Prevent move into check

app/controllers/pieces_controller.rb

@@ -1,29 +1,46 @@
+require 'pry'
 class PiecesController < ApplicationController
-  before_action :select_pc, :only => [:show, :update]
-  before_action :only => :update do
-    validate_move(:x_position, :y_position)
-  end
+	before_action :select_pc, :only => [:show, :update]
+	before_action :only => :update do
+		validate_move(:x_position, :y_position)
+	end
 
-  def show
-    @pieces = select_pc.game.pieces
-  end
+	def show
+		@pieces = select_pc.game.pieces
+	end
 
-  def update
-    row = params[:y_position].to_i
-    col = params[:x_position].to_i
-    @select_pc.move_to!(col, row)
-    redirect_to game_path(select_pc.game.id)
+	def update
+		row = params[:y_position].to_i
+		col = params[:x_position].to_i
+		select_pc.move_to!(col, row)
+		redirect_to game_path(select_pc.game.id)
 	end
 
   private
 
-  def validate_move(x_position, y_position)
-    row = params[:y_position].to_i
-    col = params[:x_position].to_i
-    if !select_pc.valid_move?(col, row)
+
+	def validate_move(x_position, y_position)
+		row = params[:y_position].to_i
+		col = params[:x_position].to_i
+    #binding.pry
+    color = select_pc.color
+		if invalid_move?(col, row)
       flash[:alert] = "That move is not allowed!  Please choose your piece and try again."
-      redirect_to game_path(select_pc.game.id)
+    elsif put_self_in_check?(color, col, row)
+      flash[:alert] = "You cannot put yourself in check"
+    else
+      return true
     end
+    redirect_to game_path(select_pc.game.id)
+    return false
+	end
+
+  def invalid_move?(col, row)
+    !select_pc.valid_move?(col, row) || select_pc.nil_move?(col, row)
+  end
+
+  def put_self_in_check?(color, col, row)
+    select_pc.game.checking_piece?(color, select_pc.id, col, row)
   end
 
   def select_pc

app/helpers/games_helper.rb

@@ -1,8 +1,8 @@
 module GamesHelper
   def piece_color(piece)
     case 
-      when piece.color == 0 && piece.active == 1 then "Black\n" + piece.type
-      when piece.color == 1 && piece.active == 1 then "White\n" + piece.type
+      when piece.color == 0 then "Black\n" + piece.type
+      when piece.color == 1 then "White\n" + piece.type
     end
   end
 

app/models/game.rb

@@ -1,9 +1,14 @@
+require 'pry'
 class Game < ActiveRecord::Base
   belongs_to :user
   has_many :pieces
 
+  #before_action only: :show do
+   # :in_check(:color)
+  #end
   after_create :populate_board!
 
+
   def populate_board!
     # These are initialized to the white pieces' y coordinates. y2 is for the
     # pawns' y coordinate.
@@ -69,5 +74,25 @@ def populate_board!
       y2 = 7
       color = 0
     end
+
+  end
+
+  def in_check?(color)
+    checking_piece?(color)
+  end
+
+  def checking_piece?(color, piece_id, col, row)
+    opponents_pieces = pieces.where.not(color: color, active: 0)
+    check_king(color, piece_id, col, row)
+    opponents_pieces.each do |piece|
+      piece.valid_move?(*@king_position) ? (return true) : false
+    end
+    return false
+  end
+
+  def check_king(color, piece_id, col, row)
+    @king = pieces.find_by(type: 'King', color: color)
+    piece_moving = pieces.find_by(id: piece_id)
+    piece_moving == @king ? (@king_position = col, row) : (@king_position = @king.x_position, @king.y_position)
   end
 end

app/models/pawn.rb

@@ -1,9 +1,10 @@
+require 'pry'
 class Pawn < Piece
 
 	def valid_move?(new_x, new_y)
-		[move_number_allowed?(new_y), 
-			no_vertical_obstacle?(new_x, new_y), 
-			not_a_backwards_move?(new_y), 
+		[move_number_allowed?(new_y),
+			no_vertical_obstacle?(new_x, new_y),
+			not_a_backwards_move?(new_y),
 			diagonal_move_allowed?(new_x, new_y)].all?
 	end
 
