text: import time
  from importlib import import_module
  
  from django.apps import apps
  from django.core.management.base import (
      BaseCommand, CommandError, no_translations,
  )
  from django.core.management.sql import (
      emit_post_migrate_signal, emit_pre_migrate_signal,
  )
  from django.db import DEFAULT_DB_ALIAS, connections, router
  from django.db.migrations.autodetector import MigrationAutodetector
  from django.db.migrations.executor import MigrationExecutor
  from django.db.migrations.loader import AmbiguityError
  from django.db.migrations.state import ModelState, ProjectState
  from django.utils.module_loading import module_has_submodule
  from django.utils.text import Truncator
  
  
  class Command(BaseCommand):
      help = "Updates database schema. Manages both apps with migrations and those without."
      requires_system_checks = False
  
      def add_arguments(self, parser):
          parser.add_argument(
              '--skip-checks', action='store_true',
              help='Skip system checks.',
          )
          parser.add_argument(
              'app_label', nargs='?',
              help='App label of an application to synchronize the state.',
          )
          parser.add_argument(
              'migration_name', nargs='?',
              help='Database state will be brought to the state after that '
                   'migration. Use the name "zero" to unapply all migrations.',
          )
          parser.add_argument(
              '--noinput', '--no-input', action='store_false', dest='interactive',
              help='Tells Django to NOT prompt the user for input of any kind.',
          )
          parser.add_argument(
              '--database',
              default=DEFAULT_DB_ALIAS,
              help='Nominates a database to synchronize. Defaults to the "default" database.',
          )
          parser.add_argument(
              '--fake', action='store_true',
              help='Mark migrations as run without actually running them.',
          )
          parser.add_argument(
              '--fake-initial', action='store_true',
              help='Detect if tables already exist and fake-apply initial migrations if so. Make sure '
                   'that the current database schema matches your initial migration before using this '
                   'flag. Django will only check for an existing table name.',
          )
          parser.add_argument(
              '--plan', action='store_true',
              help='Shows a list of the migration actions that will be performed.',
          )
          parser.add_argument(
              '--run-syncdb', action='store_true',
              help='Creates tables for apps without migrations.',
          )
  
      @no_translations
      def handle(self, *args, **options):
          database = options['database']
          if not options['skip_checks']:
              self.check(databases=[database])
  
          self.verbosity = options['verbosity']
          self.interactive = options['interactive']
  
          # Import the 'management' module within each installed app, to register
          # dispatcher events.
          for app_config in apps.get_app_configs():
              if module_has_submodule(app_config.module, "management"):
                  import_module('.management', app_config.name)
  
          # Get the database we're operating from
          connection = connections[database]
  
          # Hook for backends needing any database preparation
          connection.prepare_database()
          # Work out which apps have migrations and which do not
          executor = MigrationExecutor(connection, self.migration_progress_callback)
  
          # Raise an error if any migrations are applied before their dependencies.
          executor.loader.check_consistent_history(connection)
  
          # Before anything else, see if there's conflicting apps and drop out
          # hard if there are any
          conflicts = executor.loader.detect_conflicts()
          if conflicts:
              name_str = "; ".join(
                  "%s in %s" % (", ".join(names), app)
                  for app, names in conflicts.items()
              )
              raise CommandError(
                  "Conflicting migrations detected; multiple leaf nodes in the "
                  "migration graph: (%s).\nTo fix them run "
                  "'python manage.py makemigrations --merge'" % name_str
              )
  
          # If they supplied command line arguments, work out what they mean.
          run_syncdb = options['run_syncdb']
          target_app_labels_only = True
          if options['app_label']:
              # Validate app_label.
              app_label = options['app_label']
              try:
                  apps.get_app_config(app_label)
              except LookupError as err:
                  raise CommandError(str(err))
              if run_syncdb:
                  if app_label in executor.loader.migrated_apps:
                      raise CommandError("Can't use run_syncdb with app '%s' as it has migrations." % app_label)
              elif app_label not in executor.loader.migrated_apps:
                  raise CommandError("App '%s' does not have migrations." % app_label)
  
          if options['app_label'] and options['migration_name']:
              migration_name = options['migration_name']
              if migration_name == "zero":
                  targets = [(app_label, None)]
              else:
                  try:
                      migration = executor.loader.get_migration_by_prefix(app_label, migration_name)
                  except AmbiguityError:
                      raise CommandError(
                          "More than one migration matches '%s' in app '%s'. "
                          "Please be more specific." %
                          (migration_name, app_label)
                      )
                  except KeyError:
                      raise CommandError("Cannot find a migration matching '%s' from app '%s'." % (
                          migration_name, app_label))
                  targets = [(app_label, migration.name)]
              target_app_labels_only = False
          elif options['app_label']:
              targets = [key for key in executor.loader.graph.leaf_nodes() if key[0] == app_label]
          else:
              targets = executor.loader.graph.leaf_nodes()
  
