data[id].get('u', []))
		res.update(data[id].get('t', []))

	# filter out the strings
	strports = set(x for x in res if isinstance(x, str))

	res.update(lookupfun(x) for x in strports)
	res.difference_update(strports)

	return res

class SNMPSwitch(object):
	'''A class for manipulating switches via standard SNMP MIBs.'''

	def __init__(self, host, community):
		self._eng = SnmpEngine()
		self._cd = CommunityData(community, mpModel=0)
		self._targ = UdpTransportTarget((host, 161))

	def _getmany(self, *oids):
		oids = [ ObjectIdentity(*oid) for oid in oids ]
		[ oid.resolveWithMib(_mvc) for oid in oids ]

		errorInd, errorStatus, errorIndex, varBinds = \
		    next(getCmd(self._eng, self._cd, self._targ, ContextData(), *(ObjectType(oid) for oid in oids)))

		if errorInd: # pragma: no cover
			raise ValueError(errorIndication)
		elif errorStatus: # pragma: no cover
			raise ValueError('%s at %s' %
			    (errorStatus.prettyPrint(), errorIndex and
			    varBinds[int(errorIndex)-1][0] or '?'))
		else:
			if len(varBinds) != len(oids): # pragma: no cover
				raise ValueError('too many return values')

			return varBinds

	def _get(self, oid):
		varBinds = self._getmany(oid)

		varBind = varBinds[0]
		return varBind[1]

	def _set(self, oid, value):
		oid = ObjectIdentity(*oid)
		oid.resolveWithMib(_mvc)

		if isinstance(value, (int, long)):
			value = Integer(value)
		elif isinstance(value, str):
			value = OctetString(value)

		errorInd, errorStatus, errorIndex, varBinds = \
		    next(setCmd(self._eng, self._cd, self._targ, ContextData(), ObjectType(oid, value)))

		if errorInd: # pragma: no cover
			raise ValueError(errorIndication)
		elif errorStatus: # pragma: no cover
			raise ValueError('%s at %s' %
			    (errorStatus.prettyPrint(), errorIndex and
			    varBinds[int(errorIndex)-1][0] or '?'))
		else:
			for varBind in varBinds:
				if varBind[1] != value: # pragma: no cover
					raise RuntimeError('failed to set: %s' % ' = '.join([x.prettyPrint() for x in varBind]))

	def _walk(self, *oid):
		oid = ObjectIdentity(*oid)
		# XXX - keep these, this might stop working, no clue what managed to magically make things work
		# ref: http://snmplabs.com/pysnmp/examples/smi/manager/browsing-mib-tree.html#mib-objects-to-pdu-var-binds
		# mibdump.py --mib-source '/Users/jmg/Nextcloud/Documents/user manuals/netgear/gs7xxt-v6.3.1.19-mibs' --mib-source /usr/share/snmp/mibs  --rebuild rfc1212 pbridge vlan
		#oid.addAsn1MibSource('/usr/share/snmp/mibs', '/Users/jmg/Nextcloud/Documents/user manuals/netgear/gs7xxt-v6.3.1.19-mibs')

		oid.resolveWithMib(_mvc)

		for (errorInd, errorStatus, errorIndex, varBinds) in nextCmd(
		    self._eng, self._cd, self._targ, ContextData(),
		    ObjectType(oid),
		    lexicographicMode=False):
			if errorInd: # pragma: no cover
				raise ValueError(errorInd)
			elif errorStatus: # pragma: no cover
				raise ValueError('%s at %s' % (errorStatus.prettyPrint(), errorIndex and varBinds[int(errorIndex)-1][0] or '?'))
			else:
				for varBind in varBinds:
					yield varBind

	def getportmapping(self):
		'''Return a port name mapping.  Keys are the port index
		and the value is the name from the ifName entry.'''

		return { x[0][-1]: str(x[1]) for x in self._walk('IF-MIB', 'ifName') }

	def findport(self, name):
		'''Look up a port name and return it's port index.  This
		looks up via the ifName table in IF-MIB.'''

		return [ x[0][-1] for x in self._walk('IF-MIB', 'ifName') if str(x[1]) == name ][0]

	def getvlanname(self, vlan):
		'''Return the name for the vlan.'''

