NeteaseUrl/services/runtime.py

# -*- coding: utf-8 -*-
"""网易云音乐API服务主程序

提供网易云音乐相关API服务，包括：
- 歌曲信息获取
- 音乐搜索
- 歌单和专辑详情
- 音乐下载
- 健康检查
"""

import collections
import logging
import os
import re
import shutil
import sys
import threading
import time
import traceback
import zipfile
from pathlib import Path
from typing import Any
from urllib.parse import parse_qs, urlsplit

try:
    import auth_system
    import podcast_api
    from music_api import (
        APIException,
        NeteaseAPI,
        account_info,
        detect_vip_by_probe,
        load_cookies,
    )
    from music_downloader import (
        CountingSemaphore,
        DownloadCanceled,
        DownloadException,
        MusicDownloader,
        fetch_cover_bytes,
    )
    from qr_login import QRLoginClient
except ImportError as e:
    # 坑 11：导入失败发生在 _safe_console_print 定义之前，用纯 ASCII 保证任何编码下可打印
    print("ImportError: " + str(e))
    print("Please make sure all dependency modules exist and are importable.")
    sys.exit(1)


# ============ 框架无关核心层（core/）============
# 常量/配置、运行时状态、纯工具、音频签名已迁出至 core 包，以**同一对象/同一实现**
# 供 Flask 与迁移目标 FastAPI 共用。此处以原名称再导出（别名），既有 250+ 调用点零改动。
# QRLoginManager 等已异步化的上游方法，Flask 同步路由经 run_sync 桥接调用。
from core.config import (
    BATCH_ZIP_CONCURRENCY,
    CANCEL_AFTER_SECONDS,
    HEARTBEAT_INTERVAL,
    PAUSE_AFTER_SECONDS,
    RESULT_RETENTION_SECONDS,
    USER_COOKIE_FILE,
    Settings,
)
from core.state import (
    BATCH_DURATIONS,
    BATCH_DURATIONS_LOCK,
    DEVICE_LAST_SEEN,
    DEVICE_LAST_SEEN_LOCK,
    DOWNLOAD_TASKS,
    DOWNLOAD_TASKS_LOCK,
    REQ_LOG,
)
from core.state import GLOBAL_MUSIC_U_CACHE as _GLOBAL_MUSIC_U_CACHE
from core.state import RATE_BUCKETS as _RATE_BUCKETS
from core.state import RATE_LOCK as _RATE_LOCK
from core.state import VIP_PROBE_LOCK as _VIP_PROBE_LOCK
from core.utils import expand_shortlink as _expand_shortlink
from core.utils import format_lyric as _format_lyric

# 向后兼容别名：既有代码/文档沿用 APIConfig 名称
APIConfig = Settings


class APIResponse:
    """API响应工具类"""

    @staticmethod
    def success(data: Any = None, message: str = 'success', status_code: int = 200) -> tuple[dict[str, Any], int]:
        """成功响应"""
        response = {
            'status': status_code,
            'success': True,
            'message': message
        }
        if data is not None:
            response['data'] = data
        return response, status_code

    @staticmethod
    def error(message: str, status_code: int = 400, error_code: str | None = None) -> tuple[dict[str, Any], int]:
        """错误响应"""
        response = {
            'status': status_code,
            'success': False,
            'message': message
        }
        if error_code:
            response['error_code'] = error_code
        return response, status_code


class MusicAPIService:
    """音乐API服务类"""

    def __init__(self, config: APIConfig):
        self.config = config
        self.logger = self._setup_logger()
        self.netease_api = NeteaseAPI()
        # F97：下载目录传给下载器——原实现下载器固定 downloads，
        # 服务配置指向自定义目录时音乐落盘位置与配置分离
        self.downloader = MusicDownloader(download_dir=config.downloads_dir)

        # 创建下载目录
        self.downloads_path = Path(config.downloads_dir)
        self.downloads_path.mkdir(exist_ok=True)

        self.logger.info(f"音乐API服务初始化完成，下载目录: {self.downloads_path.absolute()}")

    def _setup_logger(self) -> logging.Logger:
        """设置日志记录器"""
        logger = logging.getLogger('music_api')
        logger.setLevel(getattr(logging, self.config.log_level.upper()))

        if not logger.handlers:
            # 控制台处理器
            console_handler = logging.StreamHandler()
            console_formatter = logging.Formatter(
                '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
            )
            console_handler.setFormatter(console_formatter)
            logger.addHandler(console_handler)

            # 文件处理器（轮转：单文件 5MB，保留 3 份，防止长期运行无限膨胀）
            try:
                from logging.handlers import RotatingFileHandler
                file_handler = RotatingFileHandler('music_api.log', maxBytes=5 * 1024 * 1024,
                                                   backupCount=3, encoding='utf-8')
                file_formatter = logging.Formatter(
                    '%(asctime)s - %(name)s - %(levelname)s - %(funcName)s:%(lineno)d - %(message)s'
                )
                file_handler.setFormatter(file_formatter)
                logger.addHandler(file_handler)
            except Exception as e:
                logger.warning(f"无法创建日志文件: {e}")

        return logger

    def _get_cookies(self) -> dict[str, str]:
        """直接从 cookie.txt 读取并解析为 dict"""
        try:
            cookies = load_cookies()
            if not cookies:
                self.logger.warning("cookie.txt 为空或不存在，部分接口（VIP 音质）将不可用")
            return cookies
        except Exception as e:
            self.logger.error(f"读取 cookie.txt 异常: {e}")
            return {}

    def _extract_music_id(self, id_or_url: str) -> str:
        """提取音乐ID（F7/F74：正规 URL 解析替代子串/删除非数字启发式）
        - 短链仅当整串就是一个 163cn.tv 短链 URL 时才请求展开（防 SSRF）
        - music.163.com 链接用 parse_qs 取 id 参数（参数顺序无关）
        """
        raw = str(id_or_url or '').strip()
        try:
            # 短链展开：仅接受"整个输入就是 163cn.tv 链接"（F7：子串包含不算）
            if re.match(r'^https?://(www\.)?163cn\.tv/\S+$', raw, re.IGNORECASE):
                raw = _expand_shortlink(raw)

            # 网易云链接：正规解析 query 取 id（F74：不再 find('id=') 误吃 userid= 尾部）
            if 'music.163.com' in raw:
                try:
                    q = parse_qs(urlsplit(raw).query)
                    for key in ('id', 'songid'):
                        if q.get(key):
                            return str(q[key][0]).strip()
                except Exception:
                    pass
                # 兜底：老格式 #/song?id=xxx 的片段部分
                m = re.search(r'[?&#]id=(\d+)', raw)
                if m:
                    return m.group(1)

            # 纯数字/普通文本直接返回
            return raw
        except Exception as e:
            self.logger.error(f"提取音乐ID失败: {e}")
            return str(id_or_url or '').strip()

    def _format_file_size(self, size_bytes) -> str:
        """格式化文件大小（上游 size 可能为 null/垃圾值：容错返回"大小未知"而非 500）"""
        try:
            size = float(size_bytes or 0)
        except (TypeError, ValueError):
            return "大小未知"
        if size <= 0:
            return "0B"

        units = ["B", "KB", "MB", "GB", "TB"]
        unit_index = 0

        while size >= 1024.0 and unit_index < len(units) - 1:
            size /= 1024.0
            unit_index += 1

        return f"{size:.2f}{units[unit_index]}"

    def _get_quality_display_name(self, quality: str) -> str:
        """获取音质显示名称"""
        quality_names = {
            'standard': "标准音质",
            'exhigh': "极高音质",
            'lossless': "无损音质",
            'hires': "Hi-Res音质",
            'sky': "沉浸环绕声",
            'jyeffect': "高清环绕声",
            'jymaster': "超清母带",
            'dolby': "杜比全景声"
        }
        return quality_names.get(quality, f"未知音质({quality})")


def _quiesce_tasks_for_restore() -> None:
    """S5：恢复数据库前取消全部在途任务（worker 不再引用旧库用户结算）"""
    with DOWNLOAD_TASKS_LOCK:
        for task in DOWNLOAD_TASKS.values():
            if task.get('status') in ('queued', 'running', 'paused'):
                task['status'] = 'canceled'
                task['msg'] = '数据库恢复中，任务已取消（费用按实际交付结算）'
                task['completed_at'] = time.time()
                try:
                    task['cancel'].set()
                except Exception:
                    pass

# 数据库恢复前静默在途任务（与 Flask 版同口径）
auth_system.register_before_restore_hook(_quiesce_tasks_for_restore)

# 服务实例（框架无关）
config = APIConfig()
api_service = MusicAPIService(config)



def _rate_ok(key: str, limit: int, window: int) -> bool:
    """滑动窗口限流：True=放行，False=超限"""
    now = time.time()
    with _RATE_LOCK:
        dq = _RATE_BUCKETS.get(key)
        if dq is None:
            # 桶数量防膨胀：超限时清理不活跃桶
            if len(_RATE_BUCKETS) > 8000:
                for k in [k for k, v in _RATE_BUCKETS.items() if not v or now - v[-1] > window]:
                    _RATE_BUCKETS.pop(k, None)
            dq = collections.deque()
            _RATE_BUCKETS[key] = dq
        while dq and now - dq[0] > window:
            dq.popleft()
        if len(dq) >= limit:
            return False
        dq.append(now)
        return True

# 旧版管理员口令已废除（2026-09-15）：管理员权限仅认站点管理员会话（admin 登录），
# 见 _verify_admin_password。管理后台（/admin/site/*）与旧版二维码接口（/admin/qr/*）
# 均通过该会话鉴权。