          plan = executor.migration_plan(targets)
  
          if options['plan']:
              self.stdout.write('Planned operations:', self.style.MIGRATE_LABEL)
              if not plan:
                  self.stdout.write('  No planned migration operations.')
              for migration, backwards in plan:
                  self.stdout.write(str(migration), self.style.MIGRATE_HEADING)
                  for operation in migration.operations:
                      message, is_error = self.describe_operation(operation, backwards)
                      style = self.style.WARNING if is_error else None
                      self.stdout.write('    ' + message, style)
              return
  
          # At this point, ignore run_syncdb if there aren't any apps to sync.
          run_syncdb = options['run_syncdb'] and executor.loader.unmigrated_apps
          # Print some useful info
          if self.verbosity >= 1:
              self.stdout.write(self.style.MIGRATE_HEADING("Operations to perform:"))
              if run_syncdb:
                  if options['app_label']:
                      self.stdout.write(
                          self.style.MIGRATE_LABEL("  Synchronize unmigrated app: %s" % app_label)
                      )
                  else:
                      self.stdout.write(
                          self.style.MIGRATE_LABEL("  Synchronize unmigrated apps: ") +
                          (", ".join(sorted(executor.loader.unmigrated_apps)))
                      )
              if target_app_labels_only:
                  self.stdout.write(
                      self.style.MIGRATE_LABEL("  Apply all migrations: ") +
                      (", ".join(sorted({a for a, n in targets})) or "(none)")
                  )
              else:
                  if targets[0][1] is None:
                      self.stdout.write(self.style.MIGRATE_LABEL(
                          "  Unapply all migrations: ") + "%s" % (targets[0][0],)
                      )
                  else:
                      self.stdout.write(self.style.MIGRATE_LABEL(
                          "  Target specific migration: ") + "%s, from %s"
                          % (targets[0][1], targets[0][0])
                      )
  
          pre_migrate_state = executor._create_project_state(with_applied_migrations=True)
          pre_migrate_apps = pre_migrate_state.apps
          emit_pre_migrate_signal(
              self.verbosity, self.interactive, connection.alias, apps=pre_migrate_apps, plan=plan,
          )
  
          # Run the syncdb phase.
          if run_syncdb:
              if self.verbosity >= 1:
                  self.stdout.write(self.style.MIGRATE_HEADING("Synchronizing apps without migrations:"))
              if options['app_label']:
                  self.sync_apps(connection, [app_label])
              else:
                  self.sync_apps(connection, executor.loader.unmigrated_apps)
  
          # Migrate!
          if self.verbosity >= 1:
              self.stdout.write(self.style.MIGRATE_HEADING("Running migrations:"))
          if not plan:
              if self.verbosity >= 1:
                  self.stdout.write("  No migrations to apply.")
                  # If there's changes that aren't in migrations yet, tell them how to fix it.
                  autodetector = MigrationAutodetector(
                      executor.loader.project_state(),
                      ProjectState.from_apps(apps),
                  )
                  changes = autodetector.changes(graph=executor.loader.graph)
                  if changes:
                      self.stdout.write(self.style.NOTICE(
                          "  Your models have changes that are not yet reflected "
                          "in a migration, and so won't be applied."
                      ))
                      self.stdout.write(self.style.NOTICE(
                          "  Run 'manage.py makemigrations' to make new "
                          "migrations, and then re-run 'manage.py migrate' to "
                          "apply them."
                      ))
              fake = False
              fake_initial = False
          else:
              fake = options['fake']
              fake_initial = options['fake_initial']
          post_migrate_state = executor.migrate(
              targets, plan=plan, state=pre_migrate_state.clone(), fake=fake,
              fake_initial=fake_initial,
          )
          # post_migrate signals have access to all models. Ensure that all models
          # are reloaded in case any are delayed.
          post_migrate_state.clear_delayed_apps_cache()
          post_migrate_apps = post_migrate_state.apps
  
