From caa68d41f836bbd0aa5cbdcb1850e2eceb6498d2 Mon Sep 17 00:00:00 2001
From: Dan Barber <github@danbarber.me>
Date: Fri, 4 May 2018 22:41:27 +0200
Subject: [PATCH] Make changeset function responsible for the move

---
 lib/chess/store/game.ex                | 6 +++++-
 lib/chess_web/channels/game_channel.ex | 6 +-----
 test/chess/store/game_test.exs         | 4 +---
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/lib/chess/store/game.ex b/lib/chess/store/game.ex
index 1d18022..d7b3fad 100644
--- a/lib/chess/store/game.ex
+++ b/lib/chess/store/game.ex
@@ -35,7 +35,11 @@ defmodule Chess.Store.Game do
     |> foreign_key_constraint(:opponent_id)
   end
 
-  def move_changeset(struct, params \\ %{}) do
+  def move_changeset(struct, move_params) do
+    params = %{
+      board: Board.move_piece(struct.board, move_params),
+    }
+
     struct
     |> cast(params, required_attrs())
     |> validate_king_in_check(struct, params)
diff --git a/lib/chess_web/channels/game_channel.ex b/lib/chess_web/channels/game_channel.ex
index 79bdecb..108e9ea 100644
--- a/lib/chess_web/channels/game_channel.ex
+++ b/lib/chess_web/channels/game_channel.ex
@@ -38,11 +38,7 @@ defmodule ChessWeb.GameChannel do
       |> Game.for_user_id()
       |> Repo.get!(socket.assigns.game_id)
 
-    changeset = Game.move_changeset(
-      game, %{
-        board: Board.move_piece(game.board, move_params),
-      }
-    )
+    changeset = Game.move_changeset(game, move_params)
 
     case Repo.update(changeset) do
       {:ok, game} ->
diff --git a/test/chess/store/game_test.exs b/test/chess/store/game_test.exs
index 32fc0c8..e55eb35 100644
--- a/test/chess/store/game_test.exs
+++ b/test/chess/store/game_test.exs
@@ -89,9 +89,7 @@ defmodule Chess.GameTest do
 
       move_params = %{"from" => [4, 1], "to" => [4, 3]}
 
-      changeset = Game.move_changeset(game, %{
-        board: Board.move_piece(game.board, move_params),
-      })
+      changeset = Game.move_changeset(game, move_params)
 
       assert {:ok, new_game} = Repo.update(changeset)
       assert new_game.turn == "black"