import os

from flask import Flask

# Please, set a config file on top project dir
# find example in ressources/app_config.py
try:
    from app_config import Config, ProdConfig, DevConfig, TestConfig
except ImportError:
    pass


def create_app(config_class=None):
    """ App Factory.
    can be called with configuration class as argument.
    """

    # Configuration Switcher
    # try to set configuration depending on environment
    # if no configuration class was given
    #
    if config_class is None:
        FLASK_ENV = os.environ.get('FLASK_ENV')
        if not FLASK_ENV:
            FLASK_ENV = 'testing'

        if FLASK_ENV == 'production':
            config_class = ProdConfig
        elif FLASK_ENV == 'development':
            config_class = DevConfig
        elif FLASK_ENV == 'testing':
            config_class = TestConfig
        else:
            config_class = Config

    # Main flask app
    #
    app = Flask(__name__)
    app.config.from_object(config_class)

    # Get and activate blueprints
    #
    from .main import bp as main_bp
    app.register_blueprint(main_bp)

    return app