          # Re-render models of real apps to include relationships now that
          # we've got a final state. This wouldn't be necessary if real apps
          # models were rendered with relationships in the first place.
          with post_migrate_apps.bulk_update():
              model_keys = []
              for model_state in post_migrate_apps.real_models:
                  model_key = model_state.app_label, model_state.name_lower
                  model_keys.append(model_key)
                  post_migrate_apps.unregister_model(*model_key)
          post_migrate_apps.render_multiple([
              ModelState.from_model(apps.get_model(*model)) for model in model_keys
          ])
  
          # Send the post_migrate signal, so individual apps can do whatever they need
          # to do at this point.
          emit_post_migrate_signal(
              self.verbosity, self.interactive, connection.alias, apps=post_migrate_apps, plan=plan,
          )
  
      def migration_progress_callback(self, action, migration=None, fake=False):
          if self.verbosity >= 1:
              compute_time = self.verbosity > 1
              if action == "apply_start":
                  if compute_time:
                      self.start = time.monotonic()
                  self.stdout.write("  Applying %s..." % migration, ending="")
                  self.stdout.flush()
              elif action == "apply_success":
                  elapsed = " (%.3fs)" % (time.monotonic() - self.start) if compute_time else ""
                  if fake:
                      self.stdout.write(self.style.SUCCESS(" FAKED" + elapsed))
                  else:
                      self.stdout.write(self.style.SUCCESS(" OK" + elapsed))
              elif action == "unapply_start":
                  if compute_time:
                      self.start = time.monotonic()
                  self.stdout.write("  Unapplying %s..." % migration, ending="")
                  self.stdout.flush()
              elif action == "unapply_success":
                  elapsed = " (%.3fs)" % (time.monotonic() - self.start) if compute_time else ""
                  if fake:
                      self.stdout.write(self.style.SUCCESS(" FAKED" + elapsed))
                  else:
                      self.stdout.write(self.style.SUCCESS(" OK" + elapsed))
              elif action == "render_start":
                  if compute_time:
                      self.start = time.monotonic()
                  self.stdout.write("  Rendering model states...", ending="")
                  self.stdout.flush()
              elif action == "render_success":
                  elapsed = " (%.3fs)" % (time.monotonic() - self.start) if compute_time else ""
                  self.stdout.write(self.style.SUCCESS(" DONE" + elapsed))
  
      def sync_apps(self, connection, app_labels):
          """Run the old syncdb-style operation on a list of app_labels."""
          with connection.cursor() as cursor:
              tables = connection.introspection.table_names(cursor)
  
          # Build the manifest of apps and models that are to be synchronized.
          all_models = [
              (
                  app_config.label,
                  router.get_migratable_models(app_config, connection.alias, include_auto_created=False),
              )
              for app_config in apps.get_app_configs()
              if app_config.models_module is not None and app_config.label in app_labels
          ]
  
          def model_installed(model):
              opts = model._meta
              converter = connection.introspection.identifier_converter
              return not (
                  (converter(opts.db_table) in tables) or
                  (opts.auto_created and converter(opts.auto_created._meta.db_table) in tables)
              )
  
          manifest = {
              app_name: list(filter(model_installed, model_list))
              for app_name, model_list in all_models
          }
  
          # Create the tables for each model
          if self.verbosity >= 1:
              self.stdout.write("  Creating tables...\n")
          with connection.schema_editor() as editor:
              for app_name, model_list in manifest.items():
                  for model in model_list:
                      # Never install unmanaged models, etc.
                      if not model._meta.can_migrate(connection):
                          continue
                      if self.verbosity >= 3:
                          self.stdout.write(
                              "    Processing %s.%s model\n" % (app_name, model._meta.object_name)
                          )
                      if self.verbosity >= 1:
                          self.stdout.write("    Creating table %s\n" % model._meta.db_table)
                      editor.create_model(model)
  
              # Deferred SQL is executed when exiting the editor's context.
              if self.verbosity >= 1:
                  self.stdout.write("    Running deferred SQL...\n")
  
      @staticmethod
      def describe_operation(operation, backwards):
          """Return a string that describes a migration operation for --plan."""
          prefix = ''
          is_error = False
          if hasattr(operation, 'code'):
              code = operation.reverse_code if backwards else operation.code
              action = (code.__doc__ or '') if code else None
          elif hasattr(operation, 'sql'):
              action = operation.reverse_sql if backwards else operation.sql
          else:
              action = ''
              if backwards:
                  prefix = 'Undo '
          if action is not None:
              action = str(action).replace('\n', '')
          elif backwards:
              action = 'IRREVERSIBLE'
              is_error = True
          if action:
              action = ' -> ' + action
          truncated = Truncator(action)
          return prefix + operation.describe() + truncated.chars(40), is_error
  