app/__init__.py

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_bcrypt import Bcrypt
from flask_jwt_extended import JWTManager

db = SQLAlchemy()
bcrypt = Bcrypt()
jwt = JWTManager()

def create_app():
    app = Flask(__name__)
    app.config.from_object('app.config.Config')

    db.init_app(app)
    bcrypt.init_app(app)
    jwt.init_app(app)

    from app.routes import auth, chat, admin, profile
    app.register_blueprint(auth.bp)
    app.register_blueprint(chat.bp)
    app.register_blueprint(admin.bp)
    app.register_blueprint(profile.bp)

    return app