#
#    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.

from heat.common import exception
from heat.common.i18n import _
from heat.engine import attributes
from heat.engine import constraints
from heat.engine import properties
from heat.engine.resources.openstack.neutron import neutron
from heat.engine import support
from heat.engine import translation


class L7Policy(neutron.NeutronResource):
    """A resource for managing LBaaS v2 L7Policies.

    This resource manages Neutron-LBaaS v2 L7Policies, which represent
    a collection of L7Rules. L7Policy holds the action that should be performed
    when the rules are matched (Redirect to Pool, Redirect to URL, Reject).
    L7Policy holds a Listener id, so a Listener can evaluate a collection of
    L7Policies. L7Policy will return True when all of the L7Rules that belong
    to this L7Policy are matched. L7Policies under a specific Listener are
    ordered and the first l7Policy that returns a match will be executed.
    When none of the policies match the request gets forwarded to
    listener.default_pool_id.
    """

    support_status = support.SupportStatus(version='7.0.0')

    required_service_extension = 'lbaasv2'

    PROPERTIES = (
        NAME, DESCRIPTION, ADMIN_STATE_UP, ACTION,
        REDIRECT_POOL, REDIRECT_URL, POSITION, LISTENER
    ) = (
        'name', 'description', 'admin_state_up', 'action',
        'redirect_pool', 'redirect_url', 'position', 'listener'
    )

    L7ACTIONS = (
        REJECT, REDIRECT_TO_POOL, REDIRECT_TO_URL
    ) = (
        'REJECT', 'REDIRECT_TO_POOL', 'REDIRECT_TO_URL'
    )

    ATTRIBUTES = (RULES_ATTR) = ('rules')

    properties_schema = {
        NAME: properties.Schema(
            properties.Schema.STRING,
            _('Name of the policy.'),
            update_allowed=True
        ),
        DESCRIPTION: properties.Schema(
            properties.Schema.STRING,
            _('Description of the policy.'),
            update_allowed=True
        ),
        ADMIN_STATE_UP: properties.Schema(
            properties.Schema.BOOLEAN,
            _('The administrative state of the policy.'),
            default=True,
            update_allowed=True
        ),
        ACTION: properties.Schema(
            properties.Schema.STRING,
            _('Action type of the policy.'),
            required=True,
            constraints=[constraints.AllowedValues(L7ACTIONS)],
            update_allowed=True
        ),
        REDIRECT_POOL: properties.Schema(
            properties.Schema.STRING,
            _('ID or name of the pool for REDIRECT_TO_POOL action type.'),
            constraints=[
                constraints.CustomConstraint('neutron.lbaas.pool')
            ],
            update_allowed=True
        ),
        REDIRECT_URL: properties.Schema(
            properties.Schema.STRING,
            _('URL for REDIRECT_TO_URL action type. '
              'This should be a valid URL string.'),
            update_allowed=True
        ),
        POSITION: properties.Schema(
            properties.Schema.NUMBER,
            _('L7 policy position in ordered policies list. This must be '
              'an integer starting from 1. If not specified, policy will be '
              'placed at the tail of existing policies list.'),
            constraints=[constraints.Range(min=1)],
            update_allowed=True
        ),
        LISTENER: properties.Schema(
            properties.Schema.STRING,
            _('ID or name of the listener this policy belongs to.'),
            required=True,
            constraints=[
                constraints.CustomConstraint('neutron.lbaas.listener')
            ]
        ),
    }

    attributes_schema = {
        RULES_ATTR: attributes.Schema(
            _('L7Rules associated with this policy.'),
            type=attributes.Schema.LIST
        ),
    }

    def translation_rules(self, props):
        return [
            translation.TranslationRule(
                props,
                translation.TranslationRule.RESOLVE,
                [self.LISTENER],
                client_plugin=self.client_plugin(),
                finder='find_resourceid_by_name_or_id',
                entity='listener'
            ),
        ]

    def __init__(self, name, definition, stack):
        super(L7Policy, self).__init__(name, definition, stack)
        self._lb_id = None

