"""MinerU OCR 服务封装，支持调用本地 MinerU HTTP 接口。"""

from __future__ import annotations

import os
from pathlib import Path
from typing import Optional, Tuple

import httpx


class MinerUServiceError(RuntimeError):
    """MinerU 调用失败时抛出的异常。"""


class MinerUService:
    def __init__(self) -> None:
        self.endpoint = os.getenv("MINERU_ENDPOINT", "http://127.0.0.1:18888").rstrip("/")
        timeout = float(os.getenv("MINERU_TIMEOUT_SECONDS", "300"))
        # MinerU 首次加载模型可能耗时较长，这里提高超时时间避免大文件 OCR 直接失败
        self._client = httpx.Client(timeout=timeout)

    def _request_markdown(self, file_path: str) -> Tuple[Optional[str], dict]:
        """
        调用 MinerU /file_parse，返回 (markdown, raw_response)。
        若接口未返回内容则返回 (None, response_dict)。
        """
        if not self.endpoint:
            raise MinerUServiceError("未配置 MINERU_ENDPOINT，无法调用 MinerU")

        url = f"{self.endpoint}/file_parse"
        file_name = Path(file_path).name
        backend = os.getenv("MINERU_DEFAULT_BACKEND", "vlm-transformers")
        model_path = os.getenv("MINERU_MODEL_PATH")
        with open(file_path, "rb") as fp:
            response = self._client.post(
                url,
                files={"files": (file_name, fp, "application/octet-stream")},
                data={
                    "return_md": "true",
                    "return_content_list": "false",
                    "return_middle_json": "false",
                    "response_format_zip": "false",
                    "backend": backend,
                    # fast_api main 会从环境注入 model_path；这里双保险随请求传递
                    **({"model_path": model_path} if model_path else {}),
                },
            )
        response.raise_for_status()
        payload = response.json()
        results = payload.get("results") or {}
        if not isinstance(results, dict) or not results:
            return None, payload
        first_key = next(iter(results.keys()))
        md_content = results.get(first_key, {}).get("md_content")
        return md_content, payload

    async def extract_markdown(self, file_url: str) -> str:
        """
        阶段 0：直接返回固定内容，保证前端流程贯通。
        阶段 1：调用 MinerU CLI / SDK，从 Supabase Storage 下载文件后解析。
        """
        return f"# OCR Placeholder\n\n源文件：{file_url}"

    def extract_markdown_sync(self, file_path: str) -> str:
        """
        Celery 任务使用的同步封装。
        - 若 MinerU 服务可用：调用 HTTP 接口返回 markdown
        - 若失败：抛出 MinerUServiceError 让上层标记失败
        """
        try:
            markdown, raw = self._request_markdown(file_path)
            if markdown:
                return markdown
            raise MinerUServiceError(f"MinerU 未返回 md_content，响应片段：{str(raw)[:300]}")
        except Exception as exc:  # pragma: no cover - IO/网络异常
            raise MinerUServiceError(f"MinerU 调用失败：{exc}") from exc


mineru_service = MinerUService()