import configparser
from mininet.net	import Mininet
from mininet.topo	import Topo
from mininet.node	import Node
from mininet.cli	import CLI
from mininet.link	import TCLink
from mininet.log	import setLogLevel

class MyRouter (Node):
	def config(self, **params):
		super(MyRouter, self).config(**params)
		self.cmd('sysctl net.ipv4.ip_forward=1')		#Enable forwarding on the router
	def terminate(self):
		self.cmd('sysctl net.ipv4.ip_forward=0')		#Disable forwarding on the router
		super(MyRouter, self).terminate

def build_topology(config_file):
	topo = Topo()

	with open(config_file, 'r') as file:
		for line in file:
			line = line.strip()
			if line.startswith('#'):		#Skip comment
				continue

			parts = line.split(" ")		#Parse the topology file using spaces
			if parts[0] == 'host':		#Parse hosts
				host_name = parts[1]
				host_ip = parts[2]
				host_nexthop = 'via ' + parts[3]
				topo.addHost(host_name, ip=host_ip, defaultRoute=host_nexthop)

			elif parts[0] == 'router':		#Parse routers
				router_name = parts[1]
				router_ip = parts[2]
				topo.addNode(router_name, cls=MyRouter, ip=router_ip)

			elif parts[0] == 'switch':		#Parse switches
				switch_name = parts[1]
				topo.addSwitch(switch_name)

			elif parts[0] == 'linkSH':		#Parse links switches to hosts
				node1 = parts[1]
				node2 = parts[2]
				topo.addLink(node1, node2)

			elif parts[0] == 'linkSS':		#Parse links switches to switches
				node1 = parts[1]
				node2 = parts[2]
				topo.addLink(node1, node2)

			elif parts[0] == 'linkHR':		#Parse links hosts to routers
				node1 = parts[1]
				node2 = parts[2]
				intf_name2 = parts[3]
				n2_ip = parts[4]
				topo.addLink(node1, node2, intfName2=intf_name2, params2={'ip' : n2_ip})

			elif parts[0] == 'linkRR':		#Parse links routers to routers
				node1 = parts[1]
				node2 = parts[2]
				intf_name1 = parts[3]
				intf_name2 = parts[4]
				ip1 = parts[5]
				ip2 = parts[6]
				topo.addLink(node1, node2, intfName1=intf_name1, intfName2=intf_name2, params1={'ip' : ip1}, params2={'ip' : ip2})
			
			# elif parts[0] == 'route':		#Parse routing tables
			# 	name = parts[1]
			# 	for node in topo.nodes():
			# 		if node == name:
			# 			(node).cmd('ip route add 0.0.0.0/0 via 10.0.0.1 dev r1-eth2')
			# 			break



			# (topo.getNodeByName('r1')).cmd('ip route add 0.0.0.0/0 via 10.0.0.1 dev r1-eth2')
	return topo

def run_topology(config_file):
	setLogLevel('info')		#Different logging levels are 'info' 'warning' 'error' 'debug'
	topo = build_topology(config_file)
	net = Mininet(topo=topo, link=TCLink)
	net.start()		#Starting the network

	with open(config_file, 'r') as file:		#Search in the configuration file for routing table
		for line in file:
			line = line.strip()
			if line.startswith('#'):		#Skip comment
				continue

			parts = line.split(" ")
			if parts[0] == 'route':		#Parse routing tables
				name = parts[1]
				pck_src = parts[2]
				pck_nexthop = parts[3]
				interf = parts[4]
				cmd = 'ip route add ' + pck_src + ' via ' + pck_nexthop + ' dev ' + interf
				(net.getNodeByName(name)).cmd(cmd)
	net.pingAll()
	# CLI(net)
	net.stop()		#Stopping the network

if __name__ == '__main__':
	run_topology('MininetTopo.conf')