from pydantic_settings import BaseSettings
from functools import lru_cache


class Settings(BaseSettings):
    """Application settings loaded from environment variables."""
    
    # Database Configuration
    DATABASE_URL: str = "postgresql+asyncpg://myuser:mypassword@127.0.0.1:5432/mydatabase"
    
    # LLM API Configuration
    LLM_API_KEY: str
    LLM_API_BASE: str = "https://api.openai.com/v1"
    LLM_DEFAULT_MODEL: str = "openai/gpt-4o"
    
    # App Configuration
    DEFAULT_APP_NAME: str = "adk_chat_app"

    class Config:
        env_file = ".env"
        extra = "ignore"


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


settings = get_settings()