#!/usr/bin/python
# -*- coding: utf-8 -*-

# Hive Appier Framework
# Copyright (C) 2008-2012 Hive Solutions Lda.
#
# This file is part of Hive Appier Framework.
#
# Hive Appier Framework is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Hive Appier Framework is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Hive Appier Framework. If not, see <http://www.gnu.org/licenses/>.

__author__ = "João Magalhães joamag@hive.pt>"
""" The author(s) of the module """

__version__ = "1.0.0"
""" The version of the module """

__revision__ = "$LastChangedRevision$"
""" The revision number of the module """

__date__ = "$LastChangedDate$"
""" The last change date of the module """

__copyright__ = "Copyright (c) 2008-2012 Hive Solutions Lda."
""" The copyright for the module """

__license__ = "GNU General Public License (GPL), Version 3"
""" The license for the module """

import util

class Observable(object):
    """
    The base class that implements the observable
    patter allowing the object to handle a series of
    event in a dynamic fashion.

    The class should be able to handle both context
    based event (instance level) and global level
    events (class level).

    This class should be friendly to multiple inheritance
    and should avoid variable naming collision.
    """

    _events_g = {}
    """ The dictionary containing the global association
    between the global event names and the handler methods """

    def __init__(self, *args, **kwargs):
        self._events = {}

    @classmethod
    def name_f(cls, name):
        cls_name = cls.__name__
        cls_name = util.camel_to_underscore(cls_name)
        name_f = cls_name + "." + name
        return name_f

    @classmethod
    def bind_g(cls, name, method):
        name_f = cls.name_f(name)
        methods = cls._events_g.get(name_f, [])
        methods.append(method)
        cls._events_g[name_f] = methods

    @classmethod
    def unbind_g(cls, name, method = None):
        name_f = cls.name_f(name)
        methods = cls._events_g.get(name_f, [])
        if method: methods.remove(method)
        else: del methods[:]

    @classmethod
    def trigger_g(cls, name, *args, **kwargs):
        name_f = cls.name_f(name)
        methods = cls._events_g.get(name_f, [])
        for method in methods: method(*args, **kwargs)

    def bind(self, name, method):
        methods = self._events.get(name, [])
        methods.append(method)
        self._events[name] = methods

    def unbind(self, name, method = None):
        methods = self._events.get(name, [])
        if method: methods.remove(method)
        else: del methods[:]

    def trigger(self, name, *args, **kwargs):
        cls = self.__class__
        self.trigger_l(name, cls, *args, **kwargs)

    def trigger_l(self, name, level, *args, **kwargs):
        methods = self._events.get(name, [])
        for method in methods: method(*args, **kwargs)
        level.trigger_g(name, self, *args, **kwargs)
