# -*- coding: utf-8 -*-
"""播客单集与整台打包 worker。

整台打包的骨架（状态机 / 暂停 / 名额 / 终态收敛 / 结算）在
:mod:`services._zipcore`，本模块只保留播客侧策略：清单组装（整台或指定单集）、
逐集顺序下载、按实际集数补扣、单条目入包（首集附封面）。

下载走 core.http_client 的流式响应（原先是 services.streaming 这个同步流垫片），
落盘写文件是阻塞 IO、ZIP 组装是整段拷贝，均经 ``asyncio.to_thread`` 卸载。
"""

import asyncio
import os
import shutil
import tempfile
import threading
import time
import traceback
import zipfile
from dataclasses import dataclass
from pathlib import Path
from typing import Any

import auth_system
from core.http_client import client as _http
from core.http_client import iter_chunks
from core.state import (
    DOWNLOAD_TASKS,
    DOWNLOAD_TASKS_LOCK,
)
from music_api import (
    APIException,
    podcast,
)
from music_downloader import (
    DownloadCanceled,
    DownloadException,
    fetch_cover_bytes,
)

from ._shared import (
    _record_log,
)
from ._taskcore import (
    _mark_task_terminal,
    _settle_batch_billing,
)
from ._zipcore import (
    ZipContext,
    ZipJob,
    run_zip_job,
)
from .api_service import (
    api_service,
)
from .downloads import (
    _abort_if_canceled,
)

# 播客流式下载的上游头（与音频直链 CDN 的口径一致）
_STREAM_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/',
}


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


def _remove_quietly(path: Path) -> None:
    """删除文件并忽略失败（Windows 上句柄未释放时 os.remove 会抛 OSError）。"""
    try:
        os.remove(str(path))
    except OSError:
        pass


def _report_progress(task_id: str, progress_label: str, done: int, total: int) -> None:
    """把一次进度写进任务表；task_id 为空或任务不在 running 时只计算不写。

    msg 的计算与「是否真有可取的任务」无关（历史实现如此），故 task_id 为空时
    仍会格式化字符串——保持这一无害的既有行为，不做「优化」。
    """
    pct = 0
    if total:
        pct = min(99, int(done / total * 100))
        msg = (f"{progress_label} {pct}% · "
               f"{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 not task_id:
        return
    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))


async def _stream_to_part(url: str, part: Path, total_size: int, cancel_ev: threading.Event,
                          task_id: str, progress_label: str) -> tuple[int, int]:
    """把响应体流式写入 part，返回 (已写字节数, 期望总大小)。

    期望总大小取入参，缺失时回落到 Content-Length（仍可能为 0，表示上游没给）。
    """
    done = 0
    last_update = 0.0
    resp = await _http.open('GET', url, headers=_STREAM_HEADERS, timeout=60)
    try:
        if resp.status >= 400:
            raise DownloadException(f"上游返回 {resp.status}")
        total = total_size or int(resp.headers.get('Content-Length') or 0)
        with open(part, 'wb') as f:
            async for chunk in iter_chunks(resp, 256 * 1024):
                if cancel_ev.is_set():
                    raise DownloadCanceled("任务已取消")
                if not chunk:
                    continue
                f.write(chunk)
                done += len(chunk)
                now = time.time()
                if now - last_update > 0.5:
                    last_update = now
                    _report_progress(task_id, progress_label, done, total)
    finally:
        resp.close()
    return done, total


def _verify_downloaded(target: Path, done: int, total_size: int) -> None:
    """完整性校验：不达标则删掉已落地的文件并抛 DownloadException。

