refactor: 推进后端分层架构治理

app/application/download/__init__.py

@@ -0,0 +1 @@
+"""下载应用服务。"""

app/application/download/tasks.py

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+"""下载任务查询与控制应用服务。"""
+
+from typing import Callable, List, Optional
+
+from app.schemas.transfer import DownloaderTorrent
+from app.schemas.types import TorrentStatus
+
+
+class DownloadTaskService:
+    """通过下载器和历史端口查询、启停及删除下载任务。"""
+
+    def __init__(
+        self,
+        list_torrents: Callable[..., List[DownloaderTorrent]],
+        get_history_by_hashes: Callable[[list[str]], dict],
+        start_torrents: Callable[..., bool],
+        stop_torrents: Callable[..., bool],
+        remove_torrents: Callable[..., bool],
+    ) -> None:
+        """注入下载器操作和历史读取端口。"""
+        self._list_torrents = list_torrents
+        self._get_history_by_hashes = get_history_by_hashes
+        self._start_torrents = start_torrents
+        self._stop_torrents = stop_torrents
+        self._remove_torrents = remove_torrents
+
+    def downloading(self, name: Optional[str] = None) -> List[DownloaderTorrent]:
+        """查询下载中任务，并附加对应下载历史的媒体与用户信息。"""
+        torrents = self._list_torrents(
+            downloader=name,
+            status=TorrentStatus.DOWNLOADING,
+        )
+        if not torrents:
+            return []
+        history_map = self._get_history_by_hashes(
+            [torrent.hash for torrent in torrents if torrent.hash]
+        )
+        for torrent in torrents:
+            history = history_map.get(torrent.hash)
+            if not history:
+                continue
+            torrent.media = {
+                "media_source": history.media_source,
+                "media_id": history.media_id,
+                "type": history.type,
+                "title": history.title,
+                "season": history.seasons,
+                "episode": history.episodes,
+                "image": history.poster,
+                "poster": history.poster,
+                "backdrop": history.image,
+            }
+            torrent.site_name = history.torrent_site
+            torrent.userid = history.userid
+            torrent.username = history.username
+        return torrents
+
+    def set_downloading(
+        self,
+        hash_str: str,
+        operation: str,
+        name: Optional[str] = None,
+    ) -> bool:
+        """按 start/stop 操作控制单个下载任务。"""
+        if operation == "start":
+            return self._start_torrents(hashs=[hash_str], downloader=name)
+        if operation == "stop":
+            return self._stop_torrents(hashs=[hash_str], downloader=name)
+        return False
+
+    def remove_downloading(
+        self,
+        hash_str: str,
+        name: Optional[str] = None,
+    ) -> bool:
+        """删除单个下载任务。"""
+        return self._remove_torrents(hashs=[hash_str], downloader=name)