Rewrite Sergei in Elixir

.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

.gitignore

@@ -1 +1,22 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+sergei-*.tar
+
 .env

Dockerfile

@@ -1,14 +1,27 @@
-FROM python:3
+FROM elixir:alpine AS build_stage
 
-# Install dependencies
-RUN apt update
-RUN apt install -y ffmpeg
-RUN pip3 install discord.py python-dotenv pynacl
+# Config
+ENV MIX_ENV prod
+WORKDIR /opt/build
 
-WORKDIR /usr/src/app
-COPY . .
+# Dependendies
+COPY mix.* ./
+COPY config ./config
 
-RUN curl -L https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -o /usr/local/bin/yt-dlp
-RUN chmod a+rx /usr/local/bin/yt-dlp
+RUN mix local.hex --force && \
+  mix local.rebar --force && \
+  mix deps.get --only prod && \
+  mix deps.compile
 
-CMD ["python3", "main.py"]
+# Build project
+COPY lib ./lib
+RUN mix release sergei
+
+FROM elixir:alpine
+
+WORKDIR /opt/sergei
+RUN apk add ffmpeg yt-dlp
+COPY --from=build_stage /opt/build/_build/prod/rel/sergei /opt/sergei
+
+ENTRYPOINT ["/opt/sergei/bin/sergei"]
+CMD ["start"]

Justfile

@@ -0,0 +1,10 @@
+set dotenv-load
+
+deploy:
+    docker build -t godmaire/sergei:latest
+    docker tag godmaire/sergei:latest registry.digitalocean.com/godmaire/sergei:latest
+    docker push registry.digitalocean.com/godmaire/sergei:latest
+
+run:
+    mix deps.get
+    DISCORD_TOK=$DISCORD_TOK mix run --no-halt

config/config.exs

@@ -0,0 +1,4 @@
+import Config
+
+config :nostrum,
+  youtubedl: "/usr/bin/yt-dlp"

config/runtime.exs

@@ -0,0 +1,4 @@
+import Config
+
+config :nostrum,
+  token: System.get_env("DISCORD_TOK")

lib/sergei.ex

@@ -0,0 +1,5 @@
+defmodule Sergei do
+  @moduledoc """
+  Sergei is poggers.
+  """
+end

lib/sergei/application.ex

@@ -0,0 +1,24 @@
+defmodule Sergei.Application do
+  @moduledoc false
+  use Application
+
+  @impl true
+  def start(_type, _args) do
+    children = [
+      # Start the Consumer
+      Sergei.Consumer,
+      Sergei.Player,
+      Sergei.VoiceStateCache,
+      {Plug.Cowboy, scheme: :http, plug: Server, options: [port: 8080]}
+    ]
+
+    # See https://hexdocs.pm/elixir/Supervisor.html
+    # for other strategies and supported options
+    opts = [
+      strategy: :one_for_one,
+      name: Sergei.Supervisor
+    ]
+
+    Supervisor.start_link(children, opts)
+  end
+end

