from kivy.properties cimport Property, PropertyStorage
from kivy._event cimport EventDispatcher

cdef inline void observable_object_dispatch(object self, str name):
    cdef Property prop = self.prop
    prop.dispatch(self.obj, name)


class ObservableObject(object):

    # Internal class to observe changes inside a native python object.
    def __init__(self, *largs):
        self.prop = largs[0]
        self.obj = largs[1]
        super(ObservableObject, self).__init__()

    def __setattr__(self, name, value):
        object.__setattr__(self, name, value)
        observable_object_dispatch(self, name)


cdef class DocProperty(Property):

    def __init__(self, defaultvalue=None, rebind=False, **kw):
        self.baseclass = kw.get('baseclass', object)
        super(DocProperty, self).__init__(defaultvalue, **kw)
        self.rebind = rebind

    cpdef link(self, EventDispatcher obj, str name):
        Property.link(self, obj, name)
        cdef PropertyStorage ps = obj.__storage[self._name]
        ps.value = ObservableObject(self, obj, ps.value)

    cdef check(self, EventDispatcher obj, value):
        if Property.check(self, obj, value):
            return True
        if not isinstance(value, object):
            raise ValueError('{}.{} accept only object based on {}'.format(
            obj.__class__.__name__,
            self.name,
            self.baseclass.__name__))

    cpdef dispatch(self, EventDispatcher obj, str name):
        '''Dispatch the value change to all observers.
       .. versionchanged:: 1.1.0
           The method is now accessible from Python.
       This can be used to force the dispatch of the property, even if the
       value didn't change::
           button = Button()
           # get the Property class instance
           prop = button.property('text')
           # dispatch this property on the button instance
           prop.dispatch(button)
       '''
        cdef PropertyStorage ps = obj.__storage[self._name]
        ps.observers.dispatch(obj, ps.value, (name,), None, 0)

from kivy.properties cimport Property, PropertyStorage
from kivy._event cimport EventDispatcher

cdef class DocProperty(Property):
    cdef object baseclass
    cdef public int rebind
    cpdef dispatch(self, EventDispatcher obj, str name)

# -*- coding: utf-8 -*-

from kivy.event import EventDispatcher
import pyximport
pyximport.install()
from properties import DocProperty

if __name__ == '__main__':

    class ED(EventDispatcher):

        doc = DocProperty()

        def on_doc(self, obj, value):
            print 'printing doc', self.doc

    class DumbObj(object):

        def __init__(self, num):
            self._num = num

        @property
        def num(self):
            return 5

        @num.setter
        def num(self, value):
            self._num = value

    ed = ED()
    ed.doc = DumbObj(3)
    ed.doc.num = 4