# Copyright (c) 2010-2012 Mitch Garnaat http://garnaat.org/
# Copyright (c) 2012 Amazon.com, Inc. or its affiliates.  All Rights Reserved
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish, dis-
# tribute, sublicense, and/or sell copies of the Software, and to permit
# persons to whom the Software is furnished to do so, subject to the fol-
# lowing conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
# ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
# SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.

import uuid
import hashlib

from boto.connection import AWSQueryConnection
from boto.regioninfo import RegionInfo
from boto.compat import json
import boto


class SNSConnection(AWSQueryConnection):
    """
    Amazon Simple Notification Service
    Amazon Simple Notification Service (Amazon SNS) is a web service
    that enables you to build distributed web-enabled applications.
    Applications can use Amazon SNS to easily push real-time
    notification messages to interested subscribers over multiple
    delivery protocols. For more information about this product see
    `http://aws.amazon.com/sns`_. For detailed information about
    Amazon SNS features and their associated API calls, see the
    `Amazon SNS Developer Guide`_.

    We also provide SDKs that enable you to access Amazon SNS from
    your preferred programming language. The SDKs contain
    functionality that automatically takes care of tasks such as:
    cryptographically signing your service requests, retrying
    requests, and handling error responses. For a list of available
    SDKs, go to `Tools for Amazon Web Services`_.
    """
    DefaultRegionName = 'us-east-1'
    DefaultRegionEndpoint = 'sns.us-east-1.amazonaws.com'
    APIVersion = '2010-03-31'

    def __init__(self, aws_access_key_id=None, aws_secret_access_key=None,
                 is_secure=True, port=None, proxy=None, proxy_port=None,
                 proxy_user=None, proxy_pass=None, debug=0,
                 https_connection_factory=None, region=None, path='/',
                 security_token=None, validate_certs=True):
        if not region:
            region = RegionInfo(self, self.DefaultRegionName,
                                self.DefaultRegionEndpoint,
                                connection_cls=SNSConnection)
        self.region = region
        AWSQueryConnection.__init__(self, aws_access_key_id,
                                    aws_secret_access_key,
                                    is_secure, port, proxy, proxy_port,
                                    proxy_user, proxy_pass,
                                    self.region.endpoint, debug,
                                    https_connection_factory, path,
                                    security_token=security_token,
                                    validate_certs=validate_certs)

    def _build_dict_as_list_params(self, params, dictionary, name):
      """
            Serialize a parameter 'name' which value is a 'dictionary' into a list of parameters.

            See: http://docs.aws.amazon.com/sns/latest/api/API_SetPlatformApplicationAttributes.html
            For example::

                dictionary = {'PlatformPrincipal': 'foo', 'PlatformCredential': 'bar'}
                name = 'Attributes'

            would result in params dict being populated with:
                Attributes.entry.1.key    = PlatformPrincipal
                Attributes.entry.1.value  = foo
                Attributes.entry.2.key    = PlatformCredential
                Attributes.entry.2.value  = bar

      :param params: the resulting parameters will be added to this dict
      :param dictionary: dict - value of the serialized parameter
      :param name: name of the serialized parameter
      """
      items = sorted(dictionary.items(), key=lambda x:x[0])
      for kv, index in zip(items, range(1, len(items)+1)):
        key, value = kv
        prefix = '%s.entry.%s' % (name, index)
        params['%s.key' % prefix] = key
        params['%s.value' % prefix] = value

    def _required_auth_capability(self):
        return ['hmac-v4']

    def get_all_topics(self, next_token=None):
        """
        :type next_token: string
        :param next_token: Token returned by the previous call to
                           this method.

        """
        params = {}
        if next_token:
            params['NextToken'] = next_token
        return self._make_request('ListTopics', params)

    def get_topic_attributes(self, topic):
        """
        Get attributes of a Topic

        :type topic: string
        :param topic: The ARN of the topic.

        """
        params = {'TopicArn': topic}
        return self._make_request('GetTopicAttributes', params)

    def set_topic_attributes(self, topic, attr_name, attr_value):
        """
        Get attributes of a Topic

        :type topic: string
        :param topic: The ARN of the topic.

        :type attr_name: string
        :param attr_name: The name of the attribute you want to set.
                          Only a subset of the topic's attributes are mutable.
                          Valid values: Policy | DisplayName

        :type attr_value: string
        :param attr_value: The new value for the attribute.

        """
        params = {'TopicArn': topic,
                  'AttributeName': attr_name,
                  'AttributeValue': attr_value}
        return self._make_request('SetTopicAttributes', params)

    def add_permission(self, topic, label, account_ids, actions):
        """
        Adds a statement to a topic's access control policy, granting
        access for the specified AWS accounts to the specified actions.

        :type topic: string
        :param topic: The ARN of the topic.

        :type label: string
        :param label: A unique identifier for the new policy statement.

        :type account_ids: list of strings
        :param account_ids: The AWS account ids of the users who will be
                            give access to the specified actions.

        :type actions: list of strings
        :param actions: The actions you want to allow for each of the
                        specified principal(s).

        """
        params = {'TopicArn': topic,
                  'Label': label}
        self.build_list_params(params, account_ids, 'AWSAccountId.member')
        self.build_list_params(params, actions, 'ActionName.member')
        return self._make_request('AddPermission', params)

    def remove_permission(self, topic, label):
        """
        Removes a statement from a topic's access control policy.

        :type topic: string
        :param topic: The ARN of the topic.

        :type label: string
        :param label: A unique identifier for the policy statement
                      to be removed.

