# Copyright (C) 2012-2013 Red Hat, Inc.  All rights reserved.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
#
# Authors: Jan Safranek <jsafrane@redhat.com>
# Authors: Michal Minar <miminar@redhat.com>
# Authors: Roman Rakus <rrakus@redhat.com>
#
"""
Base class and utilities for test suits written with plain pywbem
abastractions.
"""

import BaseHTTPServer
import pywbem
import Queue
import random
import threading
import time

from lmi.test import base

JOB_CREATED = 4096

class CIMListener(object):
    """ CIM Listener for indication events. """

    class CIMHandler(BaseHTTPServer.BaseHTTPRequestHandler):
        """ Handler for the POST request from *CIMOM*. """
        def do_POST(self):
            """ Handle the POST request. """
            data = self.rfile.read(int(self.headers['Content-Length']))
            ttree = pywbem.parse_cim(pywbem.xml_to_tupletree(data))
            # Get the instance from CIM-XML, copied from
            # http://sf.net/apps/mediawiki/pywbem/?title=Indications_Tutorial
            insts = [x[1] for x in ttree[2][2][0][2][2]]
            for inst in insts:
                self.callback(inst)
            self.send_response(200)
            self.end_headers()

        def log_message(self, _fmt, *_args):
            # suppress log messages
            pass

    def __init__(self, callback, http_port=5988):
        self.address = ('', http_port)
        self.CIMHandler.callback = callback
        self.thread = None
        self.server = None

    def start(self):
        """ Start listening. """
        BaseHTTPServer.HTTPServer.allow_reuse_address = True
        self.server = BaseHTTPServer.HTTPServer(self.address, self.CIMHandler)
        self.thread = threading.Thread(target=self.server.serve_forever)
        self.thread.start()

    def stop(self):
        """ Stop listening. """
        if self.server is not None:
            self.server.shutdown()
            self.server.socket.close()
        if self.thread is not None:
            self.thread.join()

    def running(self):
        """
        Are we listening for events?
        :rtype: bool
        """
        return self.thread is not None

class CIMTestCase(base.BaseLmiTestCase):
    """
    Base class for LMI test cases based on plain pywbem.
    """

    #: Says, whether the test case needs indication listener running or not.
    #: Each subclass shall override this property and set it to ``True`` if
    #: it want to test indication events.
    NEEDS_INDICATIONS = False

    _WBEMCONNECTION = None
    _SYSTEM_INAME = None

    @classmethod
    def needs_indications(cls):
        """
        Whether the indication listener should be started for this test case.
        In subclasses override ``NEEDS_INDICATIONS`` property and set it to
        ``True`` if indication testing is desired.
        """
        return cls.NEEDS_INDICATIONS

    @classmethod
    def setUpClass(cls):
        base.BaseLmiTestCase.setUpClass.im_func(cls)
        if cls.needs_indications():
            cls.indication_port = random.randint(12000, 13000)
            cls.indication_queue = Queue.Queue()
            cls.listener = CIMListener(
                    callback=cls._process_indication,
                    http_port=cls.indication_port)

    @classmethod
    def tearDownClass(cls):
        if cls.needs_indications():
            cls.listener.stop()

    @classmethod
    def _start_listening(cls):
        """ Start listening for incoming indications. """
        cls.listener.start()

    @classmethod
    def _process_indication(cls, indication):
        """ Callback to process one indication."""
        cls.indication_queue.put(indication)

    @property
    def wbemconnection(self):
        """
        :returns: Active connection to *CIMOM*.
        :rtype: :py:class:`pywbem.WBEMConnection`
        """
        if CIMTestCase._WBEMCONNECTION is None:
            CIMTestCase._WBEMCONNECTION = pywbem.WBEMConnection(self.url,
                    (self.username, self.password))
        return CIMTestCase._WBEMCONNECTION

