#!/usr/bin/python
# -*- coding: utf-8 -*-

# Copyright: (c) 2019, Nurfet Becirevic <nurfet.becirevic@gmail.com>
# Copyright: (c) 2017, Tomas Karasek <tom.to.the.k@gmail.com>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function

__metaclass__ = type

DOCUMENTATION = '''
---
module: packet_ip_subnet

short_description: Assign IP subnet to a bare metal server.

description:
    - Assign or unassign IPv4 or IPv6 subnets to or from a device in the Packet host.
    - IPv4 subnets must come from already reserved block.
    - IPv6 subnets must come from publicly routable /56 block from your project.
    - See U(https://support.packet.com/kb/articles/elastic-ips) for more info on IP block reservation.

version_added: '0.2.0'

author:
    - Tomas Karasek (@t0mk) <tom.to.the.k@gmail.com>
    - Nurfet Becirevic (@nurfet-becirevic) <nurfet.becirevic@gmail.com>

options:
  auth_token:
    description:
      - Packet api token. You can also supply it in env var C(PACKET_API_TOKEN).
    type: str

  hostname:
    description:
      - A hostname of a device to/from which to assign/remove a subnet.
    required: False
    type: str

  device_id:
    description:
      - UUID of a device to/from which to assign/remove a subnet.
    required: False
    type: str

  project_id:
    description:
      - UUID of a project of the device to/from which to assign/remove a subnet.
    required: True
    type: str

  device_count:
    description:
      - The number of devices to retrieve from the project. The max allowed value is 1000.
      - See U(https://www.packet.com/developers/api/#retrieve-all-devices-of-a-project) for more info.
    default: 100
    type: int

  cidr:
    description:
      - IPv4 or IPv6 subnet which you want to manage. It must come from a reserved block for your project in the Packet Host.
    aliases: [name]
    type: str

  state:
    description:
      - Desired state of the IP subnet on the specified device.
      - With state == C(present), you must specify either hostname or device_id. Subnet with given CIDR will then be assigned to the specified device.
      - With state == C(absent), you can specify either hostname or device_id. The subnet will be removed from specified devices.
      - If you leave both hostname and device_id empty, the subnet will be removed from any device it's assigned to.
    choices: ['present', 'absent']
    default: 'present'
    type: str

requirements:
     - "packet-python >= 1.35"
     - "python >= 2.6"
'''

EXAMPLES = '''
# All the examples assume that you have your Packet api token in env var PACKET_API_TOKEN.
# You can also pass it to the auth_token parameter of the module instead.

- name: Create 1 device and assign an arbitrary public IPv4 subnet to it
  hosts: localhost
  tasks:

  - packet_device:
      project_id: 89b497ee-5afc-420a-8fb5-56984898f4df
      hostnames: myserver
      operating_system: ubuntu_16_04
      plan: baremetal_0
      facility: sjc1
      state: active

# Pick an IPv4 address from a block allocated to your project.

  - packet_ip_subnet:
      project_id: 89b497ee-5afc-420a-8fb5-56984898f4df
      hostname: myserver
      cidr: "147.75.201.78/32"

# Release IP address 147.75.201.78

- name: Unassign IP address from any device in your project
  hosts: localhost
  tasks:
  - packet_ip_subnet:
      project_id: 89b497ee-5afc-420a-8fb5-56984898f4df
      cidr: "147.75.201.78/32"
      state: absent
'''

RETURN = '''
changed:
  description: True if an IP address assignments were altered in any way (created or removed).
  type: bool
  sample: True
  returned: success

device_id:
  type: str
  description: UUID of the device associated with the specified IP address.
  returned: success

subnet:
  description: Dict with data about the handled IP subnet.
  type: dict
  sample:
    address: 147.75.90.241
    address_family: 4
    assigned_to: { href : /devices/61f9aa5e-0530-47f5-97c2-113828e61ed0 }
    cidr: 31
    created_at: '2017-08-07T15:15:30Z'
    enabled: True
    gateway: 147.75.90.240
    href: /ips/31eda960-0a16-4c0f-b196-f3dc4928529f
    id: 1eda960-0a16-4c0f-b196-f3dc4928529f
    manageable: True
    management: True
    netmask: 255.255.255.254
    network: 147.75.90.240
    public: True
  returned: success
'''


import uuid
import re

from ansible.module_utils.basic import AnsibleModule, env_fallback
from ansible.module_utils._text import to_native

HAS_PACKET_SDK = True

try:
    import packet
except ImportError:
    HAS_PACKET_SDK = False


NAME_RE = r'({0}|{0}{1}*{0})'.format(r'[a-zA-Z0-9]', r'[a-zA-Z0-9\-]')
HOSTNAME_RE = r'({0}\.)*{0}$'.format(NAME_RE)
PROJECT_MAX_DEVICES = 100


PACKET_API_TOKEN_ENV_VAR = "PACKET_API_TOKEN"


