#!/usr/bin/python
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# generate_baremetal_macs method ripped from
# openstack/tripleo-incubator/scripts/configure-vm

DOCUMENTATION = '''
---
module: generate_macs
version_added: "2.0"
short_description: Generate a list of Ethernet MAC addresses
description:
   - Generate a list of Ethernet MAC addresses suitable for baremetal testing.
'''

import math
import random

MAX_NUM_MACS = math.trunc(0xff / 2)


def generate_baremetal_macs(nodes, networks):
    """Generate an Ethernet MAC address suitable for baremetal testing."""
    # NOTE(dprince): We generate our own bare metal MAC address's here
    # instead of relying on libvirt so that we can ensure the
    # locally administered bit is set low. (The libvirt default is
    # to set the 2nd MSB high.) This effectively allows our
    # fake baremetal VMs to more accurately behave like real hardware
    # and fixes issues with bridge/DHCP configurations which rely
    # on the fact that bridges assume the MAC address of the lowest
    # attached NIC.
    # MACs generated for a given machine will also be in sequential
    # order, which matches how most BM machines are laid out as well.
    # Additionally we increment each MAC by two places.
    macs = []
    count = len(nodes) * len(networks)

    if count > MAX_NUM_MACS:
        raise ValueError("The MAX num of MACS supported is %i  "
                         "(you specified %i)." % (MAX_NUM_MACS, count))

    base_nums = [0x00,
                 random.randint(0x00, 0xff),
                 random.randint(0x00, 0xff),
                 random.randint(0x00, 0xff),
                 random.randint(0x00, 0xff)]
    base_mac = ':'.join(map(lambda x: "%02x" % x, base_nums))

    start = random.randint(0x00, 0xff)
    if (start + (count * 2)) > 0xff:
        # leave room to generate macs in sequence
        start = 0xff - count * 2
    for num in range(0, count * 2, 2):
        mac = start + num
        macs.append(base_mac + ":" + ("%02x" % mac))

    result = {}
    for node in nodes:
        result[node['name']] = {}
        for network in networks:
            result[node['name']][network['name']] = macs.pop(0)

    return result


def main():
    module = AnsibleModule(
        argument_spec=dict(
            nodes=dict(required=True, type='list'),
            networks=dict(required=True, type='list')
        )
    )
    result = generate_baremetal_macs(module.params["nodes"],
                                     module.params["networks"])
    module.exit_json(**result)

# see http://docs.ansible.com/developing_modules.html#common-module-boilerplate
from ansible.module_utils.basic import AnsibleModule
if __name__ == '__main__':
    main()