#!/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

DOCUMENTATION = r'''
---
module: bigip_snmp_community
short_description: Manages SNMP communities on a BIG-IP.
description:
  - Assists in managing Simple Network Management Protocol (SNMP) communities on a BIG-IP system. Different SNMP versions are supported
    by this module. Note the different parameters offered by this module, as different
    parameters work for different versions of SNMP. This is important if you
    are mixing versions C(v2c) and C(3).
version_added: "1.0.0"
options:
  state:
    description:
      - When C(present), ensures the address list and entries exists.
      - When C(absent), ensures the address list is removed.
    type: str
    choices:
      - present
      - absent
    default: present
  version:
    description:
      - Specifies to which SNMP version the trap destination applies.
    type: str
    choices:
      - v1
      - v2c
      - v3
    default: v2c
  name:
    description:
      - Name that identifies the SNMP community.
      - When C(version) is C(v1) or C(v2c), this parameter is required.
      - The name C(public) is a reserved name on the BIG-IP. This module handles that name differently
        than others. Functionally, you should not see a difference.
    type: str
  community:
    description:
      - Specifies the community string (password) for access to the MIB.
      - This parameter is only relevant when C(version) is C(v1) or C(v2c). If C(version) is
        something else, this parameter is ignored.
    type: str
  source:
    description:
      - Specifies the source address for access to the MIB.
      - This parameter can accept a value of C(all).
      - If this parameter is not specified, the value is C(all).
      - This parameter is only relevant when C(version) is C(v1) or C(v2c). If C(version) is
        something else, this parameter is ignored.
      - If C(source) is set to C(all), it is not possible to specify an C(oid). This will
        raise an error.
      - You should provide this parameter when C(state) is C(absent), so the correct community
        is removed. To remove the C(public) SNMP community that comes with a BIG-IP, this parameter
        should be C(default).
    type: str
  port:
    description:
      - Specifies the port for the trap destination.
      - This parameter is only relevant when C(version) is C(v1) or C(v2c). If C(version) is
        something else, this parameter is ignored.
    type: int
  oid:
    description:
      - Specifies the object identifier (OID) for the record.
      - When C(version) is C(v3), this parameter is required.
      - When C(version) is either C(v1) or C(v2c), if this value is specified, then C(source)
        must not be set to C(all).
    type: str
  access:
    description:
      - Specifies the user's access level to the MIB.
      - When creating a new community, if this parameter is not specified, the default is C(ro).
      - When C(ro), specifies the user can view the MIB, but cannot modify the MIB.
      - When C(rw), specifies the user can view and modify the MIB.
    type: str
    choices:
      - ro
      - rw
      - read-only
      - read-write
  ip_version:
    description:
      - Specifies whether the record applies to IPv4 or IPv6 addresses.
      - When creating a new community, if this value is not specified, the default is C(4).
      - This parameter is only relevant when C(version) is C(v1) or C(v2c). If C(version) is
        something else, this parameter is ignored.
    type: str
    choices:
      - '4'
      - '6'
  snmp_username:
    description:
      - Specifies the name of the user for whom you want to grant access to the SNMP v3 MIB.
      - This parameter is only relevant when C(version) is C(v3). If C(version) is something
        else, this parameter is ignored.
      - When creating a new SNMP C(v3) community, this parameter is required.
      - This parameter cannot be changed once it has been set.
    type: str
  snmp_auth_protocol:
    description:
      - Specifies the authentication method for the user.
      - When C(md5), specifies the system uses the MD5 algorithm to authenticate the user.
      - When C(sha), specifies the secure hash algorithm (SHA) to authenticate the user.
      - When C(none), specifies the user does not require authentication.
      - When creating a new SNMP C(v3) community, if this parameter is not specified, the default
        is C(sha).
    type: str
    choices:
      - md5
      - sha
      - none
  snmp_auth_password:
    description:
      - Specifies the password for the user.
      - When creating a new SNMP C(v3) community, this parameter is required.
      - This value must be at least 8 characters long.
    type: str
  snmp_privacy_protocol:
    description:
      - Specifies the encryption protocol.
      - When C(aes), specifies the system encrypts the user information using AES
        (Advanced Encryption Standard).
      - When C(des), specifies the system encrypts the user information using DES
        (Data Encryption Standard).
      - When C(none), specifies the system does not encrypt the user information.
      - When creating a new SNMP C(v3) community, if this parameter is not specified, the
        default is C(aes).
    type: str
    choices:
      - aes
      - des
      - none
  snmp_privacy_password:
    description:
      - Specifies the password for the user.
      - When creating a new SNMP C(v3) community, this parameter is required.
      - This value must be at least 8 characters long.
    type: str
  update_password:
    description:
      - C(always) allows users to update passwords.
        C(on_create) only sets the password for newly created resources.
    type: str
    choices:
      - always
      - on_create
    default: always
  partition:
    description:
      - Device partition to manage resources on.
    type: str
    default: Common
extends_documentation_fragment: f5networks.f5_modules.f5
author:
  - Tim Rupp (@caphrim007)
  - Wojciech Wypior (@wojtek0806)
'''

