feat: lazy load for lyrics (#156)

* feat(lava): add async method fetch_and_update_lyrics for fetching and updating lyrics, improve handling of lyrics loading in generate_lyrics_embed, and update language files with new loading messages

* fix(lava/classes/player.py): fix the line length of doc string

* feat(lava/classes/player.py): add docstring to the fetch_and_update_lyrics method

lava/classes/player.py

@@ -40,7 +40,16 @@ def __init__(self, bot: "Bot", guild_id: int, node: Node):
         self._lyrics: Union[Lyrics[LyricLine], None] = None
 
     @property
-    def lyrics(self) -> Union[Lyrics[LyricLine], None]:
+    def guild(self) -> Optional[Guild]:
+        if not self._guild:
+            self._guild = self.bot.get_guild(self.guild_id)
+
+        return self._guild
+
+    async def fetch_and_update_lyrics(self) -> Union[Lyrics[LyricLine], None]:
+        """
+        Fetch and update the lyrics to the cache for the current playing track.
+        """
         if self._lyrics == MISSING:
             return MISSING
 
@@ -60,13 +69,6 @@ def lyrics(self) -> Union[Lyrics[LyricLine], None]:
 
         return self._lyrics
 
-    @property
-    def guild(self) -> Optional[Guild]:
-        if not self._guild:
-            self._guild = self.bot.get_guild(self.guild_id)
-
-        return self._guild
-
     async def check_autoplay(self) -> bool:
         """
         Check the autoplay status and add recommended tracks if enabled.
@@ -260,6 +262,9 @@ async def update_display(self,
         embeds = [await self.__generate_display_embed()]
 
         if self.is_playing and self.show_lyrics:
+            if self._lyrics is None:
+                _ = self.bot.loop.create_task(self.fetch_and_update_lyrics())
+
             embeds.append(await self.__generate_lyrics_embed())
 
         if interaction:
@@ -281,15 +286,25 @@ async def update_display(self,
         )
 
     async def __generate_lyrics_embed(self) -> Embed:
-        """Generate the lyrics embed for the player."""
-        if self.lyrics is MISSING:
+        """
+        Generate the lyrics embed for the player based on the cached lyrics.
+        Use fetch_and_update_lyrics to update.
+        """
+        if self._lyrics is None:
+            return Embed(
+                title=self.bot.get_text('display.lyrics.title', self.locale, '🎤 | 歌詞'),
+                description=self.bot.get_text('displa .lyrics.loading', self.locale, '正在載入歌詞...'),
+                color=Colour.blurple()
+            )
+
+        if self.fetch_and_update_lyrics is MISSING:
             return Embed(
                 title=self.bot.get_text('display.lyrics.title', self.locale, '🎤 | 歌詞'),
                 description=self.bot.get_text('display.lyrics.not_found', self.locale, '*你得自己唱出這首歌的歌詞*'),
                 color=Colour.red()
             )
 
-        lyrics_in_range = find_lyrics_within_range(self.lyrics, (self.position / 1000), 5.0)
+        lyrics_in_range = find_lyrics_within_range(self._lyrics, (self.position / 1000), 5.0)
 
         lyrics_text = '\n'.join(
             [

lava/cogs/events.py

@@ -48,7 +48,6 @@ async def on_track_start(self, event: TrackStartEvent):
         self.bot.logger.info("Received track start event for guild %s", player.guild)
 
         player.reset_lyrics()
-        _ = player.lyrics  # Fetch the lyrics
 
         try:
             await player.update_display()

locale/en_US.json

@@ -127,6 +127,7 @@
     "display.footer": "If you felt the quality of the music is kinda awful, maybe checking filters or switching region in voice channel setting will help",
     "display.lyrics.title": "🎤 | Lyrics",
     "display.lyrics.not_found": "*You need to sing the lyrics of this song yourself*",
+    "display.lyrics.loading": "Loading lyrics...",
     "display.control.pause": "Pause",
     "display.control.resume": "Resume",
     "display.control.previous": "Restart",

locale/zh_TW.json

@@ -127,6 +127,7 @@
     "display.footer": "如果你覺得音樂怪怪的，可以試著檢查看看效果器設定或是切換語音頻道地區",
     "display.lyrics.title": "🎤 | 歌詞",
     "display.lyrics.not_found": "*你得自己唱出這首歌的歌詞*",
+    "display.lyrics.loading": "正在載入歌詞...",
     "display.control.pause": "暫停",
     "display.control.resume": "繼續",
     "display.control.previous": "重新開始",