lib/sergei/consumer.ex

@@ -0,0 +1,102 @@
+defmodule Sergei.Consumer do
+  use Nostrum.Consumer
+
+  alias Nostrum.Api
+
+  # Translate params to list of maps
+  opt = fn type, name, desc, opts ->
+    %{type: type, name: name, description: desc}
+    |> Map.merge(Enum.into(opts, %{}))
+  end
+
+  @play_opts [
+    opt.(3, "url", "URL of the audio to play", required: true)
+  ]
+
+  @slash_commands [
+    {"ping", "Pong", []},
+    {"play", "Play some tunes", @play_opts}
+  ]
+
+  def start_link do
+    Consumer.start_link(__MODULE__)
+  end
+
+  # Bulk overwrite commands per guild.  While this is efficient enough for now, moving
+  # to global commands in the future is probably a good idea.
+  @spec register_commands!(integer) :: :ok
+  def register_commands!(guild_id) do
+    commands =
+      Enum.map(@slash_commands, fn {name, description, options} ->
+        %{
+          name: name,
+          description: description,
+          options: options
+        }
+      end)
+
+    case Api.bulk_overwrite_guild_application_commands(guild_id, commands) do
+      {:ok, _res} -> :ok
+      {:error, err} -> raise err
+    end
+  end
+
+  # Initialization of the Discord Client
+  def handle_event({:READY, %{guilds: guilds} = _event, _ws_state}) do
+    Api.update_status(:online, "some tunes", 0)
+
+    guilds
+    |> Enum.map(fn guild -> guild.id end)
+    |> Enum.each(&register_commands!/1)
+  end
+
+  def handle_event({:VOICE_STATE_UPDATE, state, _ws_state}) do
+    Sergei.VoiceStateCache.update_state(state)
+  end
+
+  # Handle interactions
+  def handle_event({:INTERACTION_CREATE, interaction, _ws_state}) do
+    response =
+      case do_command(interaction) do
+        {:ok, msg} ->
+          %{type: 4, data: %{content: msg, flags: 2 ** 6}}
+
+        {:error, msg} ->
+          %{type: 4, data: %{content: msg, flags: 2 ** 6}}
+      end
+
+    Api.create_interaction_response!(interaction, response)
+  end
+
+  # Ignore other events
+  def handle_event(_event) do
+    :noop
+  end
+
+  # /ping
+  def do_command(%{data: %{name: "ping"}}) do
+    {:ok, "Pong"}
+  end
+
+  # /play <url>
+  def do_command(
+        %{
+          guild_id: guild_id,
+          member: %{user: %{id: invoker_id}},
+          data: %{name: "play", options: opts}
+        } = _interaction
+      ) do
+    [%{name: "url", value: url}] = opts
+
+    case Sergei.VoiceStateCache.get_state(invoker_id) do
+      %{guild_id: id} = _res when guild_id != id ->
+        {:error, "You're not connected to a voice channel in this server."}
+
+      %{channel_id: channel_id} = _res ->
+        Sergei.Player.play(guild_id, channel_id, url)
+
+      nil ->
+        {:error, "You are not in a voice channel."}
+    end
+  end
+end

lib/sergei/player.ex

@@ -0,0 +1,87 @@
+defmodule Sergei.Player do
+  use GenServer
+
+  require Logger
+  alias Nostrum.Voice
+
+  def start_link(_) do
+    GenServer.start_link(__MODULE__, %{}, name: __MODULE__)
+  end
+
+  @impl true
+  def init(state) do
+    Process.send_after(self(), :tick, 100)
+
+    {:ok, state}
+  end
+
+  # Client
+  def play(guild_id, channel_id, url) do
+    GenServer.call(__MODULE__, {:play, guild_id, channel_id, url})
+  end
+
+  # Server
+  @impl true
+  def handle_info(:tick, state) do
+    state
+    |> Enum.each(fn {guild_id, %{url: url, paused: paused}} = _state ->
+      if not Voice.playing?(guild_id) and not paused do
+        Voice.play(guild_id, url, :ytdl)
+      end
+    end)
+
+    Process.send_after(self(), :tick, 100)
+    {:noreply, state}
+  end
+
+  @impl true
+  def handle_call({:play, guild_id, channel_id, url}, _from, state) do
+    res = play_music(guild_id, channel_id, url)
+
+    state =
+      Map.put(state, guild_id, %{
+        url: url,
+        paused: false
+      })
+
+    {:reply, res, state}
+  end
+
+  def play_music(guild_id, channel_id, url) do
+    cond do
+      Voice.get_channel_id(guild_id) != channel_id ->
+        Logger.debug("Changing channels...")
+
+        Voice.leave_channel(guild_id)
+        Voice.join_channel(guild_id, channel_id)
+
+        # Wait for the client to finish joining the voice channel
+        # TODO: check the channel ID in a loop instead
+        Process.sleep(500)
+
+        play_music(guild_id, channel_id, url)
+
+      Voice.playing?(guild_id) ->
+        Logger.debug("Stopping playback...")
+
+        Voice.stop(guild_id)
+        play_music(guild_id, channel_id, url)
+
+      Voice.ready?(guild_id) ->
+        case Voice.play(guild_id, url, :ytdl) do
+          :ok ->
+            Logger.info("Playing #{url}")
+            {:ok, "Playing music..."}
+
+          {:error, res} ->
+            Logger.error("Could not play music: #{res}")
+            {:error, "Fuck..."}
+        end
+
+      true ->
+        Logger.debug("Waiting...")
+        Process.sleep(500)
+        play_music(guild_id, channel_id, url)
+    end
+  end
+end