        """
        params = {'TopicArn': topic,
                  'Label': label}
        return self._make_request('RemovePermission', params)

    def create_topic(self, topic):
        """
        Create a new Topic.

        :type topic: string
        :param topic: The name of the new topic.

        """
        params = {'Name': topic}
        return self._make_request('CreateTopic', params)

    def delete_topic(self, topic):
        """
        Delete an existing topic

        :type topic: string
        :param topic: The ARN of the topic

        """
        params = {'TopicArn': topic}
        return self._make_request('DeleteTopic', params, '/', 'GET')

    def publish(self, topic=None, message=None, subject=None, target_arn=None,
                message_structure=None):
        """
        Get properties of a Topic

        :type topic: string
        :param topic: The ARN of the new topic.

        :type message: string
        :param message: The message you want to send to the topic.
                        Messages must be UTF-8 encoded strings and
                        be at most 4KB in size.

        :type message_structure: string
        :param message_structure: Optional parameter. If left as ``None``,
                                  plain text will be sent. If set to ``json``,
                                  your message should be a JSON string that
                                  matches the structure described at
                                  http://docs.aws.amazon.com/sns/latest/dg/PublishTopic.html#sns-message-formatting-by-protocol

        :type subject: string
        :param subject: Optional parameter to be used as the "Subject"
                        line of the email notifications.

        :type target_arn: string
        :param target_arn: Optional parameter for either TopicArn or
                           EndpointArn, but not both.

        """
        if message is None:
            # To be backwards compatible when message did not have
            # a default value and topic and message were required
            # args.
            raise TypeError("'message' is a required parameter")
        params = {'Message': message}
        if subject is not None:
            params['Subject'] = subject
        if topic is not None:
            params['TopicArn'] = topic
        if target_arn is not None:
            params['TargetArn'] = target_arn
        if message_structure is not None:
            params['MessageStructure'] = message_structure
        return self._make_request('Publish', params, '/', 'POST')

    def subscribe(self, topic, protocol, endpoint):
        """
        Subscribe to a Topic.

        :type topic: string
        :param topic: The ARN of the new topic.

        :type protocol: string
        :param protocol: The protocol used to communicate with
                         the subscriber.  Current choices are:
                         email|email-json|http|https|sqs|sms

        :type endpoint: string
        :param endpoint: The location of the endpoint for
                         the subscriber.
                         * For email, this would be a valid email address
                         * For email-json, this would be a valid email address
                         * For http, this would be a URL beginning with http
                         * For https, this would be a URL beginning with https
                         * For sqs, this would be the ARN of an SQS Queue
                         * For sms, this would be a phone number of an SMS-enabled device 
        """
        params = {'TopicArn': topic,
                  'Protocol': protocol,
                  'Endpoint': endpoint}
        return self._make_request('Subscribe', params)

    def subscribe_sqs_queue(self, topic, queue):
        """
        Subscribe an SQS queue to a topic.

        This is convenience method that handles most of the complexity involved
        in using an SQS queue as an endpoint for an SNS topic.  To achieve this
        the following operations are performed:

        * The correct ARN is constructed for the SQS queue and that ARN is
          then subscribed to the topic.
        * A JSON policy document is contructed that grants permission to
          the SNS topic to send messages to the SQS queue.
        * This JSON policy is then associated with the SQS queue using
          the queue's set_attribute method.  If the queue already has
          a policy associated with it, this process will add a Statement to
          that policy.  If no policy exists, a new policy will be created.

        :type topic: string
        :param topic: The ARN of the new topic.

        :type queue: A boto Queue object
        :param queue: The queue you wish to subscribe to the SNS Topic.
        """
        t = queue.id.split('/')
        q_arn = queue.arn
        sid = hashlib.md5(topic + q_arn).hexdigest()
        sid_exists = False
        resp = self.subscribe(topic, 'sqs', q_arn)
        attr = queue.get_attributes('Policy')
        if 'Policy' in attr:
            policy = json.loads(attr['Policy'])
        else:
            policy = {}
        if 'Version' not in policy:
            policy['Version'] = '2008-10-17'
        if 'Statement' not in policy:
            policy['Statement'] = []
        # See if a Statement with the Sid exists already.
        for s in policy['Statement']:
            if s['Sid'] == sid:
                sid_exists = True
        if not sid_exists:
            statement = {'Action': 'SQS:SendMessage',
                         'Effect': 'Allow',
                         'Principal': {'AWS': '*'},
                         'Resource': q_arn,
                         'Sid': sid,
                         'Condition': {'StringLike': {'aws:SourceArn': topic}}}
            policy['Statement'].append(statement)
        queue.set_attribute('Policy', json.dumps(policy))
        return resp

    def confirm_subscription(self, topic, token,
                             authenticate_on_unsubscribe=False):
        """
        Get properties of a Topic

        :type topic: string
        :param topic: The ARN of the new topic.

        :type token: string
        :param token: Short-lived token sent to and endpoint during
                      the Subscribe operation.

        :type authenticate_on_unsubscribe: bool
        :param authenticate_on_unsubscribe: Optional parameter indicating
                                            that you wish to disable
                                            unauthenticated unsubscription
                                            of the subscription.

        """
        params = {'TopicArn': topic, 'Token': token}
        if authenticate_on_unsubscribe:
            params['AuthenticateOnUnsubscribe'] = 'true'
        return self._make_request('ConfirmSubscription', params)

    def unsubscribe(self, subscription):
        """
        Allows endpoint owner to delete subscription.
        Confirmation message will be delivered.

        :type subscription: string
        :param subscription: The ARN of the subscription to be deleted.

        """