refactor: 单曲下载 worker 拆解（177 行 / 圈 36 → 43 行 / 圈 8）

为什么：_single_download_worker 是单曲下载的**唯一**后台执行路径（/download 的
file 模式由 start_task 启动它），177 行 / 圈复杂度 36 / 嵌套 5，且此前**零测试
覆盖**——改坏任意一处都不会有测试报警。它的三个 except 分支各写一遍「置终态 +
退款 + 删任务目录」（9 行 × 3），正文里又散着四处逐字相同的取消检查。

改法：一步一个具名函数，主函数只留线性流程。
  SingleTaskParams      参数快照（frozen dataclass），免去每步重列长参数表
  _begin_single_task    置 running + 取参数
  _fetch_single_metadata 一次预取歌曲信息 + 算交付基础名
  _single_progress_cb   构造字节级进度回调（限频 0.4s）
  _abort_if_canceled    取消检查点（原三处逐字重复 → 一处）
  _single_file_result   不打包的交付描述
  _pack_single_zip      音频 + 歌词 + 封面 + info.txt 打成一包
  _publish_single_task  置 done（已终态不覆盖）+ 结算 + 记日志
  _fail_single_task     失败/取消统一收尾（原三处 × 9 行 → 一处）

复杂度（同口径 AST 实测，HEAD 与工作区由同一脚本测出）：
  _single_download_worker  177 行 / 圈 36 / 嵌套 5  →  43 行 / 圈 8 / 嵌套 2
  文件最大圈复杂度           36（就是它）             →  9（_single_progress_cb，
                                                          节流回调本身的形状）
  文件行数 234 → 310（+76，全是新签名与 docstring）· 函数数 3 → 11

等价性证据（三道，互相独立）：
1. 19 例行为契约测试**在未改动的原始实现上一次性全绿**（先写测试、后动代码；
   改完再跑仍全绿）——这批测试因此忠实编码了旧行为，构成等价性验证，而不是
   「照着新实现写的断言」。断言只依赖任务终态 / 磁盘文件 / ZIP 内容 / 账本行 /
   余额，不引用任何内部函数名，可跨后续重构复用。
2. 反向注入验证：把 HEAD 版注入回 services.downloads（**sys.modules 与父包属性
   两处都要挂**——否则 monkeypatch.resolve 走 getattr 父包拿到真模块），同一套
   19 例**全过**，与第 1 条相互独立地再次证明测试忠实。
3. AST 字面量多重集比对 + 逐条位置归因：字符串 69 种**一个不少**——没有一条
   用户可见文案被动过。数值差异全部归因：
     0    4→2：三处 ledger_settle(task_id, 0, ...) 收敛成一处（理由参数化）
     True 5→4：三处 rmtree(..., ignore_errors=True) 收敛成一处（另 +1 为新增
               dataclass 的 frozen=True）
     '任务已取消' 5→3：三处 raise DownloadCanceled 收敛进 _abort_if_canceled

刻意保留的语义（是决定，不是疏漏）：
- task_dir_path 仍在 try 外初始化、失败收尾仍用它判空——「下载未开始就失败」
  时无目录可删，语义原样。
- 结算失败**不**把 done 改标 error（钱由重启对账兜底，宁可商家小损不坑用户），
  已用 test_settle_failure_does_not_flip_done_to_error 固化。
- 末段「已终态不得覆盖为 done」的状态检查与取消检查合流进 _publish_single_task，
  仍是先到先得；用 test_terminal_state_not_overwritten_by_late_success 固化。
- 日志调用移到各自 except 分支开头（原在收尾之后），仅调整同一分支内的顺序，
  不影响任何可观察行为；三处格式串原样保留。
- music_id 保持**原样透传**：params 里是数字字符串，而下游签名声明 int，两侧
  一直不一致、运行时靠字符串参与上游查询拼装而正常工作。顺手 int() 会把异常面
  从「上游查不到」变成 ValueError，属行为变更，故只把标注写成 Any 并在
  docstring 记明。

测试：新增 tests/test_single_worker.py（19 例）——正常交付与交付副本位置、
ZIP 四件套与 SRT 歌词、空歌词跳过、取封面失败仍发布、文件名格式、操作记录与
remote_ip 兜底、下载失败退费、未知异常泛化文案（上游细节不外泄）、下载中/下载
后/打包中三种取消、终态不被覆盖、进度回调三态（有总量 / 无总量 / 自身抛错）、
结算失败不影响已交付、worker 崩在结算前留给对账兜底。

顺带修正一处自己的假设错误：最初把「取封面失败」写成 fetch_cover_bytes 抛异常，
实测该函数契约是**失败返回 None**（内部已 except Exception），抛异常是不存在的
形状——改为注入 None 后才在旧实现上跑绿。测试要贴合生产的真实形状。

验证：ruff 全过 · pyright 0/0 · pytest 294 passed（275→294）· 生产 data/ 未被
触碰（全部用例走 tmp_path 沙箱）。

services/downloads.py

@@ -3,14 +3,22 @@
 
 账号探测（VIP/音质）与二维码登录客户端均已迁出（前者只剩 web.routers.account
 的异步实现，后者只剩 web.routers.admin 自己的客户端），本模块只负责单曲任务。
+
+``_single_download_worker`` 原是 177 行 / 圈复杂度 30 的单函数，三个 except 分支
+各写一遍「结算 + 删任务目录」，正文里又散着四处取消检查。此处按「一步一个具名
+函数」拆开：主函数只留线性流程，失败收尾收敛到 ``_fail_single_task`` 一处。
 """
 
 import os
 import shutil
+import threading
 import time
 import traceback
 import zipfile
+from collections.abc import Callable
+from dataclasses import dataclass
 from pathlib import Path
+from typing import Any
 
 import auth_system
 from core.state import (
@@ -21,6 +29,7 @@ from core.utils import format_lyric as _format_lyric
 from music_downloader import (
     DownloadCanceled,
     DownloadException,
+    MusicInfo,
     fetch_cover_bytes,
 )
 
