#! /usr/bin/python

import json
import os
import requests
import sys

from operator import itemgetter, attrgetter

REST_API="http://alpha.opencloud.us:8000/plstackapi/"

NODES_API = REST_API + "nodes/"
SLICES_API = REST_API + "slices/"
SLIVERS_API = REST_API + "slivers/"

opencloud_auth=("demo@onlab.us", "demo")

def get_slice_id(slice_name):
    r = requests.get(SLICES_API + "?name=%s" % slice_name, auth=opencloud_auth)
    return r.json()[0]["id"]

def get_node_id(host_name):
    r = requests.get(NODES_API + "?name=%s" % host_name, auth=opencloud_auth)
    return r.json()[0]["id"]

def get_slivers(slice_id=None, node_id=None):
    queries = []
    if slice_id:
        queries.append("slice=%s" % str(slice_id))
    if node_id:
        queries.append("node=%s" % str(node_id))

    if queries:
        query_string = "?" + "&".join(queries)
    else:
        query_string = ""

    r = requests.get(SLIVERS_API + query_string, auth=opencloud_auth)
    return r.json()

def main():
    global opencloud_auth

    if len(sys.argv)!=5:
        print >> sys.stderr, "syntax: get_instance_name.py <username>, <password>, <hostname> <slicename>"
        sys.exit(-1)

    username = sys.argv[1]
    password = sys.argv[2]
    hostname = sys.argv[3]
    slice_name = sys.argv[4]

    opencloud_auth=(username, password)

    slice_id = get_slice_id(slice_name)
    node_id = get_node_id(hostname)
    slivers = get_slivers(slice_id, node_id)

    # get (instance_name, ip) pairs for instances with names and ips

    slivers = [x for x in slivers if x["instance_name"] and x["ip"]]
    slivers = sorted(slivers, key = lambda sliver: sliver["instance_name"])

    # return the last one in the list (i.e. the newest one)

    print slivers[-1]["ip"]

if __name__ == "__main__":
    main()