    为什么非要校验：CDN 提前断流时流式读取会「正常」结束，文件静默截断。
    已知期望大小时要求**精确相等**（API 报的大小与实际一致；放宽到 95% 容差会
    交付截断的坏文件还照扣次数）；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:
        _remove_quietly(target)
        raise DownloadException(f"下载不完整（{done}/{total_size} 字节），请重试")
    if not total_size and done <= 0:
        _remove_quietly(target)
        raise DownloadException("下载内容为空，请重试")


async 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。

    自动加入全局下载闸排队；每 0.5s 更新一次任务进度消息。
    取消时 .part 会留存（不删）——下次下载同名文件直接覆盖，是既有行为。
    """
    part = target.with_name(target.name + '.part')
    # 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 await sem.acquire_cancellable(cancel_ev):
        raise DownloadCanceled("任务已取消")
    try:
        done, _total = await _stream_to_part(url, part, total_size, cancel_ev, task_id, progress_label)
    finally:
        sem.release()
    if part.exists():
        part.replace(target)
    _verify_downloaded(target, done, total_size)
    return done


async 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 = await podcast.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


@dataclass(frozen=True)
class _PodcastTaskSpec:
    """worker 启动时从任务表取出的不可变执行参数。

    ``program_id`` 标注 Any 与单曲 worker（SingleTaskParams.music_id）同因：
    任务 params 里历史存的是数字字符串，下游上游解析各自处理，worker 只透传
    不做 int() 转换（那是行为变更）。
    """

    program_id: Any
    quality: str
    need_zip: bool
    cookies: dict[str, Any]
    remote_ip: str
    cancel_ev: threading.Event


@dataclass(frozen=True)
class _PodcastTarget:
    """单集落盘目标与交付命名。

    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）；
    交付名保持干净（不带 ID）。
    """

    task_dir: Path
    target: Path
    filename: str   # 交付名（含扩展名）
    base: str       # 交付名去扩展名（ZIP 条目名与封面名共用）
    name: str       # 单集原始名（info.txt 与操作记录用）
    ext: str


def _begin_podcast_task(task_id: str) -> _PodcastTaskSpec:
    """置 running 并取出执行参数（任务不存在时 KeyError → 通用 except 收敛 error）。"""
    with DOWNLOAD_TASKS_LOCK:
        task = DOWNLOAD_TASKS[task_id]
        task['status'] = 'running'
        task['msg'] = '解析单集信息...'
    params = task['params']
    return _PodcastTaskSpec(
        program_id=params['program_id'],
        quality=params['quality'],
        need_zip=params['need_zip'],
        cookies=params['cookies'],
        remote_ip=params.get('remote_ip') or '-',
        cancel_ev=task['cancel'],
    )


def _prepare_podcast_target(task_id: str, program_id: Any, program: dict[str, Any],
                            url_info: dict[str, Any]) -> _PodcastTarget:
    """组装文件名与任务专属目录（顺带 mkdir）。"""
    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('.')
    task_dir = api_service.downloads_path / 'tasks' / task_id
    task_dir.mkdir(parents=True, exist_ok=True)
    return _PodcastTarget(
        task_dir=task_dir,
        target=task_dir / f"{base} [{program_id}].{ext}",
        filename=f"{base}.{ext}",
        base=base,
        name=name,
        ext=ext,
    )


def _write_podcast_zip(zip_path: str, file_path_str: str, arcname: str, base: str,
                       name: str, program: dict[str, Any], url_info: dict[str, Any],
                       fallback_quality: str, cover: bytes = b'') -> None:
    """单集入包：音频 + 封面（可选，失败不炸任务）+ info.txt。

    info.txt 不再写直链（真实 URL 不应随交付文件外泄）。
    封面字节由调用方先取好（网络等待留在协程里），本函数只做阻塞的落盘组装。
    """
    with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED) as zf:
        zf.write(file_path_str, arcname=arcname)
        if cover:
            zf.writestr(f"{base}.jpg", cover)
        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', fallback_quality))}\n"
        )
        zf.writestr("info.txt", info_txt)


def _podcast_file_result(file_path_str: str, filename: str, ext: str) -> dict[str, Any]:
    """不打包时的交付形状。"""
    return {
        'file_path': file_path_str,
        'filename': filename,
        'mimetype': f"audio/{ext}",
        'audio_files': [file_path_str],
    }


