Finish plugin and routing overhaul, there's a new model in town:

* Plugins all derive from Omnibot.Plugin. There still is a base plugin,
  in case we want to have another plugin backend instead of a GenServer
* All plugins are monitored by a unique Plugin.Supervisor, which is in
  turn started by the PluginSupervisor (yes this is confusing, yes it
  needs to be renamed)
* Any other auxiliary child processes may be started through the
  Plugin.children/1 function.
* By default, plugins have a CfgState process which is an Agent that
  keeps track of the plugin's configuration and state
* Plugin API is now called through the GenServer backend for better
  synchronicity.
* Very few changes to the front-facing Plugin API, which is nice

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

lib/contrib/markov/markov.ex

@@ -6,7 +6,7 @@ defmodule Omnibot.Contrib.Markov do
   @default_config path: "markov", order: 2, save_every: 5 * 60
 
   @impl true
-  def children(cfg, _state) do
+  def children(cfg) do
     [{Task, fn ->
       Stream.timer(cfg[:save_every] * 1000)
       |> Stream.cycle()

lib/contrib/wordbot/wordbot.ex

@@ -5,23 +5,8 @@ defmodule Omnibot.Contrib.Wordbot do
 
   @default_config wordbot_source: "words.txt", wordbot_db: "wordbot.db", words_per_round: 300, hours_per_round: 5
 
-  #def start_link(opts) do
-    #Supervisor.start_link(__MODULE__, opts[:cfg], opts)
-  #end
-
-  #@impl true
-  #def init(cfg) do
-  #  children = [
-  #    {Task.Supervisor, name: Omnibot.Contrib.Wordbot.Watchers, strategy: :one_for_one},
-  #    Wordbot.Db.child_spec(cfg[:wordbot_db]),
-  #    {Wordbot.Bot, cfg: cfg, name: Omnibot.Contrib.Wordbot.Bot},
-  #  ]
-
-  #  Supervisor.init(children, strategy: :one_for_all)
-  #end
-
   @impl true
-  def children(cfg, _state) do
+  def children(cfg) do
     [
       {Task.Supervisor, name: Omnibot.Contrib.Wordbot.Watchers, strategy: :one_for_one},
       Wordbot.Db.child_spec(cfg[:wordbot_db]),

lib/plugin/base.ex

@@ -19,6 +19,11 @@ defmodule Omnibot.Plugin.Base do
       @impl true
       def on_init(_cfg), do: nil
 
+      @impl true
+      def on_msg(irc, msg) do
+        route_msg(irc, msg)
+      end
+
       @impl true
       def default_config(), do: @default_config
 
@@ -33,11 +38,6 @@ defmodule Omnibot.Plugin.Base do
 
       @behaviour Plugin.Base
 
-      @impl Plugin.Base
-      def on_msg(irc, msg) do
-        route_msg(irc, msg)
-      end
-
       defp route_msg(irc, %Irc.Msg {prefix: nil}), do: nil
 
       defp route_msg(irc, msg) do

lib/plugin/plugin.ex

@@ -14,21 +14,24 @@ defmodule Omnibot.Plugin do
 
     def state(pid), do: Agent.get(pid, fn {_, state} -> state end)
 
-    def update_state(pid, fun, timeout \\ 5000),
-      do: Agent.update(pid, &{&1, apply(fun, [&1])}, timeout)
+    def update_state(pid, fun, timeout \\ 5000) do
+      Agent.update(pid, fn {cfg, state} -> {cfg, apply(fun, [state])} end, timeout)
+      #Agent.update(pid, &{&1, apply(fun, [&1])}, timeout)
+    end
   end
 
   defmacro __using__(opts) do
     opts = opts ++ @default_opts
 
-    quote do
-      use Supervisor
+    quote generated: true do
+      use GenServer
       use Omnibot.Plugin.Base
 
