#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright: (c) 2017, F5 Networks Inc.
# 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


ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['stableinterface'],
                    'supported_by': 'community'}

DOCUMENTATION = r'''
---
module: bigip_gtm_virtual_server
short_description: Manages F5 BIG-IP GTM virtual servers
description:
  - Manages F5 BIG-IP GTM virtual servers. A GTM server can have many virtual servers
    associated with it. They are arranged in much the same way that pool members are
    to pools.
version_added: 2.6
options:
  name:
    description:
      - Specifies the name of the virtual server.
    version_added: 2.6
  server_name:
    description:
      - Specifies the name of the server that the virtual server is associated with.
    version_added: 2.6
  address:
    description:
      - Specifies the IP Address of the virtual server.
      - When creating a new GTM virtual server, this parameter is required.
    version_added: 2.6
  port:
    description:
      - Specifies the service port number for the virtual server or pool member. For example,
        the HTTP service is typically port 80.
      - To specify all ports, use an C(*).
      - When creating a new GTM virtual server, if this parameter is not specified, a
        default of C(*) will be used.
  translation_address:
    description:
      - Specifies the translation IP address for the virtual server.
      - To unset this parameter, provide an empty string (C("")) as a value.
      - When creating a new GTM virtual server, if this parameter is not specified, a
        default of C(::) will be used.
    version_added: 2.6
  translation_port:
    description:
      - Specifies the translation port number or service name for the virtual server.
      - To specify all ports, use an C(*).
      - When creating a new GTM virtual server, if this parameter is not specified, a
        default of C(*) will be used.
    version_added: 2.6
  availability_requirements:
    description:
      - Specifies, if you activate more than one health monitor, the number of health
        monitors that must receive successful responses in order for the link to be
        considered available.
    suboptions:
      type:
        description:
          - Monitor rule type when C(monitors) is specified.
          - When creating a new virtual, if this value is not specified, the default of 'all' will be used.
        choices: ['all', 'at_least', 'require']
      at_least:
        description:
          - Specifies the minimum number of active health monitors that must be successful
            before the link is considered up.
          - This parameter is only relevant when a C(type) of C(at_least) is used.
          - This parameter will be ignored if a type of either C(all) or C(require) is used.
      number_of_probes:
        description:
          - Specifies the minimum number of probes that must succeed for this server to be declared up.
          - When creating a new virtual server, if this parameter is specified, then the C(number_of_probers)
            parameter must also be specified.
          - The value of this parameter should always be B(lower) than, or B(equal to), the value of C(number_of_probers).
          - This parameter is only relevant when a C(type) of C(require) is used.
          - This parameter will be ignored if a type of either C(all) or C(at_least) is used.
      number_of_probers:
        description:
          - Specifies the number of probers that should be used when running probes.
          - When creating a new virtual server, if this parameter is specified, then the C(number_of_probes)
            parameter must also be specified.
          - The value of this parameter should always be B(higher) than, or B(equal to), the value of C(number_of_probers).
          - This parameter is only relevant when a C(type) of C(require) is used.
          - This parameter will be ignored if a type of either C(all) or C(at_least) is used.
    version_added: 2.6
  monitors:
    description:
      - Specifies the health monitors that the system currently uses to monitor this resource.
      - When C(availability_requirements.type) is C(require), you may only have a single monitor in the
        C(monitors) list.
    version_added: 2.6
  virtual_server_dependencies:
    description:
      - Specifies the virtual servers on which the current virtual server depends.
      - If any of the specified servers are unavailable, the current virtual server is also listed as unavailable.
    suboptions:
      server:
        description:
          - Server which the dependant virtual server is part of.
        required: True
      virtual_server:
        description:
          - Virtual server to depend on.
        required: True
    version_added: 2.6
  link:
    description:
      - Specifies a link to assign to the server or virtual server.
    version_added: 2.6
  limits:
    description:
      - Specifies resource thresholds or limit requirements at the server level.
      - When you enable one or more limit settings, the system then uses that data to take servers in and out
        of service.
      - You can define limits for any or all of the limit settings. However, when a server does not meet the resource
        threshold limit requirement, the system marks the entire server as unavailable and directs load-balancing
        traffic to another resource.
      - The limit settings available depend on the type of server.
    suboptions:
      bits_enabled:
        description:
          - Whether the bits limit is enabled or not.
          - This parameter allows you to switch on or off the effect of the limit.
        type: bool
      packets_enabled:
        description:
          - Whether the packets limit is enabled or not.
          - This parameter allows you to switch on or off the effect of the limit.
        type: bool
      connections_enabled:
        description:
          - Whether the current connections limit is enabled or not.
          - This parameter allows you to switch on or off the effect of the limit.
        type: bool
      bits_limit:
        description:
          - Specifies the maximum allowable data throughput rate, in bits per second, for the virtual servers on the server.
          - If the network traffic volume exceeds this limit, the system marks the server as unavailable.
      packets_limit:
        description:
          - Specifies the maximum allowable data transfer rate, in packets per second, for the virtual servers on the server.
          - If the network traffic volume exceeds this limit, the system marks the server as unavailable.
      connections_limit:
        description:
          - Specifies the maximum number of concurrent connections, combined, for all of the virtual servers on the server.
          - If the connections exceed this limit, the system marks the server as unavailable.
    version_added: 2.6
  partition:
    description:
      - Device partition to manage resources on.
    default: Common
    version_added: 2.6
  state:
    description:
      - When C(present), ensures that the resource exists.
      - When C(absent), ensures the resource is removed.
    default: present
    choices:
      - present
      - absent
      - enabled
      - disabled
extends_documentation_fragment: f5
author:
  - Tim Rupp (@caphrim007)
'''

