app/__init__.py

import os
import logging
from logging.handlers import RotatingFileHandler
from flask import Flask
from config import Config

def create_app(config_class=Config):
    """Create and configure Flask application."""
    app = Flask(__name__)
    app.config.from_object(config_class)
    
    # Ensure upload folder exists
    if not os.path.exists(app.config['UPLOAD_FOLDER']):
        os.makedirs(app.config['UPLOAD_FOLDER'])
    
    # Ensure HuggingFace cache directory exists
    if not os.path.exists(app.config['HF_HOME']):
        os.makedirs(app.config['HF_HOME'])
    
    # Set HuggingFace environment variables
    os.environ['HF_HOME'] = app.config['HF_HOME']
    if 'HF_CACHE_DIR' in app.config:
        os.environ['HF_CACHE_DIR'] = app.config['HF_CACHE_DIR']
    
    # Register Blueprints
    from app.routes import main_bp
    app.register_blueprint(main_bp)
    
    # Setup logging
    if not app.debug and not app.testing:
        if not os.path.exists('logs'):
            os.mkdir('logs')
        
        file_handler = RotatingFileHandler(
            f'logs/{app.config.get("LOG_FILE", "tokenizer_pro.log")}',
            maxBytes=app.config.get("LOG_MAX_BYTES", 10 * 1024 * 1024),
            backupCount=app.config.get("LOG_BACKUP_COUNT", 3)
        )
        file_handler.setFormatter(logging.Formatter(
            '%(asctime)s %(levelname)s: %(message)s [in %(pathname)s:%(lineno)d]'
        ))
        
        log_level = getattr(logging, app.config.get("LOG_LEVEL", "INFO").upper())
        file_handler.setLevel(log_level)
        app.logger.addHandler(file_handler)
        app.logger.setLevel(log_level)
        app.logger.info('Tokenizer Pro startup')
    
    return app