[#62] [WIP] En Passant Logic For Pawn

README.md

@@ -36,4 +36,5 @@ Contributors
 
 * [Aleks Gorbenko](mailto:aleksedgorbenko@gmail.com) | [GitHub](https://github.com/aleksgorbenko) | [LinkedIn](https://uk.linkedin.com/in/aleks-gorbenko-web-developer) | [Portfolio](https://aleksgorbenko.github.io/) | [Blog](https://aleksgorbenko.com)
 
-* [Ethan He](mailto:ethanhe.dev@gmail.com) | [GitHub](https://github.com/Se7enB2st)
+* [Ethan He](mailto:ethanhe.dev@gmail.com) | [GitHub](https://github.com/Se7enB2st) |
+[LinkedIn](https://www.linkedin.com/in/ethan-he)

app/models/game.rb

@@ -8,6 +8,7 @@ class Game < ActiveRecord::Base
   after_save :create_players!
 
   def populate!
+    first_turn!
     populate_left_black_half!
     populate_right_black_half!
     populate_black_pawns!
@@ -16,6 +17,10 @@ def populate!
     populate_right_white_half!
   end
 
+  def end_turn!
+    increment!(:turn)
+  end
+
   def check?(color)
     king = king(color)
     enemy_pcs(color).each do |p|
@@ -96,4 +101,8 @@ def create_piece(type, color, x_pos, y_pos)
                           color: 'black', game_id: id)
     end
   end
+
+  def first_turn!
+    update(turn: 1)
+  end
 end

app/models/pawn.rb

@@ -6,7 +6,7 @@ class Pawn < Piece
   # takes place by moving forward. Check, and checkmate logic
   # are not implemented yet and thus ignored.
   def valid_move?(x, y)
-    return true if fwd_diagonal_attack?(x, y)
+    return true if fwd_diagonal_attack?(x, y) || en_passant_capture?(x, y)
     moved ? one_fwd_move?(x, y) : first_fwd_move?(x, y) && !fwd_attack?(x, y)
   end
 
@@ -20,6 +20,49 @@ def promote!(new_type)
 
   private
 
+  # En Passant Logic:
+  # 1)target pawn just moved 2 space forward
+  # 2)only capture within the next turn
+  # 3)can only capture by opponent's pawn
+  # 4)opponent pawn must be on the left or right of target piece's y axis
+
+  # En Passant Capture logic
+  def en_passant_capture?(x, y)
+    return true if en_passant_possible?(x, y) || en_passant_y_diff?(x, y)
+  end
+
+  # Return false if victim piece is nil or same color
+  # Return true  if victim piece's y axis difference is equal to 1
+  def en_passant_y_diff?(x, y)
+    victim = last_moved_piece
+    return false if victim.nil? || victim.color == color
+    return true if  x == victim.x_position &&
+                    (y == victim.y_position - 1 || y == victim.y_position + 1)
+  end
+
+  # Return false if last move piece is nil (Start of game)
+  # Return false last moved piece is not pawn or its y axis difference is !2
+  # Check both both adjacent side of pawn
+  # If any have valid En Passant pawn piece, return true
+  def en_passant_possible?(x, y)
+    return false if last_moved_piece.nil?
+    return false unless last_moved_piece.y_distance(y) == 2 &&
+                        type == 'Pawn'
+    [valid_en_passant_pawn?(x, y, true), valid_en_passant_pawn?(x, y, false)]
+      .include?(true)
+  end
+
+  # Check for any adjacent piece
+  # Return false if none if found
+  # Return true if opponent's pawn is found
+  def valid_en_passant_pawn?(x, y, adjacent)
+    adjacent_piece = occupant_piece(x + (adjacent ? 1 : -1), y)
+    return false if adjacent_piece.nil?
+    return true if adjacent_piece.type == 'Pawn' &&
+                   adjacent_piece.color != color
+    false
+  end
+
   # Returns true if the coordinates provided are 1 tile forward
   # from the piece's origin and no capture occured.
   def one_fwd_move?(x, y)
@@ -63,4 +106,9 @@ def fwd_diagonal_attack?(x, y)
            y_position - 1
          end
   end
+
+  # Find the last moved piece by subtracting current move number - 1
+  def last_moved_piece
+    game.pieces.find_by(turn_last_moved: game.turn - 1)
+  end
 end

app/models/piece.rb

@@ -24,14 +24,22 @@ def move!(x, y)
       return false unless enemy?(victim)
       capture!(victim)
     end
-    update(x_position: x, y_position: y, moved: true)
+    update(x_position: x, y_position: y, moved: true,
+           turn_last_moved: game.turn)
+    game.end_turn!
     # if checked_king(white_king)
     # elsif checked_king(black_king)
     # end
-
     true
   end
 
