"""
LibreOffice Excel→PDF 转换壳。

本文件职责：探测 soffice、在「调用方已占用 LibreOffice 单槽」的前提下同步转 PDF。
禁止：在企微回调 / H5 线程调用；禁止本进程同时起两台 soffice（由 SlotPool size=1 保证）。
"""

from __future__ import annotations

import logging
import subprocess
from dataclasses import dataclass
from pathlib import Path
from typing import Optional

from agent.config import Settings, get_settings

logger = logging.getLogger(__name__)


@dataclass
class LibreOfficeResult:
    """转换结果；ok=False 时 error 说明原因，不抛到 Worker 主循环。"""

    ok: bool
    pdf_path: str = ""
    error: str = ""
    returncode: int = 0


@dataclass
class LibreOfficeConverter:
    """
    soffice 无界面转换器。

    调用约定：仅从 WorkerRuntime.libreoffice 槽内进入 convert()。
    """

    settings: Settings

    @classmethod
    def from_settings(cls, settings: Optional[Settings] = None) -> "LibreOfficeConverter":
        return cls(settings=settings or get_settings())

    def executable(self) -> Path:
        return Path(self.settings.libreoffice_path)

    def available(self) -> bool:
        """本机是否存在配置的 soffice 可执行文件。"""
        return self.executable().is_file()

    def convert_xlsx_to_pdf(self, xlsx_path: str | Path) -> LibreOfficeResult:
        """
        将 Excel 转为同目录 PDF。

        副作用：启动 soffice 子进程（超时见 settings）；成功写 PDF 文件。
        线程：必须已在 LibreOffice 单槽内。
        """
        source = Path(xlsx_path).resolve()
        if not source.is_file():
            return LibreOfficeResult(ok=False, error="source_not_found")
        exe = self.executable()
        if not exe.is_file():
            return LibreOfficeResult(ok=False, error="libreoffice_not_installed")
        out_dir = source.parent
        target = source.with_suffix(".pdf")
        try:
            completed = subprocess.run(
                [
                    str(exe),
                    "--headless",
                    "--convert-to",
                    # calc 导出才认 Excel 的 A4/居中/页宽缩放；裸 pdf 会裁顶、偏左
                    "pdf:calc_pdf_Export",
                    "--outdir",
                    str(out_dir),
                    str(source),
                ],
                capture_output=True,
                timeout=float(self.settings.libreoffice_timeout_seconds),
                check=False,
            )
        except (OSError, subprocess.TimeoutExpired) as exc:
            logger.warning("LibreOffice 执行失败: %s", exc)
            return LibreOfficeResult(ok=False, error=f"exec_failed:{exc}")
        if completed.returncode != 0 or not target.is_file():
            stderr = (completed.stderr or b"")[:400]
            logger.warning(
                "LibreOffice 未生成 PDF rc=%s stderr=%s",
                completed.returncode,
                stderr,
            )
            return LibreOfficeResult(
                ok=False,
                error="pdf_not_generated",
                returncode=int(completed.returncode),
            )
        head = target.read_bytes()[:5]
        if head != b"%PDF-":
            target.unlink(missing_ok=True)
            return LibreOfficeResult(ok=False, error="pdf_header_invalid")
        logger.info("LibreOffice 转 PDF 成功 path=%s", target)
        return LibreOfficeResult(ok=True, pdf_path=str(target), returncode=0)