Initial commit of source - working, but needs stubs for Cocoa

src/mpd_now_playable/mpd/artwork_cache.py

@@ -0,0 +1,49 @@
+from aiocache import Cache
+
+from ..async_tools import run_background_task
+from .types import CurrentSongResponse, MpdStateHandler
+
+CACHE_TTL = 60 * 10  # ten minutes
+
+
+def calc_album_key(song: CurrentSongResponse) -> str:
+	return f'{song["albumartist"]}:-:-:{song["album"]}'
+
+
+def calc_track_key(song: CurrentSongResponse) -> str:
+	return song["file"]
+
+
+class MpdArtworkCache:
+	mpd: MpdStateHandler
+	album_cache: 'Cache[bytes | None]'
+	track_cache: 'Cache[bytes | None]'
+
+	def __init__(self, mpd: MpdStateHandler):
+		self.mpd = mpd
+		self.album_cache = Cache()
+		self.track_cache = Cache()
+
+	async def get_cached_artwork(self, song: CurrentSongResponse) -> bytes | None:
+		art = await self.track_cache.get(calc_track_key(song))
+		if art:
+			return art
+
+		# If we don't have track artwork cached, go find some.
+		run_background_task(self.cache_artwork(song))
+
+		# Even if we don't have cached track art, we can try looking for cached album art.
+		art = await self.album_cache.get(calc_album_key(song))
+		if art:
+			return art
+
+		return None
+
+	async def cache_artwork(self, song: CurrentSongResponse) -> None:
+		art = await self.mpd.readpicture(song["file"])
+		try:
+			await self.album_cache.add(calc_album_key(song), art, ttl=CACHE_TTL)
+		except ValueError:
+			pass
+		await self.track_cache.set(calc_track_key(song), art, ttl=CACHE_TTL)
+		await self.mpd.refresh()