Position = Struct.new(:x, :y) class Board DIRECTIONS = [[1, 0], [-1, 0], [0, 1], [0, -1], [-1, 1], [1, -1]].freeze BLACK = 'X'.freeze WHITE = 'O'.freeze def initialize(game) @height = game.size @width = cols(game[0]).size @fields = Array.new(@height) { Array.new(@width) } prepare_board(game) @history = {} end def cols(line) line.tr(' ', '').split('') end def prepare_board(game) game.each_with_index do |line, y| cols(line).each_with_index do |char, x| @fields[x][y] = if char == BLACK || char == WHITE char else nil end end end end def start_of(winner) case winner when BLACK then (0...@height).map { |y| Position.new(0, y) } when WHITE then (0...@width).map { |x| Position.new(x, 0) } end end def winner?(winner) start_of(winner).any? {|position| winner_on?(position, winner) } end def neighbours(pos) neighbours = [] DIRECTIONS.each do |x, y| position = Position.new pos.x + x, pos.y + y neighbours << position if into_board? position end neighbours end def into_board?(position) position.x >= 0 && position.y >= 0 && position.x < @width && position.y < @height end def reach_target?(winner, position) axis_position = winner == BLACK ? position.x : position.y axis_position == edge_of(winner) end def edge_of winner { BLACK => @width - 1, WHITE => @height - 1 }[winner] end def winner_on?(position, winner) x = position.x y = position.y if @fields[x][y] == winner return false if @history[[winner, x, y]] @history[[winner, x, y]] = true return true if reach_target? winner, position return neighbours(position).any?{|pos| winner_on? pos, winner} end false end def winner return BLACK if winner? BLACK return WHITE if winner? WHITE '' end def each_field (0...@height).each do |y| (0...@width).each do |x| yield @fields[x][y], x, y end end end def to_s s = "" each_field do |chr, x, y| s << ' ' * y if x == 0 if chr == BLACK || chr == WHITE chr = chr.downcase if @history[[chr, x, y]] s << chr + ' ' else s << '. ' end s << ?\n if x == @width - 1 end s end end