+  # Compares a piece's y_position with the
+  # coordinate provided and returns the
+  # distance between the two.
+  def y_distance(new_y_coordinate)
+    (y_position - new_y_coordinate).abs
+  end
+
   # All validation assumes white player is on the
   # 6-7 rows of the array, and black player is on
   # 0-1 rows of the array.
@@ -61,13 +69,6 @@ def x_distance(new_x_coordinate)
     (x_position - new_x_coordinate).abs
   end
 
-  # Compares a piece's y_position with the
-  # coordinate provided and returns the
-  # distance between the two.
-  def y_distance(new_y_coordinate)
-    (y_position - new_y_coordinate).abs
-  end
-
   # Returns true if the coordinates provided
   # are different from the piece's starting
   # position.

config/application.rb

@@ -1,3 +1,4 @@
+#Application.rb
 require File.expand_path('../boot', __FILE__)
 
 require 'rails/all'

config/environments/production.rb

@@ -1,5 +1,7 @@
+# Production.rb
 StoicChess::Application.configure do
-  config.action_mailer.default_url_options = { host: 'stoicchess-teamstoic.herokuapp.com' }
+  config.action_mailer.default_url_options =
+  { host: 'stoicchess-teamstoic.herokuapp.com' }
   # Settings specified here will take precedence over those in
   # config/application.rb.
 

config/environments/test.rb

@@ -1,3 +1,4 @@
+#test.rb
 StoicChess::Application.configure do
   # Settings specified here will take precedence over those in
   # config/application.rb.
@@ -19,7 +20,8 @@
 
   # Configure static asset server for tests with Cache-Control for performance.
   config.public_file_server.enabled  = true
-  config.public_file_server.headers = { 'Cache-Control' => 'public, max-age=3600' }
+  config.public_file_server.headers =
+  { 'Cache-Control' => 'public, max-age=3600' }
 
   # Show full error reports and disable caching.
   config.consider_all_requests_local       = true

config/initializers/backtrace_silencers.rb

@@ -1,7 +1,9 @@
 # Be sure to restart your server when you modify this file.
 
-# You can add backtrace silencers for libraries that you're using but don't wish to see in your backtraces.
+# You can add backtrace silencers for libraries that you're using
+# but don't wish to see in your backtraces.
 # Rails.backtrace_cleaner.add_silencer { |line| line =~ /my_noisy_library/ }
 
-# You can also remove all the silencers if you're trying to debug a problem that might stem from framework code.
+# You can also remove all the silencers if you're trying to debug a problem
+# that might stem from framework code.
 # Rails.backtrace_cleaner.remove_silencers!

config/initializers/devise.rb

@@ -33,7 +33,9 @@
   # :subdomain], so for authenticating a user, both parameters
   # are required.
   #
-  # Remember that those parameters are used only when authenticating and not when retrieving from session. If you need permissions, you should implement that in a before filter.
+  # Remember that those parameters are used only when authenticating
+  # and not when retrieving from session. If you need permissions,
+  # you should implement that in a before filter.
   #
   # You can also supply a hash where the value is a boolean
   # determining whether

config/initializers/secret_token.rb

@@ -9,4 +9,7 @@
 
 # Make sure your secret_key_base is kept private
 # if you're sharing your code publicly.
-StoicChess::Application.config.secret_key_base = 'b02af4ed78836e0a007c890e7f38df540669ad77d076cffe3899647bfbfd000e5e5080fc5841fff22763a5ce871d3f4f077b4c2693f964cdd67c0da25d6fad29'
+StoicChess::Application.config.secret_key_base =
+'b02af4ed78836e0a007c890e7f38df540669ad77d076cff
+e3899647bfbfd000e5e5080fc5841fff22763a5ce871d3f4
+f077b4c2693f964cdd67c0da25d6fad29'

config/initializers/session_store.rb

@@ -1,3 +1,4 @@
 # Be sure to restart your server when you modify this file.
 
-StoicChess::Application.config.session_store :cookie_store, key: '_StoicChess_session'
+StoicChess::Application.config.session_store :cookie_store, key:
+ '_StoicChess_session'

config/initializers/wrap_parameters.rb

@@ -3,7 +3,8 @@
 # This file contains settings for ActionController::ParamsWrapper which
 # is enabled by default.
 
-# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
+# Enable parameter wrapping for JSON. You can disable this by setting
+# :format to an empty array.
 ActiveSupport.on_load(:action_controller) do
   wrap_parameters format: [:json] if respond_to?(:wrap_parameters)
 end

db/migrate/20160629091417_devise_create_users.rb

@@ -1,3 +1,4 @@
+#devise auto migration
 class DeviseCreateUsers < ActiveRecord::Migration
   def change
     create_table(:users) do |t|

db/migrate/20160712160707_create_games.rb

@@ -1,9 +1,10 @@
+# game model 
 class CreateGames < ActiveRecord::Migration
   def change
     create_table :games do |t|
       t.string :winning_player
       t.string :game_status
- 
+
       t.integer :counter
       t.integer :turn
       t.integer :user_id

db/migrate/20160719140518_add_moved_to_pieces.rb

@@ -1,3 +1,4 @@
+# add moved to pieces table
 class AddMovedToPieces < ActiveRecord::Migration[5.0]
   def change
     add_column :pieces, :moved, :boolean, default: false

db/migrate/20160729214941_add_move_number_to_games.rb

@@ -0,0 +1,5 @@
+class AddMoveNumberToGames < ActiveRecord::Migration[5.0]
+  def change
+    add_column :games, :move_number, :integer
+  end
+end

db/migrate/20160730005057_add_en_passant_to_games.rb

@@ -0,0 +1,5 @@
+class AddEnPassantToGames < ActiveRecord::Migration[5.0]
+  def change
+    add_column :games, :en_passant, :boolean, default: false
+  end
+end

db/migrate/20160730144006_change_turn_type_to_string.rb

@@ -0,0 +1,5 @@
+class ChangeTurnTypeToString < ActiveRecord::Migration[5.0]
+  def change
+    change_column :games, :turn, :string
+  end
+end

db/migrate/20160730194959_add_last_moved_piece_to_pieces_table.rb

@@ -0,0 +1,5 @@
+class AddLastMovedPieceToPiecesTable < ActiveRecord::Migration[5.0]
+  def change
+    add_column :pieces, :last_moved_piece, :integer
+  end
+end

db/migrate/20160809143920_remove_en_passant_from_game.rb

@@ -0,0 +1,5 @@
+class RemoveEnPassantFromGame < ActiveRecord::Migration[5.0]
+  def change
+    remove_column :games, :en_passant, :boolean
+  end
+end

db/migrate/20160809145214_change_turn_from_games.rb

@@ -0,0 +1,6 @@
+class ChangeTurnFromGames < ActiveRecord::Migration[5.0]
+  def change
+    remove_column :games, :turn, :integer
+    remove_column :games, :move_number, :integer
+  end
+end

db/migrate/20160809150350_add_turn_to_games.rb

@@ -0,0 +1,5 @@
+class AddTurnToGames < ActiveRecord::Migration[5.0]
+  def change
+    add_column :games, :turn, :integer
+  end
+end

db/migrate/20160809151435_change_last_moved_piece_from_pieces.rb

@@ -0,0 +1,5 @@
+class ChangeLastMovedPieceFromPieces < ActiveRecord::Migration[5.0]
+  def change
+    rename_column :pieces, :last_moved_piece, :turn_last_moved
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160806192848) do
+ActiveRecord::Schema.define(version: 20160809151435) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -19,9 +19,9 @@
     t.string   "winning_player"
     t.string   "game_status"
     t.integer  "counter"
-    t.integer  "turn"
     t.datetime "created_at",     null: false
     t.datetime "updated_at",     null: false
+    t.integer  "turn"
   end
 
   create_table "pieces", force: :cascade do |t|
@@ -31,11 +31,12 @@
     t.integer  "y_position"
     t.integer  "game_id"
     t.integer  "player_id"
-    t.boolean  "captured",   default: false
-    t.boolean  "checkmate",  default: false
+    t.boolean  "captured",        default: false
+    t.boolean  "checkmate",       default: false
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.boolean  "moved",      default: false
+    t.boolean  "moved",           default: false
+    t.integer  "turn_last_moved"
   end
 
   create_table "players", force: :cascade do |t|

spec/models/game_spec.rb

@@ -7,18 +7,40 @@
     it 'should give us 32 pieces upon board population' do
       expect(game.pieces.count).to eq 32
     end
+
     it 'should give me the last x position of population' do
       expect(game.pieces.last.x_position).to eq 7
     end
+
     it 'should give me the last y position of population' do
       expect(game.pieces.last.y_position).to eq 7
     end
+
     it 'should give me the last piece of the population as the King' do
       expect(game.pieces.last.type).to eq 'Rook'
     end
+
     it 'should give me the last pieces color' do
       expect(game.pieces.last.color).to eq 'white'
     end
+
+    it 'should show turn as 1' do
+      expect(game.turn).to eq 1
+    end
+
+    describe 'end_turn!' do
+      it 'should increment turn by 1 once the turn ended' do
+        game.end_turn!
+
+        expect(game.turn).to eq 2
+      end
+    end
+
+    describe 'first_turn' do
+      it 'should show turn as 1' do
+        expect(game.turn).to eq 1
+      end
+    end
   end
 
   describe 'check?' do