## Amazon S3 - Access Control List representation
 ## Author: Michal Ludvig <michal@logix.cz>
 ##         http://www.logix.cz/michal
 ## License: GPL Version 2
 
 import S3Uri
 from Exceptions import ParameterError
 from Utils import getTreeFromXml
 from ACL import GranteeAnonRead
 
 try:

     import xml.etree.ElementTree as ET

 except ImportError:

     import elementtree.ElementTree as ET

 
 __all__ = []
 class AccessLog(object):

     LOG_DISABLED = "<BucketLoggingStatus></BucketLoggingStatus>"
     LOG_TEMPLATE = "<LoggingEnabled><TargetBucket></TargetBucket><TargetPrefix></TargetPrefix></LoggingEnabled>"

     def __init__(self, xml = None):
         if not xml:
             xml = self.LOG_DISABLED
         self.tree = getTreeFromXml(xml)
         self.tree.attrib['xmlns'] = "http://doc.s3.amazonaws.com/2006-03-01"

     def isLoggingEnabled(self):
         return bool(self.tree.find(".//LoggingEnabled"))

     def disableLogging(self):
         el = self.tree.find(".//LoggingEnabled")
         if el:
             self.tree.remove(el)

     def enableLogging(self, target_prefix_uri):
         el = self.tree.find(".//LoggingEnabled")
         if not el:
             el = getTreeFromXml(self.LOG_TEMPLATE)
             self.tree.append(el)
         el.find(".//TargetBucket").text = target_prefix_uri.bucket()
         el.find(".//TargetPrefix").text = target_prefix_uri.object()

     def targetPrefix(self):
         if self.isLoggingEnabled():
             el = self.tree.find(".//LoggingEnabled")
             target_prefix = "s3://%s/%s" % (
                 self.tree.find(".//LoggingEnabled//TargetBucket").text,
                 self.tree.find(".//LoggingEnabled//TargetPrefix").text)
             return S3Uri.S3Uri(target_prefix)
         else:
             return ""

     def setAclPublic(self, acl_public):
         le = self.tree.find(".//LoggingEnabled")
         if not le:
             raise ParameterError("Logging not enabled, can't set default ACL for logs")
         tg = le.find(".//TargetGrants")
         if not acl_public:
             if not tg:
                 ## All good, it's not been there
                 return
             else:
                 le.remove(tg)
         else: # acl_public == True
             anon_read = GranteeAnonRead().getElement()
             if not tg:
                 tg = ET.SubElement(le, "TargetGrants")
             ## What if TargetGrants already exists? We should check if
             ## AnonRead is there before appending a new one. Later...
             tg.append(anon_read)
 
     def isAclPublic(self):
         raise NotImplementedError()
 
     def __str__(self):
         return ET.tostring(self.tree)

 __all__.append("AccessLog")
 
 if __name__ == "__main__":

     from S3Uri import S3Uri
     log = AccessLog()
     print log
     log.enableLogging(S3Uri("s3://targetbucket/prefix/log-"))
     print log
     log.setAclPublic(True)
     print log
     log.setAclPublic(False)
     print log
     log.disableLogging()
     print log
 
 # vim:et:ts=4:sts=4:ai