Class: Board

Inherits:
Object
  • Object
show all
Defined in:
lib/ari_chess/board.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(grid = Array.new(8) { Array.new(8) }) ⇒ Board

Returns a new instance of Board.



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# File 'lib/ari_chess/board.rb', line 7

def initialize(grid = Array.new(8) { Array.new(8) })
  @grid = grid
end

Instance Attribute Details

#grid ⇒ Object (readonly)

Returns the value of attribute grid.



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# File 'lib/ari_chess/board.rb', line 5

def grid
  @grid
end

Instance Method Details

#[](pos) ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 82

def [](pos)
  x, y = pos
  @grid[x][y]
end

#[]=(pos, value) ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 87

def []=(pos, value)
  x, y = pos
  @grid[x][y] = value
end

#base_row_pieces ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 133

def base_row_pieces
  [
    Rook,
    Knight,
    Bishop,
    Queen,
    King,
    Bishop,
    Knight,
    Rook
  ]
end

#checkmate?(color) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ari_chess/board.rb', line 61

def checkmate?(color)
  in_check?(color) && find_pieces(color).all? do |piece|
    piece.valid_moves.empty?
  end
end

#dup ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 48

def dup
  new_board = Board.new

  white_pieces = find_pieces(:W)
  black_pieces = find_pieces(:B)

  (white_pieces + black_pieces).each do |piece|
      new_board[piece.pos] = piece.dup(new_board)
  end

  new_board
end

#find_pieces(color, type = nil) ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 75

def find_pieces(color, type = nil)
  colored_pieces = grid.flatten.compact.select { |piece| piece.color == color }
  colored_pieces.select! { |piece| piece.class.to_s == type } unless type.nil?

  colored_pieces
end

#in_check?(color) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ari_chess/board.rb', line 67

def in_check?(color)
  opposing_color = (color == :W ? :B : :W)
  opposing_pieces = find_pieces(opposing_color)
  king = find_pieces(color, "King")[0]

  opposing_pieces.any? { |piece| piece.moves.include?(king.pos) }
end

#inspect ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 92

def inspect
  ""
end

#move(start_pos, end_pos) ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 15

def move(start_pos, end_pos)
  validate_move(start_pos, end_pos)

  move!(start_pos, end_pos)
end

#move!(start_pos, end_pos) ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 39

def move!(start_pos, end_pos)
  piece = self[start_pos]

  self[end_pos] = piece
  piece.update_piece(end_pos)

  self[start_pos] = nil
end

#on_board?(pos) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ari_chess/board.rb', line 11

def on_board?(pos)
  pos.all? { |coord| coord.between?(0, 7) }
end

#populate_row(row_idx, color, pieces) ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 125

def populate_row(row_idx, color, pieces)
  grid[row_idx].each_index do |idx|
    self[[row_idx, idx]] = pieces[idx].new([row_idx, idx], self, color)
  end

  nil
end

#render ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 96

def render
  square_num = 0 #tracks grid for alternating color
  row_num = 0

  puts "   a  b  c  d  e  f  g  h"
  grid.each_with_index do |row, n|
    row_string = ""
    row.each do |square|
      color = (square_num + row_num).even? ? :light_white : :light_black
      row_string << (square.nil? ? "   " : " " + square.to_s + " ").colorize(:background => color)
      square_num += 1
    end
    puts "#{(-1 * n) + 8} " + row_string
    row_num += 1
  end

  nil
end

#setup_pieces ⇒ Object 



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# File 'lib/ari_chess/board.rb', line 115

def setup_pieces
  populate_row(0, :B, base_row_pieces)
  populate_row(1, :B, Array.new(8) { Pawn })

  populate_row(7, :W, base_row_pieces)
  populate_row(6, :W, Array.new(8) { Pawn })

  nil
end

#validate_move(start_pos, end_pos) ⇒ Object

Raises:



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# File 'lib/ari_chess/board.rb', line 21

def validate_move(start_pos, end_pos)
  piece = self[start_pos]

  error_message = nil

  if piece.nil?
    error_message = "Invalid move! Start position is empty."
  elsif !piece.moves.include?(end_pos)
    error_message = "Invalid move!"
  elsif !piece.valid_moves.include?(end_pos)
    error_message = "Invalid move! This move would move you into check."
  end

  raise InvalidMoveError.new(error_message) unless error_message.nil?

  nil
end