""" Django settings for the Bcfg2 server """

import os
import sys
import logging
import Bcfg2.Logger
import Bcfg2.Options

try:
    import django
    import django.core.management
    import django.conf
    HAS_DJANGO = True
except ImportError:
    HAS_DJANGO = False

# required for reporting
try:
    import south  # pylint: disable=W0611
    HAS_SOUTH = True
except ImportError:
    HAS_SOUTH = False

settings = dict(  # pylint: disable=C0103
    TIME_ZONE=None,
    TEMPLATE_DEBUG=False,
    DEBUG=False,
    ALLOWED_HOSTS=['*'],
    MEDIA_URL='/site_media/',
    MANAGERS=(('Root', 'root'),),
    ADMINS=(('Root', 'root'),),
    # Language code for this installation. All choices can be found
    # here:
    # http://www.w3.org/TR/REC-html40/struct/dirlang.html#langcodes
    # http://blogs.law.harvard.edu/tech/stories/storyReader$15
    LANGUAGE_CODE='en-us',
    SITE_ID=1,
    INSTALLED_APPS=('django.contrib.auth',
                    'django.contrib.contenttypes',
                    'django.contrib.sessions',
                    'django.contrib.sites',
                    'django.contrib.admin',
                    'Bcfg2.Server'),
    MEDIA_ROOT='',
    STATIC_URL='/media/',
    # TODO - make this unique
    SECRET_KEY='eb5+y%oy-qx*2+62vv=gtnnxg1yig_odu0se5$h0hh#pc*lmo7',
    TEMPLATE_LOADERS=('django.template.loaders.filesystem.Loader',
                      'django.template.loaders.app_directories.Loader'),
    MIDDLEWARE_CLASSES=(
        'django.middleware.common.CommonMiddleware',
        'django.contrib.sessions.middleware.SessionMiddleware',
        'django.contrib.auth.middleware.AuthenticationMiddleware'),
    ROOT_URLCONF='Bcfg2.Reporting.urls',
    AUTHENTICATION_BACKENDS=('django.contrib.auth.backends.ModelBackend'),
    LOGIN_URL='/login',
    SESSION_EXPIRE_AT_BROWSER_CLOSE=True,
    TEMPLATE_DIRS=(
        '/usr/share/python-support/python-django/django/contrib/admin/'
        'templates/'),
    TEMPLATE_CONTEXT_PROCESSORS=(
        'django.contrib.auth.context_processors.auth',
        'django.core.context_processors.debug',
        'django.core.context_processors.i18n',
        'django.core.context_processors.media',
        'django.core.context_processors.request'),
    DATABASE_ROUTERS=['Bcfg2.DBSettings.PerApplicationRouter'],
    TEST_RUNNER='django.test.simple.DjangoTestSuiteRunner')

if HAS_DJANGO and django.VERSION[0] == 1 and django.VERSION[1] >= 6:
    settings['MIDDLEWARE_CLASSES'] += \
        ('django.contrib.admindocs.middleware.XViewMiddleware',)
elif HAS_SOUTH:
    settings['MIDDLEWARE_CLASSES'] += \
        ('django.middleware.doc.XViewMiddleware',)

if HAS_DJANGO and django.VERSION[0] == 1 and django.VERSION[1] >= 7:
    settings['INSTALLED_APPS'] += ('Bcfg2.Reporting',)
elif HAS_SOUTH:
    settings['INSTALLED_APPS'] += ('south', 'Bcfg2.Reporting')
    settings['SOUTH_MIGRATION_MODULES'] = {
        'Bcfg2.Reporting': 'Bcfg2.Reporting.south_migrations'
    }
if 'BCFG2_LEGACY_MODELS' in os.environ:
    settings['INSTALLED_APPS'] += ('Bcfg2.Server.Reports.reports',)

if HAS_DJANGO and django.VERSION[0] == 1 and django.VERSION[1] < 3:
    settings['CACHE_BACKEND'] = 'locmem:///'
else:
    settings['CACHES'] = {
        'default': {
            'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
        }
    }


def finalize_django_config(opts=None, silent=False):
    """ Perform final Django configuration """
    if opts is None:
        opts = Bcfg2.Options.setup
    settings['DATABASES'] = dict(
        default=dict(
            ENGINE="django.db.backends.%s" % opts.db_engine,
            NAME=opts.db_name,
            USER=opts.db_user,
            PASSWORD=opts.db_password,
            HOST=opts.db_host,
            PORT=opts.db_port,
            OPTIONS=opts.db_opts,
            SCHEMA=opts.db_schema))