       ## Client API
 
       def start_link(opts) do
-        Supervisor.start_link(__MODULE__, {opts[:cfg], opts[:state]}, opts)
+        {cfg, opts} = Keyword.pop(opts, :cfg)
+        GenServer.start_link(__MODULE__, cfg, opts)
       end
 
       def cfg() do
@@ -48,30 +51,37 @@ defmodule Omnibot.Plugin do
         GenServer.cast(__MODULE__, {:handle_msg, irc, msg})
       end
 
-      @impl Omnibot.Plugin
-      def children(_cfg, _state), do: []
-
       ## Server callbacks
 
-      @impl Supervisor
-      def init({cfg, state}) do
-        base_children = [
-          {Omnibot.Plugin.CfgState, cfg: cfg, state: state, name: __MODULE__.CfgState},
-        ]
-        children = 
-          (if unquote(opts[:include_base]), do: base_children, else: []) ++ children(cfg, state)
-        Supervisor.init(children, unquote(opts[:opts]))
+      @impl GenServer 
+      def init(_cfg) do
+        {:ok, nil}
       end
 
+      @impl GenServer
       def handle_cast({:handle_msg, irc, msg}, state) do
         on_msg(irc, msg)
         {:noreply, state}
       end
 
+      defp base_children(cfg, state) when unquote(opts[:include_base]) do
+        [
+          {Omnibot.Plugin.CfgState, cfg: cfg, state: state, name: __MODULE__.CfgState},
+          {__MODULE__, name: __MODULE__},
+        ]
+      end
+
+      defp base_children(_cfg, _state), do: []
+
+      @impl Omnibot.Plugin
+      def children(cfg), do: []
+
+      def plugin_children(cfg, state), do: base_children(cfg, state) ++ children(cfg)
+
       @behaviour Omnibot.Plugin
       defoverridable Omnibot.Plugin
     end
   end
 
-  @callback children(cfg :: [atom: any], state :: any) :: [atom | {atom, [atom: any]} | {atom, any, [atom: any]}]
+  @callback children(cfg :: [atom: any]) :: [atom | {atom, [atom: any]} | {atom, any, [atom: any]}]
 end

lib/plugin/supervisor.ex

@@ -0,0 +1,28 @@
+defmodule Omnibot.Plugin.Supervisor do
+  use Supervisor
+
+  def start_link(opts) do
+    {plugin, opts} = Keyword.pop(opts, :plugin)
+    {cfg, opts} = Keyword.pop(opts, :cfg)
+    start_link(plugin, cfg, opts)
+  end
+
+  def start_link(plugin, cfg, opts) when is_atom(plugin) do
+    Supervisor.start_link(__MODULE__, {plugin, cfg}, opts)
+  end
+
+  def child_spec(arg) do
+    id = Module.concat(arg[:plugin], Plugin.Supervisor)
+    %{
+      id: id,
+      start: {__MODULE__, :start_link, [arg]},
+    }
+  end
+
+  @impl true
+  def init({plugin, cfg}) when is_atom(plugin) do
+    state = plugin.on_init(cfg)
+    children = IO.inspect(plugin.plugin_children(cfg, state))
+    Supervisor.init(children, strategy: :one_for_one)
+  end
+end

lib/plugin_supervisor.ex

@@ -21,14 +21,15 @@ defmodule Omnibot.PluginSupervisor do
     # Map the plugins in the configuration to the children
     children =
       for plug <- (core ++ cfg.plugins) do
-        case plug do
-          {name, cfg} -> {name, cfg: cfg ++ name.default_config(), name: name}
-          name -> {name, cfg: name.default_config(), name: name}
+        {name, cfg} = case plug do
+          {name, cfg} -> {name, cfg ++ name.default_config()}
+          name -> {name, name.default_config()}
         end
+        {Omnibot.Plugin.Supervisor, plugin: name, cfg: cfg}
       end
 
     # Add each child to the "loaded plugins" list in the State
-    Enum.each(children, fn {plugin, opts} -> State.add_loaded_plugin({plugin, opts[:cfg]}) end)
+    Enum.each(children, fn {_plugin, opts} -> State.add_loaded_plugin({opts[:plugin], opts[:cfg]}) end)
 
     Supervisor.init(children, strategy: :one_for_one)
   end