import urllib, json, networkx  as nx
class topology_parser:


    def __init__(self,url):
        self.topology = nx.MultiGraph()
        self.url=url
        self.nx_olsr(self.url,self.topology)


    def update(self):
        self.nx_olsr(self.url,self.topology)


    def nx_olsr(self,url,topol):
        response =urllib.urlopen(url)
        json_data = json.loads(response.read())
        for elem in json_data["topology"]:
            topol.add_edge(elem["lastHopIP"], elem["destinationIP"], weight=elem["tcEdgeCost"])

    def make_diff(self, old_graph):
        to_remove = nx.difference(old_graph, self.topology)
        to_add = nx.difference(self.topology, old_graph)
        return [to_remove, to_add]

def main():
    firenze="http://10.150.9.1:9090/"
    tp=topology_parser(firenze);

    #cycle every n seconds
    tp.update();
    diff= tp.make_diff(old_graph)




if __name__ == "__main__":
    main()