import httpx
from core_domain import ChatCompletionRequestContract, ChatCompletionResponseContract


class ModelGatewayClientError(Exception):
    pass


class ModelGatewayClient:
    def __init__(self, base_url: str, timeout_seconds: float = 60.0) -> None:
        self.base_url = base_url.rstrip("/")
        self.timeout_seconds = timeout_seconds

    def create_chat_completion(
        self,
        payload: ChatCompletionRequestContract) -> ChatCompletionResponseContract:
        try:
            with httpx.Client(timeout=self.timeout_seconds) as client:
                response = client.post(
                    f"{self.base_url}/models/chat-completions",
                    json=payload.model_dump(mode="json"))
                response.raise_for_status()
                return ChatCompletionResponseContract.model_validate(response.json())
        except httpx.HTTPError as exc:
            raise ModelGatewayClientError(f"model-gateway-service request failed: {exc}") from exc