__init__.py

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from os import path
from flask_login import LoginManager
# whatever mentioned in the file cna be imported to every other file as a library

db = SQLAlchemy()
DB_NAME = "flask_database.db"


def create_app():

    app = Flask(__name__)
    app.config['SECRET_KEY'] = 'rehan ahmed'
    app.config['SQLALCHEMY_DATABASE_URI'] = f'sqlite:///{DB_NAME}'
    db.init_app(app)

    from .views import views
    from .auth import auth

    app.register_blueprint(views, url_prefix='/')
    app.register_blueprint(auth, url_prefix='/')
    
    # creating the database / implementing
    from website.models import User , Note

    create_database(app)

    login_manager = LoginManager()
    login_manager.login_view = 'auth.login'
    login_manager.init_app(app)

    @login_manager.user_loader
    def load_user(id):
        return User.query.get(int(id))
    

    return app

# checks if a database exists, or creates one
def create_database(app):
    if not path.exists('website/' + DB_NAME):
        with app.app_context():
            db.create_all()
            print("Database Created")
# A database created in the Instance file