#
#    Metrix++, Copyright 2009-2013, Metrix++ Project
#    Link: http://metrixplusplus.sourceforge.net
#    
#    This file is a part of Metrix++ Tool.
#    
#    Metrix++ 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, version 3 of the License.
#    
#    Metrix++ 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 Metrix++.  If not, see <http://www.gnu.org/licenses/>.
#

class Plugin(object):
    
    class Field(object):
        def __init__(self, name, ftype, non_zero=False):
            self.name = name
            self.type = ftype
            self.non_zero = non_zero

    class Property(object):
        def __init__(self, name, value):
            self.name = name
            self.value = value
    
    def initialize(self, namespace=None, support_regions=True, fields=[], properties=[]):
        self.is_updated = False
        db_loader = self.get_plugin_loader().get_database_loader()
        if namespace == None:
            namespace = self.get_name()

        if (len(fields) != 0 or len(properties) != 0):
            prev_version = db_loader.set_property(self.get_name() + ":version", self.get_version())
            if prev_version != self.get_version():
                self.is_updated = True

        for prop in properties:
            assert(prop.name != 'version')
            prev_prop = db_loader.set_property(self.get_name() + ":" + prop.name, prop.value)
            if prev_prop != prop.value:
                self.is_updated = True

        if len(fields) != 0:
            namespace_obj = db_loader.create_namespace(namespace,
                                                       support_regions=support_regions,
                                                       version=self.get_version())
            for field in fields:
                is_created = namespace_obj.add_field(field.name, field.type, non_zero=field.non_zero)
                assert(is_created != None)
                # if field is created (not cloned from the previous db),
                # mark the plug-in as updated in order to trigger full rescan
                self.is_updated = self.is_updated or is_created
    
    def terminate(self):
        pass
    
    def set_name(self, name):
        self.name = name

    def get_name(self):
        if hasattr(self, 'name') == False:
            return None
        return self.name

    def set_version(self, version):
        self.version = version

    def get_version(self):
        if hasattr(self, 'version') == False:
            return None
        return self.version

    def set_plugin_loader(self, loader):
        self.plugin_loader = loader

    def get_plugin_loader(self):
        if hasattr(self, 'plugin_loader') == False:
            return None
        return self.plugin_loader

class InterfaceNotImplemented(Exception):
    
    def __init__(self, obj):
        import sys
        Exception.__init__(self, "Method '"
                            + sys._getframe(1).f_code.co_name
                            + "' has not been implemented for "
                            + str(obj.__class__))

class IConfigurable(object):
    
    def configure(self, options):
        raise InterfaceNotImplemented(self)

    def declare_configuration(self, optparser):
        raise InterfaceNotImplemented(self)

class IRunable(object):
    def run(self, args):
        raise InterfaceNotImplemented(self)
    
class IParser(object):
    def process(self, parent, data, is_updated):
        raise InterfaceNotImplemented(self)

class CallbackNotImplemented(Exception):
    
    def __init__(self, obj, callback_name):
        Exception.__init__(self, "Callback '"
                           + callback_name
                           + "' has not been implemented for "
                           + str(obj.__class__))

class Child(object):
    
    def notify(self, parent, callback_name, *args):
        if hasattr(self, callback_name) == False:
            raise CallbackNotImplemented(self, callback_name)
        self.__getattribute__(callback_name)(parent, *args)

class Parent(object):
    
    def init_Parent(self):
        if hasattr(self, 'children') == False:
            self.children = []
            
    def subscribe(self, obj, callback_name):
        self.init_Parent()
        if (isinstance(obj, Child) == False):
            raise TypeError()
        self.children.append((obj,callback_name))

    def unsubscribe(self, obj, callback_name):
        self.init_Parent()
        self.children.remove((obj, callback_name))

    def notify_children(self, *args):
        self.init_Parent()
        for child in self.children:
            child[0].notify(self, child[1], *args)

    def iterate_children(self):
        self.init_Parent()
        for child in self.children:
            yield child

# TODO re-factor and remove this
class ExitError(Exception):
    def __init__(self, plugin, reason):
        if plugin != None:
            Exception.__init__(self, "Plugin '"
                               + plugin.get_name()
                               + "' requested abnormal termination: "
                               + reason)
        else:
            Exception.__init__(self, "'Abnormal termination requested: "
                               + reason)
            

def subscribe_by_parents_name(parent_name, child, callback_name='callback'):
    child.get_plugin_loader().get_plugin(parent_name).subscribe(child, callback_name)


# interfaces for subscription
class ICode(object):
    pass

def subscribe_by_parents_interface(interface, child, callback_name='callback'):
    for plugin in child.get_plugin_loader().iterate_plugins():
        if isinstance(plugin, interface):
            plugin.subscribe(child, callback_name)


class ITool(object):
    
    def run(self, tool_args):
        raise InterfaceNotImplemented(self)