EXAMPLES = r'''
- name: Enable virtual server
  bigip_gtm_virtual_server:
    server: lb.mydomain.com
    user: admin
    password: secret
    server_name: server1
    name: my-virtual-server
    state: enabled
  delegate_to: localhost
'''

RETURN = r'''
server_name:
  description: The server name associated with the virtual server.
  returned: changed
  type: string
  sample: /Common/my-gtm-server
address:
  description: The new address of the resource.
  returned: changed
  type: string
  sample: 1.2.3.4
port:
  description: The new port of the resource.
  returned: changed
  type: int
  sample: 500
translation_address:
  description: The new translation address of the resource.
  returned: changed
  type: int
  sample: 500
translation_port:
  description: The new translation port of the resource.
  returned: changed
  type: int
  sample: 500
availability_requirements:
  description: The new availability requirement configurations for the resource.
  returned: changed
  type: dict
  sample: {'type': 'all'}
monitors:
  description: The new list of monitors for the resource.
  returned: changed
  type: list
  sample: ['/Common/monitor1', '/Common/monitor2']
virtual_server_dependencies:
  description: The new list of virtual server dependencies for the resource
  returned: changed
  type: list
  sample: ['/Common/vs1', '/Common/vs2']
link:
  description: The new link value for the resource.
  returned: changed
  type: string
  sample: /Common/my-link
limits:
  description: The new limit configurations for the resource.
  returned: changed
  type: dict
  sample: { 'bits_enabled': true, 'bits_limit': 100 }
'''

import os
import re

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.basic import env_fallback

try:
    from library.module_utils.compat.ipaddress import ip_address
    from library.module_utils.network.f5.bigip import HAS_F5SDK
    from library.module_utils.network.f5.bigip import F5Client
    from library.module_utils.network.f5.common import F5ModuleError
    from library.module_utils.network.f5.common import AnsibleF5Parameters
    from library.module_utils.network.f5.common import cleanup_tokens
    from library.module_utils.network.f5.common import fq_name
    from library.module_utils.network.f5.common import compare_complex_list
    from library.module_utils.network.f5.common import f5_argument_spec
    from library.module_utils.network.f5.ipaddress import is_valid_ip
    from library.module_utils.network.f5.ipaddress import validate_ip_v6_address
    try:
        from library.module_utils.network.f5.common import iControlUnexpectedHTTPError
        from f5.sdk_exception import LazyAttributesRequired
    except ImportError:
        HAS_F5SDK = False
except ImportError:
    from ansible.module_utils.compat.ipaddress import ip_address
    from ansible.module_utils.network.f5.bigip import HAS_F5SDK
    from ansible.module_utils.network.f5.bigip import F5Client
    from ansible.module_utils.network.f5.common import F5ModuleError
    from ansible.module_utils.network.f5.common import AnsibleF5Parameters
    from ansible.module_utils.network.f5.common import cleanup_tokens
    from ansible.module_utils.network.f5.common import fq_name
    from ansible.module_utils.network.f5.common import compare_complex_list
    from ansible.module_utils.network.f5.common import f5_argument_spec
    from ansible.module_utils.network.f5.ipaddress import is_valid_ip
    from ansible.module_utils.network.f5.ipaddress import validate_ip_v6_address
    try:
        from ansible.module_utils.network.f5.common import iControlUnexpectedHTTPError
        from f5.sdk_exception import LazyAttributesRequired
    except ImportError:
        HAS_F5SDK = False


