from sfa.util.faults import RecordNotFound, ConnectionKeyGIDMismatch
from sfa.util.xrn import urn_to_hrn
from sfa.util.method import Method
from sfa.util.sfalogging import logger

from sfa.trust.certificate import Certificate

from sfa.storage.parameter import Parameter, Mixed


class GetSelfCredential(Method):
    """
    Retrive a credential for an object
    @param cert certificate string
    @param type type of object (user | slice | sa | ma | node)
    @param hrn human readable name of object (hrn or urn)

    @return the string representation of a credential object
    """

    interfaces = ['registry']

    accepts = [
        Parameter(str, "certificate"),
        Parameter(str, "Human readable name (hrn or urn)"),
        Mixed(Parameter(str, "Record type"),
              Parameter(None, "Type not specified")),
    ]

    returns = Parameter(str, "String representation of a credential object")

    def call(self, cert, xrn, type):
        """
        GetSelfCredential a degenerate version of GetCredential used by a client
        to get his initial credential when de doesnt have one. This is the same as
        GetCredential(..., cred = None, ...)

        The registry ensures that the client is the principal that is named by
        (type, name) by comparing the public key in the record's  GID to the
        private key used to encrypt the client side of the HTTPS connection. Thus
        it is impossible for one principal to retrieve another principal's
        credential without having the appropriate private key.

        @param type type of object (user | slice | sa | ma | node)
        @param hrn human readable name of authority to list
        @return string representation of a credential object
        """
        if type:
            hrn = urn_to_hrn(xrn)[0]
        else:
            hrn, type = urn_to_hrn(xrn)
        self.api.auth.verify_object_belongs_to_me(hrn)

        origin_hrn = Certificate(string=cert).get_subject()
        logger.info("interface: %s\tcaller-hrn: %s\ttarget-hrn: %s\tmethod-name: %s" %
                    (self.api.interface, origin_hrn, hrn, self.name))

        # authenticate the gid
        # import here so we can load this module at build-time for sfa2wsdl
        #from sfa.storage.alchemy import dbsession
        from sfa.storage.model import RegRecord

        # xxx-local - the current code runs Resolve, which would forward to
        # another registry if needed
        # I wonder if this is truly the intention, or shouldn't we instead
        # only look in the local db ?
        records = self.api.manager.Resolve(self.api, xrn, type, details=False)
        if not records:
            raise RecordNotFound(hrn)

        record_obj = RegRecord(dict=records[0])
        # xxx-local the local-only version would read
        #record_obj = dbsession.query(RegRecord).filter_by(hrn=hrn).first()
        #if not record_obj: raise RecordNotFound(hrn)
        gid = record_obj.get_gid_object()
        gid_str = gid.save_to_string(save_parents=True)
        self.api.auth.authenticateGid(gid_str, [cert, type, hrn])
        # authenticate the certificate against the gid in the db
        certificate = Certificate(string=cert)
        if not certificate.is_pubkey(gid.get_pubkey()):
            for (obj, name) in [(certificate, "CERT"), (gid, "GID"), ]:
                logger.debug("ConnectionKeyGIDMismatch, %s pubkey: %s" % (
                    name, obj.get_pubkey().get_pubkey_string()))
                logger.debug(
                    "ConnectionKeyGIDMismatch, %s dump: %s" % (name, obj.dump_string()))
                if hasattr(obj, 'filename'):
                    logger.debug(
                        "ConnectionKeyGIDMismatch, %s filename: %s" % (name, obj.filename))
            raise ConnectionKeyGIDMismatch(gid.get_subject())

        return self.api.manager.GetCredential(self.api, xrn, type)