"""Linux 上 vnpy_ctp 连接 CTP 前须设置有效 locale（否则 C++ 层 abort）。"""
from __future__ import annotations

import locale
import logging
import os
import subprocess

logger = logging.getLogger(__name__)

_LOCALE_DONE = False
_LOCALE_NAME = ""


def _list_locale_candidates() -> list[str]:
    names: list[str] = []
    for item in (
        "C.UTF-8",
        "en_US.UTF-8",
        "en_US.utf8",
        "POSIX",
        "C",
    ):
        if item not in names:
            names.append(item)
    try:
        out = subprocess.check_output(["locale", "-a"], text=True, stderr=subprocess.DEVNULL)
        for line in out.splitlines():
            loc = line.strip()
            if not loc:
                continue
            low = loc.lower()
            if "utf" in low and loc not in names:
                names.insert(0, loc)
    except (OSError, subprocess.SubprocessError):
        pass
    return names


def ensure_process_locale() -> str:
    """强制设置进程 locale，覆盖系统里无效的旧值。"""
    global _LOCALE_DONE, _LOCALE_NAME
    if _LOCALE_DONE:
        return _LOCALE_NAME

    last_err: locale.Error | None = None
    for name in _list_locale_candidates():
        try:
            locale.setlocale(locale.LC_ALL, name)
            os.environ["LANG"] = name
            os.environ["LC_ALL"] = name
            os.environ["LC_CTYPE"] = name
            _LOCALE_DONE = True
            _LOCALE_NAME = name
            logger.info("进程 locale 已设置: %s", name)
            return name
        except locale.Error as exc:
            last_err = exc
            continue

    raise RuntimeError(
        "未找到可用 locale，vnpy_ctp 会在 CTP 登录后崩溃。"
        "请执行: apt install -y locales && locale-gen en_US.UTF-8 && "
        "update-locale LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8"
    ) from last_err