app/config.py

from pydantic_settings import BaseSettings
from functools import lru_cache


class Settings(BaseSettings):
    """Application settings loaded from environment variables."""
    
    # MongoDB
    mongodb_url: str = "mongodb://localhost:27017"
    database_name: str = "pdf_merger"
    
    # JWT
    secret_key: str = "your-super-secret-key-change-in-production"
    algorithm: str = "HS256"
    access_token_expire_minutes: int = 30
    
    # Application
    debug: bool = True
    
    # File paths
    upload_dir: str = "uploads"
    merged_dir: str = "merged"
    
    class Config:
        env_file = ".env"
        case_sensitive = False


@lru_cache()
def get_settings() -> Settings:
    """Get cached settings instance."""
    return Settings()