text: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from collections import OrderedDict
  from importlib import import_module
  import time
  import warnings
  
  from django.apps import apps
  from django.core.management import call_command
  from django.core.management.base import BaseCommand, CommandError
  from django.core.management.sql import emit_post_migrate_signal, emit_pre_migrate_signal
  from django.db import connections, router, transaction, DEFAULT_DB_ALIAS
  from django.db.migrations.executor import MigrationExecutor
  from django.db.migrations.loader import AmbiguityError
  from django.db.migrations.state import ProjectState
  from django.db.migrations.autodetector import MigrationAutodetector
  from django.utils.deprecation import RemovedInDjango20Warning
  from django.utils.module_loading import module_has_submodule
  
  
  class Command(BaseCommand):
      help = "Updates database schema. Manages both apps with migrations and those without."
  
      def add_arguments(self, parser):
          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', action='store_false', dest='interactive', default=True,
              help='Tells Django to NOT prompt the user for input of any kind.')
          parser.add_argument('--database', action='store', dest='database',
              default=DEFAULT_DB_ALIAS, help='Nominates a database to synchronize. '
                  'Defaults to the "default" database.')
          parser.add_argument('--fake', action='store_true', dest='fake', default=False,
              help='Mark migrations as run without actually running them')
          parser.add_argument('--list', '-l', action='store_true', dest='list', default=False,
              help='Show a list of all known migrations and which are applied')
  
      def handle(self, *args, **options):
  
          self.verbosity = options.get('verbosity')
          self.interactive = options.get('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
          db = options.get('database')
          connection = connections[db]
  
          # If they asked for a migration listing, quit main execution flow and show it
          if options.get("list", False):
              warnings.warn(
                  "The 'migrate --list' command is deprecated. Use 'showmigrations' instead.",
                  RemovedInDjango20Warning, stacklevel=2)
              self.stdout.ending = None  # Remove when #21429 is fixed
              return call_command(
                  'showmigrations',
                  '--list',
                  app_labels=[options['app_label']] if options['app_label'] else None,
                  database=db,
                  no_color=options.get('no_color'),
                  settings=options.get('settings'),
                  stdout=self.stdout,
                  traceback=options.get('traceback'),
                  verbosity=self.verbosity,
              )
  
          # 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)
  
          # 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 (%s).\nTo fix them run "
                  "'python manage.py makemigrations --merge'" % name_str
              )
  
          # If they supplied command line arguments, work out what they mean.
          target_app_labels_only = True
          if options['app_label'] and options['migration_name']:
              app_label, migration_name = options['app_label'], options['migration_name']
              if app_label not in executor.loader.migrated_apps:
                  raise CommandError(
                      "App '%s' does not have migrations." % app_label
                  )
              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']:
              app_label = options['app_label']
              if app_label not in executor.loader.migrated_apps:
                  raise CommandError(
                      "App '%s' does not have migrations." % 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)
          run_syncdb = options.get('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:
                  self.stdout.write(
                      self.style.MIGRATE_LABEL("  Synchronize unmigrated apps: ") +
                      (", ".join(executor.loader.unmigrated_apps))
                  )
              if target_app_labels_only:
                  self.stdout.write(
                      self.style.MIGRATE_LABEL("  Apply all migrations: ") +
                      (", ".join(set(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])
                      )
  
          emit_pre_migrate_signal(self.verbosity, self.interactive, connection.alias)
  
          # Run the syncdb phase.
          if run_syncdb:
              if self.verbosity >= 1:
                  self.stdout.write(self.style.MIGRATE_HEADING("Synchronizing apps without migrations:"))
              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."
                      ))
          else:
              executor.migrate(targets, plan, fake=options.get("fake", False))
  
          # 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)
  
      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.time()
                  self.stdout.write("  Applying %s..." % migration, ending="")
                  self.stdout.flush()
              elif action == "apply_success":
                  elapsed = " (%.3fs)" % (time.time() - self.start) if compute_time else ""
                  if fake:
                      self.stdout.write(self.style.MIGRATE_SUCCESS(" FAKED" + elapsed))
                  else:
                      self.stdout.write(self.style.MIGRATE_SUCCESS(" OK" + elapsed))
              elif action == "unapply_start":
                  if compute_time:
                      self.start = time.time()
                  self.stdout.write("  Unapplying %s..." % migration, ending="")
                  self.stdout.flush()
              elif action == "unapply_success":
                  elapsed = " (%.3fs)" % (time.time() - self.start) if compute_time else ""
                  if fake:
                      self.stdout.write(self.style.MIGRATE_SUCCESS(" FAKED" + elapsed))
                  else:
                      self.stdout.write(self.style.MIGRATE_SUCCESS(" OK" + elapsed))
              elif action == "render_start":
                  if compute_time:
                      self.start = time.time()
                  self.stdout.write("  Rendering model states...", ending="")
                  self.stdout.flush()
              elif action == "render_success":
                  elapsed = " (%.3fs)" % (time.time() - self.start) if compute_time else ""
                  self.stdout.write(self.style.MIGRATE_SUCCESS(" DONE" + elapsed))
  
      def sync_apps(self, connection, app_labels):
          "Runs the old syncdb-style operation on a list of app_labels."
          cursor = connection.cursor()
  
          try:
              # Get a list of already installed *models* so that references work right.
              tables = connection.introspection.table_names(cursor)
              created_models = set()
  
              # 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.table_name_converter
                  # Note that if a model is unmanaged we short-circuit and never try to install it
                  return not ((converter(opts.db_table) in tables) or
                      (opts.auto_created and converter(opts.auto_created._meta.db_table) in tables))
  
              manifest = OrderedDict(
                  (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 transaction.atomic(using=connection.alias, savepoint=connection.features.can_rollback_ddl):
                  deferred_sql = []
                  for app_name, model_list in manifest.items():
                      for model in model_list:
                          if model._meta.proxy or not model._meta.managed:
                              continue
                          if self.verbosity >= 3:
                              self.stdout.write(
                                  "    Processing %s.%s model\n" % (app_name, model._meta.object_name)
                              )
                          with connection.schema_editor() as editor:
                              if self.verbosity >= 1:
                                  self.stdout.write("    Creating table %s\n" % model._meta.db_table)
                              editor.create_model(model)
                              deferred_sql.extend(editor.deferred_sql)
                              editor.deferred_sql = []
                          created_models.add(model)
  
                  if self.verbosity >= 1:
                      self.stdout.write("    Running deferred SQL...\n")
                  for statement in deferred_sql:
                      cursor.execute(statement)
          finally:
              cursor.close()
  
          return created_models
  