'''\
Compatibility configuration switches

This is a transitional solution to attack the problem
of quickly changing Zope3 and Five apis.

Import checks are done centrally from here.
The point is that compatibility imports should fail here,
if anything goes wrong. Components should only check
the switches set from here.

Supported versions:
-------------------

Zope  2.9, 2.10
Zope  3.2, 3.3

Compatibility matrix
--------------------

The following table shows which Five version can and should be used 
with which Zope 2 and Zope 3 versions.

.           Zope 2.8         Zope 2.9     Zope 2.10
.           Zope X3 3.0      Zope 3.2     Zope 3.3  
Five 1.0    included                               
Five 1.2    X                                      
Five 1.3                     included              
Five 1.4                     X                      
Five trunk                                included 

'''

__all__ = ('__compat__', )

class DictLike(object):
    pass
    
__compat__ = DictLike()

try:
    import zope.component.interface
    import zope.component.location
    __compat__.zope_pre_3_3 = False
except ImportError:
    # The only supported pre_3_3 version is 3.2
    import zope.app.component.interface
    import zope.app.location
    __compat__.zope_pre_3_3 = True
    
try:
    import Products.Five
except ImportError:
    __compat__.five = False
else:
    __compat__.five = True
    try:
        # Zope 2.8 / Five 1.0.2
        from Products.Five.resource import Resource
        __compat__.five_pre_1_3 = True
    except ImportError:
        # Zope 2.9 / Five 1.3
        from Products.Five.browser.resource import Resource
        __compat__.five_pre_1_3 = False

# Unsupported versions.
if __compat__.five and __compat__.five_pre_1_3:
    raise Exception, 'Zope 2.8 or prior versions (Five 1.2 or prior versions) are unsupported, please upgrade!'

# If running on zope3, make a fake installed product. We need this because
# there is no negation of zcml:condition="installed Zope2".
import sys
if not __compat__.five:
    sys.modules['not_Zope2'] = sys.modules[globals()['__name__']]