"""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 = ""

# CTP C++ API 登录回调依赖中文 locale（见 vnpy/vnpy_ctp#24）
_CTP_REQUIRED_LOCALES = ("zh_CN.GB18030", "zh_CN.gb18030")


def _available_locales() -> set[str]:
    try:
        out = subprocess.check_output(["locale", "-a"], text=True, stderr=subprocess.DEVNULL)
        return {line.strip() for line in out.splitlines() if line.strip()}
    except (OSError, subprocess.SubprocessError):
        return set()


def missing_ctp_locales() -> list[str]:
    """CTP 所需的 zh_CN.GB18030 是否已安装。"""
    avail = {x.lower() for x in _available_locales()}
    if any(x.lower() in avail for x in _CTP_REQUIRED_LOCALES):
        return []
    return ["zh_CN.GB18030"]


def _list_locale_candidates() -> list[str]:
    avail = _available_locales()
    names: list[str] = []
    # CTP 回调优先尝试中文 locale
    for item in (
        "zh_CN.GB18030",
        "zh_CN.gb18030",
        "zh_CN.UTF-8",
        "zh_CN.utf8",
        "en_US.UTF-8",
        "en_US.utf8",
        "C.UTF-8",
        "C.utf8",
        "POSIX",
        "C",
    ):
        if item in avail and item not in names:
            names.append(item)
    for loc in sorted(avail):
        low = loc.lower()
        if "utf" in low and loc not in names:
            names.append(loc)
    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

    missing = missing_ctp_locales()
    if missing:
        raise RuntimeError(
            "CTP 需要中文 locale zh_CN.GB18030，当前系统未安装。"
            "请执行: sed -i '/^# zh_CN.GB18030/s/^# //' /etc/locale.gen && "
            "locale-gen zh_CN.GB18030"
        )

    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 zh_CN.GB18030 en_US.UTF-8"
    ) from last_err