import os
from typing import Optional

class Config:
    """Configuration class for the Flask application"""
    
    # Flask Configuration
    SECRET_KEY = os.environ.get('SECRET_KEY', 'your-secret-key-here-change-in-production')
    DEBUG = os.environ.get('DEBUG', 'False').lower() == 'true'
    
    # Server Configuration
    HOST = os.environ.get('HOST', '0.0.0.0')
    PORT = int(os.environ.get('PORT', 5000))
    
    # CORS Configuration
    CORS_ORIGINS = os.environ.get('CORS_ORIGINS', 'http://localhost:5174,http://localhost:3000').split(',')
    
    # AI Model Configuration
    MODEL_CACHE_DIR = os.environ.get('MODEL_CACHE_DIR', './model_cache')
    ENABLE_CUDA = os.environ.get('ENABLE_CUDA', 'True').lower() == 'true'
    
    # Generation Limits
    MAX_QUESTIONS_MCQ = int(os.environ.get('MAX_QUESTIONS_MCQ', 10))
    MAX_QUESTIONS_BOOLEAN = int(os.environ.get('MAX_QUESTIONS_BOOLEAN', 8))
    MAX_QUESTIONS_SHORT = int(os.environ.get('MAX_QUESTIONS_SHORT', 8))
    MAX_QUESTIONS_MIXED = int(os.environ.get('MAX_QUESTIONS_MIXED', 15))
    
    # Text Limits
    MIN_TEXT_LENGTH = int(os.environ.get('MIN_TEXT_LENGTH', 50))
    MAX_TEXT_LENGTH = int(os.environ.get('MAX_TEXT_LENGTH', 10000))
    
    # Logging Configuration
    LOG_LEVEL = os.environ.get('LOG_LEVEL', 'INFO')
    LOG_DIR = os.environ.get('LOG_DIR', './logs')
    
    # Backend Integration
    BACKEND_URL = os.environ.get('BACKEND_URL', 'http://localhost:8080')
    API_KEY = os.environ.get('API_KEY', None)  # Optional API key for authentication
    
    @classmethod
    def get_model_path(cls, model_name: str) -> str:
        """Get the path for a specific model"""
        return os.path.join(cls.MODEL_CACHE_DIR, model_name)
    
    @classmethod
    def ensure_directories(cls):
        """Ensure required directories exist"""
        os.makedirs(cls.MODEL_CACHE_DIR, exist_ok=True)
        os.makedirs(cls.LOG_DIR, exist_ok=True)

class DevelopmentConfig(Config):
    """Development configuration"""
    DEBUG = True
    LOG_LEVEL = 'DEBUG'

class ProductionConfig(Config):
    """Production configuration"""
    DEBUG = False
    LOG_LEVEL = 'INFO'
    
    # Override with production values - only enforce in actual production
    SECRET_KEY = os.environ.get('SECRET_KEY')
    if not SECRET_KEY and os.environ.get('FLASK_ENV') == 'production':
        raise ValueError("SECRET_KEY must be set in production")

class TestingConfig(Config):
    """Testing configuration"""
    TESTING = True
    DEBUG = True
    
# Configuration mapping
config = {
    'development': DevelopmentConfig,
    'production': ProductionConfig,
    'testing': TestingConfig,
    'default': DevelopmentConfig
}