# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

try:
    from PIL import Image
except ImportError:
    import Image
import os
import logging

from mediagoblin import mg_globals as mgg
from mediagoblin.processing import BadMediaFail, FilenameBuilder
from mediagoblin.tools.exif import exif_fix_image_orientation, \
    extract_exif, clean_exif, get_gps_data, get_useful, \
    exif_image_needs_rotation

_log = logging.getLogger(__name__)

PIL_FILTERS = {
    'NEAREST': Image.NEAREST,
    'BILINEAR': Image.BILINEAR,
    'BICUBIC': Image.BICUBIC,
    'ANTIALIAS': Image.ANTIALIAS}

MEDIA_TYPE = 'mediagoblin.media_types.image'


def resize_image(proc_state, resized, keyname, target_name, new_size,
                 exif_tags, workdir):
    """
    Store a resized version of an image and return its pathname.

    Arguments:
    proc_state -- the processing state for the image to resize
    resized -- an image from Image.open() of the original image being resized
    keyname -- Under what key to save in the db.
    target_name -- public file path for the new resized image
    exif_tags -- EXIF data for the original image
    workdir -- directory path for storing converted image files
    new_size -- 2-tuple size for the resized image
    """
    config = mgg.global_config['media_type:mediagoblin.media_types.image']

    resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation

    filter_config = config['resize_filter']
    try:
        resize_filter = PIL_FILTERS[filter_config.upper()]
    except KeyError:
        raise Exception('Filter "{0}" not found, choose one of {1}'.format(
            unicode(filter_config),
            u', '.join(PIL_FILTERS.keys())))

    resized.thumbnail(new_size, resize_filter)

    # Copy the new file to the conversion subdir, then remotely.
    tmp_resized_filename = os.path.join(workdir, target_name)
    with file(tmp_resized_filename, 'w') as resized_file:
        resized.save(resized_file, quality=config['quality'])
    proc_state.store_public(keyname, tmp_resized_filename, target_name)


def resize_tool(proc_state, force, keyname, filename, target_name,
                conversions_subdir, exif_tags, new_size=None):
    if not new_size:
        max_width = mgg.global_config['media:' + keyname]['max_width']
        max_height = mgg.global_config['media:' + keyname]['max_height']
        new_size = (max_width, max_height)
    # If the size of the original file exceeds the specified size for the desized
    # file, a target_name file is created and later associated with the media
    # entry.
    # Also created if the file needs rotation, or if forced.
    try:
        im = Image.open(filename)
    except IOError:
        raise BadMediaFail()
    if force \
        or im.size[0] > new_size[0]\
        or im.size[1] > new_size[1]\
        or exif_image_needs_rotation(exif_tags):
        resize_image(
            proc_state, im, unicode(keyname), target_name,
            new_size,
            exif_tags, conversions_subdir)


SUPPORTED_FILETYPES = ['png', 'gif', 'jpg', 'jpeg', 'tiff']


def sniff_handler(media_file, **kw):
    _log.info('Sniffing {0}'.format(MEDIA_TYPE))
    if kw.get('media') is not None:  # That's a double negative!
        name, ext = os.path.splitext(kw['media'].filename)
        clean_ext = ext[1:].lower()  # Strip the . from ext and make lowercase

        if clean_ext in SUPPORTED_FILETYPES:
            _log.info('Found file extension in supported filetypes')
            return MEDIA_TYPE
        else:
            _log.debug('Media present, extension not found in {0}'.format(
                    SUPPORTED_FILETYPES))
    else:
        _log.warning('Need additional information (keyword argument \'media\')'
                     ' to be able to handle sniffing')

    return None


def process_image(proc_state, reprocess_info=None):
    """Code to process an image. Will be run by celery.

    A Workbench() represents a local tempory dir. It is automatically
    cleaned up when this function exits.
    """
    entry = proc_state.entry
    workbench = proc_state.workbench

    # Conversions subdirectory to avoid collisions
    conversions_subdir = os.path.join(
        workbench.dir, 'conversions')
    os.mkdir(conversions_subdir)

    if reprocess_info:
        _reprocess_image(proc_state, reprocess_info, conversions_subdir)

    else:
        queued_filename = proc_state.get_queued_filename()
        name_builder = FilenameBuilder(queued_filename)

        # EXIF extraction
        exif_tags = extract_exif(queued_filename)
        gps_data = get_gps_data(exif_tags)

        # Always create a small thumbnail
        resize_tool(proc_state, True, 'thumb', queued_filename,
                    name_builder.fill('{basename}.thumbnail{ext}'),
                    conversions_subdir, exif_tags)

        # Possibly create a medium
        resize_tool(proc_state, False, 'medium', queued_filename,
                    name_builder.fill('{basename}.medium{ext}'),
                    conversions_subdir, exif_tags)

        # Copy our queued local workbench to its final destination
        proc_state.copy_original(name_builder.fill('{basename}{ext}'))

        # Remove queued media file from storage and database
        proc_state.delete_queue_file()

        # Insert exif data into database
        exif_all = clean_exif(exif_tags)

        if len(exif_all):
            entry.media_data_init(exif_all=exif_all)

        if len(gps_data):
            for key in list(gps_data.keys()):
                gps_data['gps_' + key] = gps_data.pop(key)
            entry.media_data_init(**gps_data)


def _reprocess_image(proc_state, reprocess_info, conversions_subdir):
    reprocess_filename = proc_state.get_reprocess_filename()
    name_builder = FilenameBuilder(reprocess_filename)

    exif_tags = extract_exif(reprocess_filename)

    if reprocess_info.get('max_width'):
        max_width = reprocess_info['max_width']
        max_height = reprocess_info['max_height']
    else:
        max_width = mgg.global_config \
            ['media:' + reprocess_info['resize']]['max_width']
        max_height = mgg.global_config \
            ['media:' + reprocess_info['resize']]['max_height']

    new_size = (max_width, max_height)

    resize_tool(proc_state, False, reprocess_info['resize'], reprocess_filename,
                name_builder.fill('{basename}.thumbnail{ext}'),
                conversions_subdir, exif_tags, new_size)


if __name__ == '__main__':
    import sys
    import pprint

    pp = pprint.PrettyPrinter()

    result = extract_exif(sys.argv[1])
    gps = get_gps_data(result)
    clean = clean_exif(result)
    useful = get_useful(clean)

    print pp.pprint(
        clean)