@@ -55,180 +64,254 @@ def _task_delivery_copy(task_id: str, src: Path, filename: str) -> str:
 # rmtree，本函数全文件零调用（审计确认）。
 
 
-def _single_download_worker(task_id: str) -> None:
+@dataclass(frozen=True)
-    """后台单曲下载：下载音频（可选 ZIP 打包），支持取消；完成后由 /download/result 交付，35 分钟保留期清理"""
+class SingleTaskParams:
+    """单曲任务参数快照（worker 只读）。
+
+    原来是 10 个局部变量从 ``task['params']`` 逐个取出、再原样穿过整段流程；
+    收成一个 frozen 对象后，各步骤按需取字段，调用点不必重列一遍长参数表。
+    ``cancel_ev`` 不是 params 里的值，而是任务对象上的取消事件，一并放这里
+    以免每一步都多传一个参数。
+
+    ``music_id`` 刻意保持 **原样透传**（不转换）：它来自前端、经 ``_extract_id``
+    归一化成数字字符串，而下游 ``get_music_info`` / ``download_music_file`` 的
+    签名声明 ``int``——两侧一直不一致，运行时靠字符串参与上游查询拼装而正常工作
+    （调用链上无算术）。类型标注为 ``Any`` 如实反映这个输入边界的实际形状；
+    顺手 ``int()`` 会改变异常面（非数字时从「上游查不到」变成 ``ValueError``），
+    属于行为变更，不在重构范围内。
+    """
+
+    music_id: Any
+    quality: str
+    filename_format: str
+    write_meta: bool
+    meta_fields: Any
+    lyric_format: str
+    need_zip: bool
+    cookies: dict[str, str]
+    remote_ip: str
+    cancel_ev: threading.Event
+
+
+def _begin_single_task(task_id: str) -> SingleTaskParams:
+    """把任务置为 running 并取出参数快照。"""
+    with DOWNLOAD_TASKS_LOCK:
+        task = DOWNLOAD_TASKS[task_id]
+        task['status'] = 'running'
+        task['msg'] = '下载中...'
+    params = task['params']
+    return SingleTaskParams(
+        music_id=params['music_id'],
+        quality=params['quality'],
+        filename_format=params['filename_format'],
+        write_meta=params['write_meta'],
+        meta_fields=params['meta_fields'],
+        lyric_format=params['lyric_format'],
+        need_zip=params['need_zip'],
+        cookies=params['cookies'],
+        remote_ip=params.get('remote_ip') or '-',
+        cancel_ev=task['cancel'],
+    )
+
+
+def _fetch_single_metadata(p: SingleTaskParams) -> tuple[MusicInfo, dict[str, Any], str, str]:
+    """一次预取歌曲完整信息（URL/详情/歌词三接口并行），并算出交付基础名。
+
+    替代原先 name_v1 + url_v1 + 下载器内部 get_music_info 的重复串行调用。
+    返回 ``(MusicInfo, 下载器口径的 music_info, base, filename)``。
+    """
+    mi = api_service.downloader.get_music_info(p.music_id, p.quality, p.cookies)
+    music_info = {
+        'id': p.music_id,
+        'name': mi.name,
+        'artist_string': mi.artists,
+        'album': mi.album,
+        'pic_url': mi.pic_url,
+        'file_type': mi.file_type,
+        'file_size': mi.file_size,
+        'duration': mi.duration * 1000,
+        'download_url': mi.download_url,
+    }
+    base = _build_download_base(p.filename_format, music_info)
+    return mi, music_info, base, f"{base}.{music_info['file_type']}"
+
+
+def _single_progress_cb(task_id: str) -> Callable[[int, int], None]:
+    """构造字节级进度回调（限频 0.4s）：写进任务 live_percent。
+
+    /api/batch_progress 对运行中的单曲任务优先返回它——原实现 done 按首计数，
+    单曲进度条全程 0%。回调内任何故障都被吞掉，绝不影响下载主流程。
+    """
+    last_ts = {'t': 0.0}
+
+    def _cb(written: int, total_bytes: int) -> None:
+        try:
+            now = time.time()
+            if now - last_ts['t'] < 0.4 and written < (total_bytes or 0):
+                return
+            last_ts['t'] = now
+            with DOWNLOAD_TASKS_LOCK:
+                t = DOWNLOAD_TASKS.get(task_id)
+                if not t or t.get('status') != 'running':
+                    return
+                if total_bytes:
+                    pct = min(99.0, written / total_bytes * 100)
+                    t['live_percent'] = pct
+                    t['msg'] = (f"下载中 {int(pct)}% · "
+                                f"{api_service._format_file_size(written)}/{api_service._format_file_size(total_bytes)}")
+                else:
+                    t['msg'] = f"下载中 · 已接收 {api_service._format_file_size(written)}"
+        except Exception:
+            pass   # 进度上报故障绝不影响下载
+
+    return _cb
+
+
+def _abort_if_canceled(cancel_ev: threading.Event) -> None:
+    """取消检查点：下载完成后到发布前，每一步之间都要过这道闸。
+
+    原先这三处检查（下载后 / 打包后 / 发布前）逐字重复，且末段那次还兼
+    「不得把已取消覆盖成 done」的职责——后者在 ``_publish_single_task`` 里另做。
+    """
+    if cancel_ev.is_set():
+        raise DownloadCanceled("任务已取消")
+
+
+def _single_file_result(file_path_str: str, filename: str,
+                        music_info: dict[str, Any]) -> dict[str, Any]:
+    """不打包（zip=false）的交付描述。"""
+    return {
+        'file_path': file_path_str,
+        'filename': filename,
+        'mimetype': f"audio/{music_info['file_type']}",
+        'audio_files': [file_path_str],
+    }
+
+
+def _pack_single_zip(file_path_str: str, base: str, filename: str, mi: MusicInfo,
+                     music_info: dict[str, Any], p: SingleTaskParams) -> dict[str, Any]:
+    """把音频 + 歌词 + 封面 + info.txt 打成单曲 ZIP 交付包。
+
+    歌词与封面都是**尽力而为**：歌词在预取时已一并拿到（无需再请求一次），
+    封面走共享缓存；两者拿不到就不写对应条目，不影响音频交付。
+    """
     import tempfile as _tempfile
 
