# Copyright 2016 Capital One Services, LLC
#
# 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 datetime import datetime, timedelta
from dateutil.parser import parse
from dateutil.tz import tzutc

from c7n.actions import BaseAction
from c7n.filters import ValueFilter, Filter
from c7n.manager import resources
from c7n.query import QueryResourceManager, ResourceQuery
from c7n.utils import local_session, type_schema


@resources.register('iam-group')
class Group(QueryResourceManager):

    class resource_type(ResourceQuery.resolve('aws.iam.group')):
        config_type = "AWS::IAM::Group"


@resources.register('iam-role')
class Role(QueryResourceManager):

    class resource_type(ResourceQuery.resolve('aws.iam.role')):
        config_type = "AWS::IAM::Role"


@resources.register('iam-user')
class User(QueryResourceManager):

    class resource_type(ResourceQuery.resolve('aws.iam.user')):
        config_type = "AWS::IAM::User"


@resources.register('iam-policy')
class Policy(QueryResourceManager):

    class resource_type(ResourceQuery.resolve('aws.iam.policy')):
        config_type = "AWS::IAM::Policy"



@resources.register('iam-profile')
class InstanceProfile(QueryResourceManager):
    resource_type = 'aws.iam.instance-profile'


@resources.register('iam-certificate')
class ServerCertificate(QueryResourceManager):
    resource_type = 'aws.iam.server-certificate'


class IamRoleUsage(Filter):

    def service_role_usage(self):
        results = set()
        results.update(self.scan_lambda_roles())
        results.update(self.scan_ecs_roles())
        results.update(self.scan_asg_roles())
        results.update(self.scan_ec2_roles())
        return results

    def instance_profile_usage(self):
        results = set()
        results.update(self.scan_asg_roles())
        results.update(self.scan_ec2_roles())
        return results

    def scan_lambda_roles(self):
        from c7n.resources.awslambda import AWSLambda
        manager = AWSLambda(self.manager.ctx, {})
        return [r['Role'] for r in manager.resources() if 'Role' in r]

    def scan_ecs_roles(self):
        results = []
        client = local_session(self.manager.session_factory).client('ecs')
        for cluster in client.describe_clusters()['clusters']:
            svcs = client.list_services(cluster=cluster)['serviceArns']
            for svc in client.describe_services(
                    cluster=cluster, services=svcs)['services']:
                if 'roleArn' not in svc:
                    continue
                results.append(svc['roleArn'])
        return results

    def scan_asg_roles(self):
        from c7n.resources.asg import LaunchConfig
        manager = LaunchConfig(self.manager.ctx, {
            'resource': 'launch-config'})
        return [r['IamInstanceProfile'] for r in manager.resources()
                if 'IamInstanceProfile' in r]

    def scan_ec2_roles(self):
        from c7n.resources.ec2 import EC2
        manager = EC2(self.manager.ctx, {})

        results = []
        for e in manager.resources():
            if 'Instances' not in e:
                continue
            for i in e['Instances']:
                if 'IamInstanceProfile' not in i:
                    continue
                results.append(i['IamInstanceProfile']['Arn'])
        return results


###################
#    IAM Roles    #
###################


@Role.filter_registry.register('used')
class UsedIamRole(IamRoleUsage):

    schema = type_schema('used')

    def process(self, resources, event=None):
        roles = self.service_role_usage()
        results = []
        for r in resources:
            if r['Arn'] in roles or r['RoleName'] in roles:
                results.append(r)
        self.log.info("%d of %d iam roles currently used." % (
            len(results), len(resources)))
        return results


@Role.filter_registry.register('unused')
class UnusedIamRole(IamRoleUsage):

    schema = type_schema('unused')

    def process(self, resources, event=None):
        roles = self.service_role_usage()