# -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
#
# Copyright (C) 2015-2017, The University of Memphis,
#                          Arizona Board of Regents,
#                          Regents of the University of California.
#
# This file is part of Mini-NDN.
# See AUTHORS.md for a complete list of Mini-NDN authors and contributors.
#
# Mini-NDN 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 3 of the License, or
# (at your option) any later version.
#
# Mini-NDN 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 Mini-NDN, e.g., in COPYING.md file.
# If not, see <http://www.gnu.org/licenses/>.

import time
import sys
from itertools import cycle

from ndn import ExperimentManager

class Experiment:

    def __init__(self, args):
        self.net = args["net"]
        self.convergenceTime = args["ctime"]
        self.nPings = args["nPings"]
        self.strategy = args["strategy"]
        self.pctTraffic = args["pctTraffic"]

        # Used to restart pings on the recovered node if any
        self.pingedDict = {}

    def start(self):
        self.setup()
        self.run()

    def setup(self):
        for host in self.net.hosts:
            # Set strategy
            host.nfd.setStrategy("/ndn/", self.strategy)

            # Start ping server
            host.cmd("ndnpingserver /ndn/" + str(host) + "-site/" + str(host) + " > ping-server &")

            # Create folder to store ping data
            host.cmd("mkdir ping-data")

        self.checkConvergence()

    def checkConvergence(self, convergenceTime = None):
        if convergenceTime is None:
            convergenceTime = self.convergenceTime

        # Wait for convergence time period
        print "Waiting " + str(convergenceTime) + " seconds for convergence..."
        time.sleep(convergenceTime)
        print "...done"

        # To check whether all the nodes of NLSR have converged
        didNlsrConverge = True

        # Checking for convergence
        for host in self.net.hosts:
            statusRouter = host.cmd("nfdc fib list | grep site/%C1.Router/cs/")
            statusPrefix = host.cmd("nfdc fib list | grep ndn | grep site | grep -v Router")
            didNodeConverge = True
            for node in self.net.hosts:
                # Node has its own router name in the fib list, but not name prefix
                if ( ("/ndn/" + node.name + "-site/%C1.Router/cs/" + node.name) not in statusRouter or
                      host.name != node.name and ("/ndn/" + node.name + "-site/" + node.name) not in statusPrefix ):
                    didNodeConverge = False
                    didNlsrConverge = False

            host.cmd("echo " + str(didNodeConverge) + " > convergence-result &")

        if didNlsrConverge:
            print("NLSR has successfully converged.")
        else:
            print("NLSR has not converged. Exiting...")
            self.net.stop()
            sys.exit(1)

    def ping(self, source, dest, nPings):
        # Use "&" to run in background and perform parallel pings
        print "Scheduling ping(s) from %s to %s" % (source.name, dest.name)
        source.cmd("ndnping -t -c "+ str(nPings) + " /ndn/" + dest.name + "-site/" + dest.name + " >> ping-data/" + dest.name + ".txt &")
        time.sleep(0.2)

    def startPings(self):
        for host in self.net.hosts:
            for other in self.net.hosts:
                # Do not ping self
                if host.name != other.name:
                    self.ping(host, other, self.nPings)

    def failNode(self, host):
        print("Bringing %s down" % host.name)
        host.nfd.stop()

    def recoverNode(self, host):
        print("Bringing %s up" % host.name)
        host.nfd.start()
        host.nlsr.createFaces()
        host.nlsr.start()
        host.nfd.setStrategy("/ndn/", self.strategy)
        host.cmd("ndnpingserver /ndn/" + str(host) + "-site/" + str(host) + " > ping-server &")

    def startPctPings(self):
        nNodesToPing = int(round(len(self.net.hosts)*self.pctTraffic))
        print "Each node will ping %d node(s)" % nNodesToPing
        # Temporarily store all the nodes being pinged by a particular node
        nodesPingedList = []

        for host in self.net.hosts:
            # Create a circular list
            pool = cycle(self.net.hosts)

            # Move iterator to current node
            next(x for x in pool if host.name == x.name)

            # Track number of nodes to ping scheduled for this node
            nNodesScheduled = 0

            while nNodesScheduled < nNodesToPing:
                other = pool.next()

                # Do not ping self
                if host.name != other.name:
                    self.ping(host, other, self.nPings)
                    nodesPingedList.append(other)

                # Always increment because in 100% case a node should not ping itself
                nNodesScheduled = nNodesScheduled + 1

            self.pingedDict[host] = nodesPingedList
            nodesPingedList = []

    @staticmethod
    def register(name, experimentClass):
        ExperimentManager.register(name, experimentClass)