    if hasattr(opts, "reporting_db_engine") and \
       opts.reporting_db_engine is not None:
        settings['DATABASES']['Reporting'] = dict(
            ENGINE="django.db.backends.%s" % opts.reporting_db_engine,
            NAME=opts.reporting_db_name,
            USER=opts.reporting_db_user,
            PASSWORD=opts.reporting_db_password,
            HOST=opts.reporting_db_host,
            PORT=opts.reporting_db_port,
            OPTIONS=opts.reporting_db_opts,
            SCHEMA=opts.reporting_db_schema)

    settings['TIME_ZONE'] = opts.time_zone

    settings['TEMPLATE_DEBUG'] = settings['DEBUG'] = \
        opts.web_debug
    if opts.web_debug:
        print("Warning: Setting web_debug to True causes extraordinary "
              "memory leaks.  Only use this setting if you know what "
              "you're doing.")

    if opts.web_prefix:
        settings['MEDIA_URL'] = \
            opts.web_prefix.rstrip('/') + \
            settings['MEDIA_URL']

    if opts.django_settings:
        settings.update(opts.django_settings)

    logger = logging.getLogger()

    logger.debug("Finalizing Django settings: %s" % settings)
    module = sys.modules[__name__]
    for name, value in settings.items():
        setattr(module, name, value)
    try:
        django.conf.settings.configure(**settings)
    except RuntimeError:
        if not silent:
            logger.warning("Failed to finalize Django settings: %s" %
                           sys.exc_info()[1])


def sync_databases(**kwargs):
    """ Synchronize all databases that we know about.  """
    if django.VERSION[0] == 1 and django.VERSION[1] >= 7:
        # Nothing needed here, it's all handled with migrate
        return

    logger = logging.getLogger()
    for database in settings['DATABASES']:
        logger.debug("Syncing database %s" % (database))
        django.core.management.call_command("syncdb", database=database,
                                            **kwargs)


def upgrade_to_django_migrations(database, logger):
    """
    Get the migration state from south and move django migrations to
    the same state by fake applying the same migration.

    Note: We cannot use south directly here, because this functions
          runs on django-1.7 or higher, that is not supported by south.
    """

    last_migration = None
    try:
        # get latest south migration
        cursor = django.db.connections[database].cursor()
        cursor.cursor.execute('SELECT migration FROM south_migrationhistory')
        applied_migrations = [name for (name,) in cursor.fetchall()]
        last_migration = sorted(applied_migrations).pop()
    except:  # pylint: disable=W0702
        # django.db.DatabaseError is not working here, because we are
        # using the low level api to interact directly with the database
        logger.debug("No south migration detected for database: %s." %
                     database)

    if last_migration is not None:
        # fake-apply matching django migrations
        django.core.management.call_command(
            "migrate", 'Reporting', last_migration,
            database=database, fake=True)


def initial_django_migration(database):
    """ Check if we ever executed an initial django migration. """
    from django.db.migrations import loader  # pylint: disable=E0611
    loader = loader.MigrationLoader(django.db.connections[database])
    return len(loader.applied_migrations) == 0


def migrate_databases(**kwargs):
    """ Do South migrations on all databases that we know about.  """
    logger = logging.getLogger()
    for database in settings['DATABASES']:
        logger.debug("Migrating database %s" % (database))
        if django.VERSION[0] == 1 and django.VERSION[1] >= 7:
            django.setup()  # pylint: disable=E1101
            if initial_django_migration(database):
                logger.warning(
                    "No applied django migrations found for database %s. "
                    "Trying to get the state from south migration in case "
                    "you just upgraded your django version." % database)
                upgrade_to_django_migrations(database, logger)

        django.core.management.call_command("migrate", database=database,
                                            **kwargs)


def get_db_label(application):
    """ Get the name of the database for a given Django "application".  The
    rule is that if a database with the same name as the application exists,
    use it.  Otherwise use the default. Returns a string suitible for use as a
    key in the Django database settings dict """
    if application in settings['DATABASES']:
        return application

    return 'default'


class PerApplicationRouter(object):
    """ Django database router for redirecting different applications to their
    own database """

    def _db_per_app(self, model, **_):
        """ If a database with the same name as the application exists, use it.
        Otherwise use the default """
        return get_db_label(model._meta.app_label)  # pylint: disable=W0212