@@ -16,13 +17,13 @@ def move_number(new_y)
 	end
 
 	def first_move?(new_y)
-	  (color == 1 && y_position == 2) || (color == 0 && y_position == 7) 
+	  (color == 1 && y_position == 2) || (color == 0 && y_position == 7)
   end
 
 	def no_vertical_obstacle?(new_x, new_y)
 		return true if x_position != new_x
-		if move_number(new_y) == 2 
-			!is_obstructed?(x_position, new_y) && no_vertical_adjacent_obstacle?(x_position, new_y) 
+		if move_number(new_y) == 2
+			!is_obstructed?(x_position, new_y) && no_vertical_adjacent_obstacle?(x_position, new_y)
 		else
 			(no_vertical_adjacent_obstacle?(x_position, new_y))
 		end
@@ -33,13 +34,13 @@ def no_vertical_adjacent_obstacle?(x_position, new_y)
 	end
 
 	def not_a_backwards_move?(new_y)
-		color == 1 ? (new_y - y_position) > 0 : (new_y - y_position) < 0 
+		color == 1 ? (new_y - y_position) > 0 : (new_y - y_position) < 0
 	end
 
 	def diagonal_move_allowed?(new_x, new_y)
 		return true if new_x == x_position
-		if (new_x - x_position).abs == 1 && (new_y - y_position).abs == 1 
-			capture_diagonally?(new_x, new_y) 
+		if (new_x - x_position).abs == 1 && (new_y - y_position).abs == 1
+			capture_diagonally?(new_x, new_y)
 		else
 			false
 		end
@@ -52,5 +53,5 @@ def capture_diagonally?(new_x, new_y)
 	def enemy_piece?(new_x, new_y)
 		obstacle_piece = Piece.find_by(:x_position => new_x, :y_position => new_y)
 		obstacle_piece.color != color
-	end  
-end
+	end
+end

app/models/piece.rb

@@ -1,7 +1,7 @@
-require 'pry'
 class Piece < ActiveRecord::Base
   belongs_to :user
   belongs_to :game
+  has_many :types
 
   def self.types
     %w(Pawn Rook Knight Bishop Queen King)
@@ -95,8 +95,8 @@ def move_to!(new_x, new_y)
       self.update(:x_position => new_x, :y_position => new_y)
 
     # Else if a friendly piece exists there, do nothing
-    elsif friend_or_foe.color == friendly_color
-      return
+    #elsif friend_or_foe.color == friendly_color
+      #return
     else
       # It's an enemy. Capture it
       friend_or_foe.update(:active => 0)
@@ -105,4 +105,26 @@ def move_to!(new_x, new_y)
       self.update(:x_position => new_x, :y_position => new_y)
     end
   end
+
+  def friendly_piece?(new_x, new_y)
+    obstacle_piece = game.pieces.find_by(
+      :x_position => new_x, :y_position => new_y, :active => 1)
+    if obstacle_piece.nil?
+      return false
+    else
+      obstacle_piece.color == color
+    end
+  end
+
+  def off_the_board?(new_x, new_y)
+    [new_x > 8, new_x < 1, new_y > 8, new_y < 1].any?
+  end
+
+  def going_nowhere?(new_x, new_y)
+    new_x == x_position && new_y == y_position
+  end
+
+  def nil_move?(new_x, new_y)
+    [off_the_board?(new_x, new_y), friendly_piece?(new_x, new_y), going_nowhere?(new_x, new_y)].any?
+  end
 end # end class

test/controllers/pieces_controller_test.rb

@@ -1,5 +1,4 @@
 require 'test_helper'
-require 'pry'
 
