import json
import os
import os.path
import base64

from flask import Flask
from flask_bootstrap import Bootstrap

config_file = os.path.abspath('config.json')
bootstrap = Bootstrap()


def create_app():
    app = Flask(__name__)

    _default_secret_key = base64.b64encode(os.urandom(32)).decode('utf-8')
    app.config['SECRET_KEY'] = os.environ.get('SECRET_KEY',
                                              _default_secret_key)

    if not hasattr(app.config, 'from_json'):
        def from_json(file, silent=True):
            try:
                with open(file, encoding='utf-8') as json_file:
                    obj = json.load(json_file)
            except IOError:
                if silent:
                    return False
                raise

            for key in obj:
                if key.isupper():
                    app.config[key] = obj[key]

            return True

        app.config.from_json = from_json

    app.config.from_json(config_file, silent=True)
    app.config.setdefault('BOOTSTRAP_SERVE_LOCAL', True)

    bootstrap.init_app(app)

    @app.after_request
    def add_headers(response):
        response.headers.setdefault('Access-Control-Allow-Origin', '*')
        response.headers.setdefault('Cache-Control', 'no-cache')

        return response

    from .views import root_views
    app.register_blueprint(root_views)

    from .state import state_views
    app.register_blueprint(state_views, url_prefix='/state')

    from .sensors import sensors_views
    app.register_blueprint(sensors_views, url_prefix='/sensors')

    from .active import reload_json
    reload_json()

    return app