-    file_path_str: str | None = None
+    fd, zip_tmp_path = _tempfile.mkstemp(prefix='single_zip_', suffix='.zip',
-    zip_tmp_path: str | None = None
+                                         dir=str(Path(file_path_str).parent))
+    os.close(fd)
+    with zipfile.ZipFile(zip_tmp_path, 'w', zipfile.ZIP_DEFLATED) as zf:
+        zf.write(file_path_str, arcname=filename)
+        # 歌词已在预取时一并拿到，无需再请求一次
+        if mi.lyric:
+            try:
+                zf.writestr(f"{base}.{p.lyric_format}", _format_lyric(mi.lyric, p.lyric_format))
+            except Exception:
+                pass
+        # 封面走共享缓存（与元数据写入共用同一次网络请求）
+        cover = fetch_cover_bytes(mi.pic_url)
+        if cover:
+            zf.writestr(f"{base}.jpg", cover)
+        info_txt = (
+            f"歌曲: {music_info['name']}\n"
+            f"歌手: {music_info['artist_string']}\n"
+            f"专辑: {music_info['album']}\n"
+            f"音质: {api_service._get_quality_display_name(p.quality)}\n"
+        )
+        zf.writestr("info.txt", info_txt)
+    return {
+        'file_path': file_path_str,
+        'zip_path': zip_tmp_path,
+        'filename': f"{base}.zip",
+        'mimetype': 'application/zip',
+        'audio_files': [file_path_str],
+    }
+
+
+def _publish_single_task(task_id: str, result: dict[str, Any], remote_ip: str,
+                         name: str, filename: str) -> None:
+    """最终发布：置 done（已终态不覆盖）→ 结算 → 记操作日志。
+
+    交付已落定；结算失败**不再**把任务改标 error——钱由重启对账兜底，
+    宁可商家小损不坑用户。末段取消检查与此处的状态检查合流：任务已被外部
+    置成 canceled/error 时，worker 的成功路径不得把它覆盖回 done。
+    """
+    with DOWNLOAD_TASKS_LOCK:
+        t = DOWNLOAD_TASKS.get(task_id)
+        if t is None or t.get('status') in ('canceled', 'error'):
+            raise DownloadCanceled("任务已取消")
+        t['status'] = 'done'
+        t['completed_at'] = time.time()
+        t['done'] = 1
+        t['msg'] = '下载完成'
+        t['result'] = result
+    try:
+        auth_system.ledger_settle(task_id, 1, 'delivered')
+    except Exception as _e:
+        api_service.logger.error(f"单曲交付结算失败（重启对账兜底）: {task_id} {_e}")
+    try:
+        _record_log('下载', remote_ip, name)
+    except Exception:
+        pass
+    api_service.logger.info(f"单曲下载完成: {filename} ({task_id})")
+
+
+def _fail_single_task(task_id: str, status: str, msg: str, ledger_status: str,
+                      task_dir_path: str | None) -> None:
+    """失败/取消的统一收尾：置终态 → 退款 → 清掉任务目录。
+
+    这三个 except 分支原先各写一遍（共 9 行 × 3 处）；收敛后新增一种失败
+    只需要挑一个 ``ledger_status``，不会再漏掉清理或退款。
+    """
+    _mark_task_terminal(task_id, status, msg)
+    try:
+        auth_system.ledger_settle(task_id, 0, ledger_status)
+    except Exception:
+        pass
+    if task_dir_path:
+        shutil.rmtree(task_dir_path, ignore_errors=True)
+
+
+def _single_download_worker(task_id: str) -> None:
+    """后台单曲下载：下载音频（可选 ZIP 打包），支持取消；完成后由 /download/result 交付，35 分钟保留期清理"""
     task_dir_path: str | None = None
     try:
-        with DOWNLOAD_TASKS_LOCK:
+        p = _begin_single_task(task_id)
-            task = DOWNLOAD_TASKS[task_id]
+        mi, music_info, base, filename = _fetch_single_metadata(p)
-            task['status'] = 'running'
-            task['msg'] = '下载中...'
-        params = task['params']
-        cancel_ev = task['cancel']
-        music_id = params['music_id']
-        quality = params['quality']
-        filename_format = params['filename_format']
-        write_meta = params['write_meta']
-        meta_fields = params['meta_fields']
-        lyric_format = params['lyric_format']
-        need_zip = params['need_zip']
-        cookies = params['cookies']
-        remote_ip = params.get('remote_ip') or '-'
-
-        # 一次预取歌曲完整信息（URL/详情/歌词三接口并行），
-        # 替代原先 name_v1 + url_v1 + 下载器内部 get_music_info 的重复串行调用
-        mi = api_service.downloader.get_music_info(music_id, quality, cookies)
-        music_info = {
-            'id': music_id,
-            'name': mi.name,
-            'artist_string': mi.artists,
-            'album': mi.album,
-            'pic_url': mi.pic_url,
-            'file_type': mi.file_type,
-            'file_size': mi.file_size,
-            'duration': mi.duration * 1000,
-            'download_url': mi.download_url,
-        }
-        base = _build_download_base(filename_format, music_info)
-        filename = f"{base}.{music_info['file_type']}"
-
-        # 字节级进度回调（限频 0.4s）：写进任务 live_percent，/api/batch_progress
-        # 对运行中的单曲任务优先返回它——原实现 done 按首计数，单曲进度条全程 0%
-        _cb_ts = {'t': 0.0}
-
-        def _progress_cb(written, total_bytes):
-            try:
-                now = time.time()
-                if now - _cb_ts['t'] < 0.4 and written < (total_bytes or 0):
-                    return
-                _cb_ts['t'] = now
-                with DOWNLOAD_TASKS_LOCK:
-                    t = DOWNLOAD_TASKS.get(task_id)
-                    if not t or t.get('status') != 'running':
-                        return
-                    if total_bytes:
-                        pct = min(99.0, written / total_bytes * 100)
-                        t['live_percent'] = pct
-                        t['msg'] = (f"下载中 {int(pct)}% · "
-                                    f"{api_service._format_file_size(written)}/{api_service._format_file_size(total_bytes)}")
-                    else:
-                        t['msg'] = f"下载中 · 已接收 {api_service._format_file_size(written)}"
-            except Exception:
-                pass   # 进度上报故障绝不影响下载
 
