# Copyright 2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
#     http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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.

# Class to create default roles for datapipeline

import logging
import warnings
from awscli.customizations.datapipeline.constants \
    import DATAPIPELINE_DEFAULT_SERVICE_ROLE_NAME, \
    DATAPIPELINE_DEFAULT_RESOURCE_ROLE_NAME, \
    DATAPIPELINE_DEFAULT_SERVICE_ROLE_ARN, \
    DATAPIPELINE_DEFAULT_RESOURCE_ROLE_ARN, \
    DATAPIPELINE_DEFAULT_SERVICE_ROLE_ASSUME_POLICY, \
    DATAPIPELINE_DEFAULT_RESOURCE_ROLE_ASSUME_POLICY
from awscli.customizations.commands import BasicCommand
from awscli.customizations.datapipeline.translator \
    import display_response, dict_to_string, get_region
from awscli.utils import create_nested_client

from botocore.exceptions import ClientError

LOG = logging.getLogger(__name__)


_DEPRECATION_NOTICE = """
Support for this command has been deprecated and may fail to create these roles
if they do not already exist. For more information on managing these policies
manually see the following documentation:

https://docs.aws.amazon.com/datapipeline/latest/DeveloperGuide/dp-iam-roles.html
"""

_DESCRIPTION = """
NOTE: {}

Creates the default IAM role "{}" and "{}" which are used while creating an EMR
cluster.

If these roles do not exist, create-default-roles will automatically create
them and set their policies.

If these roles have already been created create-default-roles will not update
their policies.
"""


class CreateDefaultRoles(BasicCommand):

    NAME = "create-default-roles"
    _UNDOCUMENTED = True
    DESCRIPTION = _DESCRIPTION.format(
        _DEPRECATION_NOTICE,
        DATAPIPELINE_DEFAULT_SERVICE_ROLE_NAME,
        DATAPIPELINE_DEFAULT_RESOURCE_ROLE_NAME,
    )

    def __init__(self, session, formatter=None):
        super(CreateDefaultRoles, self).__init__(session)

    def _run_main(self, parsed_args, parsed_globals, **kwargs):
        """Call to run the commands"""
        self._region = get_region(self._session, parsed_globals)
        self._endpoint_url = parsed_globals.endpoint_url
        self._iam_client = create_nested_client(
            self._session, 'iam', 
            region_name=self._region, 
            endpoint_url=self._endpoint_url,
            verify=parsed_globals.verify_ssl
        )
        warnings.warn(_DEPRECATION_NOTICE)
        return self._create_default_roles(parsed_args, parsed_globals)

    def _create_role(self, role_name, role_arn, role_policy):
        """Method to create a role for a given role name and arn
        if it does not exist
        """

        role_result = None
        role_policy_result = None
        # Check if the role with the name exists
        if self._check_if_role_exists(role_name):
            LOG.debug('Role ' + role_name + ' exists.')
        else:
            LOG.debug('Role ' + role_name + ' does not exist.'
                      ' Creating default role for EC2: ' + role_name)
            # Create a create using the IAM Client with a particular triplet
            # (role_name, role_arn, assume_role_policy)
            role_result = self._create_role_with_role_policy(role_name,
                                                             role_policy,
                                                             role_arn)
            role_policy_result = self._get_role_policy(role_arn)
        return role_result, role_policy_result

    def _construct_result(self, dpl_default_result,
                          dpl_default_policy,
                          dpl_default_res_result,
                          dpl_default_res_policy):
        """Method to create a resultant list of responses for create roles
        for service and resource role
        """

        result = []
        self._construct_role_and_role_policy_structure(result,
                                                       dpl_default_result,
                                                       dpl_default_policy)
        self._construct_role_and_role_policy_structure(result,
                                                       dpl_default_res_result,
                                                       dpl_default_res_policy)
        return result

    def _create_default_roles(self, parsed_args, parsed_globals):

        # Setting the role name and arn value
        (datapipline_default_result,
            datapipline_default_policy) = self._create_role(
                DATAPIPELINE_DEFAULT_SERVICE_ROLE_NAME,
                DATAPIPELINE_DEFAULT_SERVICE_ROLE_ARN,
                DATAPIPELINE_DEFAULT_SERVICE_ROLE_ASSUME_POLICY)

