import sys, unittest

def geo_suite():
    """
    Builds a test suite for the GIS package.  This is not named
    `suite` so it will not interfere with the Django test suite (since
    spatial database tables are required to execute these tests on
    some backends).
    """
    from django.conf import settings
    from django.contrib.gis.tests.utils import mysql, oracle, postgis
    from django.contrib.gis.gdal import HAS_GDAL
    from django.contrib.gis.utils import HAS_GEOIP

    # Tests that require use of a spatial database (e.g., creation of models)
    test_models = ['geoapp',]

    # Tests that do not require setting up and tearing down a spatial database.
    test_suite_names = [
        'test_geos',
        'test_measure',
        ]
    if HAS_GDAL:
        if oracle:
            # TODO: There's a problem with `select_related` and GeoQuerySet on
            # Oracle -- e.g., GeoModel.objects.distance(geom, field_name='fk__point')
            # doesn't work so we don't test `relatedapp`.
            test_models += ['distapp', 'layermap']
        elif postgis:
            test_models += ['distapp', 'layermap', 'relatedapp']
        elif mysql:
            test_models += ['relatedapp']

        test_suite_names += [
            'test_gdal_driver',
            'test_gdal_ds',
            'test_gdal_envelope',
            'test_gdal_geom',
            'test_gdal_srs',
            'test_spatialrefsys',
            ]
    else:
        print >>sys.stderr, "GDAL not available - no GDAL tests will be run."

    if HAS_GEOIP and hasattr(settings, 'GEOIP_PATH'):
        test_suite_names.append('test_geoip')

    s = unittest.TestSuite()
    for test_suite in test_suite_names:
        tsuite = getattr(__import__('django.contrib.gis.tests', globals(), locals(), [test_suite]),test_suite)
        s.addTest(tsuite.suite())
    return s, test_models

def run_gis_tests(test_labels, **kwargs):
    """
    Use this routine as the TEST_RUNNER in your settings in order to run the
    GeoDjango test suite.  This must be done as a database superuser for
    PostGIS, so read the docstring in `run_test()` below for more details.
    """
    from django.conf import settings
    from django.db.models import loading
    from django.contrib.gis.tests.utils import mysql

    # Getting initial values.
    old_installed = settings.INSTALLED_APPS
    old_root_urlconf = settings.ROOT_URLCONF

    # Based on ALWAYS_INSTALLED_APPS from django test suite --
    # this prevents us from creating tables in our test database
    # from locally installed apps.
    new_installed =  ['django.contrib.contenttypes',
                      'django.contrib.auth',
                      'django.contrib.sites',
                      'django.contrib.sitemaps',
                      'django.contrib.flatpages',
                      'django.contrib.gis',
                      'django.contrib.redirects',
                      'django.contrib.sessions',
                      'django.contrib.comments',
                      'django.contrib.admin',
                      ]

    # Setting the URLs.
    settings.ROOT_URLCONF = 'django.contrib.gis.tests.urls'

    # Creating the test suite, adding the test models to INSTALLED_APPS, and
    # adding the model test suites to our suite package.
    gis_suite, test_models = geo_suite()
    for test_model in test_models:
        module_name = 'django.contrib.gis.tests.%s' % test_model
        if mysql:
            test_module_name = 'tests_mysql'
        else:
            test_module_name = 'tests'
        new_installed.append(module_name)

        # Getting the model test suite
        tsuite = getattr(__import__('django.contrib.gis.tests.%s' % test_model, globals(), locals(), [test_module_name]), 
                         test_module_name)
        gis_suite.addTest(tsuite.suite())

    # Resetting the loaded flag to take into account what we appended to 
    # the INSTALLED_APPS (since this routine is invoked through 
    # django/core/management, it caches the apps; this ensures that syncdb 
    # will see our appended models)
    settings.INSTALLED_APPS = new_installed
    loading.cache.loaded = False

    # Running the tests using the GIS test runner.
    result = run_tests(test_labels, suite=gis_suite, **kwargs)

    # Restoring modified settings.
    settings.INSTALLED_APPS = old_installed
    settings.ROOT_URLCONF = old_root_urlconf

    return result

def run_tests(test_labels, verbosity=1, interactive=True, extra_tests=[], suite=None):
    """
    This module allows users to run tests for GIS apps that require the creation 
    of a spatial database.  Currently, this is only required for PostgreSQL as
    PostGIS needs extra overhead in test database creation.

    In order to create a PostGIS database, the DATABASE_USER (or 
    TEST_DATABASE_USER, if defined) will require superuser priviliges.  

    To accomplish this outside the `postgres` user, you have a few options:
      (A) Make your user a super user:
        This may be done at the time the user is created, for example:
        $ createuser --superuser <user_name>

        Or you may alter the user's role from the SQL shell (assuming this
        is done from an existing superuser role):
        postgres# ALTER ROLE <user_name> SUPERUSER;

      (B) Create your own PostgreSQL database as a local user:
        1. Initialize database: `initdb -D /path/to/user/db`
        2. If there's already a Postgres instance on the machine, it will need
           to use a different TCP port than 5432. Edit postgresql.conf (in 
           /path/to/user/db) to change the database port (e.g. `port = 5433`).  
        3. Start this database `pg_ctl -D /path/to/user/db start`

      (C) On Windows platforms the pgAdmin III utility may also be used as 
        a simple way to add superuser privileges to your database user.

    The TEST_RUNNER needs to be set in your settings like so:

      TEST_RUNNER='django.contrib.gis.tests.run_tests'

    Note: This test runner assumes that the PostGIS SQL files ('lwpostgis.sql'
    and 'spatial_ref_sys.sql') are installed in the directory specified by 
    `pg_config --sharedir` (and defaults to /usr/local/share if that fails).
    This behavior is overridden if POSTGIS_SQL_PATH is set in your settings.
    
    Windows users should set POSTGIS_SQL_PATH manually because the output
    of `pg_config` uses paths like 'C:/PROGRA~1/POSTGR~1/..'.

    Finally, the tests may be run by invoking `./manage.py test`.
    """
    from django.conf import settings
    from django.db import connection
    from django.db.models import get_app, get_apps
    from django.test.simple import build_suite, build_test
    from django.test.utils import setup_test_environment, teardown_test_environment

    # The `create_spatial_db` routine abstracts away all the steps needed
    # to properly construct a spatial database for the backend.
    from django.contrib.gis.db.backend import create_spatial_db

    # Setting up for testing.
    setup_test_environment()
    settings.DEBUG = False
    old_name = settings.DATABASE_NAME

    # The suite may be passed in manually, e.g., when we run the GeoDjango test,
    # we want to build it and pass it in due to some customizations.  Otherwise, 
    # the normal test suite creation process from `django.test.simple.run_tests` 
    # is used to create the test suite.
    if suite is None:
        suite = unittest.TestSuite()
        if test_labels:
            for label in test_labels:
                if '.' in label:
                    suite.addTest(build_test(label))
                else:
                    app = get_app(label)
                    suite.addTest(build_suite(app))
        else:
            for app in get_apps():
                suite.addTest(build_suite(app))
    
        for test in extra_tests:
            suite.addTest(test)

    # Creating the test spatial database.
    create_spatial_db(test=True, verbosity=verbosity)

    # Executing the tests (including the model tests), and destorying the
    # test database after the tests have completed.
    result = unittest.TextTestRunner(verbosity=verbosity).run(suite)
    connection.creation.destroy_test_db(old_name, verbosity)
    teardown_test_environment()

    # Returning the total failures and errors
    return len(result.failures) + len(result.errors)
