from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from config import config

db = SQLAlchemy()


def create_app(config_name="default"):
    """Application factory function.

    Args:
        config_name: Configuration name (development, testing, production).

    Returns:
        Configured Flask application instance.
    """
    app = Flask(__name__)
    app.config.from_object(config[config_name])

    # Initialize extensions
    db.init_app(app)

    # Register blueprints
    from app.routes import main as main_blueprint
    app.register_blueprint(main_blueprint)

    # Create database tables
    with app.app_context():
        db.create_all()

    return app