From 82a662bd035d03af29fa579ee3056bf54c4e4e51 Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <ste.pigozzi@gmail.com>
Date: Mon, 18 Nov 2019 00:02:36 +0100
Subject: [PATCH] Change things

---
 royalnet/backpack/commands/summon.py          |  2 +-
 royalnet/bard/discordbard.py                  | 76 +++++++++++++++++++
 royalnet/bard/errors.py                       |  4 +
 .../{serf/discord => bard}/fileaudiosource.py |  7 ++
 4 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 royalnet/bard/discordbard.py
 rename royalnet/{serf/discord => bard}/fileaudiosource.py (87%)

diff --git a/royalnet/backpack/commands/summon.py b/royalnet/backpack/commands/summon.py
index 97585f19..decfc408 100644
--- a/royalnet/backpack/commands/summon.py
+++ b/royalnet/backpack/commands/summon.py
@@ -28,7 +28,7 @@ class SummonCommand(Command):
         # noinspection PyUnresolvedReferences
         message: discord.Message = data.message
         member: Union[discord.User, discord.Member] = message.author
-        serf: DiscordSerf = self.interface.bot
+        serf: DiscordSerf = self.interface.serf
         client: discord.Client = serf.client
         channel_name: Optional[str] = args.joined()
 
diff --git a/royalnet/bard/discordbard.py b/royalnet/bard/discordbard.py
new file mode 100644
index 00000000..548f29e0
--- /dev/null
+++ b/royalnet/bard/discordbard.py
@@ -0,0 +1,76 @@
+from typing import Optional, AsyncGenerator, List, Tuple, Any, Dict
+from .ytdldiscord import YtdlDiscord
+from .fileaudiosource import FileAudioSource
+from .errors import UnsupportedError
+
+
+class DiscordBard:
+    """An abstract representation of a music sequence.
+
+    Possible implementation may be playlist, song pools, multilayered tracks, and so on."""
+
+    def __init__(self):
+        """Create manually a :class:`DiscordBard`.
+
+        Warning:
+            Avoid calling this method, please use :meth:`create` instead!"""
+        self.now_playing: Optional[YtdlDiscord] = None
+        """The :class:`YtdlDiscord` that's currently being played."""
+
+        self.generator: \
+            AsyncGenerator[FileAudioSource, Tuple[Tuple[Any, ...], Dict[str, Any]]] = self._generate_generator()
+        """The AsyncGenerator responsible for deciding the next song that should be played."""
+
+    async def _generate_generator(self) -> AsyncGenerator[FileAudioSource, Tuple[Tuple[Any, ...], Dict[str, Any]]]:
+        """Create an async generator that returns the next source to be played;
+        it can take a args+kwargs tuple in input to optionally select a different source.
+
+        The generator should ``yield`` once before doing anything else."""
+        args, kwargs = yield
+        raise NotImplementedError()
+
+    @classmethod
+    async def create(cls) -> "DiscordBard":
+        """Create an instance of the :class:`DiscordBard`, and initialize its async generator."""
+        bard = cls()
+        # noinspection PyTypeChecker
+        none = bard.generator.asend(None)
+        assert none is None
+        return bard
+
+    async def next(self, *args, **kwargs) -> Optional[FileAudioSource]:
+        """Get the next :class:`FileAudioSource` that should be played, and change :attr:`.now_playing`.
+
+        Args and kwargs can be passed to the generator to select differently."""
+        fas: Optional[FileAudioSource] = await self.generator.asend((args, kwargs))
+        self.now_playing = fas
+        return fas
+
+    async def add(self, ytd: YtdlDiscord):
+        """Add a new :class:`YtdlDiscord` to the :class:`DiscordBard`, if possible.
+
+        Raises:
+            UnsupportedError: If it isn't possible to add new :class:`YtdlDiscord` to the :class:`DiscordBard`.
+        """
+        raise UnsupportedError()
+
+    async def peek(self) -> Optional[List[YtdlDiscord]]:
+        """Return the contents of the :class:`DiscordBard` as a :class:`list`, if possible.
+
+        Raises:
+            UnsupportedError: If it isn't possible to display the :class:`DiscordBard` state as a :class:`list`.
+        """
+        raise UnsupportedError()
+
+    async def remove(self, ytd: YtdlDiscord):
+        """Remove a :class:`YtdlDiscord` from the :class:`DiscordBard`, if possible.
+
+        Raises:
+            UnsupportedError: If it isn't possible to remove the :class:`YtdlDiscord` from the :class:`DiscordBard`.
+        """
+        raise UnsupportedError()
+
+    async def cleanup(self):
+        """Enqueue the deletion of all :class:`YtdlDiscord` contained in the :class:`DiscordBard`, and return only once
+        all deletions are complete."""
+        raise NotImplementedError()
diff --git a/royalnet/bard/errors.py b/royalnet/bard/errors.py
index 1368a7cb..60253203 100644
--- a/royalnet/bard/errors.py
+++ b/royalnet/bard/errors.py
@@ -12,3 +12,7 @@ class NotFoundError(YtdlError):
 
 class MultipleFilesError(YtdlError):
     """The resource contains multiple media files."""
+
+
+class UnsupportedError(BardError):
+    """The method you tried to call on a :class:`DiscordBard` is not supported on that particular Bard."""
\ No newline at end of file
diff --git a/royalnet/serf/discord/fileaudiosource.py b/royalnet/bard/fileaudiosource.py
similarity index 87%
rename from royalnet/serf/discord/fileaudiosource.py
rename to royalnet/bard/fileaudiosource.py
index 6f97746a..c0695761 100644
--- a/royalnet/serf/discord/fileaudiosource.py
+++ b/royalnet/bard/fileaudiosource.py
@@ -1,3 +1,6 @@
+from typing import Optional
+from .ytdlinfo import YtdlInfo
+
 try:
     import discord
 except ImportError:
@@ -13,6 +16,10 @@ class FileAudioSource(discord.AudioSource):
         This AudioSource will consume (and close) the passed stream."""
 
     def __init__(self, file):
+        """Create a FileAudioSource.
+
+        Arguments:
+            file: the file to be played back."""
         self.file = file
 
     def __repr__(self):