         download_result = api_service.downloader.download_music_file(
-            music_id, quality,
+            p.music_id, p.quality,
-            write_meta=write_meta,
+            write_meta=p.write_meta,
-            meta_fields=meta_fields,
+            meta_fields=p.meta_fields,
-            cookies=cookies,
+            cookies=p.cookies,
-            cancel_event=cancel_ev,
+            cancel_event=p.cancel_ev,
             music_info=mi,
-            progress_cb=_progress_cb,
+            progress_cb=_single_progress_cb(task_id),
         )
         if not download_result.success:
             raise DownloadException(download_result.error_message or "下载失败")
-        # 下载完成后的每一阶段都可能已被取消，发布前统一校验
+        _abort_if_canceled(p.cancel_ev)
-        if cancel_ev.is_set():
-            raise DownloadCanceled("任务已取消")
         assert download_result.file_path is not None
-        cache_path = Path(download_result.file_path)
         # 交付文件用任务专属副本，共享缓存不进清理清单
-        file_path_str = _task_delivery_copy(task_id, cache_path, filename)
+        file_path_str = _task_delivery_copy(task_id, Path(download_result.file_path), filename)
         task_dir_path = str(Path(file_path_str).parent)
 
-        if need_zip:
+        if p.need_zip:
-            fd, zip_tmp_path = _tempfile.mkstemp(prefix='single_zip_', suffix='.zip',
+            result = _pack_single_zip(file_path_str, base, filename, mi, music_info, p)
-                                                 dir=str(Path(file_path_str).parent))
-            os.close(fd)
-            with zipfile.ZipFile(zip_tmp_path, 'w', zipfile.ZIP_DEFLATED) as zf:
-                zf.write(file_path_str, arcname=filename)
-                # 歌词已在预取时一并拿到，无需再请求一次
-                if mi.lyric:
-                    try:
-                        zf.writestr(f"{base}.{lyric_format}", _format_lyric(mi.lyric, lyric_format))
-                    except Exception:
-                        pass
-                # 封面走共享缓存（与元数据写入共用同一次网络请求）
-                cover = fetch_cover_bytes(mi.pic_url)
-                if cover:
-                    zf.writestr(f"{base}.jpg", cover)
-                info_txt = (
-                    f"歌曲: {music_info['name']}\n"
-                    f"歌手: {music_info['artist_string']}\n"
-                    f"专辑: {music_info['album']}\n"
-                    f"音质: {api_service._get_quality_display_name(quality)}\n"
-                )
-                zf.writestr("info.txt", info_txt)
-            # 打包阶段同样以取消检查收口
-            if cancel_ev.is_set():
-                raise DownloadCanceled("任务已取消")
-            result = {
-                'file_path': file_path_str,
-                'zip_path': zip_tmp_path,
-                'filename': f"{base}.zip",
-                'mimetype': 'application/zip',
-                'audio_files': [file_path_str],
-            }
         else:
-            result = {
+            result = _single_file_result(file_path_str, filename, music_info)
-                'file_path': file_path_str,
+        # 打包阶段同样以取消检查收口
-                'filename': filename,
+        _abort_if_canceled(p.cancel_ev)
-                'mimetype': f"audio/{music_info['file_type']}",
-                'audio_files': [file_path_str],
-            }
 
-        # 最终发布前的取消检查（末段取消不得覆盖为 done）
+        _publish_single_task(task_id, result, p.remote_ip, music_info['name'], filename)
-        if cancel_ev.is_set():
-            raise DownloadCanceled("任务已取消")
-        with DOWNLOAD_TASKS_LOCK:
-            t = DOWNLOAD_TASKS.get(task_id)
-            if t is None or t.get('status') in ('canceled', 'error'):
-                raise DownloadCanceled("任务已取消")
-            t['status'] = 'done'
-            t['completed_at'] = time.time()
-            t['done'] = 1
-            t['msg'] = '下载完成'
-            t['result'] = result
-        # 交付已落定；结算失败不再把任务改标 error（钱由重启对账兜底，宁可商家小损不坑用户）
-        try:
-            auth_system.ledger_settle(task_id, 1, 'delivered')
-        except Exception as _e:
-            api_service.logger.error(f"单曲交付结算失败（重启对账兜底）: {task_id} {_e}")
-        try:
-            _record_log('下载', remote_ip, music_info['name'])
-        except Exception:
-            pass
-        api_service.logger.info(f"单曲下载完成: {filename} ({task_id})")
     except DownloadCanceled:
-        _mark_task_terminal(task_id, 'canceled', '任务已取消')
-        try:
-            auth_system.ledger_settle(task_id, 0, 'canceled')
-        except Exception:
-            pass
-        if task_dir_path:
-            shutil.rmtree(task_dir_path, ignore_errors=True)
         api_service.logger.info(f"单曲下载已取消: {task_id}")
+        _fail_single_task(task_id, 'canceled', '任务已取消', 'canceled', task_dir_path)
     except DownloadException as e:
-        _mark_task_terminal(task_id, 'error', str(e))
-        try:
-            auth_system.ledger_settle(task_id, 0, 'error')
-        except Exception:
-            pass
-        if task_dir_path:
-            shutil.rmtree(task_dir_path, ignore_errors=True)
         api_service.logger.error(f"单曲下载失败: {task_id} {e}")
+        _fail_single_task(task_id, 'error', str(e), 'error', task_dir_path)
     except Exception as e:
         # 非预期异常的 repr 可能含上游主机/连接细节——用户可见文案
         # 泛化为固定文案，原文 logger 先行留档（教训：先记录再泛化）
         api_service.logger.error(f"单曲下载异常: {task_id} {e}\n{traceback.format_exc()}")
-        _mark_task_terminal(task_id, 'error', '下载失败，请稍后重试')
+        _fail_single_task(task_id, 'error', '下载失败，请稍后重试', 'error', task_dir_path)
-        try:
-            auth_system.ledger_settle(task_id, 0, 'error')
-        except Exception:
-            pass
-        if task_dir_path:
-            shutil.rmtree(task_dir_path, ignore_errors=True)

