from django.core.management.base import CommandError, NoArgsCommand
from django.conf import settings
from adim.models import AnObj
import os
import sys
from optparse import make_option


class Command(NoArgsCommand):
    help = 'Remove image files not used by an Annotable Object'
    option_list = NoArgsCommand.option_list + (
        make_option('--noinput',
            action='store_false', dest='interactive', default=True,
            help="Do NOT prompt the user for input of any kind."),
        make_option('-n', '--dry-run',
            action='store_true', dest='dry_run', default=False,
            help="Do everything except modify the filesystem."),
    )

    def __init__(self, *args, **kwargs):
        super(NoArgsCommand, self).__init__(*args, **kwargs)
        self.dry_run = False
        self.interactive = True
        self.verbosity = 1

    def set_options(self, **options):
        """
        Set instance variables based on an options dict
        """
        self.interactive = options['interactive']
        self.dry_run = options['dry_run']
        self.verbosity = int(options['verbosity']) if self.interactive else 0

    def handle_noargs(self, **options):
        self.set_options(**options)

        anobj_uuid_list = AnObj.objects.all().values_list('uuid', flat=True)
        images_path = os.path.join(settings.MEDIA_ROOT, 'ao_images')
        files_to_remove = []
        for root, dirs, files in os.walk(unicode(images_path)):
            files_to_remove.extend(os.path.join(root, f) for f in files if f[:32] not in anobj_uuid_list)

        if len(files_to_remove) == 0:
            if self.verbosity >= 1:
                print "No files to remove."
            sys.exit(0)

        if self.verbosity >= 1:
            print "List of files to be deleted: "
            print "---------------------------"
            print "\n".join(f.replace(settings.MEDIA_ROOT, '    .') for f in files_to_remove)
            print "\n"

        message = "Continue and delete {} files ? [yes/NO] ".format(len(files_to_remove))
        if self.interactive and raw_input(message) != 'yes':
            raise CommandError("Removing unused files cancelled.")

        if not self.dry_run:
            for f in files_to_remove:
                try:
                    os.unlink(f)
                except OSError:
                    if self.verbosity >= 1:
                        print "# Unable to delete file {}\n  -> {}".format(f, sys.exc_info()[1][1])

        if self.verbosity >= 1:
            print "Done."