# Distributed under the terms of the Python license
# see http://opensource.org/licenses/pythonpl.php for the full text.

# stdlib
from cStringIO import StringIO
from itertools import ifilter
from string import Template

_repr_template = Template("<$class_name at $mem_loc$attrs>")

def _object_attrs(_object, ignore_double_underscore, to_avoid_list, sort):
    attrs = dir(_object)

    if ignore_double_underscore:
        attrs = ifilter(lambda elem: not elem.startswith("__"), attrs)

    _to_avoid_list = getattr(_object, to_avoid_list, None) # Don't swallow exceptions
    if _to_avoid_list is not None:
        attrs = ifilter(lambda elem: not elem in _to_avoid_list, attrs)

    if sort:
        attrs = sorted(attrs)

    return attrs

def make_repr(_object, ignore_double_underscore=True, to_avoid_list="repr_to_avoid", sort=True):
    """ Makes a nice string representation of an object, suitable for logging
    purposes.
    """
    attrs = _object_attrs(_object, ignore_double_underscore, to_avoid_list, sort)
    buff = StringIO()

    for attr in attrs:
        attr_obj = getattr(_object, attr)
        if not callable(attr_obj):
            buff.write(" ")
            buff.write("%s=[%s]" % (attr, attr_obj))

    out = _repr_template.safe_substitute(class_name=_object.__class__.__name__,
                            mem_loc=hex(id(_object)), attrs=buff.getvalue())
    buff.close()

    return out

if __name__ == "__main__":

    class Foo(object):

        repr_to_avoid = ("x",)

        def __init__(self, x, y, z):
            self.x = x
            self.y = y
            self.z = z

        def __repr__(self):
            return make_repr(self)

    print Foo(1,2,3)