# 全局批量打包并发信号量：限制同时构建的批量 ZIP 数量。
# 大量用户同时批量下载时，超出的请求排队等待，避免磁盘/内存/CPU 被同时占满。
# （下载本身的并发已由下载器内的全局信号量控制）
# 使用带计数的信号量，供前端实时展示排队人数与预计等待时间。
# 注：信号量依赖下载器的 CountingSemaphore，属服务层对象，随下载服务搬迁，
# 暂留 main（并发上限 3 见 core.config.BATCH_ZIP_CONCURRENCY）。
BATCH_ZIP_SEM = CountingSemaphore(BATCH_ZIP_CONCURRENCY)


def _start_task_thread(task_id: str, target, args=()) -> str | None:
    """启动任务 worker（F90：启动失败时收敛任务终态并按账本退费，不留僵尸 queued 记录）。
    A2：退款只走账本（本处 settle 后装饰器看到账已关，不会重复退）。
    R5-14：线程句柄存入任务字典——监控循环对 4h 超时任务若发现 worker 线程已死
    （无法自行走到终态结算），可代为按账本结算退款（settle 幂等，无双退）。"""
    try:
        th = threading.Thread(target=target, args=args, daemon=True)
        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS.get(task_id)
            if t is not None:
                t['worker_thread'] = th
        th.start()
        return None
    except Exception as e:
        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS.pop(task_id, None)
        if t:
            try:
                auth_system.ledger_settle(task_id, 0, 'submit_failed')
            except Exception:
                pass
        api_service.logger.error(f"任务线程启动失败: {task_id} {e}")
        return f'任务启动失败：{e}'


def _mark_task_terminal(task_id: str, status: str, msg: str = '') -> None:
    """任务进入终态的统一入口（F38：记录 completed_at，保留期从完成时刻起算，
    而不是从提交时刻起算）。
    R5-14/F-E：置 error/canceled 终态时若 worker 线程已死（无人再走正常结算），
    代为按账本结算退款——ledger_settle 幂等，worker 已自行结算过则此处为 0。
    第 100 条（T1 不变量）：终态先到先得——已终态（done/error/canceled）的任务
    不再被覆盖（堵住 canceled→error 的非法迁移边：取消后解析阶段的自身失败
    不得把"已取消"改写成"失败"，completed_at 也不再刷新）。"""
    need_settle = False
    with DOWNLOAD_TASKS_LOCK:
        t = DOWNLOAD_TASKS.get(task_id)
        if t and t.get('status') in ('done', 'error', 'canceled'):
            return
        if t:
            t['status'] = status
            t['msg'] = msg or t.get('msg', '')
            t['completed_at'] = time.time()
            if status in ('canceled', 'error'):
                th = t.get('worker_thread')
                if th is not None and not th.is_alive():
                    need_settle = True
    # 第 97 条（P2-3）：settle 移到任务锁外——ledger_settle 内部要抢 _DB_LOCK 写库
    # （busy 最长 15s），持任务锁调用会让全站进度/提交/取消/领取随库停摆；
    # settle 幂等，锁外调用无双退
    if need_settle:
        try:
            auth_system.ledger_settle(task_id, 0, status)
        except Exception:
            pass


def _task_files(task: dict[str, Any]) -> list[str]:
    """任务当前关联的可清理文件路径（交付 ZIP/交付副本；缓存文件不在此列）"""
    result = task.get('result') or {}
    files = []
    for f in (result.get('zip_path'), result.get('file_path')):
        if f:
            files.append(f)
    return files


def _sweep_download_cache(max_age_seconds: int = RESULT_RETENTION_SECONDS) -> None:
    """下载缓存清扫（F27 配套：批量任务不再即时删除共享缓存，改由这里按年龄回收）。
    只清扫 downloads 根目录的普通文件，不碰 tasks/ 子目录（那是任务专属交付物）。"""
    try:
        root = api_service.downloads_path
        now = time.time()
        for p in root.iterdir():
            try:
                if p.is_file() and now - p.stat().st_mtime > max_age_seconds:
                    p.unlink()
            except OSError:
                pass
    except Exception:
        pass


_MONITOR_ERR_TS = {'ts': 0.0, 'n': 0}   # 监控线程异常限频记录（持续异常不静默也不刷屏）
# 第 95 条（P1-1）：监控线程周期兜底的三个节流字典——第 94 条补丁时定义丢失
# （只剩使用），NameError 被外层 except 吞成 WARNING，孤儿对账/账本清理/tasks
# 补扫自那以后从未执行（music_api.log 实证 2064 条 WARNING）。红转绿：重启后
# 日志零 NameError 且对账真实运行。
_LEDGER_LAST_RECOVER = {'ts': 0.0}     # 上次孤儿账本对账时间（每 60s 一次）
_LEDGER_LAST_CLEANUP = {'ts': 0.0}    # 上次 settled 账本 90 天清理时间（每 24h 一次）
_TASKS_SWEEP_LAST = {'ts': 0.0}       # 上次 tasks/ 孤儿目录补扫时间（每小时一次）


def _task_monitor_loop() -> None:
    """后台监控：
    - 心跳超时（40s）→ 暂停离线设备的批量任务，释放排队名额给下一位
    - 心跳超时 > 30 分钟 → 自动取消该设备的所有未完成任务并清理文件
    - 终态任务按 completed_at 保留 35 分钟（F38/P1-3：与前端「领取」入口对齐）
    - 运行中/排队/暂停任务超过 4 小时仍未结束 → 置取消（F38：cancel Event 一并置位）
    - 下载缓存按年龄清扫（F27 配套，同为 35 分钟口径）
    - 顺带清理限流桶中的过期项（O-5：不再只依赖"新建桶时"的清理时机）
    """
    while True:
        time.sleep(HEARTBEAT_INTERVAL)
        try:
            now = time.time()
            # ---- 终态任务清理（F38/F106：按完成时刻；删除失败保留记录下轮重试，最多 8 次）----
            # 第 91 条（P2-1）：锁内只收集过期清单，文件删除移到锁外——GB 级任务目录
            # 的删除曾阻塞锁数十秒，期间全站进度上报/提交/取消/领取全部停摆
            finished_done: list[str] = []
            finished_retry: list[str] = []
            expired: list[tuple] = []
            with DOWNLOAD_TASKS_LOCK:
                for tid, task in DOWNLOAD_TASKS.items():
                    if task.get('status') not in ('done', 'error', 'canceled'):
                        continue
                    done_at = task.get('completed_at') or 0
                    # 兼容无 completed_at 的旧记录：回退到 start
                    if not done_at:
                        done_at = task.get('start', 0)
                    if now - done_at <= RESULT_RETENTION_SECONDS:
                        continue
                    expired.append((tid, _task_files(task),
                                    api_service.downloads_path / 'tasks' / tid))
            cleanup_results: list[tuple] = []
            for tid, files, task_dir in expired:
                all_removed = True
                for f in files:
                    try:
                        os.remove(f)
                    except FileNotFoundError:
                        pass
                    except OSError:
                        all_removed = False   # F106：文件暂时不可删（被占用等）
                if task_dir.exists():
                    shutil.rmtree(str(task_dir), ignore_errors=True)
                    if task_dir.exists():
                        all_removed = False
                cleanup_results.append((tid, all_removed))
            with DOWNLOAD_TASKS_LOCK:
                for tid, all_removed in cleanup_results:
                    task = DOWNLOAD_TASKS.get(tid)
                    if task is None:
                        finished_done.append(tid)   # 锁外期间已被其他路径移除
                        continue
                    if all_removed:
                        finished_done.append(tid)
                    else:
                        task['_cleanup_tries'] = int(task.get('_cleanup_tries') or 0) + 1
                        if task['_cleanup_tries'] >= 8:
                            # 重试多次仍失败：放弃记录但大声记录日志（文件留给缓存清扫兜底）
                            api_service.logger.warning(
                                f"任务 {tid} 结果文件多次清理失败，已放弃（文件可能被占用）")
                            finished_done.append(tid)
                        else:
                            finished_retry.append(tid)
                for tid in finished_done:
                    DOWNLOAD_TASKS.pop(tid, None)
            if finished_done:
                api_service.logger.info(f"监控线程清理过期终态任务: {finished_done}")
            if finished_retry:
                api_service.logger.info(f"监控线程保留清理失败任务待重试: {finished_retry}")
            # ---- 长时间未结束的任务：置取消（含 cancel Event，唤醒可能的阻塞等待）----
            timeout_settle: list[str] = []
            with DOWNLOAD_TASKS_LOCK:
                for tid, task in DOWNLOAD_TASKS.items():
                    if (task.get('status') in ('queued', 'running', 'paused')
                            and now - task.get('start', 0) > 4 * 3600):
                        task['status'] = 'canceled'
                        task['msg'] = '任务超时未完成，已自动取消（费用按实际交付结算）'
                        task['completed_at'] = time.time()
                        try:
                            task['cancel'].set()
                        except Exception:
                            pass
                        # R5-14：worker 线程已死则无人再走终态结算——监控代为按账本
                        # 结算退款（settle 幂等：worker 若已结算过，此处返回 0）
                        th = task.get('worker_thread')
                        if th is not None and not th.is_alive():
                            timeout_settle.append(tid)
                        api_service.logger.warning(f"任务超时自动取消: {tid}")
            # 第 97 条（P2-3）：结算移到任务锁外（同 _mark_task_terminal 口径）——
            # 库忙 15s 不再随任务锁波及全站任务端点
            for tid in timeout_settle:
                try:
                    auth_system.ledger_settle(tid, 0, 'timeout')
                except Exception:
                    pass
            # ---- 下载缓存清扫（保留期同交付口径 35 分钟）+ 限流桶过期项顺手清理（O-5）----
            _sweep_download_cache(RESULT_RETENTION_SECONDS)
            _sweep_rate_buckets()
            # ---- 第 91→93 条（P2-1/P2-2）：账本周期兜底（原仅启动执行一次）----
            # 孤儿对账：长运行进程内 open 且账龄 > 5h（严格大于任务 4h 硬超时 + 监控
            # tick 抖动——账本行 created_at 整秒截断使账龄恒 ≥ 任务龄，旧 4h 相等口径
            # 存在抢退合法 4h+ 长任务的窗口，第 97 条 P2-4）的行每分钟周期检查退回；
            # settled 行 90 天清理改为每小时低频执行，防长运行进程下表无界增长
            try:
                # 第 94 条（P3-1）：时间戳门槛替代 tick 取模——单轮工作段超过周期时
                # 取模落点会被整段跳过，时间戳门槛只延迟不漏跑
                if now - _LEDGER_LAST_RECOVER['ts'] > 60:
                    _LEDGER_LAST_RECOVER['ts'] = now
                    auth_system.ledger_recover_orphans(max_age_seconds=5 * 3600)
                if now - _LEDGER_LAST_CLEANUP['ts'] > 24 * 3600:
                    _LEDGER_LAST_CLEANUP['ts'] = now
                    auth_system.ledger_cleanup_settled(90 * 86400)
            except Exception as e:
                api_service.logger.warning(f"账本周期兜底异常（下轮重试）: {e}")
            # ---- 第 91→94 条（P3-3）：tasks/ 孤儿目录每小时低频补扫（>24h 且无记录）----
            try:
                if now - _TASKS_SWEEP_LAST['ts'] > 3600:
                    _TASKS_SWEEP_LAST['ts'] = now
                    tasks_root = api_service.downloads_path / 'tasks'
                    if tasks_root.exists():
                        for d in tasks_root.iterdir():
                            try:
                                if (d.is_dir() and d.name not in DOWNLOAD_TASKS
                                        and now - d.stat().st_mtime > 24 * 3600):
                                    shutil.rmtree(str(d), ignore_errors=True)
                                    api_service.logger.info(f"tasks 孤儿目录补扫移除: {d.name}")
                            except FileNotFoundError:
                                pass   # 第 94 条（P3-3）：单条竞态不中止整轮扫描
                            except OSError:
                                pass
            except Exception as e:
                api_service.logger.warning(f"tasks 孤儿目录补扫异常（下轮重试）: {e}")
            # ---- 设备心跳离线处理 ----
            with DEVICE_LAST_SEEN_LOCK:
                offline = {d: now - ts for d, ts in DEVICE_LAST_SEEN.items() if now - ts > PAUSE_AFTER_SECONDS}
            if not offline:
                continue
            with DOWNLOAD_TASKS_LOCK:
                for tid, task in DOWNLOAD_TASKS.items():
                    dev = task.get('device_id')
                    gap = offline.get(dev) if dev else None
                    if not gap:
                        continue
                    st = task.get('status')
                    if gap > CANCEL_AFTER_SECONDS and st in ('queued', 'running', 'paused'):
                        # 离线超 30 分钟：请求取消（C3：文件删除与退款统一交给 worker 的
                        # 取消收尾/终态清理；worker 已不在时由启动对账按账本兜底）
                        task['status'] = 'canceled'
                        task['msg'] = '设备离线超过 30 分钟，任务已自动取消'
                        task['completed_at'] = time.time()
                        try:
                            task['cancel'].set()
                        except Exception:
                            pass
                        api_service.logger.info(f"设备离线超 30 分钟自动请求取消: {tid}")
                    elif task.get('type') == 'batch' and st in ('queued', 'running'):
                        # 心跳超时：先暂停，让出排队名额给下一位
                        task['status'] = 'paused'
                        task['msg'] = '设备离线，任务暂停（重新打开页面自动恢复）'
                        task['pause'].set()
        except Exception:
            # 持续异常不能完全静默（否则监控失能无人知晓）：限频记录，每 10 分钟最多一条
            _now = time.time()
            _MONITOR_ERR_TS['n'] += 1
            if _now - _MONITOR_ERR_TS['ts'] > 600:
                api_service.logger.warning(
                    f"任务监控循环异常（近 10 分钟累计 {_MONITOR_ERR_TS['n']} 次，"
                    f"最后异常见堆栈）: {traceback.format_exc()[-600:]}")
                _MONITOR_ERR_TS['ts'] = _now
                _MONITOR_ERR_TS['n'] = 0