lib/sergei/voice_cache.ex

@@ -0,0 +1,48 @@
+defmodule Sergei.VoiceStateCache do
+  use GenServer
+
+  def start_link(_) do
+    GenServer.start_link(__MODULE__, %{}, name: __MODULE__)
+  end
+
+  @impl true
+  def init(cache) do
+    {:ok, cache}
+  end
+
+  # Client
+  @spec update_state(Nostrum.Struct.Event.VoiceState.t()) :: :ok
+  def update_state(state) do
+    GenServer.cast(__MODULE__, {:update, state})
+  end
+
+  @spec get_state(non_neg_integer()) :: %{guild_id: integer(), channel_id: integer()} | nil
+  def get_state(user_id) do
+    GenServer.call(__MODULE__, {:get, user_id})
+  end
+
+  # Server
+  @impl true
+  def handle_cast({:update, state}, cache) do
+    %{
+      guild_id: guild_id,
+      channel_id: channel_id,
+      member: %{
+        user: %{
+          id: user_id
+        }
+      }
+    } = state
+
+    entry =
+      Map.new()
+      |> Map.put(user_id, %{guild_id: guild_id, channel_id: channel_id})
+
+    {:noreply, Map.merge(cache, entry)}
+  end
+
+  @impl true
+  def handle_call({:get, user_id}, _from, cache) do
+    {:reply, Map.get(cache, user_id), cache}
+  end
+end

lib/server.ex

@@ -0,0 +1,20 @@
+defmodule Server do
+  use Plug.Router
+
+  plug(:match)
+  plug(:dispatch)
+
+  get "/" do
+    conn
+    |> send_resp(200, "Ok")
+  end
+
+  match _ do
+    conn
+    |> send_resp(404, "Page not found")
+  end
+
+  def start_link(_) do
+    Plug.Adapters.Cowboy.http(Server, [])
+  end
+end

main.py

@@ -1,75 +0,0 @@
-import os
-import subprocess
-
-from dotenv import load_dotenv
-from functools import partial
-
-import discord
-
-class Client(discord.Client):
-    def __init__(self):
-        intents = discord.Intents().default()
-        intents.members = True
-        super().__init__(intents=intents)
-
-
-    async def on_ready(self):
-        print("Logged on as {}".format(self.user))
-
-
-    async def on_message(self, message: discord.Message):
-        if message.author == self.user:
-            return
-
-        if message.channel.type is not discord.ChannelType.private:
-            return
-
-        url = message.content
-        v_id = url.split("=")[1]
-        user = message.channel.recipient.id
-
-        # Download file if it doesn't exist already
-        if not os.path.exists(v_id):
-            subprocess.run(["yt-dlp", "-f", "ba/b", "-o", v_id, url])
-
-        for chan in self.get_all_channels():
-            # Check if Channel is Voice Channel
-            if type(chan) is not discord.VoiceChannel:
-                continue
-
-            # Join the voice channel the user who DM'd Sergei is in
-            if user not in [i.id for i in chan.members]:
-                continue
-
-            # Try to create a new voice client; grab existing one if available
-            try:
-                v_client: discord.VoiceClient = await chan.connect()
-            except discord.errors.ClientException:
-                for client in self.voice_clients:
-                    if client.channel.id != chan.id:
-                        continue
-
-                    v_client = client
-                    await v_client.move_to(chan)
-                    v_client.stop()
-
-            self.play(v_client, v_id)
-
-
-    @staticmethod
-    def play(vc: discord.VoiceClient, v_id: str, err=None):
-        if err is not None:
-            print(err)
-            return
-
-        if vc.is_playing():
-            return
-
-        audio = discord.FFmpegOpusAudio(v_id)
-        vc.play(audio, after=partial(Client.play, vc, v_id))
-
-
-if __name__ == "__main__":
-    load_dotenv()
-    Client().run(os.getenv("DISCORD_TOK"))
-

