from flask import Flask, Blueprint
from . import commands, login
from .settings import ProdConfig, Config
from .extensions import db, migrate, jwt
from .exceptions import ApiException


def create_app(config: Config = ProdConfig) -> Flask:
    """An application factory, as explained here:
    http://flask.pocoo.org/docs/patterns/appfactories/.

    :param config_object: The configuration object to use.
    """
    app = Flask(__name__.split('.')[0])
    app.url_map.strict_slashes = False
    app.config.from_object(config)
    register_extensions(app)
    register_blueprints(app)
    register_errorhandlers(app)
    register_shellcontext(app)
    register_commands(app)

    return app


def register_extensions(app: Flask):
    """Register Flask extensions."""
    db.init_app(app)
    migrate.init_app(app, db)
    jwt.init_app(app)


def register_blueprints(app: Flask):
    """Register Flask blueprints."""
    api_blueprint = Blueprint('api', __name__, url_prefix='/api')

    api_blueprint.register_blueprint(login.views.blueprint, url_prefix='/login')

    app.register_blueprint(api_blueprint)


def register_errorhandlers(app: Flask):
    def errorHandler(error: ApiException):
        return error.to_response()

    app.errorhandler(ApiException)(errorHandler)
    pass


def register_shellcontext(app: Flask):
    """Register shell context objects."""
    def shell_context():
        """Shell context objects."""
        return {
            'db': db,
        }

    app.shell_context_processor(shell_context)


def register_commands(app: Flask):
    """Register Click commands."""
    app.cli.add_command(commands.clean)
    app.cli.add_command(commands.urls)