# -*- coding: utf-8 -*-
"""The app module, containing the app factory function."""
import importlib

from flask import Flask, render_template

from cartunningservice import commands, public, user
from cartunningservice import controlpanel
from cartunningservice.assets import assets
from cartunningservice.extensions import bcrypt, cache, csrf_protect, db, debug_toolbar, login_manager, migrate, \
    data_api_client, babel
from cartunningservice.settings import ProdConfig

def create_app(config_object=ProdConfig):
    """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.config.from_object(config_object)

    # register resources
    register_module(app, 'resources')

    register_extensions(app)
    register_blueprints(app)
    register_errorhandlers(app)
    register_shellcontext(app)
    register_commands(app)
    return app

def register_module(app, module):
    """
    Registering module on fly
    :param app: {Flask} instance
    :param module: {str} module path
    """
    m = importlib.import_module('%s.%s' % (app.name, module))
    if hasattr(m, 'register'):
        m.register(app)


def register_extensions(app):
    """Register Flask extensions."""
    assets.init_app(app)
    bcrypt.init_app(app)
    cache.init_app(app)
    babel.init_app(app)
    db.init_app(app)
    csrf_protect.init_app(app)
    login_manager.init_app(app)
    debug_toolbar.init_app(app)
    migrate.init_app(app, db)
    data_api_client.init_app(app)
    return None


def register_blueprints(app):
    """Register Flask blueprints."""
    app.register_blueprint(public.views.blueprint)
    app.register_blueprint(user.views.blueprint)
    app.register_blueprint(controlpanel.views.blueprint)
    return None


def register_errorhandlers(app):
    """Register error handlers."""
    def render_error(error):
        """Render error template."""
        # If a HTTPException, pull the `code` attribute; default to 500
        error_code = getattr(error, 'code', 500)
        return render_template('{0}.html'.format(error_code)), error_code
    for errcode in [401, 404, 500]:
        app.errorhandler(errcode)(render_error)
    return None


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

    app.shell_context_processor(shell_context)


def register_commands(app):
    """Register Click commands."""
    app.cli.add_command(commands.initdb)
    app.cli.add_command(commands.test)
    app.cli.add_command(commands.lint)
    app.cli.add_command(commands.clean)
    app.cli.add_command(commands.urls)