EXAMPLES = r'''
- name: Create an SMNP v2c read-only community
  bigip_snmp_community:
    name: foo
    version: v2c
    source: all
    oid: .1
    access: ro
    provider:
      password: secret
      server: lb.mydomain.com
      user: admin
  delegate_to: localhost

- name: Create an SMNP v3 read-write community
  bigip_snmp_community:
    name: foo
    version: v3
    snmp_username: foo
    snmp_auth_protocol: sha
    snmp_auth_password: secret
    snmp_privacy_protocol: aes
    snmp_privacy_password: secret
    oid: .1
    access: rw
    provider:
      password: secret
      server: lb.mydomain.com
      user: admin
  delegate_to: localhost

- name: Remove the default 'public' SNMP community
  bigip_snmp_community:
    name: public
    source: default
    state: absent
    provider:
      password: secret
      server: lb.mydomain.com
      user: admin
  delegate_to: localhost
'''

RETURN = r'''
community:
  description: The new community value.
  returned: changed
  type: str
  sample: community1
oid:
  description: The new OID value.
  returned: changed
  type: str
  sample: .1
ip_version:
  description: The new IP version value.
  returned: changed
  type: str
  sample: .1
snmp_auth_protocol:
  description: The new SNMP auth protocol.
  returned: changed
  type: str
  sample: sha
snmp_privacy_protocol:
  description: The new SNMP privacy protocol.
  returned: changed
  type: str
  sample: aes
access:
  description: The new access level for the MIB.
  returned: changed
  type: str
  sample: ro
source:
  description: The new source address to access the MIB.
  returned: changed
  type: str
  sample: 1.1.1.1
snmp_username:
  description: The new SNMP username.
  returned: changed
  type: str
  sample: user1
snmp_auth_password:
  description: The new password of the given snmp_username.
  returned: changed
  type: str
  sample: secret1
snmp_privacy_password:
  description: The new password of the given snmp_username.
  returned: changed
  type: str
  sample: secret2
'''
from datetime import datetime

from ansible.module_utils.basic import (
    AnsibleModule, env_fallback
)

from ..module_utils.bigip import F5RestClient
from ..module_utils.common import (
    F5ModuleError, AnsibleF5Parameters, transform_name, f5_argument_spec
)
from ..module_utils.icontrol import tmos_version
from ..module_utils.teem import send_teem


class Parameters(AnsibleF5Parameters):
    api_map = {
        'communityName': 'community',
        'oidSubset': 'oid',
        'ipv6': 'ip_version',
        'authProtocol': 'snmp_auth_protocol',
        'privacyProtocol': 'snmp_privacy_protocol',
        'username': 'snmp_username',
        'securityLevel': 'security_level',
        'authPassword': 'snmp_auth_password',
        'privacyPassword': 'snmp_privacy_password',
    }

    api_attributes = [
        'source',
        'oidSubset',
        'ipv6',
        'communityName',
        'access',
        'authPassword',
        'authProtocol',
        'username',
        'securityLevel',
        'privacyProtocol',
        'privacyPassword',
    ]

    returnables = [
        'community',
        'oid',
        'ip_version',
        'snmp_auth_protocol',
        'snmp_privacy_protocol',
        'access',
        'source',
        'snmp_username',
        'snmp_auth_password',
        'snmp_privacy_password',
    ]

    updatables = [
        'community',
        'oid',
        'ip_version',
        'snmp_auth_protocol',
        'snmp_privacy_protocol',
        'access',
        'source',
        'snmp_auth_password',
        'snmp_privacy_password',
        'security_level',
        'snmp_username',
    ]

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


class ApiParameters(Parameters):
    @property
    def ip_version(self):
        if self._values['ip_version'] is None:
            return None
        if self._values['ip_version'] == 'enabled':
            return 6
        return 4

    @property
    def source(self):
        if self._values['source'] is None:
            return 'all'
        return self._values['source']


class ModuleParameters(Parameters):
    @property
    def ip_version(self):
        if self._values['ip_version'] is None:
            return None
        return int(self._values['ip_version'])

