__all__ = ['create_test_spatial_db', 'get_geo_where_clause', 'SpatialBackend']

from ctypes.util import find_library

from django.conf import settings

from django.db.backends.signals import connection_created

from django.contrib.gis.db.backend.base import BaseSpatialBackend

from django.contrib.gis.db.backend.spatialite.adaptor import SpatiaLiteAdaptor

from django.contrib.gis.db.backend.spatialite.creation import create_test_spatial_db

from django.contrib.gis.db.backend.spatialite.field import SpatiaLiteField

from django.contrib.gis.db.backend.spatialite.models import GeometryColumns, SpatialRefSys

from django.contrib.gis.db.backend.spatialite.query import *

# Here we are figuring out the path to the SpatiLite library (`libspatialite`).

# If it's not in the system PATH, it may be set manually in the settings via

# the `SPATIALITE_LIBRARY_PATH` setting.

spatialite_lib = getattr(settings, 'SPATIALITE_LIBRARY_PATH', find_library('spatialite'))

if spatialite_lib:

    def initialize_spatialite(sender=None, **kwargs):

        """

        This function initializes the pysqlite2 connection to enable the

        loading of extensions, and to load up the SpatiaLite library

        extension.

        """

        from django.db import connection

        connection.connection.enable_load_extension(True)

        connection.cursor().execute("SELECT load_extension(%s)", (spatialite_lib,))

    connection_created.connect(initialize_spatialite)

else:

    # No SpatiaLite library found.

    raise Exception('Unable to locate SpatiaLite, needed to use GeoDjango with sqlite3.')

SpatialBackend = BaseSpatialBackend(name='spatialite', spatialite=True,

                                    area=AREA,

                                    centroid=CENTROID,

                                    contained=CONTAINED,

                                    difference=DIFFERENCE,

                                    distance=DISTANCE,

                                    distance_functions=DISTANCE_FUNCTIONS,

                                    envelope=ENVELOPE,

                                    from_text=GEOM_FROM_TEXT,

                                    gis_terms=SPATIALITE_TERMS,

                                    intersection=INTERSECTION,

                                    length=LENGTH,

                                    num_geom=NUM_GEOM,

                                    num_points=NUM_POINTS,

                                    point_on_surface=POINT_ON_SURFACE,

                                    scale=SCALE,

                                    select=GEOM_SELECT,

                                    svg=ASSVG,

                                    sym_difference=SYM_DIFFERENCE,

                                    transform=TRANSFORM,

                                    translate=TRANSLATE,

                                    union=UNION,

                                    unionagg=UNIONAGG,

                                    Adaptor=SpatiaLiteAdaptor,

                                    Field=SpatiaLiteField,

                                    GeometryColumns=GeometryColumns,

                                    SpatialRefSys=SpatialRefSys,

                                    )