        (datapipline_default_resource_result,
            datapipline_default_resource_policy) = self._create_role(
                DATAPIPELINE_DEFAULT_RESOURCE_ROLE_NAME,
                DATAPIPELINE_DEFAULT_RESOURCE_ROLE_ARN,
                DATAPIPELINE_DEFAULT_RESOURCE_ROLE_ASSUME_POLICY)

        # Check if the default EC2 Instance Profile for DataPipeline exists.
        instance_profile_name = DATAPIPELINE_DEFAULT_RESOURCE_ROLE_NAME
        if self._check_if_instance_profile_exists(instance_profile_name):
            LOG.debug('Instance Profile ' + instance_profile_name + ' exists.')
        else:
            LOG.debug('Instance Profile ' + instance_profile_name +
                      'does not exist. Creating default Instance Profile ' +
                      instance_profile_name)
            self._create_instance_profile_with_role(instance_profile_name,
                                                    instance_profile_name)

        result = self._construct_result(datapipline_default_result,
                                        datapipline_default_policy,
                                        datapipline_default_resource_result,
                                        datapipline_default_resource_policy)

        display_response(self._session, 'create_role', result, parsed_globals)

        return 0

    def _get_role_policy(self, arn):
        """Method to get the Policy for a particular ARN
        This is used to display the policy contents to the user
        """
        pol_det = self._iam_client.get_policy(PolicyArn=arn)
        policy_version_details = self._iam_client.get_policy_version(
            PolicyArn=arn, VersionId=pol_det["Policy"]["DefaultVersionId"])
        return policy_version_details["PolicyVersion"]["Document"]

    def _create_role_with_role_policy(
            self, role_name, assume_role_policy, role_arn):
        """Method to create role with a given rolename, assume_role_policy
        and role_arn
        """
        # Create a role using IAM client CreateRole API
        create_role_response = self._iam_client.create_role(
            RoleName=role_name, AssumeRolePolicyDocument=dict_to_string(
                assume_role_policy))

        # Create a role using IAM client AttachRolePolicy API
        self._iam_client.attach_role_policy(PolicyArn=role_arn,
                                            RoleName=role_name)

        return create_role_response

    def _construct_role_and_role_policy_structure(
            self, list_val, response, policy):
        """Method to construct the message to be displayed to the user"""
        # If the response is not none they we get the role name
        # from the response and
        # append the policy information to the response
        if response is not None and response['Role'] is not None:
            list_val.append({'Role': response['Role'], 'RolePolicy': policy})
            return list_val

    def _check_if_instance_profile_exists(self, instance_profile_name):
        """Method to verify if a particular role exists"""
        try:
            # Client call to get the instance profile with that name
            self._iam_client.get_instance_profile(
                InstanceProfileName=instance_profile_name)

        except ClientError as e:
            # If the instance profile does not exist then the error message
            # would contain the required message
            if e.response['Error']['Code'] == 'NoSuchEntity':
                # No instance profile error.
                return False
            else:
                # Some other error. raise.
                raise e

        return True

    def _check_if_role_exists(self, role_name):
        """Method to verify if a particular role exists"""
        try:
            # Client call to get the role
            self._iam_client.get_role(RoleName=role_name)
        except ClientError as e:
            # If the role does not exist then the error message
            # would contain the required message.
            if e.response['Error']['Code'] == 'NoSuchEntity':
                # No role error.
                return False
            else:
                # Some other error. raise.
                raise e

        return True

    def _create_instance_profile_with_role(self, instance_profile_name,
                                           role_name):
        """Method to create the instance profile with the role"""
        # Setting the value for instance profile name
        # Client call to create an instance profile
        self._iam_client.create_instance_profile(
            InstanceProfileName=instance_profile_name)

        # Adding the role to the Instance Profile
        self._iam_client.add_role_to_instance_profile(
            InstanceProfileName=instance_profile_name, RoleName=role_name)
