config.py

import os
from dotenv import load_dotenv

basedir = os.path.abspath(os.path.dirname(__file__))
load_dotenv(os.path.join(basedir, '.env'))

class Config:
    SECRET_KEY = os.environ.get('SECRET_KEY') or 'you-will-never-guess-super-secret'
    
    # MySQL Connection String Example: mysql+pymysql://user:password@localhost/dbname
    # Fallback to SQLite if MySQL is not configured for easy testing
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
        'sqlite:///' + os.path.join(basedir, 'sentiment.sqlite')
    
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    
    # File upload handling
    UPLOAD_FOLDER = os.path.join(basedir, 'uploads')
    MAX_CONTENT_LENGTH = 16 * 1024 * 1024  # 16 MB max limit
    ALLOWED_EXTENSIONS = {'csv', 'xls', 'xlsx'}
    
    # Required for cross-site iframe sessions (Hugging Face Spaces)
    SESSION_COOKIE_SAMESITE = 'None'
    SESSION_COOKIE_SECURE = True