"""CubicWeb is a generic framework to quickly build applications which describes

relations between entitites.

"""

__docformat__ = "restructuredtext en"

import __builtin__

# '_' is available in builtins to mark internationalized string but should

# not be used to do the actual translation

if not hasattr(__builtin__, '_'):

    __builtin__._ = unicode

CW_SOFTWARE_ROOT = __path__[0]

import sys, os, logging

from StringIO import StringIO

from logilab.common.logging_ext import set_log_methods

if os.environ.get('APYCOT_ROOT'):

    logging.basicConfig(level=logging.CRITICAL)

else:

    logging.basicConfig()

from cubicweb.__pkginfo__ import version as __version__

set_log_methods(sys.modules[__name__], logging.getLogger('cubicweb'))

# make all exceptions accessible from the package

from cubicweb._exceptions import *

# convert eid to the right type, raise ValueError if it's not a valid eid

typed_eid = int

#def log_thread(f, w, a):

#    print f.f_code.co_filename, f.f_code.co_name

#import threading

#threading.settrace(log_thread)

class Binary(StringIO):

    """customize StringIO to make sure we don't use unicode"""

    def __init__(self, buf=''):

        assert isinstance(buf, (str, buffer)), \

               "Binary objects must use raw strings, not %s" % buf.__class__

        StringIO.__init__(self, buf)

    def write(self, data):

        assert isinstance(data, (str, buffer)), \

               "Binary objects must use raw strings, not %s" % data.__class__

        StringIO.write(self, data)

# use this dictionary to rename entity types while keeping bw compat

ETYPE_NAME_MAP = {}

# XXX cubic web cube migration map. See if it's worth keeping this mecanism

#     to help in cube renaming

CW_MIGRATION_MAP = {}

def neg_role(role):

    if role == 'subject':

        return 'object'

    return 'subject'

def role(obj):

    try:

        return obj.role

    except AttributeError:

        return neg_role(obj.target)

def target(obj):

    try:

        return obj.target

    except AttributeError:

        return neg_role(obj.role)

class CubicWebEventManager(object):

    """simple event / callback manager.

    Typical usage to register a callback::

      >>> from cubicweb import CW_EVENT_MANAGER

      >>> CW_EVENT_MANAGER.bind('after-registry-reload', mycallback)

    Typical usage to emit an event::

      >>> from cubicweb import CW_EVENT_MANAGER

      >>> CW_EVENT_MANAGER.emit('after-registry-reload')

    emit() accepts an additional context parameter that will be passed

    to the callback if specified (and only in that case)

    """

    def __init__(self):

        self.callbacks = {}

    def bind(self, event, callback, *args, **kwargs):

        self.callbacks.setdefault(event, []).append( (callback, args, kwargs) )

    def emit(self, event, context=None):

        for callback, args, kwargs in self.callbacks.get(event, ()):

            if context is None:

                callback(*args, **kwargs)

            else:

                callback(context, *args, **kwargs)

CW_EVENT_MANAGER = CubicWebEventManager()

def onevent(event, *args, **kwargs):

    """decorator to ease event / callback binding

    >>> from cubicweb import onevent

    >>> @onevent('before-registry-reload')

    ... def mycallback():

    ...     print 'hello'

    ...

    >>>

    """

    def _decorator(func):

        CW_EVENT_MANAGER.bind(event, func, *args, **kwargs)

        return func

    return _decorator