Add downloading song by query

bot/modules/youtube/downloader.py

@@ -0,0 +1,59 @@
+from attrs import define
+from pytube import YouTube, Stream
+
+from pydub import AudioSegment
+from io import BytesIO
+
+
+@define
+class YouTubeBytestream:
+    file: bytes
+    filename: str
+
+    @classmethod
+    def from_bytestream(
+            cls,
+            bytestream: BytesIO,
+            filename: str
+    ):
+        bytestream.seek(0)
+        return cls(
+            file=bytestream.read(),
+            filename=filename
+        )
+
+    @property
+    def dict(self):
+        return {
+            "file": self.file,
+            "filename": self.filename
+        }
+
+
+@define
+class Downloader:
+    audio_stream: Stream
+    filename: str
+
+    @classmethod
+    def from_id(cls, yt_id: str):
+        video = YouTube.from_id(yt_id)
+        audio_stream = video.streams.filter(
+            only_audio=True,
+        ).order_by('abr').desc().first()
+        return cls(
+            audio_stream=audio_stream,
+            filename=f'{audio_stream.default_filename}.mp3',
+        )
+
+    def to_bytestream(self):
+        audio_io = BytesIO()
+        self.audio_stream.stream_to_buffer(audio_io)
+        audio_io.seek(0)
+
+        return YouTubeBytestream.from_bytestream(
+            AudioSegment.from_file(
+                file=audio_io
+            ).export(BytesIO(), format='mp3', codec='libmp3lame'),
+            self.filename,
+        )