ALLOWED_STATES = ['absent', 'present']


def is_valid_hostname(hostname):
    return re.match(HOSTNAME_RE, hostname) is not None


def is_valid_uuid(myuuid):
    try:
        val = uuid.UUID(myuuid, version=4)
    except ValueError:
        return False
    return str(val) == myuuid


def get_existing_devices(module, packet_conn):
    project_id = module.params.get('project_id')
    if not is_valid_uuid(project_id):
        raise Exception("Project ID {0} does not seem to be valid".format(project_id))

    per_page = module.params.get('device_count')
    return packet_conn.list_devices(
        project_id, params={'per_page': per_page})


def get_specified_device_identifiers(module):
    if module.params.get('device_id'):
        _d_id = module.params.get('device_id')
        if not is_valid_uuid(_d_id):
            raise Exception("Device ID '{0}' does not seem to be valid".format(_d_id))
        return {'device_id': _d_id, 'hostname': None}
    elif module.params.get('hostname'):
        _hn = module.params.get('hostname')
        if not is_valid_hostname(_hn):
            raise Exception("Hostname '{0}' does not seem to be valid".format(_hn))
        return {'hostname': _hn, 'device_id': None}
    else:
        return {'hostname': None, 'device_id': None}


def parse_subnet_cidr(cidr):
    if "/" not in cidr:
        raise Exception("CIDR expression in wrong format, must be address/prefix_len")
    addr, prefixlen = cidr.split("/")
    try:
        prefixlen = int(prefixlen)
    except ValueError:
        raise("Wrong prefix length in CIDR expression {0}".format(cidr))
    return addr, prefixlen


def act_on_assignment(target_state, module, packet_conn):
    return_dict = {'changed': False}
    specified_cidr = module.params.get("cidr")
    address, prefixlen = parse_subnet_cidr(specified_cidr)

    specified_identifier = get_specified_device_identifiers(module)

    if module.check_mode:
        return return_dict

    if (specified_identifier['hostname'] is None) and (
            specified_identifier['device_id'] is None):
        if target_state == 'absent':
            # The special case to release the IP from any assignment
            for d in get_existing_devices(module, packet_conn):
                for ia in d.ip_addresses:
                    if address == ia['address'] and prefixlen == ia['cidr']:
                        packet_conn.call_api(ia['href'], "DELETE")
                        return_dict['changed'] = True
                        return_dict['subnet'] = ia
                        return_dict['device_id'] = d.id
                        return return_dict
        raise Exception("If you assign an address, you must specify either "
                        "target device ID or target unique hostname.")

    if specified_identifier['device_id'] is not None:
        device = packet_conn.get_device(specified_identifier['device_id'])
    else:
        all_devices = get_existing_devices(module, packet_conn)
        hn = specified_identifier['hostname']
        matching_devices = [d for d in all_devices if d.hostname == hn]
        if len(matching_devices) > 1:
            raise Exception("There are more than one devices matching given hostname {0}".format(hn))
        if len(matching_devices) == 0:
            raise Exception("There is no device matching given hostname {0}".format(hn))
        device = matching_devices[0]

    return_dict['device_id'] = device.id
    assignment_dicts = [i for i in device.ip_addresses
                        if i['address'] == address and i['cidr'] == prefixlen]
    if len(assignment_dicts) > 1:
        raise Exception("IP address {0} is assigned more than once for device {1}".format(
                        specified_cidr, device.hostname))

    if target_state == "absent":
        if len(assignment_dicts) == 1:
            packet_conn.call_api(assignment_dicts[0]['href'], "DELETE")
            return_dict['subnet'] = assignment_dicts[0]
            return_dict['changed'] = True
    elif target_state == "present":
        if len(assignment_dicts) == 0:
            new_assignment = packet_conn.call_api(
                "devices/{0}/ips".format(device.id), "POST", {"address": "{0}".format(specified_cidr)})
            return_dict['changed'] = True
            return_dict['subnet'] = new_assignment
    return return_dict


def main():
    module = AnsibleModule(
        argument_spec=dict(
            auth_token=dict(
                type='str',
                fallback=(env_fallback, [PACKET_API_TOKEN_ENV_VAR]),
                no_log=True
            ),
            device_id=dict(type='str'),
            hostname=dict(type='str'),
            project_id=dict(type='str'),
            device_count=dict(type='int', default=PROJECT_MAX_DEVICES),
            cidr=dict(type='str', required=True, aliases=['name']),
            state=dict(choices=ALLOWED_STATES, default='present'),
        ),
        supports_check_mode=True,
        mutually_exclusive=[('hostname', 'device_id')],
        required_one_of=[['hostname', 'device_id', 'project_id']],
        required_by=dict(
            hostname=('project_id',),
        ),
    )

    if not HAS_PACKET_SDK:
        module.fail_json(msg='packet required for this module')

    if not module.params.get('auth_token'):
        _fail_msg = ("if Packet API token is not in environment variable {0}, "
                     "the auth_token parameter is required".format(PACKET_API_TOKEN_ENV_VAR))
        module.fail_json(msg=_fail_msg)

    auth_token = module.params.get('auth_token')

    packet_conn = packet.Manager(auth_token=auth_token)

    state = module.params.get('state')

    try:
        module.exit_json(**act_on_assignment(state, module, packet_conn))
    except Exception as e:
        module.fail_json(
            msg="failed to set IP subnet to state {0}, error: {1}".format(state, to_native(e)))


if __name__ == '__main__':
    main()
