"""Nougat OCR integration.

Converts PDF files to Mathpix Markdown (mmd) by calling a self-hosted
Nougat HTTP server.  No network fetching of papers happens here — the
caller is expected to pass a local PDF path.
"""

from __future__ import annotations

import httpx
import tenacity

from codex.config import Settings


def pdf_to_markdown(pdf_path: str, nougat_url: str | None = None) -> str:
    """Convert a local PDF to Mathpix Markdown via the Nougat HTTP API.

    Parameters
    ----------
    pdf_path:
        Absolute (or relative) path to the PDF file on disk.
    nougat_url:
        Base URL of the Nougat server.  Defaults to ``Settings().nougat_url``.

    Returns
    -------
    str
        The raw ``.mmd`` text returned by the server.

    Raises
    ------
    httpx.HTTPStatusError
        If the server returns a non-2xx status code.
    """
    if nougat_url is None:
        nougat_url = Settings().nougat_url

    @tenacity.retry(
        retry=tenacity.retry_if_exception_type(httpx.ConnectError),
        stop=tenacity.stop_after_attempt(3),  # 1 original + 2 retries
        wait=tenacity.wait_fixed(0),
        reraise=True,
    )
    def _post() -> str:
        with open(pdf_path, "rb") as fh, httpx.Client(timeout=120.0) as client:
            response = client.post(
                f"{nougat_url}/predict",
                files={"file": (pdf_path, fh, "application/pdf")},
            )
        response.raise_for_status()
        return response.text

    return _post()