def _sweep_rate_buckets() -> None:
    """限流桶周期清扫（O-5）：把超过 10 分钟无新请求的桶移出，防止低流量长期运行下
    缓慢累积（原实现只在"新建第 8001 个桶"时才触发清理，时机太晚）"""
    now = time.time()
    with _RATE_LOCK:
        stale = [k for k, v in _RATE_BUCKETS.items() if not v or now - v[-1] > 600]
        for k in stale:
            _RATE_BUCKETS.pop(k, None)


def _touch_device(device_id: str) -> None:
    """记录设备心跳时间（P2-10：设备表容量上限——device_id 是客户端任意串，
    登录用户可提交海量随机 ID 使字典无界增长，超限清最旧；
    第 98 条：入口已统一钳 64，此处兜底再钳一次防新调用点绕过）"""
    device_id = str(device_id or '')[:64]
    if not device_id:
        return
    with DEVICE_LAST_SEEN_LOCK:
        if len(DEVICE_LAST_SEEN) >= 5000:
            # 保留最近心跳的设备：按最后心跳时间排序，砍掉最旧的一半
            for d in sorted(DEVICE_LAST_SEEN, key=lambda k: DEVICE_LAST_SEEN.get(k, 0.0))[:2500]:
                DEVICE_LAST_SEEN.pop(d, None)
        DEVICE_LAST_SEEN[device_id] = time.time()


# _safe_int / _safe_console_print 已迁出至 core.utils（此处 import 同名共享）


# ============ 接口请求统计 ============
# REQUEST_STATS / _STATS_LOCK / REQ_LOG 已迁出至 core.state（此处 import 同名共享）

# 只统计真实业务接口（排除首页/健康检查/统计/账号探测等内部调用）
# F09：兼容别名（/Search、/Song_V1、/Playlist、/Album、/Download）一并纳入统计与限流，
# 防止用大写别名绕过业务限流
COUNTED_PATHS = {
    '/song', '/search', '/playlist', '/album', '/toplist', '/artist_songs',
    '/comments', '/download', '/download/batch_zip',
    '/podcast/parse', '/podcast/programs', '/podcast/search', '/podcast/hot',
    '/podcast/download', '/podcast/download/batch_zip',
    '/user/playlists', '/user/playlist', '/user/status', '/user/logout',
    '/user/qr/create', '/user/qr/check',
    # P1-2/P2-17/P3-6：账号探测与个人操作端点此前漏在限流名单外——
    # /account/vip 每请求最多 9 次上游探测、/user/comment 与 /user/collect 携
    # 任意 cookie 触发上游 weapi、/auth/me 可匿名无限刷，全部纳入免费 30/分桶
    '/account/vip', '/user/collect', '/user/comment', '/auth/me',
    '/admin/qr/create', '/admin/qr/check', '/admin/cookie/status',
    '/admin/cookie/delete', '/admin/logs',
'/admin/site/play_key/get', '/admin/site/play_key/rotate',
    '/global/playlists', '/global/playlist', '/api/playlist/play',
    '/song_v1',
}
_COUNTED_LOWER = {p.lower() for p in COUNTED_PATHS}

ENDPOINT_NAMES = {
    '/song': '歌曲信息', '/search': '搜索', '/playlist': '歌单详情',
    '/album': '专辑详情', '/toplist': '榜单列表', '/artist_songs': '歌手歌曲',
    '/comments': '评论', '/download': '音乐下载', '/download/batch_zip': '批量ZIP',
    '/health': '健康检查', '/api/info': '服务信息', '/api/topen': '请求统计',
    '/account/vip': '账号VIP信息',
    '/podcast/parse': '播客解析', '/podcast/programs': '播客单集列表',
    '/podcast/search': '播客搜索', '/podcast/hot': '热门播客',
    '/podcast/download': '播客单集下载', '/podcast/download/batch_zip': '播客整台打包',
    '/user/playlists': '个人歌单', '/user/playlist': '个人歌单详情',
    '/user/status': '个人登录状态', '/user/logout': '个人退出',
    '/user/qr/create': '个人二维码', '/user/qr/check': '个人登录轮询',
    '/admin/qr/create': '管理员二维码', '/admin/qr/check': '管理员登录轮询',
    '/admin/cookie/status': 'Cookie状态', '/admin/cookie/delete': 'Cookie管理',
    '/admin/logs': '操作记录',
    '/global/playlists': '全局账号歌单', '/global/playlist': '全局歌单详情',
    '/api/playlist/play': '公开歌单播放API',
}

# 用户解析/下载操作记录（IP）——REQ_LOG 已迁出至 core.state（此处 import 同名共享）


def _record_log(action: str, ip: str, song: str) -> None:
    """记录用户操作（解析/下载）。P3-4：歌名截断（来自上游/用户输入，不设上限会撑内存与后台页）"""
    REQ_LOG.append({
        'action': action,
        'ip': ip,
        'song': str(song or '')[:100],
        'time': time.strftime('%Y-%m-%d %H:%M:%S'),
    })
    if len(REQ_LOG) > 2000:
        del REQ_LOG[:len(REQ_LOG) - 2000]


def _parse_cookie_str(raw) -> dict[str, str]:
    """将 'k=v;k2=v2' 格式的 Cookie 字符串解析为字典"""
    cookies: dict[str, str] = {}
    if not raw:
        return cookies
    for part in str(raw).split(';'):
        if '=' in part:
            k, v = part.strip().split('=', 1)
            if k:
                cookies[k] = v
    return cookies