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

    @property
    def access(self):
        if self._values['access'] is None:
            return None
        elif self._values['access'] in ['ro', 'read-only']:
            return 'ro'
        elif self._values['access'] in ['rw', 'read-write']:
            return 'rw'
        else:
            raise F5ModuleError(
                "Unknown access format specified: '{0}'.".format(self._values['access'])
            )

    @property
    def snmp_auth_password(self):
        if self._values['snmp_auth_password'] is None:
            return None
        if len(self._values['snmp_auth_password']) < 8:
            raise F5ModuleError(
                "snmp_auth_password must be at least 8 characters long."
            )
        return self._values['snmp_auth_password']

    @property
    def snmp_privacy_password(self):
        if self._values['snmp_privacy_password'] is None:
            return None
        if len(self._values['snmp_privacy_password']) < 8:
            raise F5ModuleError(
                "snmp_privacy_password must be at least 8 characters long."
            )
        return self._values['snmp_privacy_password']

    @property
    def name(self):
        if self._values['name'] == 'public':
            return 'comm-public'
        return self._values['name']


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 ip_version(self):
        if self._values['ip_version'] is None:
            return None
        elif self._values['ip_version'] == 4:
            return 'disabled'
        return 'enabled'

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


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

    def _check_source_and_oid(self):
        if self.have.oid is not None:
            if self.want.source == 'all' and self.want.oid != '':
                raise F5ModuleError(
                    "When specifying an 'all' source for a resource with an existing OID, "
                    "you must specify a new, empty, OID."
                )
        if self.want.source == 'all' and self.want.oid != '':
            raise F5ModuleError(
                "When specifying an 'all' source for a resource, you may not specify an OID."
            )

    @property
    def source(self):
        self._check_source_and_oid()
        if self.want.source != self.have.source:
            return self.want.source

    @property
    def oid(self):
        self._check_source_and_oid()
        if self.want.oid != self.have.oid:
            return self.want.oid

    @property
    def snmp_privacy_password(self):
        if self.want.update_password == 'always' and self.want.snmp_privacy_password is not None:
            return self.want.snmp_privacy_password

    @property
    def snmp_auth_password(self):
        if self.want.update_password == 'always' and self.want.snmp_auth_password is not None:
            return self.want.snmp_auth_password


class ModuleManager(object):
    def __init__(self, *args, **kwargs):
        self.kwargs = kwargs
        self.client = kwargs.get('client', None)
        self.module = kwargs.get('module', None)

    def exec_module(self):
        if self.version_is_less_than_3():
            manager = self.get_manager('v1')
        else:
            manager = self.get_manager('v2')
        return manager.exec_module()

    def get_manager(self, type):
        if type == 'v1':
            return V1Manager(**self.kwargs)
        elif type == 'v2':
            return V2Manager(**self.kwargs)

    def version_is_less_than_3(self):
        version = self.module.params.get('version')
        if version == 'v3':
            return False
        else:
            return True


class BaseManager(object):
    def __init__(self, *args, **kwargs):
        self.module = kwargs.get('module', None)
        self.client = F5RestClient(**self.module.params)
        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):
        start = datetime.now().isoformat()
        version = tmos_version(self.client)
        changed = False
        result = dict()
        state = self.want.state

        if state == "present":
            changed = self.present()
        elif state == "absent":
            changed = self.absent()

        reportable = ReportableChanges(params=self.changes.to_return())
        changes = reportable.to_return()
        result.update(**changes)
        result.update(dict(changed=changed))
        self._announce_deprecations(result)
        send_teem(start, self.client, self.module, version)
        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 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 absent(self):
        if self.exists():
            return self.remove()
        return False


class V1Manager(BaseManager):
    """Handles SNMP v1 and v2c

    """
    def create(self):
        if self.want.ip_version is None:
            self.want.update({'ip_version': 4})
        if self.want.access is None:
            self.want.update({'access': 'ro'})
        self._set_changed_options()
        if self.want.oid is not None and self.want.source == 'all':
            raise F5ModuleError(
                "When specify an oid, source may not be set to 'all'."
            )
        if self.module.check_mode:
            return True
        self.create_on_device()
        return True

    def exists(self):
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/communities/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.name)
        )
        resp = self.client.api.get(uri)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if resp.status == 404 or 'code' in response and response['code'] == 404:
            return False
        if resp.status in [200, 201] or 'code' in response and response['code'] in [200, 201]:
            return True

        errors = [401, 403, 409, 500, 501, 502, 503, 504]

        if resp.status in errors or 'code' in response and response['code'] in errors:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)

    def create_on_device(self):
        params = self.changes.api_params()
        params['name'] = self.want.name
        params['partition'] = self.want.partition
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/communities/".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
        )
        resp = self.client.api.post(uri, json=params)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if 'code' in response and response['code'] in [400, 403]:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)