class Parameters(AnsibleF5Parameters):
    api_map = {
        'limitMaxBps': 'bits_limit',
        'limitMaxBpsStatus': 'bits_enabled',
        'limitMaxConnections': 'connections_limit',
        'limitMaxConnectionsStatus': 'connections_enabled',
        'limitMaxPps': 'packets_limit',
        'limitMaxPpsStatus': 'packets_enabled',
        'translationAddress': 'translation_address',
        'translationPort': 'translation_port',
        'dependsOn': 'virtual_server_dependencies',
        'explicitLinkName': 'link',
        'monitor': 'monitors'
    }

    api_attributes = [
        'dependsOn',
        'destination',
        'disabled',
        'enabled',
        'explicitLinkName',
        'limitMaxBps',
        'limitMaxBpsStatus',
        'limitMaxConnections',
        'limitMaxConnectionsStatus',
        'limitMaxPps',
        'limitMaxPpsStatus',
        'translationAddress',
        'translationPort',
        # The monitor attribute is not included here, because it can break the
        # API calls to the device. If this bug is ever fixed, uncomment this code.
        #
        # monitor
    ]

    returnables = [
        'bits_enabled',
        'bits_limit',
        'connections_enabled',
        'connections_limit',
        'destination',
        'disabled',
        'enabled',
        'link',
        'monitors',
        'packets_enabled',
        'packets_limit',
        'translation_address',
        'translation_port',
        'virtual_server_dependencies',
    ]

    updatables = [
        'bits_enabled',
        'bits_limit',
        'connections_enabled',
        'connections_limit',
        'destination',
        'enabled',
        'link',
        'monitors',
        'packets_limit',
        'packets_enabled',
        'translation_address',
        'translation_port',
        'virtual_server_dependencies',
    ]


class ApiParameters(Parameters):
    @property
    def address(self):
        if self._values['destination'].count(':') >= 2:
            # IPv6
            parts = self._values['destination'].split('.')
        else:
            # IPv4
            parts = self._values['destination'].split(':')
        if is_valid_ip(parts[0]):
            return str(parts[0])
        raise F5ModuleError(
            "'address' parameter from API was not an IP address."
        )

    @property
    def port(self):
        if self._values['destination'].count(':') >= 2:
            # IPv6
            parts = self._values['destination'].split('.')
            return parts[1]
        # IPv4
        parts = self._values['destination'].split(':')
        return int(parts[1])

    @property
    def virtual_server_dependencies(self):
        if self._values['virtual_server_dependencies'] is None:
            return None
        results = []
        for dependency in self._values['virtual_server_dependencies']:
            parts = dependency['name'].split(':')
            result = dict(
                server=parts[0],
                virtual_server=parts[1],
            )
            results.append(result)
        if results:
            results = sorted(results, key=lambda k: k['server'])
        return results

    @property
    def enabled(self):
        if 'enabled' in self._values:
            return True
        else:
            return False

    @property
    def disabled(self):
        if 'disabled' in self._values:
            return True
        return False

    @property
    def availability_requirement_type(self):
        if self._values['monitors'] is None:
            return None
        if 'min ' in self._values['monitors']:
            return 'at_least'
        elif 'require ' in self._values['monitors']:
            return 'require'
        else:
            return 'all'

    @property
    def monitors_list(self):
        if self._values['monitors'] is None:
            return []
        try:
            result = re.findall(r'/\w+/[^\s}]+', self._values['monitors'])
            result.sort()
            return result
        except Exception:
            return self._values['monitors']

    @property
    def monitors(self):
        if self._values['monitors'] is None:
            return None
        monitors = [fq_name(self.partition, x) for x in self.monitors_list]
        if self.availability_requirement_type == 'at_least':
            monitors = ' '.join(monitors)
            result = 'min {0} of {{ {1} }}'.format(self.at_least, monitors)
        elif self.availability_requirement_type == 'require':
            monitors = ' '.join(monitors)
            result = 'require {0} from {1} {{ {2} }}'.format(self.number_of_probes, self.number_of_probers, monitors)
        else:
            result = ' and '.join(monitors).strip()

        return result

    @property
    def number_of_probes(self):
        """Returns the probes value from the monitor string.