# _GLOBAL_MUSIC_U_CACHE 已迁出至 core.state（此处 import 同名共享）


def _global_music_u() -> str:
    """全局账号 MUSIC_U（5 分钟缓存；后台重新扫码后自动跟随新值）"""
    now = time.time()
    if _GLOBAL_MUSIC_U_CACHE['v'] is None or now - _GLOBAL_MUSIC_U_CACHE['ts'] > 300:
        try:
            ck = api_service._get_cookies()
            _GLOBAL_MUSIC_U_CACHE['v'] = (ck.get('MUSIC_U') or '').strip()
        except Exception:
            _GLOBAL_MUSIC_U_CACHE['v'] = ''
        _GLOBAL_MUSIC_U_CACHE['ts'] = now
    return _GLOBAL_MUSIC_U_CACHE['v']


def _build_download_base(filename_format: str, music_info: dict[str, Any]) -> str:
    """按文件名格式生成下载基础名（不含扩展名）"""
    name = music_info.get('name', '未知歌曲')
    artist = music_info.get('artist_string', '') or '未知歌手'

    def _safe(s: str) -> str:
        # P2-14：交付文件名必须剔除控制字符——歌名含 \r\n 时交付头的
        # Content-Disposition 会抛 ValueError，任务完成已扣费但领取必 500
        # （F79 当年只修了下载器磁盘名这条同型路径，交付名漏网）
        s = re.sub(r'[\x00-\x1f\x7f]', '', s)
        return ''.join(c for c in s if c not in r'<>:"/\|?*').strip() or 'unknown'

    if filename_format == 'song':
        return _safe(name)
    if filename_format == 'song_artist':
        return _safe(f"{name} - {artist}")
    return _safe(f"{artist} - {name}")  # artist_song（默认）


def _vip_name(vip_type: int) -> str:
    """根据 vipType 返回会员类型名称（兼容新旧取值）"""
    return {
        0: '普通用户',
        1: '音乐包',
        11: '黑胶VIP',
        100: '黑胶VIP',
        10: '黑胶SVIP',
        110: '黑胶SVIP'
    }.get(vip_type, '普通用户')


def _detect_vip(cookies: dict[str, str]) -> tuple[int, str, list[str]]:
    """检测账号会员类型与可解析音质：
    优先账号接口（vipType 精确），并始终用音质探测接口实测可解析列表。
    第 100 条：探测单飞锁（有界等待 0.5s）——上游黑洞时并发请求不再各自串行
    8 级探测（最坏 16 分钟线程滞留），等锁超时者直接用账号接口给降级结果"""
    if not _VIP_PROBE_LOCK.acquire(timeout=0.5):
        info = account_info(cookies)
        if info:
            return info.get('vipType', 0), 'account', []
        return 0, 'probe', []
    try:
        probe = detect_vip_by_probe(cookies)
        levels_ok = probe.get('levels_ok', [])
        info = account_info(cookies)
        if info:
            return info.get('vipType', 0), 'account', levels_ok
        return probe.get('vip_type', 0), 'probe', levels_ok
    finally:
        _VIP_PROBE_LOCK.release()


# 高频轮询/流式端点：不写逐请求日志（3s 排队轮询、1.5s 进度轮询、15s 心跳、
# Range 分段流、错误上报都会在忙碌站点把 5MB×3 的轮转日志几小时刷一圈，排障信息被冲掉）。
# 用户主动动作（任务列表/取消）保留日志。
_QUIET_LOG_PATHS = {'/api/queue', '/api/batch_progress', '/api/task/heartbeat',
                    '/audio_stream', '/api/fe_error'}


def _podcast_safe_name(s: str, fallback: str = 'unknown') -> str:
    """文件名安全化（去除非法字符）"""
    s = ''.join(c for c in str(s or '') if c not in r'<>:"/\|?*' and ord(c) >= 32).strip()
    return s or fallback



class _SyncStreamResponse:
    """同步流式响应包装（把 aiohttp 的异步流按需拉成同步迭代）。

    供流式下载使用：worker 是同步线程，这里经 core.async_bridge 在后台事件循环
    逐块取数据，避免引入 requests 依赖（Flask 已删除、requests 已移出依赖）。
    """

    def __init__(self, url: str, timeout: float):
        from core import async_bridge
        self._bridge = async_bridge
        self._url = url
        self._timeout = timeout
        self._agent = None
        self.status = 0
        self.headers: dict[str, str] = {}
        self._resp = None

    def __enter__(self):
        self._agent = self._bridge.run_sync(self._open())
        self.status = self._agent[0]
        self.headers = self._agent[1]
        return self

    async def _open(self):
        from core.http_client import client
        resp = await client.open('GET', self._url, headers={
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 '
                          '(KHTML, like Gecko) Safari/537.36',
            'Referer': 'https://music.163.com/',
        }, timeout=self._timeout)
        return resp.status, dict(resp.headers), resp

    def iter_content(self, chunk_size: int = 256 * 1024):
        assert self._agent is not None
        resp = self._agent[2]
        it = resp.content.iter_chunked(chunk_size)
        while True:
            try:
                chunk = self._bridge.run_sync(it.__anext__())
            except StopAsyncIteration:
                break
            yield chunk

    def __exit__(self, *exc):
        if self._agent is not None and self._agent[2] is not None:
            try:
                self._agent[2].close()
            except Exception:
                pass
        return False


def _stream_open(url: str, timeout: float = 60) -> _SyncStreamResponse:
    """打开同步可迭代的流式响应（见 _SyncStreamResponse）。"""
    return _SyncStreamResponse(url, timeout)

def _podcast_stream_download(url: str, target: Path, total_size: int,
                             cancel_ev: threading.Event,
                             task_id: str = '', progress_label: str = '') -> int:
    """流式下载播客音频到 target（先写 .part 再改名），返回实际字节数

    自动加入全局下载信号量排队；每 0.5s 更新一次任务进度消息。
    """
    done = 0
    last_update = 0.0
    part = target.with_name(target.name + '.part')
    # B2：等待全局下载名额期间可被取消（与音乐批量 BATCH_ZIP_SEM 同语义）
    sem = api_service.downloader._download_semaphore
    if not sem.acquire_cancellable(cancel_ev):
        raise DownloadCanceled("任务已取消")
    try:
        with _stream_open(url, timeout=60) as r:
            if r.status >= 400:
                raise DownloadException(f"上游返回 {r.status}")
            total = total_size or int(r.headers.get('Content-Length') or 0)
            with open(part, 'wb') as f:
                for chunk in r.iter_content(chunk_size=256 * 1024):
                    if cancel_ev.is_set():
                        raise DownloadCanceled("任务已取消")
                    if chunk:
                        f.write(chunk)
                        done += len(chunk)
                        now = time.time()
                        if now - last_update > 0.5:
                            last_update = now
                            if total:
                                pct = min(99, int(done / total * 100))
                                msg = f"{progress_label} {pct}% · {api_service._format_file_size(done)}/{api_service._format_file_size(total)}"
                            else:
                                msg = f"{progress_label} 已下载 {api_service._format_file_size(done)}"
                            if task_id:
                                with DOWNLOAD_TASKS_LOCK:
                                    t = DOWNLOAD_TASKS.get(task_id)
                                    if t and t['status'] == 'running':
                                        t['msg'] = msg
                                        # 单集任务的字节级进度（批量任务保持按集数口径）
                                        if t.get('type') == 'single' and total:
                                            t['live_percent'] = min(99.0, float(pct))
    finally:
        sem.release()
    if part.exists():
        part.replace(target)
    # 完整性校验：CDN 提前断流时 iter_content 会"正常"结束，文件静默截断
    # （F29 同口径：API 报告的期望大小时精确相等——95% 容差会交付截断的坏文件还扣次数；
    # 期望未知时退化为非空校验，Content-Length 兜底值可能是压缩口径不做精确比对）
    if total_size and done != total_size:
        try:
            os.remove(str(target))
        except OSError:
            pass
        raise DownloadException(f"下载不完整（{done}/{total_size} 字节），请重试")
    if not total_size and done <= 0:
        try:
            os.remove(str(target))
        except OSError:
            pass
        raise DownloadException("下载内容为空，请重试")
    return done


def _podcast_resolve_audio(program: dict[str, Any], quality: str,
                           cookies: dict[str, str]) -> dict[str, Any]:
    """解析单集音频直链，失败抛 DownloadException"""
    song_id = program.get('main_song_id')
    if not song_id:
        raise DownloadException("该单集缺少音频信息（mainSong）")
    url_info = podcast_api.resolve_episode_url(song_id, cookies, quality)
    if not url_info or not url_info.get('url'):
        raise DownloadException("未获取到音频直链（单集可能已下架或受版权限制）")
    return url_info


# ============ 管理员设置（二维码登录 / Cookie 管理） ============

def _admin_client() -> QRLoginClient:
    """创建二维码登录客户端（基于 cookie.txt）"""
    return QRLoginClient()