mix.exs

@@ -0,0 +1,37 @@
+defmodule Sergei.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :sergei,
+      version: "0.1.0",
+      elixir: "~> 1.14",
+      start_permanent: Mix.env() == :prod,
+      deps: deps(),
+      releases: [
+        sergei: [
+          include_executables_for: [:unix]
+        ]
+      ]
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      mod: {Sergei.Application, []},
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+      {:plug_cowboy, "~> 2.0"},
+      {:cowlib, "~> 2.11", hex: :remedy_cowlib, override: true},
+      {:nostrum, "~> 0.6"}
+    ]
+  end
+end

mix.lock

@@ -0,0 +1,23 @@
+%{
+  "certifi": {:hex, :certifi, "2.10.0", "a4ab316320bfca83bd0b57fd022d091555d42a30eefabb38063887158294773a", [:rebar3], [], "hexpm", "e87a9dd6e7fe9c5804887850d4cdbcd83db4da7a27f928174f11e4e06fb7902e"},
+  "chacha20": {:hex, :chacha20, "1.0.4", "0359d8f9a32269271044c1b471d5cf69660c362a7c61a98f73a05ef0b5d9eb9e", [:mix], [], "hexpm", "2027f5d321ae9903f1f0da7f51b0635ad6b8819bc7fe397837930a2011bc2349"},
+  "cowboy": {:hex, :cowboy, "2.9.0", "865dd8b6607e14cf03282e10e934023a1bd8be6f6bacf921a7e2a96d800cd452", [:make, :rebar3], [{:cowlib, "2.11.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "1.8.0", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "2c729f934b4e1aa149aff882f57c6372c15399a20d54f65c8d67bef583021bde"},
+  "cowboy_telemetry": {:hex, :cowboy_telemetry, "0.4.0", "f239f68b588efa7707abce16a84d0d2acf3a0f50571f8bb7f56a15865aae820c", [:rebar3], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "7d98bac1ee4565d31b62d59f8823dfd8356a169e7fcbb83831b8a5397404c9de"},
+  "cowlib": {:hex, :remedy_cowlib, "2.11.1", "7abb4d0779a7d1c655f7642dc0bd0af754951e95005dfa01b500c68fe35a5961", [:rebar3], [], "hexpm", "0b613dc308e080cb6134285f1b1b55c3873e101652e70c70010fc6651c91b130"},
+  "curve25519": {:hex, :curve25519, "1.0.5", "f801179424e4012049fcfcfcda74ac04f65d0ffceeb80e7ef1d3352deb09f5bb", [:mix], [], "hexpm", "0fba3ad55bf1154d4d5fc3ae5fb91b912b77b13f0def6ccb3a5d58168ff4192d"},
+  "ed25519": {:hex, :ed25519, "1.4.1", "479fb83c3e31987c9cad780e6aeb8f2015fb5a482618cdf2a825c9aff809afc4", [:mix], [], "hexpm", "0dacb84f3faa3d8148e81019ca35f9d8dcee13232c32c9db5c2fb8ff48c80ec7"},
+  "equivalex": {:hex, :equivalex, "1.0.3", "170d9a82ae066e0020dfe1cf7811381669565922eb3359f6c91d7e9a1124ff74", [:mix], [], "hexpm", "46fa311adb855117d36e461b9c0ad2598f72110ad17ad73d7533c78020e045fc"},
+  "gen_stage": {:hex, :gen_stage, "1.2.0", "ee49244b57803f54bdab08a60a927e1b4e5bb5d635c52eca0f376a0673af3f8c", [:mix], [], "hexpm", "c3e40992c72e74d9c4eda16d7515bf32c9e7b634e827ab11091fff3290f7b503"},
+  "gun": {:hex, :remedy_gun, "2.0.1", "0f0caed812ed9e4da4f144df2d5bf73b0a99481d395ecde990a3791decf321c6", [:rebar3], [{:cowlib, "~> 2.11.1", [hex: :remedy_cowlib, repo: "hexpm", optional: false]}], "hexpm", "b6685a85fbd12b757f86809be1b3d88fcef365b77605cd5aa34db003294c446e"},
+  "jason": {:hex, :jason, "1.4.0", "e855647bc964a44e2f67df589ccf49105ae039d4179db7f6271dfd3843dc27e6", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "79a3791085b2a0f743ca04cec0f7be26443738779d09302e01318f97bdb82121"},