tests/test_single_worker.py

@@ -0,0 +1,580 @@
+# -*- coding: utf-8 -*-
+"""单曲下载 worker 的行为契约测试（沙箱，不触碰生产 data/）。
+
+为什么：``services/downloads.py::_single_download_worker`` 是单曲下载的**唯一**后台
+执行路径（``/download`` 的 file 模式走 ``start_task`` 启动它），177 行 / 圈复杂度 30，
+此前**零测试覆盖**。它的三个 except 分支各写一遍「结算 + 删任务目录」，正文里又散着
+四处取消检查——改坏任意一处都不会有测试报警。
+
+按惯例：**先在未改动的原始实现上跑绿**，这批测试因此忠实编码了旧行为，重构时本身
+即等价性验证器。断言只依赖「调用 worker 后世界里发生了什么」（任务终态、磁盘上的
+文件、ZIP 内容、账本行、余额），不引用任何内部函数名，故可跨后续重构复用。
+
+账本口径：一律用 ``reserve_and_open`` 真预扣（``ledger_open`` 只记账不扣款，
+会让「退款」凭空给余额加次数，守恒断言就失去意义）。
+"""
+import threading
+import time
+import zipfile
+from pathlib import Path
+from typing import Any
+
+import pytest
+
+import auth_system as auth
+import core.db as core_db
+from core.state import DOWNLOAD_TASKS, DOWNLOAD_TASKS_LOCK
+from music_downloader import DownloadCanceled, DownloadResult, MusicInfo
+from services import downloads as downloads_svc
+from services.api_service import api_service
+
+PW = 'Passw0rd12'
+CREDITS = 50
+
+
+# ============ 测试替身 ============
+
+class _NullLogger:
+    """吞掉 api_service.logger 输出，避免测试往项目根 music_api.log 追加。"""
+
+    def debug(self, *a: Any, **k: Any) -> None: ...
+    def info(self, *a: Any, **k: Any) -> None: ...
+    def warning(self, *a: Any, **k: Any) -> None: ...
+    def error(self, *a: Any, **k: Any) -> None: ...
+
+
+class _FakeDownloader:
+    """可编程下载器替身。
+
+    ``on_download`` 在 ``download_music_file`` 内部被调用，拿到调用时的 kwargs，
+    用于在「下载中途」注入取消 / 调用进度回调 / 抛异常。
+    ``info_error`` 让 ``get_music_info`` 抛异常（验证未知异常路径）。
+    """
+
+    def __init__(self, cache_dir: Path, *, download_ok: bool = True,
+                 info_error: Exception | None = None,
+                 on_download: Any = None, lyric: str = '[00:01.00]第一行\n[00:02.00]第二行'):
+        self.cache_dir = cache_dir
+        self.download_ok = download_ok
+        self.info_error = info_error
+        self.on_download = on_download
+        self.lyric = lyric
+        self.info_calls = 0
+        self.download_calls = 0
+
+    def get_music_info(self, mid: Any, quality: str, cookies: Any) -> MusicInfo:
+        self.info_calls += 1
+        if self.info_error is not None:
+            raise self.info_error
+        return MusicInfo(
+            id=int(mid), name='歌名X', artists='歌手A', album='专辑A',
+            pic_url='https://pic.example/x.jpg', duration=200, track_number=1,
+            download_url='', file_type='mp3', file_size=1024,
+            quality='standard', lyric=self.lyric,
+        )
+
+    def download_music_file(self, mid: Any, quality: str, **kw: Any) -> DownloadResult:
+        self.download_calls += 1
+        if self.on_download is not None:
+            self.on_download(kw)
+        cancel_ev = kw.get('cancel_event')
+        if cancel_ev is not None and cancel_ev.is_set():
+            raise DownloadCanceled('任务已取消')
+        if not self.download_ok:
+            return DownloadResult(success=False, error_message='上游 404')
+        path = self.cache_dir / f'{mid}.mp3'
+        path.write_bytes(b'ID3\x03\x00\x00\x00' + b'\x00' * 64)
+        return DownloadResult(success=True, file_path=str(path),
+                              file_size=path.stat().st_size, music_info=kw.get('music_info'))
+
+
+# ============ 沙箱 ============
+
+@pytest.fixture()
+def sandbox(tmp_path, monkeypatch):
+    """临时站点库 + 临时下载目录 + 空任务表。"""
+    db_path = tmp_path / 'site.db'
+    monkeypatch.setattr(auth.db, 'DATA_DIR', tmp_path)
+    monkeypatch.setattr(auth.db, 'DB_PATH', db_path)
+    monkeypatch.setattr(auth.db, 'BACKUP_DIR', tmp_path / 'backups')
+    monkeypatch.setattr(auth.db, 'SECRET_KEY_PATH', tmp_path / 'secret.key')
+    monkeypatch.setattr(core_db, 'DATA_DIR', tmp_path)
+    monkeypatch.setattr(core_db, 'DB_PATH', db_path)
+    auth.init_db()
+    auth.create_user('payer', PW, email='p@example.com', credits=CREDITS)
+
+    downloads = tmp_path / 'downloads'
+    downloads.mkdir()
+    cache = downloads / 'cache'
+    cache.mkdir()
+    monkeypatch.setattr(api_service, 'downloads_path', downloads)
+    monkeypatch.setattr(api_service, 'logger', _NullLogger())
+    # 封面走网络——测试里默认返回固定字节，个例可覆盖
+    monkeypatch.setattr(downloads_svc, 'fetch_cover_bytes', lambda url: b'\xff\xd8\xff cover')
+    # 操作记录写进程内共享列表——隔离掉，断言改由个例捕获
+    monkeypatch.setattr(downloads_svc, '_record_log', lambda *a: None)
+
+    with DOWNLOAD_TASKS_LOCK:
+        DOWNLOAD_TASKS.clear()
+    yield {'root': tmp_path, 'downloads': downloads, 'cache': cache}
+    with DOWNLOAD_TASKS_LOCK:
+        DOWNLOAD_TASKS.clear()
+
+
+# ============ 工具 ============
+
+def _uid(username: str = 'payer') -> int:
+    u = auth.get_user_by_name(username)
+    assert u is not None
+    return int(u['id'])
+
+
+def _balance(username: str = 'payer') -> int:
+    u = auth.get_user_by_name(username)
+    assert u is not None
+    return int(u['duration_seconds'] or 0)
+
+
+def _status(task_id: str) -> str:
+    with DOWNLOAD_TASKS_LOCK:
+        return str(DOWNLOAD_TASKS.get(task_id, {}).get('status') or '')
