import os

from django.conf import settings

from django.core.management import call_command

from django.db import connection

def spatialite_init_file():

    # SPATIALITE_SQL may be placed in settings to tell

    # GeoDjango to use a specific user-supplied file.

    return getattr(settings, 'SPATIALITE_SQL', 'init_spatialite-2.3.sql')

def create_test_spatial_db(verbosity=1, autoclobber=False, interactive=False):

    "Creates a spatial database based on the settings."

    # Making sure we're using PostgreSQL and psycopg2

    if settings.DATABASE_ENGINE != 'sqlite3':

        raise Exception('SpatiaLite database creation only supported on sqlite3 platform.')

    # Getting the test database name using the SQLite backend's

    # `_create_test_db`.  Unless `TEST_DATABASE_NAME` is defined,

    # it returns ":memory:".

    db_name = connection.creation._create_test_db(verbosity, autoclobber)

    # Closing out the current connection to the database set in

    # originally in the settings.  This makes it so `initialize_spatialite`

    # function will be run on the connection for the _test_ database instead.

    connection.close()

    # Point to the new database

    settings.DATABASE_NAME = db_name

    connection.settings_dict["DATABASE_NAME"] = db_name

    can_rollback = connection.creation._rollback_works()

    settings.DATABASE_SUPPORTS_TRANSACTIONS = can_rollback

    connection.settings_dict["DATABASE_SUPPORTS_TRANSACTIONS"] = can_rollback

    # Finally, loading up the SpatiaLite SQL file.

    load_spatialite_sql(db_name, verbosity=verbosity)

    if verbosity >= 1:

        print 'Creation of spatial database %s successful.' % db_name

    # Syncing the database

    call_command('syncdb', verbosity=verbosity, interactive=interactive)

def load_spatialite_sql(db_name, verbosity=1):

    """

    This routine loads up the SpatiaLite SQL file.

    """

    # Getting the location of the SpatiaLite SQL file, and confirming

    # it exists.

    spatialite_sql = spatialite_init_file()

    if not os.path.isfile(spatialite_sql):

        raise Exception('Could not find the SpatiaLite initialization SQL file: %s' % spatialite_sql)

    # Opening up the SpatiaLite SQL initialization file and executing

    # as a script.

    sql_fh = open(spatialite_sql, 'r')

    try:

        cur = connection.cursor()

        cur.executescript(sql_fh.read())

    finally:

        sql_fh.close()