# app/config.py
import os
from functools import lru_cache

# v2-first import, fallback to v1
try:
    from pydantic_settings import BaseSettings, SettingsConfigDict  # pydantic v2
    from pydantic import AnyUrl, Field
    IS_V2 = True
except Exception:
    from pydantic import BaseSettings, AnyUrl  # pydantic v1
    from pydantic import Field
    IS_V2 = False

class Settings(BaseSettings):
    # Read from env: set this in your Space Secrets as AMQP_URL
    AMQP_URL: AnyUrl = Field(..., description="amqps://user:pass@host:5671/%2F?heartbeat=30")

    RABBIT_INSTANCE_NAME: str = "prod"
    RABBIT_EXCHANGE_TYPE: str = "topic"
    RABBIT_ROUTING_KEY: str = ""
    RABBIT_PREFETCH: int = 1

    SERVICE_ID: str = "gradllm"
    USE_TLS: bool = True

    # Optional: prefix->type map, e.g. {"llmStartSession": "topic"}
    EXCHANGE_TYPES: dict[str, str] = {}

    if IS_V2:
        # pydantic v2
        model_config = SettingsConfigDict(
            case_sensitive=True,
            env_file=".env",        # for local dev; ignored on HF unless you commit it
            env_file_encoding="utf-8",
        )
    else:
        # pydantic v1
        class Config:
            case_sensitive = True
            env_file = ".env"
            env_file_encoding = "utf-8"

@lru_cache
def get_settings() -> Settings:
    try:
        return Settings()
    except Exception as e:
        # Friendlier message when AMQP_URL is missing/invalid
        raise RuntimeError(
            "AMQP_URL is not set or invalid. In your Hugging Face Space, add a Secret "
            "named AMQP_URL (e.g. amqps://user:pass@host:5671/%2F?heartbeat=30)."
        ) from e

settings = get_settings()