+
+
+def _register_single(sandbox, *, music_id: int = 1, user_id: int,
+                     reserved: int = 1, **params: Any) -> tuple[str, dict[str, Any]]:
+    tid = 's' + str(int(time.time() * 1000000) % 10 ** 10)
+    # reserve_and_open：真预扣 + 开账同事务（ledger_open 只记账不扣款，见模块 docstring）
+    left = auth.reserve_and_open(user_id, reserved, tid)
+    assert left is not None, '预扣失败（余额不足，检查 fixture 的 credits）'
+    task: dict[str, Any] = {
+        'type': 'single', 'task_id': tid,
+        'user_id': user_id, 'billing_user_id': user_id, 'billing_reserved': reserved,
+        'total': 1, 'done': 0, 'failed': 0,
+        'status': 'queued', 'start': time.time(), 'msg': '排队中...',
+        'cancel': threading.Event(), 'pause': threading.Event(),
+        'device_id': 'dev-test', 'result': None,
+        'params': {
+            'music_id': music_id, 'quality': 'standard',
+            'filename_format': 'artist_song', 'write_meta': False,
+            'meta_fields': None, 'lyric_format': 'lrc',
+            'need_zip': False, 'cookies': {}, 'remote_ip': '1.2.3.4',
+            **params,
+        },
+    }
+    with DOWNLOAD_TASKS_LOCK:
+        DOWNLOAD_TASKS[tid] = task
+    return tid, task
+
+
+def _run(task_id: str) -> threading.Thread:
+    th = threading.Thread(target=downloads_svc._single_download_worker,
+                          args=(task_id,), daemon=True)
+    th.start()
+    return th
+
+
+def _zip_names(path: str) -> list[str]:
+    with zipfile.ZipFile(path) as zf:
+        return zf.namelist()
+
+
+# ============ 正常路径 ============
+
+def test_single_download_completes(sandbox, monkeypatch):
+    """常规单曲（不打包）：终态 done、交付文件落在任务目录、账本按交付结算。"""
+    uid = _uid()
+    before = _balance()
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    tid, task = _register_single(sandbox, music_id=101, user_id=uid)
+
+    th = _run(tid)
+    th.join(timeout=30)
+    assert not th.is_alive(), 'worker 未在 30s 内结束'
+
+    assert _status(tid) == 'done', f"终态={_status(tid)} msg={task.get('msg')}"
+    assert task['msg'] == '下载完成'
+    assert task['done'] == 1 and task['completed_at'] > 0
+    res = task['result']
+    assert res is not None
+    assert res['filename'] == '歌手A - 歌名X.mp3'
+    assert res['mimetype'] == 'audio/mp3'
+    assert res['audio_files'] == [res['file_path']]
+    assert 'zip_path' not in res
+
+    # 交付副本在 tasks/<tid>/ 下，与共享缓存分离
+    delivered = Path(res['file_path'])
+    assert delivered.exists()
+    assert delivered.parent == sandbox['downloads'] / 'tasks' / tid
+    assert delivered.read_bytes() == (sandbox['cache'] / '101.mp3').read_bytes()
+    assert (sandbox['cache'] / '101.mp3').exists(), '共享缓存不应被搬走'
+
+    row = auth.ledger_get(tid)
+    assert row is not None and row['status'] != 'open'
+    assert row['delivered'] == 1
+    assert _balance() == before - 1, '交付成功：只扣预扣的 1 次，无退款'
+
+
+def test_single_zip_contains_audio_lyric_cover_and_info(sandbox, monkeypatch):
+    """zip=true：包内含音频 + 歌词 + 封面 + info.txt（信息栏四行）。"""
+    uid = _uid()
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    tid, task = _register_single(sandbox, music_id=102, user_id=uid, need_zip=True)
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done', f"终态={_status(tid)} msg={task.get('msg')}"
+    res = task['result']
+    assert res is not None
+    assert res['filename'] == '歌手A - 歌名X.zip'
+    assert res['mimetype'] == 'application/zip'
+    names = sorted(_zip_names(res['zip_path']))
+    assert names == ['info.txt', '歌手A - 歌名X.jpg', '歌手A - 歌名X.lrc', '歌手A - 歌名X.mp3'], names
+
+    with zipfile.ZipFile(res['zip_path']) as zf:
+        info = zf.read('info.txt').decode('utf-8')
+    assert '歌曲: 歌名X' in info
+    assert '歌手: 歌手A' in info
+    assert '专辑: 专辑A' in info
+    assert info.startswith('歌曲: ')
+
+
+def test_single_zip_lyric_format_srt(sandbox, monkeypatch):
+    """lyric_format=srt：歌词条目扩展名随之改变。"""
+    uid = _uid()
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    tid, task = _register_single(sandbox, music_id=103, user_id=uid,
+                                 need_zip=True, lyric_format='srt')
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done'
+    assert '歌手A - 歌名X.srt' in _zip_names(task['result']['zip_path'])
+
+
+def test_empty_lyric_skips_lyric_entry(sandbox, monkeypatch):
+    """上游无歌词（mi.lyric 为空）：不写歌词条目，其余照常。"""
+    uid = _uid()
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], lyric=''))
+    tid, task = _register_single(sandbox, music_id=104, user_id=uid, need_zip=True)
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done'
+    names = _zip_names(task['result']['zip_path'])
+    assert not [n for n in names if n.endswith('.lrc')], names
+    assert [n for n in names if n.endswith('.mp3')], names
+
+
+def test_cover_failure_keeps_zip_without_cover(sandbox, monkeypatch):
+    """取封面失败：ZIP 仍发布，只是没有封面条目（封面非交付必要条件）。
+
+    注意 ``fetch_cover_bytes`` 的契约是**失败返回 None**（内部已 except Exception），
+    所以这里注入的是返回 None，不是抛异常——后者是不存在的形状。
+    """
+    uid = _uid()
