require_relative "piece"
require "colorize"

module ChessEngine
  class Board
    def initialize
      @board = Array.new(8) { Array.new(8) { nil } }
    end

    def set_default
      [[:white, 0, 1], [:black, 7, 6]].each do |color, row1, row2|
        ["Rook", "Knight", "Elephant", "Queen", "King", "Elephant", "Knight", "Rook"].each.with_index do |class_name, column|
          self[column, row1] = Module.const_get("ChessEngine::#{class_name}").new(color)
        end

        0.upto(7) do |column|
          self[column, row2] = Pawn.new(color)
        end
      end
    end

    def [](column, row)
      @board[column][row]
    end

    def []=(column, row, piece)
      @board[column][row] = piece
    end

    def at(coordinates)
      return nil unless self.exists_at?(coordinates)
      @board[coordinates[0]][coordinates[1]]
    end

    def set_at(coordinates, piece)
      @board[coordinates[0]][coordinates[1]] = piece
    end

    def exists_at?(coordinates)
      coordinates.all? { |c| c.between?(0, 7) }
    end

    def to_s
      string = ""
      colors = [[:default, :light_white].cycle, [:light_white, :default].cycle].cycle

      7.downto(0) do |row|
        string += "#{row + 1} "
        colors_cycle = colors.next

        0.upto(7) do |column|
          piece = self[column, row]
          string += piece.nil? ? " " : piece.symbol
          string += " "
          string[-2..-1] = string[-2..-1].colorize(background: colors_cycle.next)
        end
        string += "\n"
      end

      string += "  a b c d e f g h"
      string
    end

    def move_piece(from, to)
      piece = self.at(from)
      self.set_at(from, nil)
      self.set_at(to, piece)
    end

    def pieces(color)
      @board.flatten.compact.select { |piece| piece.color == color }
    end

    def Board.coordinates_list
      list = []
      (0..7).each do |x|
        (0..7).each { |y| list << [x, y]}
      end
      list
    end

    def king_coords(color)
      Board.coordinates_list.find do |coord|
        at(coord) && at(coord).king? && at(coord).color == color
      end
    end

    def piece_coordinates(color)
      Board.coordinates_list.select do |coord|
        piece = at(coord)
        !piece.nil? && piece.color == color
      end
    end
  end
end