        The monitor string for a Require monitor looks like this.

            require 1 from 2 { /Common/tcp }

        This method parses out the first of the numeric values. This values represents
        the "probes" value that can be updated in the module.

        Returns:
             int: The probes value if found. None otherwise.
        """
        if self._values['monitors'] is None:
            return None
        pattern = r'require\s+(?P<probes>\d+)\s+from'
        matches = re.search(pattern, self._values['monitors'])
        if matches is None:
            return None
        return matches.group('probes')

    @property
    def number_of_probers(self):
        """Returns the probers value from the monitor string.

        The monitor string for a Require monitor looks like this.

            require 1 from 2 { /Common/tcp }

        This method parses out the first of the numeric values. This values represents
        the "probers" value that can be updated in the module.

        Returns:
             int: The probers value if found. None otherwise.
        """
        if self._values['monitors'] is None:
            return None
        pattern = r'require\s+\d+\s+from\s+(?P<probers>\d+)\s+'
        matches = re.search(pattern, self._values['monitors'])
        if matches is None:
            return None
        return matches.group('probers')

    @property
    def at_least(self):
        """Returns the 'at least' value from the monitor string.

        The monitor string for a Require monitor looks like this.

            min 1 of { /Common/gateway_icmp }

        This method parses out the first of the numeric values. This values represents
        the "at_least" value that can be updated in the module.

        Returns:
             int: The at_least value if found. None otherwise.
        """
        if self._values['monitors'] is None:
            return None
        pattern = r'min\s+(?P<least>\d+)\s+of\s+'
        matches = re.search(pattern, self._values['monitors'])
        if matches is None:
            return None
        return matches.group('least')


class ModuleParameters(Parameters):
    def _get_limit_value(self, type):
        if self._values['limits'] is None:
            return None
        if self._values['limits'][type] is None:
            return None
        return int(self._values['limits'][type])

    def _get_availability_value(self, type):
        if self._values['availability_requirements'] is None:
            return None
        if self._values['availability_requirements'][type] is None:
            return None
        return int(self._values['availability_requirements'][type])

    def _get_limit_status(self, type):
        if self._values['limits'] is None:
            return None
        if self._values['limits'][type] is None:
            return None
        if self._values['limits'][type]:
            return 'enabled'
        return 'disabled'

    @property
    def address(self):
        if self._values['address'] is None:
            return None
        if is_valid_ip(self._values['address']):
            ip = str(ip_address(u'{0}'.format(self._values['address'])))
            return ip
        raise F5ModuleError(
            "Specified 'address' is not an IP address."
        )

    @property
    def port(self):
        if self._values['port'] is None:
            return None
        if self._values['port'] == '*':
            return 0
        return int(self._values['port'])

    @property
    def destination(self):
        if self.address is None:
            return None
        if self.port is None:
            return None
        if validate_ip_v6_address(self.address):
            result = '{0}.{1}'.format(self.address, self.port)
        else:
            result = '{0}:{1}'.format(self.address, self.port)
        return result

    @property
    def link(self):
        if self._values['link'] is None:
            return None
        return fq_name(self.partition, self._values['link'])

    @property
    def bits_limit(self):
        return self._get_limit_value('bits_limit')

    @property
    def packets_limit(self):
        return self._get_limit_value('packets_limit')

    @property
    def connections_limit(self):
        return self._get_limit_value('connections_limit')

    @property
    def bits_enabled(self):
        return self._get_limit_status('bits_enabled')

    @property
    def packets_enabled(self):
        return self._get_limit_status('packets_enabled')

    @property
    def connections_enabled(self):
        return self._get_limit_status('connections_enabled')