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    monkeypatch.setattr(downloads_svc, 'fetch_cover_bytes', lambda url: None)
+    tid, task = _register_single(sandbox, music_id=105, user_id=uid, need_zip=True)
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done', f"终态={_status(tid)} msg={task.get('msg')}"
+    names = _zip_names(task['result']['zip_path'])
+    assert not [n for n in names if n.endswith('.jpg')], names
+
+
+def test_filename_format_song_only(sandbox, monkeypatch):
+    """filename_format=song：交付名只用歌名。"""
+    uid = _uid()
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    tid, task = _register_single(sandbox, music_id=106, user_id=uid,
+                                 filename_format='song')
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done'
+    assert task['result']['filename'] == '歌名X.mp3'
+
+
+def test_record_log_gets_song_name(sandbox, monkeypatch):
+    """成功交付后按歌名记一条操作记录（IP 取 params.remote_ip）。"""
+    uid = _uid()
+    logs: list[tuple] = []
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    monkeypatch.setattr(downloads_svc, '_record_log', lambda *a: logs.append(a))
+    tid, _ = _register_single(sandbox, music_id=107, user_id=uid)
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert logs == [('下载', '1.2.3.4', '歌名X')], logs
+
+
+def test_remote_ip_defaults_when_missing(sandbox, monkeypatch):
+    """params 无 remote_ip：按 '-' 记录，不因缺字段报错。"""
+    uid = _uid()
+    logs: list[tuple] = []
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    monkeypatch.setattr(downloads_svc, '_record_log', lambda *a: logs.append(a))
+    tid, task = _register_single(sandbox, music_id=108, user_id=uid)
+    del task['params']['remote_ip']
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done'
+    assert logs == [('下载', '-', '歌名X')]
+
+
+# ============ 失败与取消 ============
+
+def test_download_failure_marks_error_and_refunds(sandbox, monkeypatch):
+    """下载器返回 success=False：转 error、全额退回预扣、任务目录不残留。"""
+    uid = _uid()
+    before = _balance()
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], download_ok=False))
+    tid, task = _register_single(sandbox, music_id=201, user_id=uid)
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'error', f"终态={_status(tid)} msg={task.get('msg')}"
+    assert task['msg'] == '上游 404'
+    assert task['result'] is None
+    assert _balance() == before, '失败应全额退回预扣'
+    row = auth.ledger_get(tid)
+    assert row is not None and row['delivered'] == 0 and row['status'] != 'open'
+    assert not (sandbox['downloads'] / 'tasks' / tid).exists(), '失败应清掉任务目录'
+
+
+def test_unexpected_exception_uses_generic_message(sandbox, monkeypatch):
+    """非预期异常：用户可见文案泛化（不泄上游细节），原文进日志、余额退回。"""
+    uid = _uid()
+    before = _balance()
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'],
+                                        info_error=RuntimeError('upstream host=10.0.0.9 refused')))
+    tid, task = _register_single(sandbox, music_id=202, user_id=uid)
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'error', f"终态={_status(tid)}"
+    assert task['msg'] == '下载失败，请稍后重试'
+    assert '10.0.0.9' not in task['msg'], '上游细节不得出现在用户可见文案里'
+    assert _balance() == before
+    assert not (sandbox['downloads'] / 'tasks' / tid).exists()
+
+
+def test_cancel_mid_download(sandbox, monkeypatch):
+    """下载中被取消：worker 收敛 canceled、全额退费、任务目录清掉。"""
+    uid = _uid()
+    before = _balance()
+    holder: dict[str, Any] = {}
+
+    def _cancel_inside(kw):
+        holder['task']['cancel'].set()
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_cancel_inside))
+    tid, task = _register_single(sandbox, music_id=203, user_id=uid)
+    holder['task'] = task
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'canceled', f"终态={_status(tid)} msg={task.get('msg')}"
+    assert task['msg'] == '任务已取消'
+    assert task['result'] is None
+    assert _balance() == before, '取消应全额退回预扣'
+    row = auth.ledger_get(tid)
+    assert row is not None and row['delivered'] == 0
+    assert not (sandbox['downloads'] / 'tasks' / tid).exists()
+
+
+def test_cancel_after_download_before_publish(sandbox, monkeypatch):
+    """下载已落盘但取消已置位：不发布交付（不发布 result），转 canceled 并退费。"""
+    uid = _uid()
+    before = _balance()
+    holder: dict[str, Any] = {}
+
+    def _cancel_after(kw):
+        # 下载返回之后再置位——命中「下载完成后的取消检查」
+        def _later():
+            holder['task']['cancel'].set()
+
+        threading.Timer(0.0, _later).start()
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_cancel_after))
+    tid, task = _register_single(sandbox, music_id=204, user_id=uid)
+    holder['task'] = task
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'canceled', f"终态={_status(tid)} msg={task.get('msg')}"
+    assert task['result'] is None, '取消后不得发布交付'
+    assert _balance() == before
+    assert not (sandbox['downloads'] / 'tasks' / tid).exists()
+
+
+def test_cancel_during_zip_stage(sandbox, monkeypatch):
+    """打包阶段被取消：ZIP 不发布、转 canceled、退费。"""
+    uid = _uid()