    @property
    def system_iname(self):
        """
        :returns: Instance of ``CIM_ComputerSystem`` registered with *CIMOM*.
        :rtype: :py:class:`lmi.shell.LMIInstanceName`
        """
        if CIMTestCase._SYSTEM_INAME is None:
            CIMTestCase._SYSTEM_INAME = self.wbemconnection. \
                    EnumerateInstanceNames(self.system_cs_name, 'root/cimv2')[0]
        return CIMTestCase._SYSTEM_INAME.copy()

    def setUp(self):
        self.subscribed = {}

    def tearDown(self):
        for name in self.subscribed.keys():
            self.unsubscribe(name)

    def assertCIMIsSubclass(self, cls, base_cls):
        """
        Checks, whether cls is subclass of base_cls from CIM perspective.
        @param cls name of subclass
        @param base_cls name of base class
        """
        if not isinstance(cls, basestring):
            raise TypeError("cls must be a string")
        if not isinstance(base_cls, basestring):
            raise TypeError("base_cls must be a string")
        return self.assertTrue(pywbem.is_subclass(self.wbemconnection,
            "root/cimv2", base_cls, cls))

    def get_indication(self, timeout):
        """ Wait for an indication for given nr. of seconds and return it."""
        try:
            indication = self.indication_queue.get(timeout=timeout)
        except Queue.Empty:
            raise AssertionError("Timeout when waiting for indication")
        self.indication_queue.task_done()
        return indication

    def make_filter_iname(self, filter_name):
        """
        Create an instance name of ``CIM_IndicationFilter``.

        :rtype: :py:class:`pywbem.CIMInstanceName`
        """
        return pywbem.CIMInstanceName(
                    classname="CIM_IndicationFilter",
                    namespace="root/interop",
                    keybindings={
                        'CreationClassName': 'CIM_IndicationFilter',
                        'SystemClassName': self.system_cs_name,
                        'SystemName': self.SYSTEM_NAME,
                        'Name': filter_name})

    def make_filter_inst(self, filter_name, query, query_lang="DMTF:CQL"):
        """
        Create an instance of ``CIM_IndicationFilter``.

        :rtype: :py:class:`pywbem.CIMInstance`
        """
        inst = pywbem.CIMInstance('CIM_IndicationFilter')
        inst['CreationClassName'] = 'CIM_IndicationFilter'
        inst['SystemCreationClassName'] = self.system_cs_name
        inst['SystemName'] = self.SYSTEM_NAME
        inst['Name'] = filter_name
        inst['Query'] = query
        inst['QueryLanguage'] = query_lang
        inst['SourceNamespace'] = "root/cimv2"
        inst.path = self.make_filter_iname(filter_name)
        return inst

    def subscribe(self, filter_name, query=None, querylang="DMTF:CQL"):
        """
        Create indication subscription for given filter name.
        """
        if not self.needs_indications():
            raise Exception("can not subscribe to indications, enable them"
                    " with NEEDS_INDICATIONS")

        if query is not None:
            # Create filter first
            indfilter = self.wbemconnection.CreateInstance(
                    self.make_filter_inst(filter_name, query, querylang))
        else:
            # the filter is already created, assemble its name
            indfilter = self.make_filter_iname(filter_name)

        # create destination
        destinst = pywbem.CIMInstance('CIM_ListenerDestinationCIMXML')
        destinst['CreationClassName'] = 'CIM_ListenerDestinationCIMXML'
        destinst['SystemCreationClassName'] = self.system_cs_name
        destinst['SystemName'] = self.SYSTEM_NAME
        destinst['Name'] = filter_name
        destinst['Destination'] = "http://localhost:%d" % (self.indication_port)
        destinst['PersistenceType'] = pywbem.Uint16(3) # Transient
        cop = pywbem.CIMInstanceName(
                'CIM_ListenerDestinationCIMXML', namespace="root/interop")
        cop.keybindings = {
                'CreationClassName' : 'CIM_ListenerDestinationCIMXML',
                'SystemClassName'   : self.system_cs_name,
                'SystemName'        : self.SYSTEM_NAME,
                'Name'              : filter_name }
        destinst.path = cop
        destname = self.wbemconnection.CreateInstance(destinst)