    @property
    def translation_address(self):
        if self._values['translation_address'] is None:
            return None
        if self._values['translation_address'] == '':
            return 'none'
        return self._values['translation_address']

    @property
    def translation_port(self):
        if self._values['translation_port'] is None:
            return None
        if self._values['translation_port'] in ['*', ""]:
            return 0
        return int(self._values['translation_port'])

    @property
    def virtual_server_dependencies(self):
        if self._values['virtual_server_dependencies'] is None:
            return None
        results = []
        for dependency in self._values['virtual_server_dependencies']:
            result = dict(
                server=fq_name(self.partition, dependency['server']),
                virtual_server=os.path.basename(dependency['virtual_server'])
            )
            results.append(result)
        if results:
            results = sorted(results, key=lambda k: k['server'])
        return results

    @property
    def enabled(self):
        if self._values['state'] == 'enabled':
            return True
        elif self._values['state'] == 'disabled':
            return False
        else:
            return None

    @property
    def disabled(self):
        if self._values['state'] == 'enabled':
            return False
        elif self._values['state'] == 'disabled':
            return True
        else:
            return None

    @property
    def monitors_list(self):
        if self._values['monitors'] is None:
            return []
        try:
            result = re.findall(r'/\w+/[^\s}]+', self._values['monitors'])
            result.sort()
            return result
        except Exception:
            return self._values['monitors']

    @property
    def monitors(self):
        if self._values['monitors'] is None:
            return None
        monitors = [fq_name(self.partition, x) for x in self.monitors_list]
        if self.availability_requirement_type == 'at_least':
            if self.at_least > len(self.monitors_list):
                raise F5ModuleError(
                    "The 'at_least' value must not exceed the number of 'monitors'."
                )
            monitors = ' '.join(monitors)
            result = 'min {0} of {{ {1} }}'.format(self.at_least, monitors)
        elif self.availability_requirement_type == 'require':
            monitors = ' '.join(monitors)
            if self.number_of_probes > self.number_of_probers:
                raise F5ModuleError(
                    "The 'number_of_probes' must not exceed the 'number_of_probers'."
                )
            result = 'require {0} from {1} {{ {2} }}'.format(self.number_of_probes, self.number_of_probers, monitors)
        else:
            result = ' and '.join(monitors).strip()

        return result

    @property
    def availability_requirement_type(self):
        if self._values['availability_requirements'] is None:
            return None
        return self._values['availability_requirements']['type']

    @property
    def number_of_probes(self):
        return self._get_availability_value('number_of_probes')

    @property
    def number_of_probers(self):
        return self._get_availability_value('number_of_probers')

    @property
    def at_least(self):
        return self._get_availability_value('at_least')


class Changes(Parameters):
    def to_return(self):
        result = {}
        try:
            for returnable in self.returnables:
                result[returnable] = getattr(self, returnable)
            result = self._filter_params(result)
        except Exception:
            pass
        return result


class UsableChanges(Changes):
    @property
    def virtual_server_dependencies(self):
        if self._values['virtual_server_dependencies'] is None:
            return None
        results = []
        for depend in self._values['virtual_server_dependencies']:
            name = '{0}:{1}'.format(depend['server'], depend['virtual_server'])
            results.append(dict(name=name))
        return results


class ReportableChanges(Changes):
    pass


class Difference(object):
    def __init__(self, want, have=None):
        self.want = want
        self.have = have

    def compare(self, param):
        try:
            result = getattr(self, param)
            return result
        except AttributeError:
            return self.__default(param)

    def __default(self, param):
        attr1 = getattr(self.want, param)
        try:
            attr2 = getattr(self.have, param)
            if attr1 != attr2:
                return attr1
        except AttributeError:
            return attr1

    @property
    def destination(self):
        if self.want.port is None:
            self.want.update({'port': self.have.port})
        if self.want.address is None:
            self.want.update({'address': self.have.address})
        if self.want.destination != self.have.destination:
            return self.want.destination

    @property
    def virtual_server_dependencies(self):
        if self.have.virtual_server_dependencies is None:
            return self.want.virtual_server_dependencies
        if self.want.virtual_server_dependencies is None and self.have.virtual_server_dependencies is None:
            return None
        if self.want.virtual_server_dependencies is None:
            return None
        result = compare_complex_list(self.want.virtual_server_dependencies, self.have.virtual_server_dependencies)
        return result