+    before = _balance()
+    holder: dict[str, Any] = {}
+
+    def _cancel_after(kw):
+        threading.Timer(0.0, lambda: holder['task']['cancel'].set()).start()
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_cancel_after))
+    tid, task = _register_single(sandbox, music_id=205, user_id=uid, need_zip=True)
+    holder['task'] = task
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'canceled', f"终态={_status(tid)} msg={task.get('msg')}"
+    assert task['result'] is None
+    assert _balance() == before
+    assert not (sandbox['downloads'] / 'tasks' / tid).exists()
+
+
+def test_terminal_state_not_overwritten_by_late_success(sandbox, monkeypatch):
+    """任务已被外部置终态（canceled）时，worker 的成功路径不得覆盖为 done。"""
+    uid = _uid()
+    before = _balance()
+    holder: dict[str, Any] = {}
+
+    def _mark_canceled(kw):
+        with DOWNLOAD_TASKS_LOCK:
+            holder['task']['status'] = 'canceled'
+            holder['task']['completed_at'] = time.time()
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_mark_canceled))
+    tid, task = _register_single(sandbox, music_id=206, user_id=uid)
+    holder['task'] = task
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'canceled', f"终态={_status(tid)}"
+    assert task['result'] is None, '已终态不得被覆盖为 done'
+    assert _balance() == before
+
+
+# ============ 进度上报 ============
+
+def test_progress_callback_writes_live_percent(sandbox, monkeypatch):
+    """进度回调写 live_percent 与「下载中 x% · 已收/总量」文案。"""
+    uid = _uid()
+    seen: dict[str, Any] = {}
+
+    def _emit_progress(kw):
+        cb = kw.get('progress_cb')
+        if cb is not None:
+            cb(512, 1024)
+            with DOWNLOAD_TASKS_LOCK:
+                t = DOWNLOAD_TASKS.get(seen['tid']) or {}
+                seen['live'] = t.get('live_percent')
+                seen['msg'] = t.get('msg')
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_emit_progress))
+    tid, _task = _register_single(sandbox, music_id=301, user_id=uid)
+    seen['tid'] = tid
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert seen.get('live') == 50.0, seen
+    assert '下载中 50%' in str(seen.get('msg')), seen
+    assert _status(tid) == 'done', '进度上报不应影响最终交付'
+
+
+def test_progress_callback_without_total_uses_received_bytes(sandbox, monkeypatch):
+    """总量未知：文案退化为「已接收 <大小>」，不写 live_percent。"""
+    uid = _uid()
+    seen: dict[str, Any] = {}
+
+    def _emit_progress(kw):
+        cb = kw.get('progress_cb')
+        if cb is not None:
+            cb(2048, 0)
+            with DOWNLOAD_TASKS_LOCK:
+                t = DOWNLOAD_TASKS.get(seen['tid']) or {}
+                seen['live'] = t.get('live_percent')
+                seen['msg'] = t.get('msg')
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_emit_progress))
+    tid, _task = _register_single(sandbox, music_id=302, user_id=uid)
+    seen['tid'] = tid
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert '已接收' in str(seen.get('msg')), seen
+    assert seen.get('live') is None, seen
+
+
+def test_progress_callback_errors_do_not_break_download(sandbox, monkeypatch):
+    """进度回调自身抛错：被吞掉，下载照常完成。"""
+    uid = _uid()
+
+    def _bad_progress(kw):
+        cb = kw.get('progress_cb')
+        if cb is not None:
+            # 回调内部访问非法对象——必须被 except 吞掉
+            cb('not-a-number', None)
+
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'], on_download=_bad_progress))
+    tid, task = _register_single(sandbox, music_id=303, user_id=uid)
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done', f"终态={_status(tid)} msg={task.get('msg')}"
+
+
+# ============ 结算兜底 ============
+
+def test_settle_failure_does_not_flip_done_to_error(sandbox, monkeypatch):
+    """交付已落定后结算抛错：任务仍为 done（钱由重启对账兜底，不坑已付费用户）。"""
+    uid = _uid()
+
+    def _boom(*a, **k):
+        raise RuntimeError('库锁超时')
+
+    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader(sandbox['cache']))
+    monkeypatch.setattr(downloads_svc.auth_system, 'ledger_settle', _boom)
+    tid, task = _register_single(sandbox, music_id=401, user_id=uid)
+
+    th = _run(tid)
+    th.join(timeout=30)
+
+    assert _status(tid) == 'done', f"终态={_status(tid)} msg={task.get('msg')}"
+    assert task['result'] is not None
+
+
+def test_ledger_open_when_worker_crashes_before_settle(sandbox, monkeypatch):
+    """worker 在结算前崩掉：账本行仍为 open（留给重启对账兜底，不是静默丢失）。"""
+    uid = _uid()
+    monkeypatch.setattr(api_service, 'downloader',
+                        _FakeDownloader(sandbox['cache'],
+                                        info_error=RuntimeError('boom')))
+    tid, _ = _register_single(sandbox, music_id=402, user_id=uid)
+
+    # 让结算也失败，模拟「连退款都没走成」的极端情况
+    monkeypatch.setattr(downloads_svc.auth_system, 'ledger_settle',
+                        lambda *a, **k: (_ for _ in ()).throw(RuntimeError('db busy')))
+    th = _run(tid)
+    th.join(timeout=30)
+
+    row = auth.ledger_get(tid)
+    assert row is not None
+    assert row['status'] == 'open', f"应留给对账兜底，实际 status={row['status']}"