# ============ 个人歌单（游客扫码登录自己的账号） ============

def _user_client() -> QRLoginClient:
    """创建个人用户二维码登录客户端（第 91 条后不再落盘 user_cookie.txt，
    USER_COOKIE_FILE 仅作 QRLoginClient 构造参数遗留）"""
    return QRLoginClient(USER_COOKIE_FILE)


def _settle_batch_billing(task_id: str, ok_count: int, final_status: str = 'settled') -> int:
    """批量任务结算（F25/F26：走持久账本，按实际预扣-实际交付幂等退款；
    重复调用/重启后调用都只会退一次）"""
    try:
        refund = auth_system.ledger_settle(task_id, ok_count, final_status)
    except Exception:
        # 第 97 条（P3）：本函数多在异常处理器内被调用——结算再抛错（库忙超时）
        # 会杀死 worker 收尾路径，跳过终态标记；失败留周期对账兜底（幂等）
        api_service.logger.error(
            f"批量结算异常（留对账兜底）: {task_id}\n{traceback.format_exc()}")
        return 0
    if refund:
        try:
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id) or {}
            uid = int(t.get('billing_user_id') or 0)
            u = auth_system.get_user_by_id(uid) if uid else None
            uname = u['username'] if u else 'system'
            remaining = u['duration_seconds'] if u else '?'
            auth_system.add_log('success', uname, 'system', '批量退费',
                                f'失败部分 {refund} 次已退回，剩余 {remaining} 次')
        except Exception:
            pass
    return refund


def _batch_zip_worker(task_id: str) -> None:
    """后台批量打包：窗口化下载 → 写 ZIP（音频免压缩），支持取消与断线暂停

    - 断线暂停：设备心跳超时后，当前窗口下载完即释放 BATCH_ZIP_SEM 名额给下一位，
      保存进度进入暂停等待；重新打开网站（心跳恢复）后自动回到队列继续下载
    - 音频入包即删，缓解磁盘占用
    """
    import tempfile as _tempfile
    from concurrent.futures import ThreadPoolExecutor, as_completed

    zip_tmp_path: str | None = None
    ok_count = 0
    failed: list[str] = []
    used_arcnames = set()   # ZIP 内已占用文件名（同名歌曲去重，防止包内互相覆盖）
    info_pool = None
    info_futures = {}
    try:
        with DOWNLOAD_TASKS_LOCK:
            task = DOWNLOAD_TASKS[task_id]
            task['status'] = 'running'
            task['msg'] = '下载打包中...'
        params = task['params']
        cancel_ev = task['cancel']
        pause_ev = task['pause']
        ids = list(params['ids'])
        quality = params['quality']
        filename_format = params['filename_format']
        write_meta = params['write_meta']
        meta_fields = params['meta_fields']
        lyric_format = params['lyric_format']
        concurrency = params['concurrency']
        cookies = params['cookies']
        batch_start = time.time()

        # P2-7：预取按窗口进行——原实现一次性提交全部（最多 500 首 ×3 接口）预取任务，
        # 大歌单瞬间以 10 并发连发上游约 1500 次请求打风控；改为每个下载窗口只预取本窗口
        # 的歌（与下载节奏对齐），_download_one 语义不变（等预取结果再下载）
        from concurrent.futures import ThreadPoolExecutor as _InfoPool
        info_pool = _InfoPool(max_workers=min(4, max(1, concurrency)))

        def _prefetch(window_ids):
            for mid in window_ids:
                if mid not in info_futures:
                    info_futures[mid] = info_pool.submit(
                        api_service.downloader.get_music_info, mid, quality, cookies
                    )

        def _download_one(mid):
            """并行下载单元：等待预取信息 → 下载 → 复用预取歌词与缓存封面（零重复请求）"""
            info = info_futures[mid].result()
            result = api_service.downloader.download_music_file(
                mid, quality,
                write_meta=write_meta,
                meta_fields=meta_fields,
                cookies=cookies,
                cancel_event=cancel_ev,
                music_info=info,
            )
            extra = {'lyric': '', 'cover': b''}
            if result.success:
                # 歌词已随 get_music_info 预取返回，无需再调一次歌词接口
                extra['lyric'] = getattr(info, 'lyric', '') or ''
                # 封面走共享缓存（同一专辑只拉一次网络）；取消后不再发起新请求
                if not cancel_ev.is_set() and info.pic_url:
                    cover = fetch_cover_bytes(info.pic_url)
                    if cover:
                        extra['cover'] = cover
            return result, extra

        def _update_progress() -> None:
            with DOWNLOAD_TASKS_LOCK:
                DOWNLOAD_TASKS[task_id]['done'] = ok_count + len(failed)
                DOWNLOAD_TASKS[task_id]['failed'] = len(failed)

        def _wait_if_paused() -> None:
            """暂停时等待恢复或取消（不持有 BATCH_ZIP_SEM）"""
            if not (pause_ev.is_set() or task['status'] == 'paused'):
                return
            with DOWNLOAD_TASKS_LOCK:
                task['status'] = 'paused'
                task['done'] = ok_count + len(failed)
                task['msg'] = '已暂停（重新打开页面自动恢复）'
            while not cancel_ev.is_set() and (pause_ev.is_set() or task['status'] == 'paused'):
                time.sleep(1)
            if cancel_ev.is_set():
                raise DownloadCanceled("任务已取消")
            pause_ev.clear()
            with DOWNLOAD_TASKS_LOCK:
                task['status'] = 'running'
                task['msg'] = '继续下载...'

        # P3-26：ZIP 构建放 downloads 卷（原实现落系统 %TEMP%——500 首无损可达 GB 级，
        # 小系统盘一次大单即塞爆；单曲/播客早已指定 dir，唯批量漏了）
        # F-A（第 76 条）：临时包建在任务专属目录 tasks/<task_id>/——原放根目录会被
        # 缓存清扫线程按 mtime 回收（Linux 上已打开文件也能被 unlink，Docker 部署
        # 排队超 35 分钟即出现"扣费后领取 404"的悬空交付），根目录从此碰不到交付物
        _task_dir_for_zip = api_service.downloads_path / 'tasks' / task_id
        _task_dir_for_zip.mkdir(parents=True, exist_ok=True)
        zip_valid = False   # F-B：ZIP 中央目录完整写出才置 True，否则一律按失败全额退费
        with _tempfile.NamedTemporaryFile(prefix='batch_zip_', suffix='.zip',
                                          dir=str(_task_dir_for_zip),
                                          delete=False) as zip_tmp:
            zip_tmp_path = zip_tmp.name
            # 音频本身已压缩，用 ZIP_STORED（免压缩）大幅提速；歌词等文本仍压缩
            with zipfile.ZipFile(zip_tmp, 'w', zipfile.ZIP_DEFLATED) as zf:
                # P3-27：不用 with 管理下载池——取消时 with 退出会 wait=True 等在途
                # future（其内部阻塞在预取 HTTP 上最长 30s），改为不等待 + 取消排队任务
                pool = ThreadPoolExecutor(max_workers=concurrency)
                try:
                    while ids:
                        if cancel_ev.is_set():
                            raise DownloadCanceled("任务已取消")
                        # 断线暂停：释放名额等待恢复/取消，恢复后重新进入排队
                        _wait_if_paused()
                        # 每个窗口持有 BATCH_ZIP_SEM（同一时刻全局最多 3 个批量任务在下载）
                        # F91：等待名额期间可被取消，不再无限阻塞线程与退款
                        if not BATCH_ZIP_SEM.acquire_cancellable(cancel_ev):
                            raise DownloadCanceled("任务已取消")
                        try:
                            if cancel_ev.is_set() or pause_ev.is_set() or task['status'] == 'paused':
                                continue  # 立即释放名额，回到循环顶部处理暂停
                            window = ids[:concurrency]
                            ids = ids[concurrency:]
                            _prefetch(window)   # P2-7：只预取本窗口
                            future_map = {
                                pool.submit(_download_one, mid): mid
                                for mid in window
                            }
                            for future in as_completed(future_map):
                                if cancel_ev.is_set():
                                    raise DownloadCanceled("任务已取消")
                                mid = future_map[future]
                                try:
                                    result, extra = future.result()
                                except DownloadCanceled:
                                    raise
                                except Exception as e:
                                    failed.append(f"{mid}({e})")
                                    _update_progress()
                                    continue
                                if not result.success:
                                    failed.append(str(mid))
                                    _update_progress()
                                    continue
                                assert result.file_path is not None
                                fp = Path(result.file_path)
                                if not fp.exists():
                                    # 文件可能已被同名并发任务入包删除，按失败处理而非炸掉整个任务
                                    failed.append(str(mid))
                                    _update_progress()
                                    continue
                                mi = result.music_info
                                if mi is None:
                                    # 与上面 fp.exists() 同口径：成功但缺元信息（上游详情缺失）
                                    # 按单曲失败计，不让 mi.name 抛 AttributeError 把整批转 error
                                    failed.append(str(mid))
                                    _update_progress()
                                    continue
                                base = _build_download_base(filename_format, {'name': mi.name, 'artist_string': mi.artists})
                                # 同名去重：歌单里同一首歌出现两次/同名不同版本时，
                                # 追加序号避免 ZIP 内重名互相覆盖（用户被扣 2 次只拿到 1 首）
                                # F-C：音频/歌词/封面三个 arcname 都要查重——同名同歌手但
                                # 音源扩展不同（flac vs mp3）时歌词/封面条目也会互相覆盖
                                final_name = f"{base}.{mi.file_type}"
                                lrc_name = f"{base}.{lyric_format}"
                                jpg_name = f"{base}.jpg"
                                k = 2
                                while (final_name in used_arcnames
                                       or lrc_name in used_arcnames
                                       or jpg_name in used_arcnames):
                                    final_name = f"{base} ({k}).{mi.file_type}"
                                    lrc_name = f"{base} ({k}).{lyric_format}"
                                    jpg_name = f"{base} ({k}).jpg"
                                    k += 1
                                used_arcnames.update((final_name, lrc_name, jpg_name))
                                # F-D：exists 与 zf.write 之间的缓存竞态（另一任务缓存 miss
                                # 删文件）按单曲失败计，不再让整批转 error
                                try:
                                    zf.write(str(fp), arcname=final_name, compress_type=zipfile.ZIP_STORED)
                                except OSError as e:
                                    failed.append(f"{mid}(缓存文件读取失败: {e})")
                                    _update_progress()
                                    continue
                                # F27：缓存文件是跨任务共享资源，任务不得删除；
                                # 磁盘回收交给监控线程的下载缓存清扫（按文件年龄）
                                # 歌词与封面已在并行下载线程中拉取，直接写入 ZIP（无网络等待）
                                lrc = extra.get('lyric', '')
                                if lrc:
                                    try:
                                        zf.writestr(lrc_name, _format_lyric(lrc, lyric_format), compress_type=zipfile.ZIP_DEFLATED)
                                    except Exception:
                                        pass
                                if extra.get('cover'):
                                    try:
                                        zf.writestr(jpg_name, extra['cover'], compress_type=zipfile.ZIP_STORED)
                                    except Exception:
                                        pass
                                ok_count += 1
                                _update_progress()
                        finally:
                            BATCH_ZIP_SEM.release()
                finally:
                    # P3-27：取消/异常时不等待在途下载线程（其可能阻塞在预取 HTTP 上），
                    # 排队任务一并取消；在途线程自行收尾（.part 残片由续传/清扫兜底）
                    try:
                        pool.shutdown(wait=False, cancel_futures=True)
                    except TypeError:
                        pool.shutdown(wait=False)
        # 第 93 条复审 P2-1 修正：zip_valid = True 必须在内层 with zipfile 退出之后
        # （中央目录在 close 时才写出）——原缩进 16 在 with 内部，守卫不可达
        zip_valid = True

