import os
from datetime import timedelta

class Config:
    """Base configuration"""
    SECRET_KEY = os.environ.get('SECRET_KEY', 'dev-secret-key-change-in-production')
    
    # JWT Configuration
    JWT_SECRET_KEY = os.environ.get('JWT_SECRET_KEY', 'jwt-secret-key-change-in-production')
    JWT_ACCESS_TOKEN_EXPIRES = timedelta(days=2)
    JWT_REFRESH_TOKEN_EXPIRES = timedelta(days=7)
    
    # SQLAlchemy Configuration
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    
    # Celery Configuration
    CELERY_BROKER_URL = os.environ.get('CELERY_BROKER_URL', 'redis://localhost:6379/0')
    CELERY_RESULT_BACKEND = os.environ.get('CELERY_RESULT_BACKEND', 'redis://localhost:6379/1')
    
    # File Storage
    UPLOAD_FOLDER = os.environ.get('UPLOAD_FOLDER', 'uploads')
    REPORTS_FOLDER = os.environ.get('REPORTS_FOLDER', 'reports')
    SCAN_DATA_FOLDER = os.environ.get('SCAN_DATA_FOLDER', 'uploads/scan_data')
    MAX_CONTENT_LENGTH = 50 * 1024 * 1024  # 50MB max file size for CloudShell scan uploads
    
    # Encryption key for sensitive data
    ENCRYPTION_KEY = os.environ.get('ENCRYPTION_KEY', 'encryption-key-change-in-production')


class DevelopmentConfig(Config):
    """Development configuration"""
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.environ.get(
        'DATABASE_URL', 
        'sqlite:///dev.db'
    )


class TestingConfig(Config):
    """Testing configuration"""
    TESTING = True
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = 'sqlite:///:memory:'
    
    # Use shorter token expiry for testing
    JWT_ACCESS_TOKEN_EXPIRES = timedelta(minutes=5)


class ProductionConfig(Config):
    """Production configuration"""
    DEBUG = False
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL')
    
    # Ensure these are set in production
    @classmethod
    def init_app(cls, app):
        Config.init_app(app)
        
        # Validate required environment variables
        required_vars = ['SECRET_KEY', 'JWT_SECRET_KEY', 'DATABASE_URL', 'ENCRYPTION_KEY']
        missing = [var for var in required_vars if not os.environ.get(var)]
        if missing:
            raise ValueError(f"Missing required environment variables: {', '.join(missing)}")


config = {
    'development': DevelopmentConfig,
    'testing': TestingConfig,
    'production': ProductionConfig,
    'default': DevelopmentConfig
}