import logging
from logging.handlers import RotatingFileHandler
import os
from flask import Flask, render_template
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_wtf.csrf import CSRFProtect
from config import Config

db = SQLAlchemy()
migrate = Migrate()
csrf = CSRFProtect()

def create_app(config_class=Config):
    app = Flask(__name__)
    app.config.from_object(config_class)
    
    # Initialisierung der Erweiterungen
    db.init_app(app)
    migrate.init_app(app, db)
    csrf.init_app(app)
    
    # Logging-Konfiguration
    if not app.debug and not app.testing:
        if not os.path.exists('logs'):
            os.mkdir('logs')
        file_handler = RotatingFileHandler('logs/app.log', maxBytes=10240, backupCount=10)
        file_handler.setFormatter(logging.Formatter(
            '%(asctime)s %(levelname)s: %(message)s [in %(pathname)s:%(lineno)d]'
        ))
        file_handler.setLevel(logging.INFO)
        app.logger.addHandler(file_handler)
        app.logger.setLevel(logging.INFO)
        app.logger.info('Anwendung startet')
    
    # Blueprints registrieren
    from app.routes.main import bp as main_bp
    app.register_blueprint(main_bp)
    
    # Fehlerbehandlung
    @app.errorhandler(404)
    def not_found_error(error):
        return render_template('errors/404.html'), 404
    
    @app.errorhandler(500)
    def internal_error(error):
        db.session.rollback()
        return render_template('errors/500.html'), 500
    
    @app.context_processor
    def utility_processor():
        return dict(enumerate=enumerate)
    
    return app