Players take turns

Restricts players to only be able to move their own pieces and only when
it's their turn.

assets/js/components/chess-board-square.js

@@ -3,7 +3,7 @@ import _ from "lodash";
 import $ from "jquery";
 import classNames from "classnames";
 
-import { selectPiece, setBoard } from "../store/actions";
+import { selectPiece, setGame } from "../store/actions";
 
 class ChessBoardSquare extends React.Component {
   constructor(props) {
@@ -16,19 +16,35 @@ class ChessBoardSquare extends React.Component {
 
   selectSquare() {
     var { piece, store } = this.props;
-    var { gameId, selectedSquare } = store.getState();
+    var { gameId, selectedSquare, player } = store.getState();
 
-    if (selectedSquare != null) {
+    if (selectedSquare != null && this.moveIsValid()) {
       $.ajax({
         method: "PATCH",
         url: "/api/games/" + gameId,
         data: { move: { from: selectedSquare, to: this.squareCoords() } }
-      }).then((data) => store.dispatch(setBoard(data)));
+      }).then((data) => store.dispatch(setGame(data)));
     }
-    else if (piece != undefined) {
+    else if (selectedSquare != null) {
+      store.dispatch(selectPiece(null));
+    }
+    else if (this.playerCanSelectPiece(player, piece)) {
       store.dispatch(selectPiece(this.squareCoords()));
     }
-  };
+  }
+
+  moveIsValid() {
+    return !this.isSelectedSquare();
+  }
+
+  playerCanSelectPiece(player, piece) {
+    var { store } = this.props;
+    var { turn } = store.getState();
+
+    return piece != undefined &&
+      piece.colour == player &&
+      player == turn;
+  }
 
   isSelectedSquare() {
     var { store } = this.props;

assets/js/components/chess-board.js

@@ -2,7 +2,7 @@ import React from "react";
 import _ from "lodash";
 import $ from "jquery";
 import { connect } from "react-redux";
-import { setBoard, setPlayer, setGameId } from "../store/actions";
+import { setGame, setGameId } from "../store/actions";
 
 import ChessBoardSquare from "./chess-board-square";
 
@@ -14,8 +14,7 @@ class ChessBoard extends React.Component {
 
     $.ajax({ method: "GET", url: `/api/games/${gameId}` })
       .then((data) => {
-        store.dispatch(setBoard(data.board));
+        store.dispatch(setGame(data));
-        store.dispatch(setPlayer(data.player));
       });
   }
 

assets/js/reducers/chess-board.js

@@ -4,15 +4,12 @@ import defaultState from "../store/default-state";
 
 const chessBoardReducer = (state = defaultState, action) => {
   switch (action.type) {
-    case "SET_BOARD":
+    case "SET_GAME":
       return Immutable.fromJS(state)
         .set("board", action.board)
-        .set("selectedSquare", null)
-        .toJS();
-
-    case "SET_PLAYER":
-      return Immutable.fromJS(state)
         .set("player", action.player)
+        .set("turn", action.turn)
+        .set("selectedSquare", null)
         .toJS();
 
     case "SET_GAME_ID":

assets/js/store/actions.js

@@ -1,12 +1,13 @@
-const SET_BOARD = "SET_BOARD";
+const SET_GAME = "SET_GAME";
-const SET_PLAYER = "SET_PLAYER";
 const SET_GAME_ID = "SET_GAME_ID";
 const SELECT_PIECE = "SELECT_PIECE";
 
-export const setBoard = (board) => {
+export const setGame = (data) => {
   return {
-    type: SET_BOARD,
+    type: SET_GAME,
-    board: board
+    board: data.board,
+    player: data.player,
+    turn: data.turn
   }
 }
 

assets/js/store/default-state.js

@@ -1,8 +1,8 @@
 const defaultState = {
   selectedSquare: null,
 
-  player: "white",
+  player: null,
-  turn: "white",
+  turn: null,
 
   board: {
     8: { a: null, b: null, c: null, d: null, e: null, f: null, g: null, h: null },

lib/chess/board.ex

@@ -9,6 +9,15 @@ defmodule Chess.Board do
     end)
   end
 
+  def move_piece(board, move_params) do
+    [from_file, from_rank] = move_params["from"]
+    [to_file, to_rank] = move_params["to"]
+
+    {piece, board} = Map.pop(board, "#{from_file},#{from_rank}")
+
+    Map.put(board, "#{to_file},#{to_rank}", piece)
+  end
+
   def default do
     %{
       "0,7" => %{type: :rook,   colour: :black},

