"""
kombu.compression
=================

Compression utilities.

:copyright: (c) 2009 - 2010 by Ask Solem.
:license: BSD, see LICENSE for more details.

"""

_aliases = {}
_encoders = {}
_decoders = {}


def register(encoder, decoder, content_type, aliases=[]):
    """Register new compression method.

    :param encoder: Function used to compress text.
    :param decoder: Function used to decompress previously compressed text.
    :param content_type: The mime type this compression method identifies as.
    :param aliases: A list of names to associate with this compression method.

    """
    _encoders[content_type] = encoder
    _decoders[content_type] = decoder
    _aliases.update((alias, content_type) for alias in aliases)


def encoders():
    """Returns a list of available compression methods."""
    return _encoders.keys()


def get_encoder(t):
    """Get encoder by alias name."""
    t = _aliases.get(t, t)
    return _encoders[t], t


def get_decoder(t):
    """Get decoder by alias name."""
    return _decoders[_aliases.get(t, t)]


def compress(body, content_type):
    """Compress text.

    :param body: The text to compress.
    :param content_type: mime-type of compression method to use.

    """
    encoder, content_type = get_encoder(content_type)
    return encoder(body), content_type


def decompress(body, content_type):
    """Decompress compressed text.

    :param body: Previously compressed text to uncompress.
    :param content_type: mime-type of compression method used.

    """
    return get_decoder(content_type)(body)


register(lambda x: x.encode("zlib"),
         lambda x: x.decode("zlib"),
         "application/x-gzip", aliases=["gzip", "zlib"])
register(lambda x: x.encode("bz2"),
         lambda x: x.decode("bz2"),
         "application/x-bz2", aliases=["bzip2", "bzip"])