        if ok_count > 0:
            with BATCH_DURATIONS_LOCK:
                BATCH_DURATIONS.append(time.time() - batch_start)

        # F-B：ZIP 未正常完成（磁盘满写坏中央目录等）——不发布坏包，按全额退费收敛
        if not zip_valid:
            if zip_tmp_path:
                try:
                    os.remove(zip_tmp_path)
                except OSError:
                    pass
                zip_tmp_path = None
            refunded = _settle_batch_billing(task_id, 0, 'error')
            _mark_task_terminal(task_id, 'error',
                                f"ZIP 打包失败（可能磁盘空间不足），已退回 {refunded} 次" if refunded
                                else "ZIP 打包失败（可能磁盘空间不足），费用未扣或已退回")
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['failed'] = t.get('failed', 0) + ok_count
                    t['refunded'] = refunded
            api_service.logger.error(f"批量ZIP构建失败未发布: {task_id} ok_count={ok_count} 退回{refunded}次")
            return

        # F41：全部失败不发布空 ZIP、不标 done —— 按失败收敛并全额退费
        if ok_count == 0 and failed:
            if zip_tmp_path:
                try:
                    os.remove(zip_tmp_path)
                except OSError:
                    pass
                zip_tmp_path = None
            refunded = _settle_batch_billing(task_id, 0, 'error')
            _mark_task_terminal(task_id, 'error',
                                f"全部失败（{len(failed)} 首）" + (f"，已退回 {refunded} 次" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                DOWNLOAD_TASKS[task_id]['failed'] = len(failed)
                DOWNLOAD_TASKS[task_id]['refunded'] = refunded
            api_service.logger.info(f"批量ZIP全部失败: {task_id} 失败{len(failed)} 退回{refunded}次")
            return

        refunded = _settle_batch_billing(task_id, ok_count)
        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS.get(task_id)
            # S3：发布前锁内复查取消/失效状态——取消请求落在"检查后、拿锁前"的窗口也不得覆盖终态
            if t is None or t.get('status') in ('canceled', 'error'):
                raise DownloadCanceled("任务已取消")
            if cancel_ev.is_set():
                raise DownloadCanceled("任务已取消")
            t['status'] = 'done'
            t['completed_at'] = time.time()
            t['done'] = ok_count + len(failed)
            t['failed'] = len(failed)
            t['msg'] = f"成功{ok_count} 失败{len(failed)}" + (f" 退回{refunded}次" if refunded else '')
            t['refunded'] = refunded
            t['result'] = {
                'zip_path': zip_tmp_path,
                'filename': f"批量下载_{ok_count}首.zip",
                'audio_files': [],   # F27：缓存文件不归任务所有，不进入清理清单
            }
        api_service.logger.info(f"批量ZIP完成: 成功{ok_count} 失败{len(failed)} 退回{refunded}次")
    except DownloadCanceled:
        # F24：部分成功后取消——已入包部分照常交付（成果守恒），未完成部分按账本退费
        # F-B：ZIP 未正常完成（写坏）时不按 ok_count 交付——按全额退费收敛
        delivered = ok_count if zip_valid else 0
        refunded = _settle_batch_billing(task_id, delivered, 'canceled')
        if delivered > 0 and zip_tmp_path:
            _mark_task_terminal(task_id, 'canceled',
                                f"已取消（已打包 {ok_count} 首可领取）" +
                                (f"，退回 {refunded} 次" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['refunded'] = refunded
                    t['result'] = {
                        'zip_path': zip_tmp_path,
                        'filename': f"批量下载_{ok_count}首.zip",
                        'audio_files': [],
                    }
        else:
            if zip_tmp_path:
                try:
                    os.remove(zip_tmp_path)
                except OSError:
                    pass
            _mark_task_terminal(task_id, 'canceled',
                                '任务已取消' + (f"（已退回 {refunded} 次下载次数）" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['refunded'] = refunded
        api_service.logger.info(f"批量ZIP已取消: {task_id}（成功{ok_count} 退回{refunded}次）")
    except Exception as e:
        # F24：通用异常与取消同一套交付/结算规则：有成果则交付，按账本退未交付部分
        # F-B：ZIP 未正常完成（写坏）时按全额退费，不发布坏包
        # 第 97 条（对抗复审）：非预期异常原文 logger 先行，用户可见文案泛化
        api_service.logger.error(f"批量打包异常: {task_id} {e}\n{traceback.format_exc()}")
        delivered = ok_count if zip_valid else 0
        refunded = _settle_batch_billing(task_id, delivered, 'error')
        if delivered > 0 and zip_tmp_path:
            _mark_task_terminal(task_id, 'error',
                                "部分歌曲已打包完成，可领取" +
                                (f"，退回 {refunded} 次" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['refunded'] = refunded
                    t['result'] = {
                        'zip_path': zip_tmp_path,
                        'filename': f"批量下载_{ok_count}首.zip",
                        'audio_files': [],
                    }
        else:
            _mark_task_terminal(task_id, 'error',
                                '打包失败，请稍后重试' + (f"（已退回 {refunded} 次下载次数）" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['refunded'] = refunded
            if zip_tmp_path:
                try:
                    os.remove(zip_tmp_path)
                except OSError:
                    pass
        api_service.logger.error(f"批量ZIP任务异常: {task_id} {e}（成功{ok_count} 退回{refunded}次）\n{traceback.format_exc()}")
    finally:
        # 回收信息预取线程池，避免线程泄漏（未启动的预取任务一并取消）
        if info_pool is not None:
            try:
                info_pool.shutdown(wait=False, cancel_futures=True)
            except TypeError:
                info_pool.shutdown(wait=False)


def _podcast_download_worker(task_id: str) -> None:
    """后台播客单集下载：解析单集 → 音质降级取直链 → 流式下载（可选 ZIP 打包）

    任务 type 为 'single'，完成后经 /download/result 交付，与单曲下载共用交付通道。
    F28：落盘文件进入任务专属目录且带节目 ID，跨任务永不重名；清理只动本任务目录。
    """
    import tempfile as _tempfile

    file_path_str: str | None = None
    zip_tmp_path: str | None = None
    task_dir: Path | None = None
    try:
        with DOWNLOAD_TASKS_LOCK:
            task = DOWNLOAD_TASKS[task_id]
            task['status'] = 'running'
            task['msg'] = '解析单集信息...'
        params = task['params']
        cancel_ev = task['cancel']
        program_id = params['program_id']
        quality = params['quality']
        need_zip = params['need_zip']
        cookies = params['cookies']
        remote_ip = params.get('remote_ip') or '-'

        program = podcast_api.get_program_detail(program_id, cookies)
        url_info = _podcast_resolve_audio(program, quality, cookies)

        serial = int(program.get('serial_num') or 0)
        name = program.get('name') or program.get('main_song_name') or '播客单集'
        prefix = f"{serial:03d} - " if serial else ''
        base = _podcast_safe_name(f"{prefix}{name}")
        ext = (url_info.get('type') or 'mp3').lower().lstrip('.')
        # F28：磁盘名附节目 ID + 任务目录隔离（两个任务同下载一集互不覆盖、互不删除）
        task_dir = api_service.downloads_path / 'tasks' / task_id
        task_dir.mkdir(parents=True, exist_ok=True)
        disk_name = f"{base} [{program_id}].{ext}"
        target = task_dir / disk_name
        filename = f"{base}.{ext}"   # 交付名保持干净（不带 ID）