    def update_on_device(self):
        params = self.changes.api_params()
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/communities/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.name)
        )
        resp = self.client.api.patch(uri, json=params)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if 'code' in response and response['code'] == 400:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)

    def remove_from_device(self):
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/communities/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.name)
        )
        resp = self.client.api.delete(uri)
        if resp.status == 200:
            return True

    def read_current_from_device(self):
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/communities/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.name)
        )
        resp = self.client.api.get(uri)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if 'code' in response and response['code'] == 400:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)
        return ApiParameters(params=response)


class V2Manager(BaseManager):
    """Handles SNMP v3

    SNMP v3 has (almost) a completely separate set of variables than v2c or v1.
    The functionality is placed in this separate class to handle these differences.

    """
    def create(self):
        if self.want.access is None:
            self.want.update({'access': 'ro'})
        if self.want.snmp_auth_protocol is None:
            self.want.update({'snmp_auth_protocol': 'sha'})
        if self.want.snmp_privacy_protocol is None:
            self.want.update({'snmp_privacy_protocol': 'aes'})

        self._set_changed_options()
        if self.want.snmp_username is None:
            raise F5ModuleError(
                "snmp_username must be specified when creating a new v3 community."
            )
        if self.want.snmp_auth_password is None:
            raise F5ModuleError(
                "snmp_auth_password must be specified when creating a new v3 community."
            )
        if self.want.snmp_privacy_password is None:
            raise F5ModuleError(
                "snmp_privacy_password must be specified when creating a new v3 community."
            )
        if self.want.oid is None:
            raise F5ModuleError(
                "oid must be specified when creating a new v3 community."
            )
        if self.module.check_mode:
            return True
        self.create_on_device()
        return True

    def exists(self):
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/users/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.snmp_username)
        )
        resp = self.client.api.get(uri)
        try:
            response = resp.json()
        except ValueError:
            return False
        if resp.status == 404 or 'code' in response and response['code'] == 404:
            return False
        return True

    def create_on_device(self):
        params = self.changes.api_params()
        params['name'] = self.want.snmp_username
        params['partition'] = self.want.partition
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/users/".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
        )
        resp = self.client.api.post(uri, json=params)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if 'code' in response and response['code'] in [400, 403]:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)

    def update_on_device(self):
        params = self.changes.api_params()
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/users/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.snmp_username)
        )
        resp = self.client.api.patch(uri, json=params)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if 'code' in response and response['code'] == 400:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)

    def remove_from_device(self):
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/users/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.snmp_username)
        )
        resp = self.client.api.delete(uri)
        if resp.status == 200:
            return True

    def read_current_from_device(self):
        uri = "https://{0}:{1}/mgmt/tm/sys/snmp/users/{2}".format(
            self.client.provider['server'],
            self.client.provider['server_port'],
            transform_name(self.want.partition, self.want.snmp_username)
        )
        resp = self.client.api.get(uri)
        try:
            response = resp.json()
        except ValueError as ex:
            raise F5ModuleError(str(ex))

        if 'code' in response and response['code'] == 400:
            if 'message' in response:
                raise F5ModuleError(response['message'])
            else:
                raise F5ModuleError(resp.content)
        return ApiParameters(params=response)


class ArgumentSpec(object):
    def __init__(self):
        self.supports_check_mode = True
        argument_spec = dict(
            version=dict(
                default='v2c',
                choices=['v1', 'v2c', 'v3']
            ),
            name=dict(),
            community=dict(),
            source=dict(),
            port=dict(type='int'),
            oid=dict(),
            access=dict(
                choices=['ro', 'rw', 'read-only', 'read-write']
            ),
            ip_version=dict(
                choices=['4', '6']
            ),
            snmp_username=dict(),
            snmp_auth_protocol=dict(
                choices=['md5', 'sha', 'none']
            ),
            snmp_auth_password=dict(no_log=True),
            snmp_privacy_protocol=dict(
                choices=['aes', 'des', 'none']
            ),
            snmp_privacy_password=dict(no_log=True),
            update_password=dict(
                default='always',
                choices=['always', 'on_create'],
                no_log=False
            ),
            state=dict(default='present', choices=['absent', 'present']),
            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)
        self.required_if = [
            ['version', 'v1', ['name']],
            ['version', 'v2', ['name']],
            ['version', 'v3', ['snmp_username']]
        ]


def main():
    spec = ArgumentSpec()

    module = AnsibleModule(
        argument_spec=spec.argument_spec,
        supports_check_mode=spec.supports_check_mode,
        required_if=spec.required_if
    )

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


if __name__ == '__main__':
    main()