    @property
    def enabled(self):
        if self.want.state == 'enabled' and self.have.disabled:
            result = dict(
                enabled=True,
                disabled=False
            )
            return result
        elif self.want.state == 'disabled' and self.have.enabled:
            result = dict(
                enabled=False,
                disabled=True
            )
            return result

    @property
    def monitors(self):
        if self.have.monitors is None:
            return self.want.monitors
        if self.have.monitors != self.want.monitors:
            return self.want.monitors


class ModuleManager(object):
    def __init__(self, *args, **kwargs):
        self.module = kwargs.get('module', None)
        self.client = kwargs.get('client', None)
        self.want = ModuleParameters(params=self.module.params)
        self.have = ApiParameters()
        self.changes = UsableChanges()

    def _set_changed_options(self):
        changed = {}
        for key in Parameters.returnables:
            if getattr(self.want, key) is not None:
                changed[key] = getattr(self.want, key)
        if changed:
            self.changes = UsableChanges(params=changed)

    def _update_changed_options(self):
        diff = Difference(self.want, self.have)
        updatables = Parameters.updatables
        changed = dict()
        for k in updatables:
            change = diff.compare(k)
            if change is None:
                continue
            else:
                if isinstance(change, dict):
                    changed.update(change)
                else:
                    changed[k] = change
        if changed:
            self.changes = UsableChanges(params=changed)
            return True
        return False

    def should_update(self):
        result = self._update_changed_options()
        if result:
            return True
        return False

    def exec_module(self):
        changed = False
        result = dict()
        state = self.want.state

        try:
            if state in ['present', 'enabled', 'disabled']:
                changed = self.present()
            elif state == 'absent':
                changed = self.absent()
        except iControlUnexpectedHTTPError as e:
            raise F5ModuleError(str(e))

        reportable = ReportableChanges(params=self.changes.to_return())
        changes = reportable.to_return()
        result.update(**changes)
        result.update(dict(changed=changed))
        self._announce_deprecations(result)
        return result

    def _announce_deprecations(self, result):
        warnings = result.pop('__warnings', [])
        for warning in warnings:
            self.client.module.deprecate(
                msg=warning['msg'],
                version=warning['version']
            )

    def present(self):
        if self.exists():
            return self.update()
        else:
            return self.create()

    def exists(self):
        resource = self.client.api.tm.gtm.servers.server.load(
            name=self.want.server_name,
            partition=self.want.partition
        )
        result = resource.virtual_servers_s.virtual_server.exists(
            name=self.want.name
        )
        return result

    def update(self):
        self.have = self.read_current_from_device()
        if not self.should_update():
            return False
        if self.module.check_mode:
            return True
        self.update_on_device()
        return True

    def remove(self):
        if self.module.check_mode:
            return True
        self.remove_from_device()
        if self.exists():
            raise F5ModuleError("Failed to delete the resource.")
        return True

    def create(self):
        if self.want.port in [None, ""]:
            self.want.update({'port': '*'})
        if self.want.translation_port in [None, ""]:
            self.want.update({'translation_port': '*'})
        if self.want.translation_address in [None, ""]:
            self.want.update({'translation_address': '::'})

        self._set_changed_options()

        if self.want.address is None:
            raise F5ModuleError(
                "You must supply an 'address' when creating a new virtual server."
            )
        if self.want.availability_requirement_type == 'require' and len(self.want.monitors_list) > 1:
            raise F5ModuleError(
                "Only one monitor may be specified when using an availability_requirement type of 'require'"
            )
        if self.module.check_mode:
            return True
        self.create_on_device()
        return True

    def create_on_device(self):
        params = self.changes.api_params()
        resource = self.client.api.tm.gtm.servers.server.load(
            name=self.want.server_name,
            partition=self.want.partition
        )
        resource.virtual_servers_s.virtual_server.create(
            name=self.want.name,
            **params
        )
        if self.want.monitors:
            self.update_monitors_on_device()

    def update_on_device(self):
        params = self.changes.api_params()
        resource = self.client.api.tm.gtm.servers.server.load(
            name=self.want.server_name,
            partition=self.want.partition
        )
        resource = resource.virtual_servers_s.virtual_server.load(
            name=self.want.name
        )
        resource.modify(**params)
        if self.want.monitors:
            self.update_monitors_on_device()

