#!/usr/bin/env python3
"""completion-notice.md 变更通知：供 Hermes cron 调用。

行为（严格）:
- 通知文件缺失: 静默退出 0，无任何输出
- 文件存在: 计算 sha256；与上次已通知 hash 相同 -> 静默退出 0
- hash 为新值: 把文件内容原样打印到 stdout 一次（供 cron 捕获后发 Slack），并原子记录该 hash
- 每个新内容 hash 只打印一次；内容再次变化会再次打印
- 状态文件损坏/不可读: 视为未通知过（打印一次）
- 不依赖任何模型凭据；纯本地文件与 hash

用法:
  completion_notify.py [--notice PATH] [--state PATH] [--selftest]
默认 notice=<cwd>/docs/completion-notice.md, state=<脚本所在目录>/completion_notify_state.json。
脚本放项目中，由 Hermes 复制到 cron 脚本目录时建议显式传 --notice/--state。

--selftest: 全部合成测试（临时文件模拟 缺失/新hash/重复/变更/损坏状态），不伪造真实结果。
"""
import argparse
import hashlib
import json
import os
import sys
import tempfile
from pathlib import Path

SCRIPT_DIR = Path(__file__).resolve().parent
DEFAULT_NOTICE = Path.cwd() / "docs/completion-notice.md"
DEFAULT_STATE = SCRIPT_DIR / "completion_notify_state.json"


def content_hash(data: bytes) -> str:
    return hashlib.sha256(data).hexdigest()


def load_state(path: Path):
    try:
        v = json.loads(Path(path).read_text())
        if isinstance(v, dict) and isinstance(v.get("hash"), str):
            return v["hash"]
    except Exception:
        pass
    return None


def save_state(path: Path, h: str):
    p = Path(path)
    p.parent.mkdir(parents=True, exist_ok=True)
    fd, tmp = tempfile.mkstemp(dir=str(p.parent), prefix=".notify_state.", suffix=".tmp")
    try:
        with os.fdopen(fd, "w") as fh:
            fh.write(json.dumps({"hash": h}, indent=1) + "\n")
        os.replace(tmp, p)
    except BaseException:
        try:
            os.unlink(tmp)
        except OSError:
            pass
        raise


def run_once(notice_path, state_path, out=sys.stdout):
    """返回 'printed' | 'silent' | 'missing'。打印发生在 out 上。"""
    p = Path(notice_path)
    try:
        data = p.read_bytes()
    except OSError:
        return "missing"  # 缺失静默
    h = content_hash(data)
    if load_state(state_path) == h:
        return "silent"
    out.write(data.decode("utf-8", "replace"))
    save_state(state_path, h)
    return "printed"


def run_once_str(notice_path, state_path):
    """测试用: 返回 (action, printed_text)。"""
    import io
    buf = io.StringIO()
    action = run_once(notice_path, state_path, out=buf)
    return action, buf.getvalue()


def selftest():
    ok = True

    def check(name, cond):
        nonlocal ok
        print(("PASS " if cond else "FAIL ") + name)
        ok = ok and cond

    import tempfile
    with tempfile.TemporaryDirectory() as td:
        td = Path(td)
        notice = td / "completion-notice.md"
        state = td / "state" / "notify.json"
        action, text = run_once_str(notice, state)
        check("missing -> silent no output", action == "missing" and text == "")
        notice.write_text("# 完成\n- 测试内容\n")
        action, text = run_once_str(notice, state)
        check("new content printed once", action == "printed" and text == notice.read_text())
        action, text = run_once_str(notice, state)
        check("same hash silent", action == "silent" and text == "")
        notice.write_text("# 完成 v2\n")
        action, text = run_once_str(notice, state)
        check("changed content printed again", action == "printed" and text == "# 完成 v2\n")
        action, text = run_once_str(notice, state)
        check("second view silent", action == "silent" and text == "")
        state.write_text("not-json{{{")
        action, text = run_once_str(notice, state)
        check("corrupt state treated as new", action == "printed" and text == "# 完成 v2\n")
        check("state saved after corrupt", load_state(state) == content_hash("# 完成 v2\n".encode()))

    print("SELFTEST=" + ("PASS" if ok else "FAIL"))
    return 0 if ok else 1


def main():
    ap = argparse.ArgumentParser(description="completion-notice.md new-hash notifier")
    ap.add_argument("--notice", default=str(DEFAULT_NOTICE))
    ap.add_argument("--state", default=str(DEFAULT_STATE))
    ap.add_argument("--selftest", action="store_true")
    args = ap.parse_args()
    if args.selftest:
        return selftest()
    action = run_once(args.notice, args.state)
    return 0


if __name__ == "__main__":
    sys.exit(main())