From e5d97870a12ec87bd463b7657923bb79d3bcb4cc Mon Sep 17 00:00:00 2001
From: Logan Hunt <logan.hunt@usu.edu>
Date: Tue, 31 Jan 2023 12:44:15 -0700
Subject: [PATCH] Rate limit game creation

---
 config/config.exs                  |  4 +-
 lib/chessh/ssh/client/client.ex    | 21 +++++----
 lib/chessh/ssh/client/game/game.ex | 73 ++++++++++++++++++++----------
 3 files changed, 65 insertions(+), 33 deletions(-)

diff --git a/config/config.exs b/config/config.exs
index a5782d4..e9fca38 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -12,7 +12,9 @@ config :chessh, RateLimits,
   max_concurrent_user_sessions: 5,
   player_session_message_burst_ms: 500,
   player_session_message_burst_rate: 8,
-  player_public_keys: 15
+  player_public_keys: 15,
+  create_game_ms: 60 * 1000,
+  create_game_rate: 2
 
 config :chessh, Web,
   github_oauth_login_url: "https://github.com/login/oauth/access_token",
diff --git a/lib/chessh/ssh/client/client.ex b/lib/chessh/ssh/client/client.ex
index 67aa920..461dfbe 100644
--- a/lib/chessh/ssh/client/client.ex
+++ b/lib/chessh/ssh/client/client.ex
@@ -45,17 +45,20 @@ defmodule Chessh.SSH.Client do
           screen_state_initials: screen_state_initials
         } = state
       ) do
-    {:ok, new_screen_pid} =
-      GenServer.start_link(module, [%{screen_state_initial | client_pid: self()}])
+    case GenServer.start_link(module, [%{screen_state_initial | client_pid: self()}]) do
+      {:ok, new_screen_pid} ->
+        send(new_screen_pid, {:render, width, height})
 
-    send(new_screen_pid, {:render, width, height})
+        {:noreply,
+         %State{
+           state
+           | screen_pid: new_screen_pid,
+             screen_state_initials: [{module, screen_state_initial} | screen_state_initials]
+         }}
 
-    {:noreply,
-     %State{
-       state
-       | screen_pid: new_screen_pid,
-         screen_state_initials: [{module, screen_state_initial} | screen_state_initials]
-     }}
+      _ ->
+        {:noreply, state}
+    end
   end
 
   @impl true
diff --git a/lib/chessh/ssh/client/game/game.ex b/lib/chessh/ssh/client/game/game.ex
index 3ecd2e4..4a79d05 100644
--- a/lib/chessh/ssh/client/game/game.ex
+++ b/lib/chessh/ssh/client/game/game.ex
@@ -59,32 +59,59 @@ defmodule Chessh.SSH.Client.Game do
   end
 
   def init([
-        %State{player_session: player_session, color: color, game: nil} = state
+        %State{player_session: player_session, color: color, game: nil, client_pid: client_pid} =
+          state
         | tail
       ]) do
-    # Starting a new game
-    {:ok, %Game{} = game} =
-      Game.changeset(
-        %Game{},
-        Map.merge(
-          if(color == :light,
-            do: %{light_player_id: player_session.player_id},
-            else: %{dark_player_id: player_session.player_id}
-          ),
-          %{
-            fen: @default_fen
-          }
-        )
-      )
-      |> Repo.insert()
+    [create_game_ms, create_game_rate] =
+      Application.get_env(:chessh, RateLimits)
+      |> Keyword.take([:create_game_ms, :create_game_rate])
+      |> Keyword.values()
 
-    init([
-      %State{
-        state
-        | game: game
-      }
-      | tail
-    ])
+    case Hammer.check_rate_inc(
+           :redis,
+           "player-#{state.player_session.id}-create-game-rate",
+           create_game_ms,
+           create_game_rate,
+           1
+         ) do
+      {:allow, _count} ->
+        # Starting a new game
+        {:ok, %Game{} = game} =
+          Game.changeset(
+            %Game{},
+            Map.merge(
+              if(color == :light,
+                do: %{light_player_id: player_session.player_id},
+                else: %{dark_player_id: player_session.player_id}
+              ),
+              %{
+                fen: @default_fen
+              }
+            )
+          )
+          |> Repo.insert()
+
+        init([
+          %State{
+            state
+            | game: game
+          }
+          | tail
+        ])
+
+      {:deny, _limit} ->
+        send(
+          client_pid,
+          {:send_to_ssh,
+           [
+             Utils.clear_codes(),
+             "You are creating too many games, and have been rate limited. Try again later.\n"
+           ]}
+        )
+
+        {:stop, :normal, state}
+    end
   end
 
   def init([