"""每日 02:00 数据库备份 job —— 包装 backend/scripts/pg_backup.sh。

独立脚本可手动/CI 直跑；系统调度经此包装，保证与脚本同一份备份逻辑与轮转策略。
Windows 下须显式定位 Git Bash（PATH 里的 bash 可能是 WSL shim，mount/PATH 均不匹配），
脚本路径统一转 MSYS /d/... 格式传给子进程。
"""

import asyncio
import logging
import shutil
from pathlib import Path

logger = logging.getLogger(__name__)

# backend/app/utils/backup_job.py → parents[2] = backend/
_SCRIPT = Path(__file__).resolve().parents[2] / "scripts" / "pg_backup.sh"

_GIT_BASH_CANDIDATES = (
    Path(r"C:\Program Files\Git\bin\bash.exe"),
    Path(r"C:\Program Files\Git\usr\bin\bash.exe"),
)


def _find_git_bash() -> str | None:
    for cand in _GIT_BASH_CANDIDATES:
        if cand.exists():
            return str(cand)
    return shutil.which("bash")


def _msys_path(p: Path) -> str:
    """D:/dpb/... → /d/dpb/...（Git Bash 挂载约定）。"""
    s = p.as_posix()
    if len(s) >= 2 and s[1] == ":":
        return f"/{s[0].lower()}{s[2:]}"
    return s


async def run_daily_backup() -> bool:
    """每日备份：调用 pg_backup.sh（独立脚本，pg_dump 自定义格式 + N 天轮转）。"""
    script = _SCRIPT
    if not script.exists():
        alt = Path.cwd() / "scripts" / "pg_backup.sh"
        script = alt if alt.exists() else script
    if not script.exists():
        logger.error(f"备份脚本不存在: {script}")
        return False
    git_bash = _find_git_bash()
    if not git_bash:
        logger.error("未找到 Git Bash（C:/Program Files/Git/bin/bash.exe）")
        return False
    proc = await asyncio.create_subprocess_exec(
        git_bash, _msys_path(script),
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE,
    )
    stdout, stderr = await proc.communicate()
    if proc.returncode == 0:
        logger.info(f"每日备份完成: {stdout.decode().strip()}")
        return True
    logger.error(f"每日备份失败(rc={proc.returncode}): {stderr.decode()[:500]}")
    return False