    def db_for_read(self, model, **hints):
        """ Called when Django wants to find out what database to read from """
        return self._db_per_app(model, **hints)

    def db_for_write(self, model, **hints):
        """ Called when Django wants to find out what database to write to """
        return self._db_per_app(model, **hints)

    def allow_relation(self, obj1, obj2, **_):
        """ Called when Django wants to determine what relations to allow. Only
        allow relations within an app """
        # pylint: disable=W0212
        return obj1._meta.app_label == obj2._meta.app_label
        # pylint: enable=W0212

    def allow_syncdb(self, *_):
        """ Called when Django wants to determine which models to sync to a
        given database.  Take the cowards way out and sync all models to all
        databases to allow for easy migrations. This method is replaced with
        allow_migrate in django 1.7 and higher. """
        return True

    def allow_migrate(self, *_args, **_kwargs):
        """ Called when Django wants to determine which migrations should
        be run on a given database. Take the cowards way out and run all
        migrations to all databases to allow for easy migrations. """
        return True


class _OptionContainer(object):
    """ Container for options loaded at import-time to configure
    databases """
    parse_first = True
    options = [
        Bcfg2.Options.Common.repository,
        Bcfg2.Options.PathOption(
            '-W', '--web-config', cf=('reporting', 'config'),
            default="/etc/bcfg2-web.conf",
            action=Bcfg2.Options.ConfigFileAction,
            help='Web interface configuration file'),
        # default database options
        Bcfg2.Options.Option(
            cf=('database', 'engine'), default='sqlite3',
            help='Database engine', dest='db_engine'),
        Bcfg2.Options.RepositoryMacroOption(
            cf=('database', 'name'), default='<repository>/etc/bcfg2.sqlite',
            help="Database name", dest="db_name"),
        Bcfg2.Options.Option(
            cf=('database', 'user'), help='Database username', dest='db_user'),
        Bcfg2.Options.Option(
            cf=('database', 'password'), help='Database password',
            dest='db_password'),
        Bcfg2.Options.Option(
            cf=('database', 'host'), help='Database host', dest='db_host'),
        Bcfg2.Options.Option(
            cf=('database', 'port'), help='Database port', dest='db_port'),
        Bcfg2.Options.Option(
            cf=('database', 'schema'), help='Database schema',
            dest='db_schema', default='public'),
        Bcfg2.Options.Option(
            cf=('database', 'options'), help='Database options',
            dest='db_opts', type=Bcfg2.Options.Types.literal_dict,
            default=dict()),
        # reporting database options
        Bcfg2.Options.Option(
            cf=('database', 'reporting_engine'),
            help='Reporting database engine', dest='reporting_db_engine'),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_name'),
            default='<repository>/etc/reporting.sqlite',
            help="Reporting database name", dest="reporting_db_name"),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_user'),
            help='Reporting database username', dest='reporting_db_user'),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_password'),
            help='Reporting database password', dest='reporting_db_password'),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_host'),
            help='Reporting database host', dest='reporting_db_host'),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_port'),
            help='Reporting database port', dest='reporting_db_port'),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_schema'),
            help='Reporting database schema', dest='reporting_db_schema',
            default='public'),
        Bcfg2.Options.Option(
            cf=('database', 'reporting_options'),
            help='Reporting database options', dest='reporting_db_opts',
            type=Bcfg2.Options.Types.literal_dict, default=dict()),
        # Django options
        Bcfg2.Options.Option(
            cf=('reporting', 'time_zone'), help='Django timezone'),
        Bcfg2.Options.BooleanOption(
            cf=('reporting', 'web_debug'), help='Django debug'),
        Bcfg2.Options.Option(
            cf=('reporting', 'web_prefix'), help='Web prefix'),
        Bcfg2.Options.Option(
            cf=('reporting', 'django_settings'),
            help='Additional django settings',
            type=Bcfg2.Options.Types.literal_dict, default=dict())]

    @staticmethod
    def component_parsed_hook(opts):
        """ Finalize the Django config after this component's options
        are parsed. """
        if HAS_DJANGO:
            finalize_django_config(opts=opts)

    @staticmethod
    def options_parsed_hook():
        """ Finalize the Django config after all options are parsed.
        This is added in case the DBSettings component isn't added
        early enough in option parsing to be parsed in the 'early'
        phase.  Chances are good that things will break if that
        happens, but we do our best to be a good citizen. """
        if HAS_DJANGO:
            finalize_django_config(silent=True)

Bcfg2.Options.get_parser().add_component(_OptionContainer)