        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS[task_id]
            t['msg'] = '下载中...'
        _podcast_stream_download(url_info['url'], target, url_info.get('size', 0),
                                 cancel_ev, task_id, '下载中')
        if cancel_ev.is_set():
            raise DownloadCanceled("任务已取消")
        file_path_str = str(target)

        result: dict[str, Any]
        if need_zip:
            fd, zip_tmp_path = _tempfile.mkstemp(prefix='podcast_zip_', suffix='.zip',
                                                 dir=str(task_dir))
            os.close(fd)
            with zipfile.ZipFile(zip_tmp_path, 'w', zipfile.ZIP_DEFLATED) as zf:
                zf.write(file_path_str, arcname=filename)
                cover_url = program.get('cover_url') or ''
                if cover_url:
                    try:
                        cover = fetch_cover_bytes(cover_url)
                        if cover:
                            zf.writestr(f"{base}.jpg", cover)
                    except Exception:
                        pass
                # F17：info.txt 不再写直链（真实 URL 不应随交付文件外泄）
                info_txt = (
                    f"单集: {name}\n"
                    f"播客: {program.get('radio_name') or ''}\n"
                    f"主播: {program.get('dj_name') or ''}\n"
                    f"时长: {program.get('duration_text') or ''}\n"
                    f"音质: {api_service._get_quality_display_name(url_info.get('level', quality))}\n"
                )
                zf.writestr("info.txt", info_txt)
            # F42：打包阶段后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 = {
                'file_path': file_path_str,
                'filename': filename,
                'mimetype': f"audio/{ext}",
                'audio_files': [file_path_str],
            }

        # F42：最终发布前的取消检查（末段取消不得覆盖为 done）
        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
        # C1：交付已落定；结算失败不再把任务改标 error（同单曲）
        try:
            auth_system.ledger_settle(task_id, 1, 'delivered')
        except Exception as _e:
            api_service.logger.error(f"播客单集交付结算失败（重启对账兜底）: {task_id} {_e}")
        try:
            _record_log('下载', remote_ip, f"[播客] {name}")
        except Exception:
            pass
        api_service.logger.info(f"播客单集下载完成: {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 is not None:
            shutil.rmtree(str(task_dir), ignore_errors=True)
        api_service.logger.info(f"播客单集下载已取消: {task_id}")
    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 is not None:
            shutil.rmtree(str(task_dir), ignore_errors=True)
        api_service.logger.error(f"播客单集下载失败: {task_id} {e}")
    except Exception as e:
        # 第 97 条（P3）：非预期异常原文 logger 先行，用户可见文案泛化（第 84 条教训）
        api_service.logger.error(f"播客单集下载异常: {task_id} {e}\n{traceback.format_exc()}")
        _mark_task_terminal(task_id, 'error', '下载失败，请稍后重试')
        try:
            auth_system.ledger_settle(task_id, 0, 'error')
        except Exception:
            pass
        if task_dir is not None:
            shutil.rmtree(str(task_dir), ignore_errors=True)


def _podcast_cleanup_files(paths: list[str | None]) -> None:
    """清理播客任务产生的临时/残留文件"""
    for p in paths:
        if not p:
            continue
        try:
            os.remove(p)
        except OSError:
            pass
        # 连带清理可能残留的 .part 文件
        try:
            part = Path(str(p) + '.part')
            if part.exists():
                part.unlink()
        except OSError:
            pass


def _podcast_zip_worker(task_id: str) -> None:
    """整台播客打包：逐集 下载→入包即删，支持取消与断线暂停（复用批量任务机制）"""
    import tempfile as _tempfile

    zip_tmp_path: str | None = None
    ok_count = 0
    failed: list[str] = []
    # 第 97 条（P1-1）：zip_valid 必须在函数头初始化——空电台/无单集/补扣失败等
    # 正常业务错误在 try 内早期 raise，异常处理器引用未绑定名会二次崩溃 worker 线程
    zip_valid = False
    try:
        with DOWNLOAD_TASKS_LOCK:
            task = DOWNLOAD_TASKS[task_id]
            task['status'] = 'running'
            task['msg'] = '解析单集列表...'
        params = task['params']
        cancel_ev = task['cancel']
        pause_ev = task['pause']
        radio_id = params['radio_id']
        preset_ids = params.get('ids')
        limit = params['limit']
        quality = params['quality']
        cookies = params['cookies']
        remote_ip = params.get('remote_ip') or '-'

        # 组装单集清单：整台电台（正序全量）或指定单集ID列表
        if radio_id:
            episodes = podcast_api.list_radio_all_program_ids(radio_id, cookies, max_count=limit)
            if not episodes:
                raise DownloadException("该电台暂无可下载的单集")
        else:
            episodes = []
            for pid in (preset_ids or []):
                try:
                    prog = podcast_api.get_program_detail(pid, cookies)
                    episodes.append({
                        'id': prog['id'],
                        'name': prog['name'],
                        'main_song_id': prog['main_song_id'],
                        'serial_num': prog['serial_num'],
                        'cover_url': prog['cover_url'],
                        'detail': prog,
                    })
                except APIException as ae:
                    failed.append(f"{pid}({ae})")
            episodes = episodes[:limit]
        if not episodes:
            raise DownloadException("没有可下载的单集")

        radio_name = _podcast_safe_name(params.get('radio_name') or '', '播客')
        with DOWNLOAD_TASKS_LOCK:
            DOWNLOAD_TASKS[task_id]['total'] = len(episodes)

        # 按次计费补扣（F21）：整台电台提交时只预扣 1 次，此处按实际单集数补足差额。
        # 补扣失败（余额不足/数据库异常）任务必须失败并按账本退费——不允许无账本继续交付
        try:
            _buid = params.get('billing_uid')
            _extra = len(episodes) - int(params.get('billed') or 1)
            if _buid and _extra > 0:
                if not auth_system.ledger_supplement(task_id, _extra):
                    raise DownloadException(
                        f"补扣下载次数失败（需补扣 {_extra} 次），任务已取消，预扣部分将退回")
            if _buid:
                with DOWNLOAD_TASKS_LOCK:
                    DOWNLOAD_TASKS[task_id]['billing_user_id'] = int(_buid)
                    DOWNLOAD_TASKS[task_id]['billing_cost'] = len(episodes)
        except DownloadCanceled:
            raise
        except DownloadException:
            raise
        except Exception as e:
            raise DownloadException(f"补扣下载次数异常: {e}") from e

        def _wait_if_paused() -> None:
            """暂停时等待恢复或取消"""
            if not (pause_ev.is_set() or task['status'] == 'paused'):
                return
            with DOWNLOAD_TASKS_LOCK:
                task['status'] = 'paused'
                task['done'] = ok_count + len(failed)
                task['msg'] = '已暂停（重新打开页面自动恢复）'
            while not cancel_ev.is_set() and (pause_ev.is_set() or task['status'] == 'paused'):
                time.sleep(1)
            if cancel_ev.is_set():
                raise DownloadCanceled("任务已取消")
            pause_ev.clear()
            with DOWNLOAD_TASKS_LOCK:
                task['status'] = 'running'
                task['msg'] = '继续下载...'

        def _update_progress(msg: str = '') -> None:
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS[task_id]
                t['done'] = ok_count + len(failed)
                t['failed'] = len(failed)
                if msg:
                    t['msg'] = msg

        # 第 91 条（P1-1）：对齐音乐批量 F-B 口径——zip_valid 仅在 ZIP with 块正常
        # 退出（中央目录完整写出）后才置 True（初始 False 已上移函数头，第 97 条）；
        # 未 valid 一律不发布、不按 ok_count 结算
        # P3-26：同音乐批量——ZIP 构建放 downloads 卷，不落系统 %TEMP%
        # R5-P3/W-A 同口径：建在任务专属目录 tasks/<task_id>/，根目录缓存清扫不再触及交付物
        _podcast_task_dir = api_service.downloads_path / 'tasks' / task_id
        _podcast_task_dir.mkdir(parents=True, exist_ok=True)
        with _tempfile.NamedTemporaryFile(prefix='podcast_batch_', suffix='.zip',
                                          dir=str(_podcast_task_dir),
                                          delete=False) as zip_tmp:
            zip_tmp_path = zip_tmp.name
            used_arcnames = set()   # F73：包内条目名去重（同名单集/同号不同集不得互相覆盖）
            with zipfile.ZipFile(zip_tmp, 'w', zipfile.ZIP_DEFLATED) as zf:
                for idx, ep in enumerate(episodes, 1):
                    if cancel_ev.is_set():
                        raise DownloadCanceled("任务已取消")
                    _wait_if_paused()
                    # 并发对齐音乐批量：播客打包同样占用全局批量名额（BATCH_ZIP_SEM，全局 3），
                    # 逐集 acquire/release——暂停等待/取消时不长期占名额；音频本身仍受
                    # 全局下载信号量约束。原实现不受批量并发控制，多用户同时打包会无限并发
                    if not BATCH_ZIP_SEM.acquire_cancellable(cancel_ev):
                        raise DownloadCanceled("任务已取消")
                    try:
                        label = f"[{idx}/{len(episodes)}] {ep['name'][:24]}"
                        _update_progress(f"{label} 解析中...")
                        try:
                            prog = ep.get('detail') or podcast_api.get_program_detail(ep['id'], cookies)
                            url_info = _podcast_resolve_audio(prog, quality, cookies)
                            _update_progress(f"{label} 下载中...")
                            ext = (url_info.get('type') or 'mp3').lower().lstrip('.')
                            serial = int(ep.get('serial_num') or 0)
                            prefix = f"{serial:03d} - " if serial else ''
                            base = _podcast_safe_name(f"{prefix}{ep['name']}")
                            # 第 91 条（P3-5）：中间文件移入任务目录——落 downloads 根目录会被
                            # 缓存清扫按 mtime 打断慢速单集（Linux 上 unlink 打开中的文件）
                            tmp_audio = _podcast_task_dir / f"podcast_zip_tmp_{task_id}_{idx}.{ext}"
                            try:
                                _podcast_stream_download(url_info['url'], tmp_audio,
                                                         url_info.get('size', 0), cancel_ev)
                                # F73：重名条目自动追加序号
                                arcname = f"{base}.{ext}"
                                k = 2
                                while arcname in used_arcnames:
                                    arcname = f"{base} ({k}).{ext}"
                                    k += 1
                                used_arcnames.add(arcname)
                                zf.write(str(tmp_audio), arcname=arcname, compress_type=zipfile.ZIP_STORED)
                            finally:
                                # P3-5：finally 连带清理 .part 残片（原实现只删正文，
                                # 取消/失败时残片要等 1 小时缓存清扫兜底）
                                _podcast_cleanup_files([str(tmp_audio)])
                            # 首集附带封面，便于识别
                            if idx == 1 and ep.get('cover_url'):
                                try:
                                    cover = fetch_cover_bytes(ep['cover_url'])
                                    if cover:
                                        zf.writestr("cover.jpg", cover, compress_type=zipfile.ZIP_STORED)
                                except Exception:
                                    pass
                            ok_count += 1
                            _update_progress(f"{label} 完成")
                        except DownloadCanceled:
                            raise
                        except Exception as e:
                            failed.append(f"{ep['name']}({e})")
                            _update_progress()
                    finally:
                        BATCH_ZIP_SEM.release()

