"""Async client for the Langflow authoring server (visual designer).

Only used for the authoring pipeline (list/export flows). Execution always
goes through LFX (see lfx_client.py).
"""

from __future__ import annotations

import httpx


class LangflowError(Exception):
    pass


class LangflowNotFound(LangflowError):
    pass


class LangflowUnavailable(LangflowError):
    pass


class LangflowClient:
    """Thin async wrapper around the Langflow `/api/v1/flows` endpoints."""

    def __init__(self, base_url: str, api_key: str = "", timeout: float = 60.0) -> None:
        self.base_url = base_url.rstrip("/")
        self.api_key = api_key
        self.timeout = timeout

    def _headers(self) -> dict[str, str]:
        return {"x-api-key": self.api_key} if self.api_key else {}

    async def list_flows(self) -> list[dict]:
        """List flows (header mode keeps payloads small)."""
        try:
            async with httpx.AsyncClient(
                base_url=self.base_url, timeout=self.timeout, headers=self._headers()
            ) as client:
                response = await client.get("/api/v1/flows/", params={"header_flows": "true"})
                if response.status_code == 404:
                    raise LangflowNotFound("flow list not found")
                response.raise_for_status()
                data = response.json()
                return data if isinstance(data, list) else data.get("items", [])
        except httpx.HTTPStatusError as exc:
            raise LangflowError(f"Langflow error {exc.response.status_code}") from exc
        except httpx.HTTPError as exc:
            raise LangflowUnavailable(f"Langflow unreachable: {exc}") from exc

    async def export_flow(self, langflow_flow_id: str) -> dict:
        """Export one flow as Langflow JSON (FlowRead: id/name/description/data)."""
        try:
            async with httpx.AsyncClient(
                base_url=self.base_url, timeout=self.timeout, headers=self._headers()
            ) as client:
                response = await client.get(f"/api/v1/flows/{langflow_flow_id}")
                if response.status_code == 404:
                    raise LangflowNotFound(f"flow {langflow_flow_id} not found")
                response.raise_for_status()
                return response.json()
        except httpx.HTTPStatusError as exc:
            raise LangflowError(f"Langflow error {exc.response.status_code}") from exc
        except httpx.HTTPError as exc:
            raise LangflowUnavailable(f"Langflow unreachable: {exc}") from exc