		v = self._get(('Q-BRIDGE-MIB', 'dot1qVlanStaticName', vlan))

		return str(v).decode('utf-8')

	def createvlan(self, vlan, name):
		# createAndGo(4)
		self._set(('Q-BRIDGE-MIB', 'dot1qVlanStaticRowStatus',
		    int(vlan)), 4)
		self._set(('Q-BRIDGE-MIB', 'dot1qVlanStaticName', int(vlan)),
		    name)

	def deletevlan(self, vlan):
		self._set(('Q-BRIDGE-MIB', 'dot1qVlanStaticRowStatus',
		    int(vlan)), 6) # destroy(6)

	def getvlans(self):
		'''Return an iterator with all the vlan ids.'''

		return (x[0][-1] for x in self._walk('Q-BRIDGE-MIB', 'dot1qVlanStatus'))

	def staticvlans(self):
		'''Return an iterator of the staticly defined/configured
		vlans.  This sometimes excludes special built in vlans,
		like vlan 1.'''

		return (x[0][-1] for x in self._walk('Q-BRIDGE-MIB', 'dot1qVlanStaticName'))

	def getpvid(self):
		'''Returns a dictionary w/ the interface index as the key,
		and the pvid of the interface.'''

		return { x[0][-1]: int(x[1]) for x in self._walk('Q-BRIDGE-MIB', 'dot1qPvid') }

	def getegress(self, *vlans):
		r = { x[-1]: _octstrtobits(y) for x, y in
		    self._getmany(*(('Q-BRIDGE-MIB',
		    'dot1qVlanStaticEgressPorts', x) for x in vlans)) }

		return r

	def getuntagged(self, *vlans):
		r = { x[-1]: _octstrtobits(y) for x, y in
		    self._getmany(*(('Q-BRIDGE-MIB',
		    'dot1qVlanStaticUntaggedPorts', x) for x in vlans)) }

		return r

if __name__ == '__main__': # pragma: no cover
	print `checkchanges('data')`

class _TestMisc(unittest.TestCase):
	def setUp(self):
		import test_data

		self._test_data = test_data

	def test_intstobits(self):
		self.assertEqual(_intstobits(1, 5, 10), '1000100001')
		self.assertEqual(_intstobits(3, 4, 9), '001100001')

	def test_octstrtobits(self):
		self.assertEqual(_octstrtobits('\x00'), '0' * 8)
		self.assertEqual(_octstrtobits('\xff'), '1' * 8)
		self.assertEqual(_octstrtobits('\xf0'), '1' * 4 + '0' * 4)
		self.assertEqual(_octstrtobits('\x0f'), '0' * 4 + '1' * 4)

	def test_pvidegressuntagged(self):
		data = {
			1: {
				'u':	[ 1, 5, 10 ] + range(13, 20),
				't':    [ 'lag2', 6, 7 ],
			},
			10: {
				'u':	[ 2, 3, 6, 7, 8, 'lag2' ],
			},
			13: {
				'u':	[ 4, 9 ],
				't':    [ 'lag2', 6, 7 ],
			},
			14: {
				't':	[ 'lag2' ],
			},
		}
		lookup = {
			'lag2': 30
		}
		lufun = lookup.__getitem__

		check = dict(itertools.chain(enumerate([ 1, 10, 10, 13, 1, 10,
		    10, 10, 13, 1 ], 1), enumerate([ 1 ] * 7, 13),
		    [ (30, 10) ]))

		# That a pvid mapping
		res = getpvidmapping(data, lufun)

		# is correct
		self.assertEqual(res, check)

		self.assertEqual(getportlist(data, lufun),
		    set(xrange(1, 11)) | set(xrange(13, 20)) | set([30]))

		checkegress = {
			1:	'1000111001001111111' + '0' * (30 - 20) + '1',
			10:	'01100111' + '0' * (30 - 9) + '1',
			13:	'000101101' + '0' * (30 - 10) + '1',
			14:	'0' * (30 - 1) + '1',
		}

		self.assertEqual(getegress(data, lufun), checkegress)

		checkuntagged = {
			1:	'1000100001001111111',
			10:	'01100111' + '0' * (30 - 9) + '1',
			13:	'000100001',
			14:	'',
		}
		self.assertEqual(getuntagged(data, lufun), checkuntagged)

	#@unittest.skip('foo')
	@mock.patch('vlanmang.SNMPSwitch.getuntagged')
	@mock.patch('vlanmang.SNMPSwitch.getegress')
	@mock.patch('vlanmang.SNMPSwitch.getpvid')
	@mock.patch('vlanmang.SNMPSwitch.getportmapping')
	@mock.patch('importlib.import_module')
	def test_checkchanges(self, imprt, portmapping, gpvid, gegress, guntagged):
		# that import returns the test data
		imprt.side_effect = itertools.repeat(self._test_data)

