"""Testing support for :mod:`waeup.sirp`.
"""
import os.path
import warnings
import grok
import zope.component
import waeup.sirp
from zope.app.testing.functional import ZCMLLayer
from zope.component import getGlobalSiteManager
from zope.testing.cleanup import cleanUp

ftesting_zcml = os.path.join(
    os.path.dirname(waeup.sirp.__file__), 'ftesting.zcml')
FunctionalLayer = ZCMLLayer(ftesting_zcml, __name__, 'FunctionalLayer',
                            allow_teardown=True)

def setUpZope(test=None):
    """Initialize a Zope-compatible environment.

    Currently, we only initialize the event machinery.
    """
    zope.component.eventtesting.setUp(test)

def cleanUpZope(test=None):
    """Clean up Zope-related registrations.

    Cleans up all registrations and the like.
    """
    cleanUp()

def maybe_grok():
    """Try to grok the :mod:`waeup.sirp` package.

    For many tests, even simple ones, we want the components defined
    somewhere in the :mod:`waeup.sirp` package being registered. While
    grokking the complete package can become expensive when done many
    times, we only want to grok if it did not happen
    before. Furthermore regrokking the whole package makes no sense if
    done already.

    :func:`maybe_grok` checks whether any eventhandlers are already
    registered and does nothing in that case.

    The grokking of :mod:`waeup.sirp` is done with warnings disabled.

    Returns ``True`` if grokking was done, ``False`` else.

    .. The following samples should go into Sphinx docs directly....
    
    Sample
    ******

    Usage with plain Python testrunners
    -----------------------------------
    
    Together with the :func:`setUpZope` and :func:`cleanUpZope`
    functions we then can do unittests with all components registered
    and the event dispatcher in place like this::

      import unittest2 as unittest # Want Python 2.7 features
      from waeup.sirp.testing import (
        maybe_grok, setUpZope, cleanUpZope,
        )
      from waeup.sirp.app import University

      class MyTestCase(unittest.TestCase):

          @classmethod
          def setUpClass(cls):
              grokked = maybe_grok()
              if grokked:
                  setUpZope(None)
              return

          @classmethod
          def tearDownClass(cls):
              cleanUpZope(None)

          def setUp(self):
              pass
        
          def tearDown(self):
              pass

          def test_jambdata_in_site(self):
              u = University()
              self.assertTrue('jambdata' in u.keys())
              return

    Here the component registration is done only once for the whole
    :class:`unittest.TestCase` and no ZODB is needed. That means
    inside the tests you can expect to have all :mod:`waeup.sirp`
    components (utilities, adapter, events) registered but as objects
    have here still have no place inside a ZODB things like 'browsing'
    won't work out of the box. The benefit is the faster test
    setup/teardown.

    .. note:: This works only with the default Python testrunners.
    
         If you use the Zope testrunner (from :mod:`zope.testing`)
         then you have to use appropriate layers like the
         :class:`waeup.sirp.testing.WAeUPSIRPUnitTestLayer`.

    Usage with :mod:`zope.testing` testrunners
    ------------------------------------------

    If you use the standard Zope testrunner, classmethods like
    `setUpClass` are not executed. Instead you have to use a layer
    like the one defined in this module.

    .. seealso:: :class:`waeup.sirp.testing.WAeUPSIRPUnitTestLayer`
    
    """
    gsm =  getGlobalSiteManager()
    # If there are any event handlers registered already, we assume
    # that waeup.sirp was grokked already. There might be a batter
    # check, though.
    if len(list(gsm.registeredHandlers())) > 0:
        return False
    warnings.simplefilter('ignore') # disable (erraneous) warnings
    grok.testing.grok('waeup.sirp')
    warnings.simplefilter('default') # reenable warnings
    return True


class WAeUPSIRPUnitTestLayer(object):
    """A layer for tests that groks `waeup.sirp`.

    A Zope test layer that registers all :mod:`waeup.sirp` components
    before attached tests are run and cleans this registrations up
    afterwards. Also basic (non-waeup.sirp) components like the event
    dispatcher machinery are registered, set up and cleaned up.

    This layer does not provide a complete ZODB setup (and is
    therefore much faster than complete functional setups) but does
    only the registrations (which also takes some time, so running
    this layer is slower than test cases that need none or only a
    few registrations).

    The registrations are done for all tests the layer is attached to
    once before all these tests are run (and torn down once
    afterwards).
    
    To make use of this layer, you have to write a
    :mod:`unittest.TestCase` class that provides an attribute called
    ``layer`` with this class as value like this::

      import unittest
      from waeup.sirp.testing import WAeUPSIRPUnitTestLayer
      
      class MyTestCase(unittest.TestCase):

          layer = WAeUPSIRPUnitTestLayer

          # per-test setups and real tests go here...
          def test_foo(self):
              self.assertEqual(1, 1)
              return

    """
    @classmethod
    def setUp(cls):
        grokked = maybe_grok()
        if grokked:
            setUpZope(None)
        return

    @classmethod
    def tearDown(cls):
        cleanUpZope(None)