    def absent(self):
        if self.exists():
            return self.remove()
        return False

    def remove_from_device(self):
        resource = self.client.api.tm.gtm.servers.server.load(
            name=self.want.server_name,
            partition=self.want.partition
        )
        resource = resource.virtual_servers_s.virtual_server.load(
            name=self.want.name
        )
        if resource:
            resource.delete()

    def read_current_from_device(self):
        resource = self.client.api.tm.gtm.servers.server.load(
            name=self.want.server_name,
            partition=self.want.partition
        )
        resource = resource.virtual_servers_s.virtual_server.load(
            name=self.want.name
        )
        result = resource.attrs
        return ApiParameters(params=result)

    def update_monitors_on_device(self):
        """Updates the monitors string on a virtual server

        There is a long-standing bug in GTM virtual servers where the monitor value
        is a string that includes braces. These braces cause the REST API to panic and
        fail to update or create any resources that have an "at_least" or "require"
        set of availability_requirements.

        This method exists to do a tmsh command to cause the update to take place on
        the device.

        Preferably, this method can be removed and the bug be fixed. The API should
        be working, obviously, but the more concerning issue is if tmsh commands change
        over time, breaking this method.
        """
        command = 'tmsh modify gtm server /{0}/{1} virtual-servers modify {{ {2} {{ monitor {3} }} }}'.format(
            self.want.partition, self.want.server_name, self.want.name, self.want.monitors
        )
        output = self.client.api.tm.util.bash.exec_cmd(
            'run',
            utilCmdArgs='-c "{0}"'.format(command)
        )
        try:
            if hasattr(output, 'commandResult'):
                if len(output.commandResult.strip()) > 0:
                    raise F5ModuleError(output.commandResult)
        except (AttributeError, NameError, LazyAttributesRequired):
            pass
        return True


class ArgumentSpec(object):
    def __init__(self):
        self.supports_check_mode = True
        argument_spec = dict(
            name=dict(required=True),
            server_name=dict(required=True),
            address=dict(),
            port=dict(type='int'),
            translation_address=dict(),
            translation_port=dict(),
            availability_requirements=dict(
                type='dict',
                options=dict(
                    type=dict(
                        choices=['all', 'at_least', 'require'],
                        required=True
                    ),
                    at_least=dict(type='int'),
                    number_of_probes=dict(type='int'),
                    number_of_probers=dict(type='int')
                ),
                mutually_exclusive=[
                    ['at_least', 'number_of_probes'],
                    ['at_least', 'number_of_probers'],
                ],
                required_if=[
                    ['type', 'at_least', ['at_least']],
                    ['type', 'require', ['number_of_probes', 'number_of_probers']]
                ]
            ),
            monitors=dict(type='list'),
            virtual_server_dependencies=dict(
                type='list',
                options=dict(
                    server=dict(required=True),
                    virtual_server=dict(required=True)
                )
            ),
            link=dict(),
            limits=dict(
                type='dict',
                options=dict(
                    bits_enabled=dict(type='bool'),
                    packets_enabled=dict(type='bool'),
                    connections_enabled=dict(type='bool'),
                    bits_limit=dict(type='int'),
                    packets_limit=dict(type='int'),
                    connections_limit=dict(type='int')
                )
            ),
            state=dict(
                default='present',
                choices=['present', 'absent', 'disabled', 'enabled']
            ),
            partition=dict(
                default='Common',
                fallback=(env_fallback, ['F5_PARTITION'])
            )
        )
        self.argument_spec = {}
        self.argument_spec.update(f5_argument_spec)
        self.argument_spec.update(argument_spec)


def main():
    spec = ArgumentSpec()

    module = AnsibleModule(
        argument_spec=spec.argument_spec,
        supports_check_mode=spec.supports_check_mode,
    )
    if not HAS_F5SDK:
        module.fail_json(msg="The python f5-sdk module is required")

    try:
        client = F5Client(**module.params)
        mm = ModuleManager(module=module, client=client)
        results = mm.exec_module()
        cleanup_tokens(client)
        module.exit_json(**results)
    except F5ModuleError as ex:
        cleanup_tokens(client)
        module.fail_json(msg=str(ex))


if __name__ == '__main__':
    main()
