import datetime

import functools

import decimal

__all__ = ['json', 'simplejson', 'stdjson']

def _is_aware(value):

    """

    Determines if a given datetime.time is aware.

    The logic is described in Python's docs:

    http://docs.python.org/library/datetime.html#datetime.tzinfo

    """

    return (value.tzinfo is not None

            and value.tzinfo.utcoffset(value) is not None)

def _obj_dump(obj):

    """

    Custom function for dumping objects to JSON, if obj has __json__ attribute

    or method defined it will be used for serialization

    :param obj:

    """

    if isinstance(obj, complex):

        return [obj.real, obj.imag]

    # See "Date Time String Format" in the ECMA-262 specification.

    # some code borrowed from django 1.4

    elif isinstance(obj, datetime.datetime):

        r = obj.isoformat()

        if obj.microsecond:

            r = r[:23] + r[26:]

        if r.endswith('+00:00'):

            r = r[:-6] + 'Z'

        return r

    elif isinstance(obj, datetime.date):

        return obj.isoformat()

    elif isinstance(obj, decimal.Decimal):

        return str(obj)

    elif isinstance(obj, datetime.time):

        if _is_aware(obj):

            raise ValueError("JSON can't represent timezone-aware times.")

        r = obj.isoformat()

        if obj.microsecond:

            r = r[:12]

        return r

    elif isinstance(obj, set):

        return list(obj)

    elif hasattr(obj, '__json__'):

        if callable(obj.__json__):

            return obj.__json__()

        else:

            return obj.__json__

    else:

        raise NotImplementedError

# Import simplejson

try:

    # import simplejson initially

    import simplejson

    def extended_encode(obj):

        try:

            return _obj_dump(obj)

        except NotImplementedError:

            pass

        raise TypeError("%r is not JSON serializable" % (obj,))

    # we handle decimals our own it makes unified behavior of json vs

    # simplejson

    simplejson.dumps = functools.partial(simplejson.dumps,

                                         default=extended_encode,

                                         use_decimal=False)

    simplejson.dump = functools.partial(simplejson.dump,

                                        default=extended_encode,

                                        use_decimal=False)

except ImportError:

    # no simplejson set it to None

    simplejson = None

try:

    # simplejson not found try out regular json module

    import json

    # extended JSON encoder for json

    class ExtendedEncoder(json.JSONEncoder):

        def default(self, obj):

            try:

                return _obj_dump(obj)

            except NotImplementedError:

                pass

    # monkey-patch JSON encoder to use extended version

    json.dumps = functools.partial(json.dumps, cls=ExtendedEncoder)

    json.dump = functools.partial(json.dump, cls=ExtendedEncoder)

except ImportError:

    json = None

stdlib = json

# set all available json modules

if simplejson:

    json = simplejson

elif json:

    json = json

else:

    raise ImportError('Could not find any json modules')