#----------------------------------------------------------------------
# Copyright (c) 2014 Raytheon BBN Technologies
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from sfa.util.sfalogging import logger
from sfa.trust.credential import Credential
from sfa.trust.abac_credential import ABACCredential

import json
import re

# Factory for creating credentials of different sorts by type.
# Specifically, this factory can create standard SFA credentials
# and ABAC credentials from XML strings based on their identifying content


class CredentialFactory:

    UNKNOWN_CREDENTIAL_TYPE = 'geni_unknown'

    # Static Credential class method to determine the type of a credential
    # string depending on its contents
    @staticmethod
    def getType(credString):
        credString_nowhitespace = re.sub('\s', '', credString)
        if credString_nowhitespace.find('<type>abac</type>') > -1:
            return ABACCredential.ABAC_CREDENTIAL_TYPE
        elif credString_nowhitespace.find('<type>privilege</type>') > -1:
            return Credential.SFA_CREDENTIAL_TYPE
        else:
            st = credString_nowhitespace.find('<type>')
            end = credString_nowhitespace.find('</type>', st)
            return credString_nowhitespace[st + len('<type>'):end]
#            return CredentialFactory.UNKNOWN_CREDENTIAL_TYPE

    # Static Credential class method to create the appropriate credential
    # (SFA or ABAC) depending on its type
    @staticmethod
    def createCred(credString=None, credFile=None):
        if not credString and not credFile:
            raise Exception(
                "CredentialFactory.createCred called with no argument")
        if credFile:
            try:
                credString = open(credFile).read()
            except Exception as e:
                logger.info("Error opening credential file %s: %s" %
                            credFile, e)
                return None

        # Try to treat the file as JSON, getting the cred_type from the struct
        try:
            credO = json.loads(credString, encoding='ascii')
            if 'geni_value' in credO and 'geni_type' in credO:
                cred_type = credO['geni_type']
                credString = credO['geni_value']
        except Exception as e:
            # It wasn't a struct. So the credString is XML. Pull the type
            # directly from the string
            logger.debug("Credential string not JSON: %s" % e)
            cred_type = CredentialFactory.getType(credString)

        if cred_type == Credential.SFA_CREDENTIAL_TYPE:
            try:
                cred = Credential(string=credString)
                return cred
            except Exception as e:
                if credFile:
                    msg = "credString started: %s" % credString[:50]
                    raise Exception(
                        "%s not a parsable SFA credential: %s. " % (credFile, e) + msg)
                else:
                    raise Exception(
                        "SFA Credential not parsable: %s. Cred start: %s..." % (e, credString[:50]))

        elif cred_type == ABACCredential.ABAC_CREDENTIAL_TYPE:
            try:
                cred = ABACCredential(string=credString)
                return cred
            except Exception as e:
                if credFile:
                    raise Exception(
                        "%s not a parsable ABAC credential: %s" % (credFile, e))
                else:
                    raise Exception(
                        "ABAC Credential not parsable: %s. Cred start: %s..." % (e, credString[:50]))
        else:
            raise Exception("Unknown credential type '%s'" % cred_type)

if __name__ == "__main__":
    c2 = open('/tmp/sfa.xml').read()
    cred1 = CredentialFactory.createCred(credFile='/tmp/cred.xml')
    cred2 = CredentialFactory.createCred(credString=c2)

    print("C1 = %s" % cred1)
    print("C2 = %s" % cred2)
    c1s = cred1.dump_string()
    print("C1 = %s" % c1s)
#    print "C2 = %s" % cred2.dump_string()