"""
Functions responsible for returning filenames for the given image generator.
Users are free to define their own functions; these are just some some sensible
choices.

"""

from django.conf import settings
import os
from ..utils import suggest_extension


def spec_slug_as_path(generator):
    """
    A namer that, given the following source file name::

        <asset_uuid>/original/bulldog.jpg

    will generate a relative name like this::

            <spec_slug>/5ff3233527c5ac3e4b596343b440ff67.jpg

    which is meant to be added to both

        <asset_uuid>/cache/
        <asset_uuid>/manual/
    .

    """
    source_filename = getattr(generator.source, 'name', None)
    spec_slug = getattr(generator, 'slug', None)

    ext = suggest_extension(source_filename or '', generator.format)


    if source_filename is None or os.path.isabs(source_filename):
        # Generally, we put the file right in the cache file directory.
        dir = settings.IMAGEKIT_CACHEFILE_DIR
    else:
        # For source files with relative names (like Django media files),
        # use the source's name to create the new filename.
        dir = os.path.join(settings.IMAGEKIT_CACHEFILE_DIR,
                           os.path.splitext(source_filename)[0])

    return os.path.normpath(os.path.join(dir,
                                         '%s%s' % (generator.get_hash(), ext)))