lib/chess/store/game.ex

@@ -12,6 +12,7 @@ defmodule Chess.Store.Game do
 
   schema "games" do
     field :board, :map
+    field :turn, :string
 
     belongs_to :user, Chess.Auth.User
     belongs_to :opponent, Chess.Auth.User, references: :id
@@ -24,7 +25,8 @@ defmodule Chess.Store.Game do
     |> cast(params, required_attrs())
     |> foreign_key_constraint(:user_id)
     |> foreign_key_constraint(:opponent_id)
-    |> put_change(:board, Board.default)
+    |> put_change(:board, Board.default())
+    |> put_change(:turn, default_turn())
     |> validate_required(required_attrs())
   end
 
@@ -36,6 +38,13 @@ defmodule Chess.Store.Game do
     |> validate_required(required_attrs())
   end
 
+  def change_turn(turn) do
+    case turn do
+      "white" -> "black"
+      "black" -> "white"
+    end
+  end
+
   def for_user(user) do
     from game in Game,
       where: game.user_id == ^user.id,
@@ -47,5 +56,9 @@ defmodule Chess.Store.Game do
     |> order_by([game], desc: game.inserted_at)
   end
 
-  defp required_attrs, do: ~w[board user_id opponent_id]a
+  defp required_attrs, do: ~w[board turn user_id opponent_id]a
+
+  defp default_turn do
+    "white"
+  end
 end

lib/chess_web/controllers/api/game_controller.ex

@@ -25,20 +25,24 @@ defmodule ChessWeb.Api.GameController do
       |> Repo.get!(id)
 
     changeset = Game.changeset(
-      game, %{board: new_board(game.board, move_params)}
+      game, %{
+        board: Board.move_piece(game.board, move_params),
+        turn: Game.change_turn(game.turn)
+      }
     )
 
     case Repo.update(changeset) do
       {:ok, game} ->
         conn
-        |> json(Board.transform(game.board))
+        |> json(game_attrs(conn, game))
     end
   end
 
   defp game_attrs(conn, game) do
     %{
       board: Board.transform(game.board),
-      player: player(conn, game)
+      player: player(conn, game),
+      turn: game.turn
     }
   end
 
@@ -49,13 +53,4 @@ defmodule ChessWeb.Api.GameController do
       "black"
     end
   end
-
-  defp new_board(board, move_params) do
-    [from_file, from_rank] = move_params["from"]
-    [to_file, to_rank] = move_params["to"]
-
-    {piece, board} = Map.pop(board, "#{from_file},#{from_rank}")
-
-    Map.put(board, "#{to_file},#{to_rank}", piece)
-  end
 end

priv/repo/migrations/20161209105511_create_game.exs

@@ -7,6 +7,5 @@ defmodule Chess.Repo.Migrations.CreateGame do
 
       timestamps()
     end
-
   end
 end

priv/repo/migrations/20180223223018_add_turn_to_game.exs

@@ -0,0 +1,9 @@
+defmodule Chess.Repo.Migrations.AddTurnToGame do
+  use Ecto.Migration
+
+  def change do
+    alter table("games") do
+      add :turn, :string, default: "white"
+    end
+  end
+end

test/chess/store/game_test.exs

@@ -11,7 +11,12 @@ defmodule Chess.GameTest do
       user = create_user("link", "ilovezelda")
       opponent = create_user("zelda", "ganonsucks")
 
-      attrs = %{board: %{}, user_id: user.id, opponent_id: opponent.id}
+      attrs = %{
+        board: %{},
+        user_id: user.id,
+        opponent_id: opponent.id,
+        turn: "white"
+      }
       changeset = Game.changeset(%Game{}, attrs)
 
       assert changeset.valid?
@@ -19,7 +24,12 @@ defmodule Chess.GameTest do
     end
 
     test "game cannot be saved if the user or opponent do not exist" do
-      attrs = %{board: %{}, user_id: 1, opponent_id: 2}
+      attrs = %{
+        board: %{},
+        user_id: 1,
+        opponent_id: 2,
+        turn: "white"
+      }
       changeset = Game.changeset(%Game{}, attrs)
 
       assert changeset.valid?