""" 

SyncData

========

Django command similar to 'loaddata' but also deletes.

After 'syncdata' has run, the database will have the same data as the fixture - anything

missing will of been added, anything different will of been updated,

and anything extra will of been deleted.

"""

from django.core.management.base import BaseCommand

from django.core.management.color import no_style

from optparse import make_option

import sys

import os

class Command(BaseCommand):

    """ syncdata command """

    help = 'Makes the current database have the same data as the fixture(s), no more, no less.'

    args = "fixture [fixture ...]"

    def remove_objects_not_in(self, objects_to_keep, verbosity):

        """

        Deletes all the objects in the database that are not in objects_to_keep.

        - objects_to_keep: A map where the keys are classes, and the values are a

         set of the objects of that class we should keep.

        """

        for class_ in objects_to_keep.keys():

            current = class_.objects.all()

            current_ids = set( [x.id for x in current] )

            keep_ids = set( [x.id for x in objects_to_keep[class_]] )

            remove_these_ones = current_ids.difference(keep_ids)

            if remove_these_ones:

                for obj in current:

                    if obj.id in remove_these_ones:

                        obj.delete()

                        if verbosity >= 2:

                            print "Deleted object: "+ unicode(obj)

            if verbosity > 0 and remove_these_ones:

                num_deleted = len(remove_these_ones)

                if num_deleted > 1:

                    type_deleted = unicode(class_._meta.verbose_name_plural)

                else:

                    type_deleted = unicode(class_._meta.verbose_name)

                print "Deleted "+ str(num_deleted) +" "+ type_deleted

    def handle(self, *fixture_labels, **options):

        """ Main method of a Django command """

        from django.db.models import get_apps

        from django.core import serializers

        from django.db import connection, transaction

        from django.conf import settings

        self.style = no_style()

        verbosity = int(options.get('verbosity', 1))

        show_traceback = options.get('traceback', False)

        # Keep a count of the installed objects and fixtures

        fixture_count = 0

        object_count = 0

        objects_per_fixture = []

        models = set()

        humanize = lambda dirname: dirname and "'%s'" % dirname or 'absolute path'

        # Get a cursor (even though we don't need one yet). This has

        # the side effect of initializing the test database (if

        # it isn't already initialized).

        cursor = connection.cursor()

        # Start transaction management. All fixtures are installed in a

        # single transaction to ensure that all references are resolved.

        transaction.commit_unless_managed()

        transaction.enter_transaction_management()

        transaction.managed(True)

        app_fixtures = [os.path.join(os.path.dirname(app.__file__), 'fixtures') \

                        for app in get_apps()]

        for fixture_label in fixture_labels:

            parts = fixture_label.split('.')

            if len(parts) == 1:

                fixture_name = fixture_label

                formats = serializers.get_public_serializer_formats()

            else:

                fixture_name, format = '.'.join(parts[:-1]), parts[-1]

                if format in serializers.get_public_serializer_formats():

                    formats = [format]

                else:

                    formats = []

            if formats:

                if verbosity > 1:

                    print "Loading '%s' fixtures..." % fixture_name

            else:

                sys.stderr.write(

                    self.style.ERROR("Problem installing fixture '%s': %s is not a known "+ \

                                     "serialization format." % (fixture_name, format))

                    )

                transaction.rollback()

                transaction.leave_transaction_management()

                return

            if os.path.isabs(fixture_name):

                fixture_dirs = [fixture_name]

            else:

                fixture_dirs = app_fixtures + list(settings.FIXTURE_DIRS) + ['']

            for fixture_dir in fixture_dirs:

                if verbosity > 1:

                    print "Checking %s for fixtures..." % humanize(fixture_dir)

                label_found = False

                for format in formats:

                    serializer = serializers.get_serializer(format)

                    if verbosity > 1:

                        print "Trying %s for %s fixture '%s'..." % \

                            (humanize(fixture_dir), format, fixture_name)

                    try:

                        full_path = os.path.join(fixture_dir, '.'.join([fixture_name, format]))

                        fixture = open(full_path, 'r')

                        if label_found:

                            fixture.close()

                            print self.style.ERROR("Multiple fixtures named '%s' in %s. Aborting." %

                                (fixture_name, humanize(fixture_dir)))

                            transaction.rollback()

                            transaction.leave_transaction_management()

                            return

                        else:

                            fixture_count += 1

                            objects_per_fixture.append(0)

                            if verbosity > 0:

                                print "Installing %s fixture '%s' from %s." % \

                                    (format, fixture_name, humanize(fixture_dir))

                            try:

                                objects_to_keep = {}

                                objects = serializers.deserialize(format, fixture)

                                for obj in objects:

                                    object_count += 1

                                    objects_per_fixture[-1] += 1

                                    class_ = obj.object.__class__

                                    if not class_ in objects_to_keep:

                                        objects_to_keep[class_] = set()

                                    objects_to_keep[class_].add(obj.object)

                                    models.add(class_)

                                    obj.save()

                                self.remove_objects_not_in(objects_to_keep, verbosity)

                                label_found = True

                            except (SystemExit, KeyboardInterrupt):

                                raise

                            except Exception:

                                import traceback

                                fixture.close()

                                transaction.rollback()

                                transaction.leave_transaction_management()

                                if show_traceback:

                                    traceback.print_exc()

                                else:

                                    sys.stderr.write(

                                        self.style.ERROR("Problem installing fixture '%s': %s\n" %

                                             (full_path, traceback.format_exc())))

                                return

                            fixture.close()

                    except:

                        if verbosity > 1:

                            print "No %s fixture '%s' in %s." % \

                                (format, fixture_name, humanize(fixture_dir))

        # If any of the fixtures we loaded contain 0 objects, assume that an 

        # error was encountered during fixture loading.

        if 0 in objects_per_fixture:

            sys.stderr.write(

                self.style.ERROR("No fixture data found for '%s'. (File format may be invalid.)" %

                    (fixture_name)))

            transaction.rollback()

            transaction.leave_transaction_management()

            return

        # If we found even one object in a fixture, we need to reset the 

        # database sequences.

        if object_count > 0:

            sequence_sql = connection.ops.sequence_reset_sql(self.style, models)

            if sequence_sql:

                if verbosity > 1:

                    print "Resetting sequences"

                for line in sequence_sql:

                    cursor.execute(line)

        transaction.commit()

        transaction.leave_transaction_management()

        if object_count == 0:

            if verbosity > 1:

                print "No fixtures found."

        else:

            if verbosity > 0:

                print "Installed %d object(s) from %d fixture(s)" % (object_count, fixture_count)

        # Close the DB connection. This is required as a workaround for an

        # edge case in MySQL: if the same connection is used to

        # create tables, load data, and query, the query can return

        # incorrect results. See Django #7572, MySQL #37735.

        connection.close()

# Backwards compatibility for Django r9110

if not [opt for opt in Command.option_list if opt.dest=='verbosity']:

    Command.option_list += (

        make_option('--verbosity', '-v', action="store", dest="verbosity",

            default='1', type='choice', choices=['0', '1', '2'],

            help="Verbosity level; 0=minimal output, 1=normal output, 2=all output"),

    )