        # create the subscription
        subinst = pywbem.CIMInstance(
                'CIM_IndicationSubscription')
        subinst['Filter'] = indfilter
        subinst['Handler'] = destname
        cop = pywbem.CIMInstanceName(
                'CIM_IndicationSubscription', namespace="root/interop")
        cop.keybindings = {
                'Filter': indfilter,
                'Handler': destname }
        subinst.path = cop
        subscription = self.wbemconnection.CreateInstance(subinst)

        self.subscribed[filter_name] = [subscription, destname]

        if not self.listener.running():
            self._start_listening()
        return subscription

    def unsubscribe(self, filter_name):
        """
        Unsubscribe from given filter.
        """
        if not self.needs_indications():
            raise Exception("can not unsubscribe to indications, enable them"
                    " with NEEDS_INDICATIONS")
        for instance in self.subscribed.pop(filter_name):
            self.wbemconnection.DeleteInstance(instance)

    def finish_job(self,
            jobname,
            assoc_class,
            return_constructor=int):
        """
        Wait until the job finishes and return ``(ret, outparams)``just as
        ``InvokeMethod`` would.

        It's hard to reconstruct these outparams, since the embedded
        instances / ojects do not work in our ``CIMOMS``, therefore special
        care is needed.

        :param jobname: Name of the job.
        :type jobname: :py:class:`pywbem.CIMInstanceName`
        :param callable return_constructor: Callable, which converts
            string to the right type, for example ``int``.
        :returns: ``(retvalue, outparams)`` in the same way as
            ``finish_method()`` would.
        :rtype: tuple
        """
        # Use busy loop for now
        # TODO: rework to something sane
        while True:
            job = self.wbemconnection.GetInstance(jobname)
            if job['JobState'] > 5:  # all states higher than 5 are final
                break
            time.sleep(0.1)

        # get the MethodResult
        resultname = self.wbemconnection.AssociatorNames(
                jobname,
                AssocClass=assoc_class)[0]
        result = self.wbemconnection.GetInstance(resultname)
        ind = result['PostCallIndication']
        # check for error
        if ind['Error'] is not None:
            err = ind['Error'][0]
            code = err['CIMStatusCode']
            msg = err['Message']
            raise pywbem.CIMError(code, msg)

        ret = return_constructor(ind['ReturnValue'])

        # convert output parameters to format returned by InvokeMethod
        outparams = pywbem.NocaseDict()
        try:
            params = ind['MethodParameters']
        except KeyError:
            params = {}
        if params:
            for (key, value) in params.iteritems():
                outparams[key] = value

        return (ret, outparams)

    def invoke_async_method(self,
            method_name,
            object_name,
            return_constructor=int,
            *args, **kwargs):
        """
        Invoke a method and if it returns a job, wait for the job.

        :param string method_name: Name of the method.
        :param object_name: Instance, on which the method should be invoked.
        :type object_name: :py:class:`pywbem.CIMInstanceName`
        :param callable return_constructor: Callable, which converts
            string to the right type, for example ``int``.
        :param list args: Positional arguments passed to invoked method.
        :param dictionary kwargs: Keyword arguments passed to invoked method.
        :returns: ``(retvalue, outparams)`` in the same way as
            ``finish_method()`` would.
        :rtype: tuple
        """
        (ret, outparams) = self.wbemconnection.InvokeMethod(
                method_name,
                object_name,
                *args,
                **kwargs)
        if ret == JOB_CREATED:
            # wait for the job
            jobname = outparams['Job']
            (ret, outparams) = self.finish_job(jobname, return_constructor)
        return (ret, outparams)