chess_pieces.rb

class Piece
  DIAGONALS = [[1, 1], [1, -1], [-1, -1], [-1, 1]]
  STRAIGHTS = [[0, 1], [1, 0], [-1, 0], [0, -1]]
  
  attr_accessor :position
  attr_reader :color
  def initialize(board, start_pos, color)
    @board = board
    @position = start_pos
    @color = color
  end
  
  def valid_moves
    self.possible_moves.select do |move|
      !move_into_check?(move)
    end
  end

  def target_pos_empty?(target_pos)
    @board.empty?(target_pos)
  end
  
  def inspect
    unicode_hash = {
      King:   ["\u2654",	"\u265a"],
      Queen:  ["\u2655",	"\u265b"],
      Rook:   ["\u2656",	"\u265c"],
      Bishop: ["\u2657",	"\u265d"],
      Knight: ["\u2658",	"\u265e"],
      Pawn:   ["\u2659",	"\u265f"]
    }
    
    color_option = @color == :white ? 0 : 1
    
    return unicode_hash[self.class.to_s.to_sym][color_option]
  end
  
  def move_into_check?(pos)
    # will making this move leave me in check?
    dupped_board = @board.deep_dup
    dupped_board.move!(@position, pos)
    dupped_board.in_check?(@color)
  end
end