# Copyright (c) 2006-2009 Mitch Garnaat http://garnaat.org/
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the
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# 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,
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# IN THE SOFTWARE.

from boto.connection import AWSQueryConnection
import xml.sax
from boto.sqs.regioninfo import SQSRegionInfo
from boto.sqs.queue import Queue
from boto.sqs.message import Message
from boto.sqs.attributes import Attributes
from boto import handler
from boto.resultset import ResultSet
from boto.exception import SQSError

class SQSConnection(AWSQueryConnection):
    """
    A Connection to the SQS Service.
    """
    DefaultRegionName = 'us-east-1'
    DefaultRegionEndpoint = 'queue.amazonaws.com'
    APIVersion = '2009-02-01'
    SignatureVersion = '2'
    DefaultContentType = 'text/plain'
    ResponseError = SQSError
    
    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='/'):
        if not region:
            region = SQSRegionInfo(self, self.DefaultRegionName, self.DefaultRegionEndpoint)
        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)

    def create_queue(self, queue_name, visibility_timeout=None):
        """
        Create an SQS Queue.

        :type queue_name: str or unicode
        :param queue_name: The name of the new queue.  Names are scoped to an account and need to
                           be unique within that account.  Calling this method on an existing
                           queue name will not return an error from SQS unless the value for
                           visibility_timeout is different than the value of the existing queue
                           of that name.  This is still an expensive operation, though, and not
                           the preferred way to check for the existence of a queue.  See the
                           :func:`boto.sqs.connection.SQSConnection.lookup` method.

        :type visibility_timeout: int
        :param visibility_timeout: The default visibility timeout for all messages written in the
                                   queue.  This can be overridden on a per-message.

        :rtype: :class:`boto.sqs.queue.Queue`
        :return: The newly created queue.

        """
        params = {'QueueName': queue_name}
        if visibility_timeout:
            params['DefaultVisibilityTimeout'] = '%d' % (visibility_timeout,)
        return self.get_object('CreateQueue', params, Queue)

    def delete_queue(self, queue, force_deletion=False):
        """
        Delete an SQS Queue.

        :type queue: A Queue object
        :param queue: The SQS queue to be deleted
        
        :type force_deletion: Boolean
        :param force_deletion: Normally, SQS will not delete a queue that contains messages.
                               However, if the force_deletion argument is True, the
                               queue will be deleted regardless of whether there are messages in
                               the queue or not.  USE WITH CAUTION.  This will delete all
                               messages in the queue as well.
                               
        :rtype: bool
        :return: True if the command succeeded, False otherwise
        """
        return self.get_status('DeleteQueue', None, queue.id)

    def get_queue_attributes(self, queue, attribute='All'):
        """
        Gets one or all attributes of a Queue
        
        :type queue: A Queue object
        :param queue: The SQS queue to be deleted

        :type attribute: str
        :type attribute: The specific attribute requested.  If not supplied, the default
                         is to return all attributes.  Valid attributes are:
                         ApproximateNumberOfMessages,
                         ApproximateNumberOfMessagesNotVisible,
                         VisibilityTimeout,
                         CreatedTimestamp,
                         LastModifiedTimestamp,
                         Policy
                         
        :rtype: :class:`boto.sqs.attributes.Attributes`
        :return: An Attributes object containing request value(s).
        """
        params = {'AttributeName' : attribute}
        return self.get_object('GetQueueAttributes', params, Attributes, queue.id)

    def set_queue_attribute(self, queue, attribute, value):
        params = {'Attribute.Name' : attribute, 'Attribute.Value' : value}
        return self.get_status('SetQueueAttributes', params, queue.id)

    def receive_message(self, queue, number_messages=1, visibility_timeout=None,
                        attributes=None):
        """
        Read messages from an SQS Queue.

        :type queue: A Queue object
        :param queue: The Queue from which messages are read.
        
        :type number_messages: int
        :param number_messages: The maximum number of messages to read (default=1)
        
        :type visibility_timeout: int
        :param visibility_timeout: The number of seconds the message should remain invisible
                                   to other queue readers (default=None which uses the Queues default)

        :type attributes: list of strings
        :param attributes: A list of additional attributes that will be returned
                           with the response.  Valid values:
                           All
                           SenderId
                           SentTimestamp
                           ApproximateReceiveCount
                           ApproximateFirstReceiveTimestamp
        
        """
        params = {'MaxNumberOfMessages' : number_messages}
        if visibility_timeout:
            params['VisibilityTimeout'] = visibility_timeout
        if attributes:
            self.build_list_params(self, params, attributes, 'AttributeName')
        return self.get_list('ReceiveMessage', params, [('Message', queue.message_class)],
                             queue.id, queue)

    def delete_message(self, queue, message):
        params = {'ReceiptHandle' : message.receipt_handle}
        return self.get_status('DeleteMessage', params, queue.id)

    def send_message(self, queue, message_content):
        params = {'MessageBody' : message_content}
        return self.get_object('SendMessage', params, Message, queue.id, verb='POST')

    def change_message_visibility(self, queue, receipt_handle, visibility_timeout):
        """
        Extends the read lock timeout for the specified message from the specified queue
        to the specified value.

        :type queue: A :class:`boto.sqs.queue.Queue` object
        :param queue: The Queue from which messages are read.
        
        :type receipt_handle: str
        :param queue: The receipt handle associated with the message whose
                      visibility timeout will be changed.
        
        :type visibility_timeout: int
        :param visibility_timeout: The new value of the message's visibility timeout
                                   in seconds.
        """
        params = {'ReceiptHandle' : receipt_handle,
                  'VisibilityTimeout' : visibility_timeout}
        return self.get_status('ChangeMessageVisibility', params, queue.id)

    def get_all_queues(self, prefix=''):
        params = {}
        if prefix:
            params['QueueNamePrefix'] = prefix
        return self.get_list('ListQueues', params, [('QueueUrl', Queue)])
        
    def get_queue(self, queue_name):
        rs = self.get_all_queues(queue_name)
        for q in rs:
            if q.url.endswith(queue_name):
                return q
        return None

    lookup = get_queue

    #
    # Permissions methods
    #

    def add_permission(self, queue, label, aws_account_id, action_name):
        """
        Add a permission to a queue.

        :type queue: :class:`boto.sqs.queue.Queue`
        :param queue: The queue object

        :type label: str or unicode
        :param label: A unique identification of the permission you are setting.
                      Maximum of 80 characters ``[0-9a-zA-Z_-]``
                      Example, AliceSendMessage

        :type aws_account_id: str or unicode
        :param principal_id: The AWS account number of the principal who will be given
                             permission.  The principal must have an AWS account, but
                             does not need to be signed up for Amazon SQS. For information
                             about locating the AWS account identification.

        :type action_name: str or unicode
        :param action_name: The action.  Valid choices are:
                            \*|SendMessage|ReceiveMessage|DeleteMessage|
                            ChangeMessageVisibility|GetQueueAttributes

        :rtype: bool
        :return: True if successful, False otherwise.

        """
        params = {'Label': label,
                  'AWSAccountId' : aws_account_id,
                  'ActionName' : action_name}
        return self.get_status('AddPermission', params, queue.id)

    def remove_permission(self, queue, label):
        """
        Remove a permission from a queue.

        :type queue: :class:`boto.sqs.queue.Queue`
        :param queue: The queue object

        :type label: str or unicode
        :param label: The unique label associated with the permission being removed.

        :rtype: bool
        :return: True if successful, False otherwise.
        """
        params = {'Label': label}
        return self.get_status('RemovePermission', params, queue.id)