from typing import Literal

from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    """Application configuration loaded from environment variables."""

    llm_mode: Literal["local", "remote", "openai", "asksage"] = "local"
    llm_remote_url: str = ""
    llm_remote_token: str = ""

    # OpenAI configuration
    openai_api_key: str = ""
    openai_model: str = "gpt-4o-mini"

    # AskSage configuration
    asksage_email: str = ""
    asksage_api_key: str = ""
    asksage_model: str = "gpt-4o"

    # CORS configuration
    cors_origins: str = "http://localhost:3000"

    # Authentication settings
    auth_enabled: bool = False  # Set to True in production
    auth_audience: str = ""  # Backend Cloud Run URL (e.g., https://backend-xxx.run.app)
    allowed_service_accounts: str = ""  # Comma-separated list of allowed service account emails

    @property
    def cors_origins_list(self) -> list[str]:
        """Parse comma-separated CORS origins into a list."""
        return [origin.strip() for origin in self.cors_origins.split(",") if origin.strip()]

    @property
    def allowed_service_accounts_list(self) -> list[str]:
        """Parse comma-separated allowed service accounts into a list."""
        return [sa.strip() for sa in self.allowed_service_accounts.split(",") if sa.strip()]

    class Config:
        env_file = ".env"
        env_file_encoding = "utf-8"


# Constants
MAX_MESSAGE_LENGTH: int = 10_000

# Global settings instance
settings = Settings()