[Audio] V3/auto autostart only (#1420)

* Download jar at audio load

* Messy...

* Remove leftover log file stuff

* Keep application.yml

* Damn you windows

redbot/cogs/audio/__init__.py

@@ -1,8 +1,57 @@
+from pathlib import Path
+from aiohttp import ClientSession
+import shutil
+import asyncio
+
 from .audio import Audio
+from .manager import start_lavalink_server
 from discord.ext import commands
+from redbot.core.data_manager import cog_data_path
+
+LAVALINK_BUILD = 3065
+LAVALINK_BUILD_URL = (
+    "https://ci.fredboat.com/repository/download/"
+    "Lavalink_Build/{}:id/Lavalink.jar?guest=1"
+).format(LAVALINK_BUILD)
+
+LAVALINK_DOWNLOAD_DIR = cog_data_path(raw_name="Audio")
+LAVALINK_JAR_FILE = LAVALINK_DOWNLOAD_DIR / "Lavalink.jar"
+
+APP_YML_FILE = LAVALINK_DOWNLOAD_DIR / "application.yml"
+BUNDLED_APP_YML_FILE = Path(__file__).parent / "application.yml"
+
+
+async def download_lavalink(session):
+    with LAVALINK_JAR_FILE.open(mode='wb') as f:
+        async with session.get(LAVALINK_BUILD_URL) as resp:
+            while True:
+                chunk = await resp.content.read(512)
+                if not chunk:
+                    break
+                f.write(chunk)
+
+
+async def maybe_download_lavalink(loop, cog):
+    jar_exists = LAVALINK_JAR_FILE.exists()
+    current_build = await cog.config.current_build()
+
+    if not jar_exists or current_build < LAVALINK_BUILD:
+        LAVALINK_DOWNLOAD_DIR.mkdir(parents=True, exist_ok=True)
+        with ClientSession(loop=loop) as session:
+            await download_lavalink(session)
+        await cog.config.current_build.set(LAVALINK_BUILD)
+
+    shutil.copyfile(str(BUNDLED_APP_YML_FILE), str(APP_YML_FILE))
 
 
 async def setup(bot: commands.Bot):
     cog = Audio(bot)
-    await cog.init_config()
-    bot.add_cog(cog)
+    await maybe_download_lavalink(bot.loop, cog)
+    await start_lavalink_server(bot.loop)
+
+    async def _finish():
+        await asyncio.sleep(10)
+        await cog.init_config()
+        bot.add_cog(cog)
+
+    bot.loop.create_task(_finish())