        # 第 91 条（P1-1）：走到这里说明 ZIP with 块正常退出、中央目录完整，才允许发布
        zip_valid = True

        if ok_count == 0:
            raise DownloadException(f"全部单集下载失败: {'; '.join(failed[:3])}")

        # 第 91 条（P1-1）：ZIP 未正常完成（磁盘满写坏中央目录等）——不发布坏包，按全额退费收敛
        if not zip_valid:
            if zip_tmp_path:
                try:
                    os.remove(zip_tmp_path)
                except OSError:
                    pass
                zip_tmp_path = None
            refunded = _settle_batch_billing(task_id, 0, 'error')
            _mark_task_terminal(task_id, 'error',
                                f"ZIP 打包失败（可能磁盘空间不足），已退回 {refunded} 次" if refunded
                                else "ZIP 打包失败（可能磁盘空间不足），费用未扣或已退回")
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['failed'] = t.get('failed', 0) + ok_count
                    t['refunded'] = refunded
            api_service.logger.error(f"播客打包构建失败未发布: {task_id} ok_count={ok_count} 退回{refunded}次")
            return

        # F42：最终发布前的取消检查（末段取消不得覆盖为 done）
        if cancel_ev.is_set():
            raise DownloadCanceled("任务已取消")
        refunded = _settle_batch_billing(task_id, ok_count)
        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS.get(task_id)
            # S3：发布前锁内复查取消/失效状态（同音乐批量）
            if t is None or t.get('status') in ('canceled', 'error'):
                raise DownloadCanceled("任务已取消")
            if cancel_ev.is_set():
                raise DownloadCanceled("任务已取消")
            t['status'] = 'done'
            t['completed_at'] = time.time()
            t['done'] = ok_count + len(failed)
            t['failed'] = len(failed)
            t['msg'] = f"成功{ok_count} 失败{len(failed)}" + (f" 退回{refunded}次" if refunded else '')
            t['refunded'] = refunded
            t['result'] = {
                'zip_path': zip_tmp_path,
                'filename': f"播客_{radio_name}_{ok_count}集.zip",
                'audio_files': [],
            }
        try:
            first_name = episodes[0].get('name') if episodes else ''
            _record_log('下载', remote_ip, f"[播客打包] {radio_name} · {first_name}")
        except Exception:
            pass
        api_service.logger.info(f"播客打包完成: {radio_name} 成功{ok_count} 失败{len(failed)} ({task_id})")
    except DownloadCanceled:
        # F24：部分成功后取消——已入包部分照常交付，未完成部分按账本退费
        # 第 91 条（P1-1）：ZIP 未正常完成（写坏）时不按 ok_count 交付——按全额退费收敛
        delivered = ok_count if zip_valid else 0
        refunded = _settle_batch_billing(task_id, delivered, 'canceled')
        if delivered > 0 and zip_tmp_path:
            _mark_task_terminal(task_id, 'canceled',
                                f"已取消（已打包 {ok_count} 集可领取）" +
                                (f"，退回 {refunded} 次" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['refunded'] = refunded
                    t['result'] = {
                        'zip_path': zip_tmp_path,
                        'filename': f"播客_{radio_name or '打包'}_{ok_count}集.zip",
                        'audio_files': [],
                    }
        else:
            _mark_task_terminal(task_id, 'canceled',
                                '任务已取消' + (f"（已退回 {refunded} 次下载次数）" if refunded else ''))
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id)
                if t is not None:
                    t['refunded'] = refunded
            if zip_tmp_path:
                try:
                    os.remove(zip_tmp_path)
                except OSError:
                    pass
        api_service.logger.info(f"播客打包已取消: {task_id}（成功{ok_count} 退回{refunded}次）")
    except DownloadException as e:
        delivered = ok_count if zip_valid else 0
        refunded = _settle_batch_billing(task_id, delivered)
        with DOWNLOAD_TASKS_LOCK:
            _t = DOWNLOAD_TASKS.get(task_id)
            # 第 100 条（T1 不变量）：终态先到先得——已终态（如用户取消/超时兜底）
            # 不再被覆盖为 error（堵 canceled→error 非法迁移边）
            if _t and _t.get('status') not in ('done', 'error', 'canceled'):
                _t['status'] = 'error'
                _t['completed_at'] = time.time()   # F38：保留期从完成时刻起算
                _t['msg'] = str(e) + (f"（已退回 {refunded} 次下载次数）" if refunded else '')
                _t['refunded'] = refunded
            elif _t:
                _t['refunded'] = refunded
        if zip_tmp_path:
            try:
                os.remove(zip_tmp_path)
            except OSError:
                pass
        api_service.logger.error(f"播客打包失败: {task_id} {e}（退回{refunded}次）")
    except Exception as e:
        # 第 97 条（对抗复审）：非预期异常原文 logger 先行，用户可见文案泛化
        # （DownloadException 的文案是我们自己拼的用户可读文本，保留 str(e)）
        api_service.logger.error(f"播客打包异常: {task_id} {e}\n{traceback.format_exc()}")
        delivered = ok_count if zip_valid else 0
        refunded = _settle_batch_billing(task_id, delivered)
        with DOWNLOAD_TASKS_LOCK:
            _t = DOWNLOAD_TASKS.get(task_id)
            # 第 100 条（T1 不变量）：同上——已终态不再覆盖为 error
            if _t and _t.get('status') not in ('done', 'error', 'canceled'):
                _t['status'] = 'error'
                _t['completed_at'] = time.time()   # F38：保留期从完成时刻起算
                _t['msg'] = '打包失败，请稍后重试' + (f"（已退回 {refunded} 次下载次数）" if refunded else '')
                _t['refunded'] = refunded
            elif _t:
                _t['refunded'] = refunded
        if zip_tmp_path:
            try:
                os.remove(zip_tmp_path)
            except OSError:
                pass
        api_service.logger.error(f"播客打包异常: {task_id} {e}（退回{refunded}次）\n{traceback.format_exc()}")


def _task_delivery_copy(task_id: str, src: Path, filename: str) -> str:
    """把共享缓存文件复制/硬链接为任务专属交付文件（F27：任务成果与共享缓存分离，
    任何任务的清理都不会再删掉别的任务的成果）"""
    task_dir = api_service.downloads_path / 'tasks' / task_id
    task_dir.mkdir(parents=True, exist_ok=True)
    dst = task_dir / filename
    if dst.exists():
        return str(dst)
    try:
        os.link(str(src), str(dst))   # 同卷硬链接：零拷贝
    except OSError:
        shutil.copy2(str(src), str(dst))
    return str(dst)


# 第 91 条（P3）：_cleanup_task_dir 死代码删除——worker 直接 rmtree、监控线程直接
# rmtree，本函数全文件零调用（审计确认）。


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"""
    import tempfile as _tempfile

    file_path_str: str | None = None
    zip_tmp_path: str | None = None
    task_dir_path: str | None = None
    try:
        with DOWNLOAD_TASKS_LOCK:
            task = DOWNLOAD_TASKS[task_id]
            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,
            write_meta=write_meta,
            meta_fields=meta_fields,
            cookies=cookies,
            cancel_event=cancel_ev,
            music_info=mi,
            progress_cb=_progress_cb,
        )
        if not download_result.success:
            raise DownloadException(download_result.error_message or "下载失败")
        # F42：下载完成后的每一阶段都可能已被取消，发布前统一校验
        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)
        # F27：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)
        task_dir_path = str(Path(file_path_str).parent)

        if need_zip:
            fd, zip_tmp_path = _tempfile.mkstemp(prefix='single_zip_', suffix='.zip',
                                                 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)
            # F42：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 = {
                'file_path': file_path_str,
                'filename': filename,
                'mimetype': f"audio/{music_info['file_type']}",
                'audio_files': [file_path_str],
            }

        # F42：最终发布前的取消检查（末段取消不得覆盖为 done）
        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
        # C1：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}")
    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}")
    except Exception as e:
        # 第 97 条（P3）：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（第 84 条教训：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')
        try:
            auth_system.ledger_settle(task_id, 0, 'error')
        except Exception:
            pass
        if task_dir_path:
            shutil.rmtree(task_dir_path, ignore_errors=True)