async def _podcast_zip_result(prep: _PodcastTarget, file_path_str: str,
                              program: dict[str, Any], url_info: dict[str, Any],
                              spec: _PodcastTaskSpec) -> dict[str, Any]:
    """打包交付形状：ZIP 中间文件建在任务目录下（失败收尾 rmtree 一并覆盖）。"""
    cover: bytes = b''
    cover_url = program.get('cover_url') or ''
    if cover_url:
        try:
            cover = await fetch_cover_bytes(cover_url) or b''
        except Exception:
            cover = b''
    fd, zip_tmp_path = tempfile.mkstemp(prefix='podcast_zip_', suffix='.zip',
                                        dir=str(prep.task_dir))
    os.close(fd)
    await asyncio.to_thread(_write_podcast_zip, zip_tmp_path, file_path_str,
                            arcname=prep.filename, base=prep.base, name=prep.name,
                            program=program, url_info=url_info,
                            fallback_quality=spec.quality, cover=cover)
    return {
        'file_path': file_path_str,
        'zip_path': zip_tmp_path,
        'filename': f"{prep.base}.zip",
        'mimetype': 'application/zip',
        'audio_files': [file_path_str],
    }


async def _publish_podcast_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（与单曲 _publish_single_task 同口径）。
    """
    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:
        await asyncio.to_thread(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})")


async def _fail_podcast_task(task_id: str, status: str, msg: str, ledger_status: str,
                             task_dir: Path | None) -> None:
    """失败/取消的统一收尾：置终态 → 退款 → 清掉任务目录（含 ZIP 中间件）。"""
    await _mark_task_terminal(task_id, status, msg)
    try:
        await asyncio.to_thread(auth_system.ledger_settle, task_id, 0, ledger_status)
    except Exception:
        pass
    if task_dir is not None:
        await asyncio.to_thread(shutil.rmtree, str(task_dir), ignore_errors=True)


async 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。
    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。
    """
    task_dir: Path | None = None
    try:
        spec = _begin_podcast_task(task_id)
        program = await podcast.get_program_detail(spec.program_id, spec.cookies)
        url_info = await _podcast_resolve_audio(program, spec.quality, spec.cookies)
        prep = _prepare_podcast_target(task_id, spec.program_id, program, url_info)
        task_dir = prep.task_dir

        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS[task_id]
            t['msg'] = '下载中...'
        await _podcast_stream_download(url_info['url'], prep.target, url_info.get('size', 0),
                                       spec.cancel_ev, task_id, '下载中')
        _abort_if_canceled(spec.cancel_ev)
        file_path_str = str(prep.target)

        if spec.need_zip:
            result = await _podcast_zip_result(prep, file_path_str, program, url_info, spec)
        else:
            result = _podcast_file_result(file_path_str, prep.filename, prep.ext)
        # 打包阶段同样以取消检查收口（末段取消不得覆盖为 done）
        _abort_if_canceled(spec.cancel_ev)

        await _publish_podcast_task(task_id, result, spec.remote_ip, prep.name, prep.filename)
    except DownloadCanceled:
        api_service.logger.info(f"播客单集下载已取消: {task_id}")
        await _fail_podcast_task(task_id, 'canceled', '任务已取消', 'canceled', task_dir)
    except DownloadException as e:
        api_service.logger.error(f"播客单集下载失败: {task_id} {e}")
        await _fail_podcast_task(task_id, 'error', str(e), 'error', task_dir)
    except Exception as e:
        # 非预期异常原文 logger 先行，用户可见文案泛化（教训）
        api_service.logger.error(f"播客单集下载异常: {task_id} {e}\n{traceback.format_exc()}")
        await _fail_podcast_task(task_id, 'error', '下载失败，请稍后重试', 'error', task_dir)


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


@dataclass(frozen=True)
class _EpisodePayload:
    """一集下载完成后的入包素材（下载协程产出，落包协程消费）。"""

    path: str
    base: str
    ext: str


class _PodcastZipJob(ZipJob):
    """整台播客打包：逐集顺序下载（窗口=1）→ 单条目入包，首集附封面。

    并发刻意等于音乐批量：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
    下载闸约束。原实现不受批量并发控制，多用户同时打包会无限并发。
    """

    tag = '播客打包'
    noun = '集'
    item_noun = '单集'
    tmp_prefix = 'podcast_batch_'
    start_msg = '解析单集列表...'
    concurrency = 1

