# encoding: utf-8

from __future__ import absolute_import, division, print_function, unicode_literals

from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from pkg_resources import DistributionNotFound, get_distribution, parse_version

from haystack import signals
from haystack.constants import DEFAULT_ALIAS
from haystack.utils import loading

__author__ = 'Daniel Lindsley'

try:
    pkg_distribution = get_distribution(__name__)
    __version__ = pkg_distribution.version
    version_info = pkg_distribution.parsed_version
except DistributionNotFound:
    __version__ = '0.0.dev0'
    version_info = parse_version(__version__)

default_app_config = 'haystack.apps.HaystackConfig'


# Help people clean up from 1.X.
if hasattr(settings, 'HAYSTACK_SITECONF'):
    raise ImproperlyConfigured('The HAYSTACK_SITECONF setting is no longer used & can be removed.')
if hasattr(settings, 'HAYSTACK_SEARCH_ENGINE'):
    raise ImproperlyConfigured('The HAYSTACK_SEARCH_ENGINE setting has been replaced with HAYSTACK_CONNECTIONS.')
if hasattr(settings, 'HAYSTACK_ENABLE_REGISTRATIONS'):
    raise ImproperlyConfigured('The HAYSTACK_ENABLE_REGISTRATIONS setting is no longer used & can be removed.')
if hasattr(settings, 'HAYSTACK_INCLUDE_SPELLING'):
    raise ImproperlyConfigured('The HAYSTACK_INCLUDE_SPELLING setting is now a per-backend setting & belongs in HAYSTACK_CONNECTIONS.')


# Check the 2.X+ bits.
if not hasattr(settings, 'HAYSTACK_CONNECTIONS'):
    raise ImproperlyConfigured('The HAYSTACK_CONNECTIONS setting is required.')
if DEFAULT_ALIAS not in settings.HAYSTACK_CONNECTIONS:
    raise ImproperlyConfigured("The default alias '%s' must be included in the HAYSTACK_CONNECTIONS setting." % DEFAULT_ALIAS)

# Load the connections.
connections = loading.ConnectionHandler(settings.HAYSTACK_CONNECTIONS)

# Just check HAYSTACK_ROUTERS setting validity, routers will be loaded lazily
if hasattr(settings, 'HAYSTACK_ROUTERS'):
    if not isinstance(settings.HAYSTACK_ROUTERS, (list, tuple)):
        raise ImproperlyConfigured("The HAYSTACK_ROUTERS setting must be either a list or tuple.")

# Load the router(s).
connection_router = loading.ConnectionRouter()


# Per-request, reset the ghetto query log.
# Probably not extraordinarily thread-safe but should only matter when
# DEBUG = True.
def reset_search_queries(**kwargs):
    for conn in connections.all():
        if conn:
            conn.reset_queries()


if settings.DEBUG:
    from django.core import signals as django_signals
    django_signals.request_started.connect(reset_search_queries)