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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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##

"""
WebDAV REPORT method
"""

__all__ = ["http_REPORT"]

import string

from twisted.internet.defer import inlineCallbacks, returnValue
from twext.web2 import responsecode
from twext.web2.http import HTTPError, StatusResponse
from twext.web2.dav.util import davXMLFromStream
from txdav.xml import element as davxml
from txdav.xml.base import encodeXMLName
from txdav.xml.element import lookupElement

from twext.python.log import Logger
from twext.web2.dav.http import ErrorResponse

from twistedcaldav import caldavxml

log = Logger()

@inlineCallbacks
def http_REPORT(self, request):
    """
    Respond to a REPORT request. (RFC 3253, section 3.6)
    """
    if not self.exists():
        log.error("Resource not found: %s" % (self,))
        raise HTTPError(responsecode.NOT_FOUND)

    #
    # Read request body
    #
    try:
        doc = (yield davXMLFromStream(request.stream))
    except ValueError, e:
        log.error("Error while handling REPORT body: %s" % (e,))
        raise HTTPError(StatusResponse(responsecode.BAD_REQUEST, str(e)))

    if doc is None:
        raise HTTPError(StatusResponse(
            responsecode.BAD_REQUEST,
            "REPORT request body may not be empty"
        ))

    #
    # Parse request
    #
    namespace = doc.root_element.namespace
    name = doc.root_element.name

    if namespace:
        if namespace == davxml.dav_namespace:
            request.submethod = "DAV:" + name
        elif namespace == caldavxml.caldav_namespace:
            request.submethod = "CalDAV:" + name
        else:
            request.submethod = encodeXMLName(namespace, name)
    else:
        request.submethod = name


    def to_method(namespace, name):
        if namespace:
            s = "_".join((namespace, name))
        else:
            s = name

        ok = string.ascii_letters + string.digits + "_"
        out = []
        for c in s:
            if c in ok:
                out.append(c)
            else:
                out.append("_")
        return "report_" + "".join(out)

    method_name = to_method(namespace, name)

    try:
        method = getattr(self, method_name)

        # Also double-check via supported-reports property
        reports = self.supportedReports()
        test = lookupElement((namespace, name))
        if not test:
            raise AttributeError()
        test = davxml.Report(test())
        if test not in reports:
            raise AttributeError()
    except AttributeError:
        #
        # Requested report is not supported.
        #
        log.error("Unsupported REPORT %s for resource %s (no method %s)"
                  % (encodeXMLName(namespace, name), self, method_name))

        raise HTTPError(ErrorResponse(
            responsecode.FORBIDDEN,
            davxml.SupportedReport(),
            "Report not supported on this resource",
        ))

    #
    # Check authentication and access controls
    #
    privileges = (davxml.Read(),)
    if method_name == "report_urn_ietf_params_xml_ns_caldav_free_busy_query":
        privileges = (caldavxml.ReadFreeBusy(),)
    yield self.authorize(request, privileges)

    result = (yield method(request, doc.root_element))
    returnValue(result)
