Add deezer module

bot/modules/deezer/downloader.py

@@ -0,0 +1,98 @@
+from attrs import define
+
+from io import BytesIO
+
+from .driver import DeezerDriver
+
+from . import track_formats
+from .util import UrlDecrypter, ChunkDecrypter
+from .song import FullSongItem
+
+
+@define
+class DeezerBytestream:
+    file: bytes
+    filename: str
+    song: FullSongItem
+
+    @classmethod
+    def from_bytestream(
+            cls,
+            bytestream: BytesIO,
+            filename: str,
+            full_song: FullSongItem
+    ):
+        bytestream.seek(0)
+        return cls(
+            file=bytestream.read(),
+            filename=filename,
+            song=full_song,
+        )
+
+
+@define
+class Downloader:
+    driver: DeezerDriver
+    song_id: int
+    track: dict
+    song: FullSongItem
+
+    @classmethod
+    async def build(
+            cls,
+            song_id: int,
+            driver: DeezerDriver
+    ):
+        track = await driver.reverse_get_track(song_id)
+        return cls(
+            song_id=song_id,
+            driver=driver,
+            track=track['results'],
+            song=await FullSongItem.from_deezer(track)
+        )
+
+    async def to_bytestream(self) -> DeezerBytestream:
+        quality = track_formats.MP3_128
+
+        decrypter = ChunkDecrypter.from_track_id(self.song_id)
+        i = 0
+        audio = BytesIO()
+
+        async for chunk in self.driver.engine.get_data_iter(
+                await self._get_download_url(quality=quality)
+        ):
+            if i % 3 > 0 or len(chunk) < 2 * 1024:
+                audio.write(chunk)
+            else:
+                audio.write(decrypter.decrypt_chunk(chunk))
+            i += 1
+
+        return DeezerBytestream.from_bytestream(
+            filename=self.song.full_name + track_formats.TRACK_FORMAT_MAP[quality].ext,
+            bytestream=audio,
+            full_song=self.song
+        )
+
+    async def _get_download_url(self, quality: str = 'MP3_128'):
+        md5_origin = self.track["MD5_ORIGIN"]
+        track_id = self.track["SNG_ID"]
+        media_version = self.track["MEDIA_VERSION"]
+
+        url_decrypter = UrlDecrypter(
+            md5_origin=md5_origin,
+            track_id=track_id,
+            media_version=media_version
+        )
+
+        return url_decrypter.get_url_for(track_formats.TRACK_FORMAT_MAP[quality])
+
+
+@define
+class DownloaderBuilder:
+    driver: DeezerDriver
+
+    async def from_id(self, song_id: int):
+        return await Downloader.build(
+            song_id=song_id,
+            driver=self.driver
+        )