AOC 2020 - Day 12, part 2

aoc_2020_day_12_part_two.rb

class Ship
  def initialize
    @x = 0
    @y = 0
    @waypoint_x = 10
    @waypoint_y = 1
  end

  def rotate!(direction, degrees_to_turn)
    puts "Waypoint was: #{current_waypoint}"

    if direction == 'R'
      (degrees_to_turn / 90).times do
        tmp_y = @waypoint_y.dup
        @waypoint_y = 0 - @waypoint_x
        @waypoint_x = tmp_y
      end
    else
      (degrees_to_turn / 90).times do
        tmp_x = @waypoint_x.dup
        @waypoint_x = 0 - @waypoint_y
        @waypoint_y = tmp_x
      end
    end

    puts "Waypoint is: #{current_waypoint}"
  end

  def forward!(distance)
    @x += (@waypoint_x * distance)
    @y += (@waypoint_y * distance)

    puts "Moved to: #{current_position}"
  end

  def move_waypoint!(direction, distance)
    if direction == 'N'
      @waypoint_y += distance
    elsif direction == 'S'
      @waypoint_y -= distance
    elsif direction == 'E'
      @waypoint_x += distance
    elsif direction == 'W'
      @waypoint_x -= distance
    end

    puts "Waypoint is: #{current_waypoint}"
  end

  def current_waypoint
    [
      "X: #{@waypoint_x}",
      "Y: #{@waypoint_y}"
    ]
  end

  def current_position
    [
      "X: #{@x}",
      "Y: #{@y}"
    ]
  end

  def manhattan_position
    @x.abs + @y.abs
  end
end

class Command
  def initialize(string)
    @direction = string[0]
    @distance = string[1..].to_i
  end

  def call(ship)
    if @direction == 'R' ||  @direction == 'L'
      ship.rotate!(@direction, @distance)
    elsif @direction == 'F'
      ship.forward!(@distance)
    else
      ship.move_waypoint!(@direction, @distance)
    end
  end
end

@ship = Ship.new

@commands = File.open('input.real.txt').read.split("\n").compact.each do |command|
  puts command
  Command.new(command).call(@ship)
  puts ""
end

puts ""
puts "Manhatten Position: #{@ship.manhattan_position}"