		# that getportmapping returns the following dict
		ports = { x: 'g%d' % x for x in xrange(1, 24) }
		ports[30] = 'lag1'
		ports[31] = 'lag2'
		portmapping.side_effect = itertools.repeat(ports)

		# that the switch's pvid returns
		spvid = { x: 283 for x in xrange(1, 24) }
		spvid[30] = 5
		gpvid.side_effect = itertools.repeat(spvid)

		# the the extra port is caught
		self.assertRaises(ValueError, checkchanges, 'data')

		# that the functions were called
		imprt.assert_called_with('data')
		portmapping.assert_called()

		# XXX - check that an ignore statement is honored

		# delete the extra port
		del ports[31]

		# that the egress data provided
		gegress.side_effect = [ {
			1: '1' * 10,
			5: '1' * 10,
			283: '000000001111111111100110000001',
		} ]

		# that the untagged data provided
		guntagged.side_effect = [ {
			1: '1' * 10,
			5: '1' * 8,
			283: '00000000111111111110011',
		} ]

		res = checkchanges('data')

		validres = [ ('setpvid', x, 5, 283) for x in xrange(1, 9) ] + \
		    [ ('setpvid', 20, 1, 283),
		    ('setpvid', 21, 1, 283),
		    ('setpvid', 30, 1, 5),
		    ('setegress', 1, '0' * 19 + '11' + '0' * 8 + '1', '1' * 10),
		    ('setuntagged', 1, '0' * 19 + '11' + '0' * 8 + '1', '1' * 10),
		    ('setegress', 5, '1' * 8 + '0' * 11 + '11' + '0' * 8 + '1', '1' * 10),
		    ]

		self.assertEqual(set(res), set(validres))

_skipSwitchTests = False

class _TestSwitch(unittest.TestCase):
	def setUp(self):
		# If we don't have it, pretend it's true for now and
		# we'll recheck it later
		model = 'GS108T smartSwitch'
		if getattr(self, 'switchmodel', model) != model or \
		    _skipSwitchTests: # pragma: no cover
			self.skipTest('Need a GS108T switch to run these tests')

		args = open('test.creds').read().split()
		self.switch = SNMPSwitch(*args)

		self.switchmodel = self.switch._get(('ENTITY-MIB',
		    'entPhysicalModelName', 1))
		if self.switchmodel != model: # pragma: no cover
			self.skipTest('Need a GS108T switch to run these tests')

	def test_misc(self):
		switch = self.switch

		self.assertEqual(switch.findport('g1'), 1)
		self.assertEqual(switch.findport('l1'), 14)

	def test_portnames(self):
		switch = self.switch

		resp = dict((x, 'g%d' % x) for x in xrange(1, 9))
		resp.update({ 13: 'cpu' })
		resp.update((x, 'l%d' % (x - 13)) for x in xrange(14, 18))

		self.assertEqual(switch.getportmapping(), resp)

	def test_egress(self):
		switch = self.switch

		egress = switch.getegress(1, 2, 3)

		checkegress = {
			1: '1' * 8 + '0' * 5 + '1' * 4 + '0' * 23,
			2: '0' * 8 * 5,
			3: '0' * 8 * 5,
		}

		self.assertEqual(egress, checkegress)

	def test_untagged(self):
		switch = self.switch

		untagged = switch.getuntagged(1, 2, 3)

		checkuntagged = {
			1: '1' * 8 * 5,
			2: '1' * 8 * 5,
			3: '1' * 8 * 5,
		}

		self.assertEqual(untagged, checkuntagged)

	def test_vlan(self):
		switch = self.switch

		existingvlans = set(switch.getvlans())

		while True:
			testvlan = random.randint(1,4095)
			if testvlan not in existingvlans:
				break

		# Test that getting a non-existant vlans raises an exception
		self.assertRaises(ValueError, switch.getvlanname, testvlan)

		self.assertTrue(set(switch.staticvlans()).issubset(existingvlans))

		pvidres = { x: 1 for x in xrange(1, 9) }
		pvidres.update({ x: 1 for x in xrange(14, 18) })
		self.assertEqual(switch.getpvid(), pvidres)

		testname = 'Sometestname'

		# Create test vlan
		switch.createvlan(testvlan, testname)
		try:
			# make sure the test vlan was created
			self.assertIn(testvlan, set(switch.staticvlans()))

			self.assertEqual(testname, switch.getvlanname(testvlan))
		finally:
			switch.deletevlan(testvlan)