    def __init__(self) -> None:
        self._radio_name = ''

    async def prepare(self, params: dict[str, Any], task_id: str, failed: list[str]) -> list[Any]:
        cookies = params['cookies']
        radio_id = params['radio_id']
        limit = params['limit']
        # 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 = await podcast.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 (params.get('ids') or []):
                try:
                    prog = await podcast.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")

        self._radio_name = _podcast_safe_name(params.get('radio_name') or '', '播客')
        return episodes

    async def supplement(self, task_id: str, params: dict[str, Any], count: int) -> None:
        """按次计费补扣：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 = count - int(params.get('billed') or 1)
            if _buid and _extra > 0:
                if not await asyncio.to_thread(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'] = count
        except DownloadCanceled:
            raise
        except DownloadException:
            raise
        except Exception as e:
            raise DownloadException(f"补扣下载次数异常: {e}") from e

    async def download_one(self, item: Any, idx: int, ctx: ZipContext) -> _EpisodePayload:
        ep = item
        label = f"[{idx}/{ctx.total}] {ep['name'][:24]}"
        ctx.progress(f"{label} 解析中...")
        cookies = ctx.params['cookies']
        prog = ep.get('detail') or await podcast.get_program_detail(ep['id'], cookies)
        url_info = await _podcast_resolve_audio(prog, ctx.params['quality'], cookies)
        ctx.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']}")
        # 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 = ctx.work_dir / f"podcast_zip_tmp_{ctx.task_id}_{idx}.{ext}"
        try:
            await _podcast_stream_download(url_info['url'], tmp_audio,
                                           url_info.get('size', 0), ctx.cancel_ev)
        except Exception:
            # 下载失败即清（.part 残片同清）；成功时由 write_entry 的 finally 清
            _podcast_cleanup_files([str(tmp_audio)])
            raise
        return _EpisodePayload(path=str(tmp_audio), base=base, ext=ext)

    async def write_entry(self, item: Any, idx: int, payload: _EpisodePayload, ctx: ZipContext) -> None:
        ep = item
        try:
            # 重名条目自动追加序号（同名单集/同号不同集不得互相覆盖）
            arcname = f"{payload.base}.{payload.ext}"
            k = 2
            while arcname in ctx.used_arcnames:
                arcname = f"{payload.base} ({k}).{payload.ext}"
                k += 1
            ctx.used_arcnames.add(arcname)
            await asyncio.to_thread(ctx.zf.write, payload.path, arcname=arcname,
                                    compress_type=zipfile.ZIP_STORED)
            # 首集附带封面，便于识别
            if idx == 1 and ep.get('cover_url'):
                try:
                    cover = await fetch_cover_bytes(ep['cover_url'])
                    if cover:
                        ctx.zf.writestr("cover.jpg", cover, compress_type=zipfile.ZIP_STORED)
                except Exception:
                    pass
        finally:
            # 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([payload.path])

    def fail_label(self, item: Any) -> str:
        """失败文案用单集名而非整个条目字典（引擎拼成「单集名(异常)」）。"""
        return str(item.get('name') or '')

    def done_msg(self, item: Any, idx: int, ctx: ZipContext) -> str:
        return f"[{idx}/{ctx.total}] {item['name'][:24]} 完成"

    def zip_filename(self, ok_count: int) -> str:
        return f"播客_{self._radio_name or '打包'}_{ok_count}集.zip"

    def log_label(self) -> str:
        return f"{self._radio_name} "

    def all_failed_msg(self, failed: list[str], refunded: int) -> str:
        return f"全部单集下载失败: {'; '.join(failed[:3])}" + (
            f"（已退回 {refunded} 次下载次数）" if refunded else '')

    async def on_delivered(self, items: list[Any], task_id: str, params: dict[str, Any]) -> None:
        try:
            first_name = items[0].get('name') if items else ''
            _record_log('下载', params.get('remote_ip') or '-',
                        f"[播客打包] {self._radio_name} · {first_name}")
        except Exception:
            pass


async 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）"""
    await run_zip_job(_PodcastZipJob(), task_id, settle=_settle_batch_billing)