#!/usr/bin/env python
"""
usage: onos-gen-config [-h] [-s PARTITION_SIZE] [-n NUM_PARTITIONS]
                            [filename] [node_ip [node_ip ...]]

Generate the partitions json file given a list of IPs or from the $OCC*
environment variables.

positional arguments:
  filename              File to write output to. If none is provided, output
                        is written to stdout.
  node_ip               IP Address(es) of the node(s) in the cluster. If no
                        IPs are given, will use the $OC* environment
                        variables. NOTE: these arguments are only processed
                        after the filename argument.

optional arguments:
  -h, --help            show this help message and exit
  -s PARTITION_SIZE, --partition-size PARTITION_SIZE
                        Number of nodes per partition. Note that partition
                        sizes smaller than 3 are not fault tolerant. Defaults
                        to 3.
  -n NUM_PARTITIONS, --num-partitions NUM_PARTITIONS
                        Number of partitions. Defaults to the number of nodes
                        in the cluster.
"""

from os import environ
import argparse
import re
import json

convert = lambda text: int(text) if text.isdigit() else text.lower()
alphanum_key = lambda key: [convert(c) for c in re.split('([0-9]+)', key)]

def get_OCC_vars():
  vars = []
  for var in environ:
    if re.match(r"OCC[0-9]+", var):
      vars.append(var)
  return sorted(vars, key=alphanum_key)

def get_nodes(ips=None, default_port=5679):
    node = lambda id, ip, port : { 'id': id, 'ip': ip, 'port': port }
    result = []
    if not ips:
        ips = [ environ[v] for v in get_OCC_vars() ]
    i = 1
    for ip_string in ips:
        address_tuple = ip_string.split(":")
        if len(address_tuple) == 3:
            id=address_tuple[0]
            ip=address_tuple[1]
            port=int(address_tuple[2])
        else:
            id='atomix-{}'.format(i)
            i += 1
            ip=ip_string
            port=default_port
        result.append(node(id, ip, port))
    return result

if __name__ == '__main__':
  parser = argparse.ArgumentParser(
      description="Generate the partitions json file given a list of IPs or from the $OC* environment variables.")
  parser.add_argument(
      '-s', '--partition-size', type=int, default=3,
      help="Number of nodes per partition. Note that partition sizes smaller than 3 are not fault tolerant. Defaults to 3." )
  parser.add_argument(
      '-n', '--num-partitions', type=int,
      help="Number of partitions. Defaults to the number of nodes in the cluster." )
 # TODO: make filename and nodes independent. This will break backwards compatibility with existing usage.
  parser.add_argument(
     'filename', metavar='filename', type=str, nargs='?',
     help='File to write output to. If none is provided, output is written to stdout.')
  parser.add_argument(
      'nodes', metavar='node_ip', type=str, nargs='*',
      help='IP Address(es) of the node(s) in the cluster. If no IPs are given, ' +
           'will use the $OC* environment variables. NOTE: these arguemnts' +
           ' are only processed after the filename argument.')

  args = parser.parse_args()
  filename = args.filename
  partition_size = args.partition_size
  cluster = get_nodes(args.nodes)
  num_partitions = args.num_partitions
  if not num_partitions:
    num_partitions = len(cluster)

  data = {
           'name': 'onos',
           'cluster': cluster
         }
  output = json.dumps(data, indent=4)

  if filename:
    with open(filename, 'w') as f:
      f.write(output)
  else:
    print output