+  "kcl": {:hex, :kcl, "1.4.2", "8b73a55a14899dc172fcb05a13a754ac171c8165c14f65043382d567922f44ab", [:mix], [{:curve25519, ">= 1.0.4", [hex: :curve25519, repo: "hexpm", optional: false]}, {:ed25519, "~> 1.3", [hex: :ed25519, repo: "hexpm", optional: false]}, {:poly1305, "~> 1.0", [hex: :poly1305, repo: "hexpm", optional: false]}, {:salsa20, "~> 1.0", [hex: :salsa20, repo: "hexpm", optional: false]}], "hexpm", "9f083dd3844d902df6834b258564a82b21a15eb9f6acdc98e8df0c10feeabf05"},
+  "mime": {:hex, :mime, "2.0.3", "3676436d3d1f7b81b5a2d2bd8405f412c677558c81b1c92be58c00562bb59095", [:mix], [], "hexpm", "27a30bf0db44d25eecba73755acf4068cbfe26a4372f9eb3e4ea3a45956bff6b"},
+  "nostrum": {:hex, :nostrum, "0.6.1", "aaad13e8e8ce8ace1f218685c6824972e7ea4f979e5ba3242a98f22bda52e605", [:mix], [{:certifi, "~> 2.8", [hex: :certifi, repo: "hexpm", optional: false]}, {:gen_stage, "~> 0.11 or ~> 1.0", [hex: :gen_stage, repo: "hexpm", optional: false]}, {:gun, "== 2.0.1", [hex: :remedy_gun, repo: "hexpm", optional: false]}, {:jason, "~> 1.2", [hex: :jason, repo: "hexpm", optional: false]}, {:kcl, "~> 1.4", [hex: :kcl, repo: "hexpm", optional: false]}, {:mime, "~> 1.6 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}], "hexpm", "27925a47e413766664928fbeb38c9887a7fd23066cdba831d5fd8241072bf76a"},
+  "plug": {:hex, :plug, "1.14.0", "ba4f558468f69cbd9f6b356d25443d0b796fbdc887e03fa89001384a9cac638f", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "bf020432c7d4feb7b3af16a0c2701455cbbbb95e5b6866132cb09eb0c29adc14"},
+  "plug_cowboy": {:hex, :plug_cowboy, "2.6.0", "d1cf12ff96a1ca4f52207c5271a6c351a4733f413803488d75b70ccf44aebec2", [:mix], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:cowboy_telemetry, "~> 0.3", [hex: :cowboy_telemetry, repo: "hexpm", optional: false]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "073cf20b753ce6682ed72905cd62a2d4bd9bad1bf9f7feb02a1b8e525bd94fa6"},
+  "plug_crypto": {:hex, :plug_crypto, "1.2.3", "8f77d13aeb32bfd9e654cb68f0af517b371fb34c56c9f2b58fe3df1235c1251a", [:mix], [], "hexpm", "b5672099c6ad5c202c45f5a403f21a3411247f164e4a8fab056e5cd8a290f4a2"},
+  "poly1305": {:hex, :poly1305, "1.0.4", "7cdc8961a0a6e00a764835918cdb8ade868044026df8ef5d718708ea6cc06611", [:mix], [{:chacha20, "~> 1.0", [hex: :chacha20, repo: "hexpm", optional: false]}, {:equivalex, "~> 1.0", [hex: :equivalex, repo: "hexpm", optional: false]}], "hexpm", "e14e684661a5195e149b3139db4a1693579d4659d65bba115a307529c47dbc3b"},
+  "ranch": {:hex, :ranch, "1.8.0", "8c7a100a139fd57f17327b6413e4167ac559fbc04ca7448e9be9057311597a1d", [:make, :rebar3], [], "hexpm", "49fbcfd3682fab1f5d109351b61257676da1a2fdbe295904176d5e521a2ddfe5"},
+  "salsa20": {:hex, :salsa20, "1.0.4", "404cbea1fa8e68a41bcc834c0a2571ac175580fec01cc38cc70c0fb9ffc87e9b", [:mix], [], "hexpm", "745ddcd8cfa563ddb0fd61e7ce48d5146279a2cf7834e1da8441b369fdc58ac6"},
+  "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
+}