## 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