#!/usr/bin/env python3

# Copyright (c) 2019, Alchemy Meister
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#     * Redistributions of source code must retain the above copyright notice,
#       this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice,this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the copyright holder nor the names of its
#       contributors may be used to endorse or promote products derived from
#       this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

"""
"""
from enum import Enum, EnumMeta
from .subscriber import Subscriber

class Publisher:
    """
    """
    def __init__(self, *events):
        if isinstance(events[0], (Enum, EnumMeta)):
            self.events = {event.value: dict() for event in events[0]}
        else:
            self.events = dict()
            for event in events:
                if not self.events.get(event, False):
                    self.events[event] = dict()
                else:
                    raise ValueError('duplicated event value: {}'.format(event))

    def dispatch(self, event, *args, **kwargs):
        for callback_tuple in tuple(self.__get_subscribers(event).values()):
            callback_tuple[0](
                callback_tuple[1], event, *args, **kwargs
            )

    def register(self, event, subscriber: Subscriber, callback=None):
        self.__get_subscribers(event)[subscriber.subscriber_id] = (
            subscriber.update, callback
        )

    def unregister(self, event, subscriber):
        del self.__get_subscribers(event)[subscriber.subscriber_id]

    def __get_subscribers(self, event):
        return self.events[event]