 class PiecesControllerTest < ActionController::TestCase
   def setup

test/models/in_check_test.rb

@@ -0,0 +1,20 @@
+require 'test_helper'
+
+class GameInCheckTest < ActiveSupport::TestCase
+  test "game in check state" do
+     g = Game.create
+     expected = true
+
+     black_p = g.pieces.find_by(:x_position => 4, :y_position => 7, :type => 'Pawn', color: 0)
+     deactivate_white_pawn = g.pieces.find_by(:x_position => 4, :y_position => 2).update_attributes(:active => 0)
+     black_p.update_attributes(:y_position => 2)
+
+     white_k = g.pieces.find_by(:x_position => 5, :y_position => 1, :color => 1, :type => 'King')
+     check_color = white_k.color
+     position_in_check = black_p.x_position, black_p.y_position
+     actual = g.checking_piece?(black_p.id, check_color, *position_in_check)
+
+     assert_equal expected, actual
+  end
+
+end

test/models/pawn_test.rb

@@ -1,5 +1,4 @@
 require 'test_helper'
-require 'pry'
 
 class PawnTest < ActiveSupport::TestCase
 

test/models/piece_test.rb

@@ -299,24 +299,6 @@ class PieceTest < ActiveSupport::TestCase
     assert_equal expected, actual
   end
 
-  test "move to a new destination that's occupied by a friendly" do
-    # Assume that is_obstructed? and is_valid? give the green light
-
-    game = Game.create
-
-    # Find the white king
-    white_king = game.pieces.find_by(:color => 1, :type => 'King')
-
-    # Test when a new destination is occupied by a friendly
-    white_king.move_to!(5, 2)
-
-    expected = [5, 1]
-
-    actual = [white_king.x_position, white_king.y_position]
-
-    assert_equal expected, actual
-  end
-
   test "move to a new destination that's occupied by an enemy" do
     game = Game.create
 
@@ -347,6 +329,64 @@ class PieceTest < ActiveSupport::TestCase
     actual = black_king.active
 
     # Assert the black piece's new :active status as captured (or 0)
+    assert_equal expected, actual
+  end
+#--------------------Test nil_move? logic-----------------------------------
+  test "invalid move to a new destination that's occupied by a friendly" do
+    # Corrected this test so that this move cannot take place
+    game = Game.create
+
+    # Find the white king
+    white_king = game.pieces.find_by(:color => 1, :type => 'King', :x_position => 5, :y_position => 1)
+    obstacle = game.pieces.find_by(:color => 1, :type => "Pawn")
+    obstacle.update_attributes(:x_position => 5, :y_position => 2)
+
+    # Test a destination that is occupied by a friendly
+    actual = white_king.nil_move?(5, 2)
+
+    expected = true
+
+    assert_equal expected, actual
+  end
+
+  test "invalid move off of the board" do 
+    game = Game.create
+
+    # Remove all pieces except Queen
+    pieces_to_deactivate = game.pieces.where.not(:type => "Queen")
+    pieces_to_deactivate.update_all(:active => 0)
+
+    white_queen = game.pieces.find_by(:color => 1, :type => 'Queen')
+
+    expected = true
+    # Test position far north
+    actual = white_queen.nil_move?(4, 9)
+
+    assert_equal expected, actual
+
+    # Test position far east
+    actual = white_queen.nil_move?(9, 1)
+
+    assert_equal expected, actual
+
+    # Test position far west
+    actual = white_queen.nil_move?(0, 1)
+
+    assert_equal expected, actual
+
+    # Test position south
+    actual = white_queen.nil_move?(4, 0)
+    assert_equal expected, actual
+  end
+
+  test "invalid attempt - choosing current location" do 
+    game = Game.create
+    white_pawn = game.pieces.find_by(
+      :type => "Pawn", :color => 1, :x_position => 1, :y_position => 2)
+
+    actual = white_pawn.nil_move?(1,2)
+    expected = true
+
     assert_equal expected, actual
   end
 end