    @property
    def lb_id(self):
        if self._lb_id is None:
            listener_id = self.properties[self.LISTENER]
            listener = self.client().show_listener(listener_id)['listener']
            self._lb_id = listener['loadbalancers'][0]['id']
        return self._lb_id

    def validate(self):
        res = super(L7Policy, self).validate()
        if res:
            return res

        if (self.properties[self.ACTION] == self.REJECT and
                (self.properties[self.REDIRECT_POOL] is not None or
                 self.properties[self.REDIRECT_URL] is not None)):
            msg = (_('Properties %(pool)s and %(url)s are not required when '
                     '%(action)s type is set to %(action_type)s.') %
                   {'pool': self.REDIRECT_POOL,
                    'url': self.REDIRECT_URL,
                    'action': self.ACTION,
                    'action_type': self.REJECT})
            raise exception.StackValidationFailed(message=msg)

        if self.properties[self.ACTION] == self.REDIRECT_TO_POOL:
            if self.properties[self.REDIRECT_URL] is not None:
                raise exception.ResourcePropertyValueDependency(
                    prop1=self.REDIRECT_URL,
                    prop2=self.ACTION,
                    value=self.REDIRECT_TO_URL)
            if self.properties[self.REDIRECT_POOL] is None:
                msg = (_('Property %(pool)s is required when %(action)s '
                         'type is set to %(action_type)s.') %
                       {'pool': self.REDIRECT_POOL,
                        'action': self.ACTION,
                        'action_type': self.REDIRECT_TO_POOL})
                raise exception.StackValidationFailed(message=msg)

        if self.properties[self.ACTION] == self.REDIRECT_TO_URL:
            if self.properties[self.REDIRECT_POOL] is not None:
                raise exception.ResourcePropertyValueDependency(
                    prop1=self.REDIRECT_POOL,
                    prop2=self.ACTION,
                    value=self.REDIRECT_TO_POOL)
            if self.properties[self.REDIRECT_URL] is None:
                msg = (_('Property %(url)s is required when %(action)s '
                         'type is set to %(action_type)s.') %
                       {'url': self.REDIRECT_URL,
                        'action': self.ACTION,
                        'action_type': self.REDIRECT_TO_URL})
                raise exception.StackValidationFailed(message=msg)

    def _check_lb_status(self):
        return self.client_plugin().check_lb_status(self.lb_id)

    def handle_create(self):
        properties = self.prepare_properties(
            self.properties,
            self.physical_resource_name())

        properties['listener_id'] = properties.pop(self.LISTENER)
        if self.properties[self.REDIRECT_POOL] is not None:
            self.client_plugin().resolve_pool(
                properties, self.REDIRECT_POOL, 'redirect_pool_id')

        return properties

    def check_create_complete(self, properties):
        if self.resource_id is None:
            try:
                l7policy = self.client().create_lbaas_l7policy(
                    {'l7policy': properties})['l7policy']
                self.resource_id_set(l7policy['id'])
            except Exception as ex:
                if self.client_plugin().is_invalid(ex):
                    return False
                raise

        return self._check_lb_status()

    def _show_resource(self):
        return self.client().show_lbaas_l7policy(self.resource_id)['l7policy']

    def handle_update(self, json_snippet, tmpl_diff, prop_diff):
        self._update_called = False
        if self.REDIRECT_POOL in prop_diff:
            if prop_diff[self.REDIRECT_POOL] is not None:
                self.client_plugin().resolve_pool(
                    prop_diff, self.REDIRECT_POOL, 'redirect_pool_id')
            else:
                prop_diff.pop(self.REDIRECT_POOL)
                prop_diff['redirect_pool_id'] = None
        return prop_diff

    def check_update_complete(self, prop_diff):
        if not prop_diff:
            return True

        if not self._update_called:
            try:
                self.client().update_lbaas_l7policy(
                    self.resource_id, {'l7policy': prop_diff})
                self._update_called = True
            except Exception as ex:
                if self.client_plugin().is_invalid(ex):
                    return False
                raise

        return self._check_lb_status()

    def handle_delete(self):
        self._delete_called = False

    def check_delete_complete(self, data):
        if self.resource_id is None:
            return True

        if not self._delete_called:
            try:
                self.client().delete_lbaas_l7policy(self.resource_id)
                self._delete_called = True
            except Exception as ex:
                if self.client_plugin().is_invalid(ex):
                    return False
                elif self.client_plugin().is_not_found(ex):
                    return True
                raise

        return self._check_lb_status()


def resource_mapping():
    return {
        'OS::Neutron::LBaaS::L7Policy': L7Policy
    }
