#!/usr/bin/env python3

from lxc_net import parse_network
import sys
import signal
import libvirt
import argparse


def parse_args():
    parser = argparse.ArgumentParser(description="Spawns a network of LXC containers.")
    parser.add_argument("topology", help="A YAML file defining the network topology")

    args = parser.parse_args()
    return args


def main():
    args = parse_args()

    received_sigint = False

    def handle_sigint(signum, frame):
        """ Called upon SIGINT (^C) """
        nonlocal received_sigint

        print(" >> Received SIGINT, stopping network...")
        received_sigint = True

    signal.signal(signal.SIGINT, handle_sigint)

    conn = libvirt.open("lxc:///")

    topology = parse_network.YamlTopology(args.topology, conn)

    print(">> Spawning networks: ", end="")
    sys.stdout.flush()
    for link in topology.links:
        if received_sigint:
            return
        print(link.name, end="... ")
        sys.stdout.flush()
        link.create()
    print("Done.")

    print(">> Spawning containers: ", end="")
    sys.stdout.flush()
    for c_dom in topology.domains:
        if received_sigint:
            return
        print(c_dom.name, end="... ")
        sys.stdout.flush()
        c_dom.create()
    print("Done.")

    print("Network running. Press ^C to terminate.")
    while not received_sigint:  # Wait for SIGINT
        signal.pause()


if __name__ == "__main__":
    main()