Finish up Plugin.Supervisor, replace markov and wordbot implementations with it

Both markov and wordbot have some auxiliary processes that run to keep
track of things. Previously, they both had custom supervisors grafted on
to the Plugin.Base - now, this grafting is automated with
Plugin.Supervisor.

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

lib/contrib/markov/markov.ex

@@ -1,32 +1,64 @@
 defmodule Omnibot.Contrib.Markov do
-  use Omnibot.Plugin.Base
-  alias Omnibot.Contrib.Markov
-  use Supervisor
+  use Omnibot.Plugin.Supervisor
+  alias Omnibot.Contrib.Markov.Chain
+  require Logger
 
   @default_config path: "markov", order: 2, save_every: 5 * 60
 
-  def start_link(opts) do
-    Supervisor.start_link(__MODULE__, opts[:cfg], opts)
+  @impl true
+  def children(_cfg, _state) do
+    [{Task, fn ->
+      Stream.timer(1000)
+      |> Stream.cycle()
+      |> Stream.each(fn _ -> save_chains() end)
+      |> Stream.run()
+    end}]
   end
 
   @impl true
-  def init(cfg) do
-    children = [
-      {Markov.Bot, cfg: cfg, name: Omnibot.Contrib.Markov.Bot},
-      {Task, fn -> save_loop(cfg) end}
-    ]
-    Supervisor.init(children, strategy: :one_for_all)
-  end
-
-  defp save_loop(cfg) do
-    save_every = cfg[:save_every]
-    Process.sleep(save_every * 1000)
-    Markov.Bot.save_chains()
+  def on_init(_cfg) do
+    # Create the markov database
+    path = String.to_atom(cfg()[:path])
+    {:ok, db} = :dets.open_file(path, [:named_table])
+    chains = :ets.new(:markov_chains, [:public])
+    :dets.to_ets(db, chains)
+    :dets.close(db)
   end
 
   @impl true
-  def on_msg(irc, msg), do: Markov.Bot.on_msg(irc, msg)
+  def on_channel_msg(_irc, channel, nick, msg) do
+    train(channel, nick, msg)
+  end
 
-  @impl true
-  def on_channel_msg(irc, channel, nick, msg), do: Markov.Bot.on_channel_msg(irc, channel, nick, msg)
+  def train(channel, user, msg) do
+    chain = (user_chain(channel, user) || create_user_chain(channel, user))
+            |> Chain.train(msg)
+    true = update_user_chain(channel, user, chain)
+  end
+
+  def user_chain(channel, user) do
+    db = state()
+    case :ets.lookup(db, {channel, user}) do
+      [] -> nil
+      [{{^channel, ^user}, chains}] -> chains
+    end
+  end
+
+  def update_user_chain(channel, user, chain) do
+    db = state()
+    case user_chain(channel, user) do
+      nil -> :ets.insert_new(db, {{channel, user}, chain})
+      chain -> :ets.insert(db, {{channel, user}, chain})
+    end
+  end
+
+  defp create_user_chain(channel, user) do
+    true = update_user_chain(channel, user, %Chain{order: cfg()[:order]})
+    user_chain(channel, user)
+  end
+
+  def save_chains() do
+    # TODO
+    Logger.info("Saved markov chains")
+  end
 end