import os
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_bcrypt import Bcrypt
from flask_login import LoginManager

# Initialize Flask extensions
db = SQLAlchemy()
migrate = Migrate()
bcrypt = Bcrypt()
login_manager = LoginManager()

login_manager.login_view = 'auth.login'
login_manager.login_message_category = 'info'

def create_app():
    app = Flask(__name__)
    
    # Load configuration
    config_name = os.getenv('FLASK_CONFIG', 'DevelopmentConfig')  # Default to DevelopmentConfig
    app.config.from_object(f'app.config.{config_name}')

    # Initialize extensions
    db.init_app(app)
    migrate.init_app(app, db)
    bcrypt.init_app(app)
    login_manager.init_app(app)

    # Import models here to avoid circular imports
    from app.models import User  # Import the User model

    # Set up the user_loader function
    @login_manager.user_loader
    def load_user(user_id):
        return User.query.get(int(user_id))  # Query the User model by ID

    # Register blueprints
    from app.routes import main, auth, user
    app.register_blueprint(main, url_prefix='/')
    app.register_blueprint(auth, url_prefix='/auth')
    app.register_blueprint(user, url_prefix='/user')

    return app