# Copyright (c) 2006, 2007, 2008, 2009, 2010, 2011, 2012  Andrey Golovizin
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

from pybtex.plugin import Plugin


class BaseSortingStyle(Plugin):
    default_plugin = 'none'

    def sorting_key(self, entry):
        raise NotImplementedError

    def sort(self, entries):
        entry_dict = dict(
            (self.sorting_key(entry), entry)
            for entry in entries
        )
        sorted_keys = sorted(entry_dict)
        sorted_entries = [entry_dict[key] for key in sorted_keys]
        return sorted_entries