#!/usr/bin/env ruby

require_relative '../common'

class Grid
  def initialize(robosanta: false)
    @robosanta = robosanta

    @santa_position = Position.new
    @robosanta_position = Position.new

    @grid = Hash.new(0)

    give_from_santa
    give_from_robosanta
  end

  def houses_count
    @grid.size
  end

  def move_santa(direction)
    @santa_position.move direction
    give_from_santa
  end

  def move_robosanta(direction)
    @robosanta_position.move direction
    give_from_robosanta
  end

  def give_from_santa
    @grid[@santa_position.position] += 1
  end

  def give_from_robosanta
    return unless @robosanta
    @grid[@robosanta_position.position] += 1
  end
end

class Position
  attr_accessor :position

  def initialize
    self.position = [0, 0]
  end

  def move(direction)
    case direction
    when '^'
      up
    when 'v'
      down
    when '<'
      left
    when '>'
      right
    end
  end

  def up
    self.position = [position[0] - 1, position[1]]
  end

  def down
    self.position = [position[0] + 1, position[1]]
  end

  def left
    self.position = [position[0], position[1] - 1]
  end

  def right
    self.position = [position[0], position[1] + 1]
  end
end

def part1
  Input.new(__dir__).readlines.join.chars.each_with_object(Grid.new) do |direction, grid|
    grid.move_santa direction
  end.houses_count
end

def part2(input)
  input.chars.each_with_object(Grid.new(robosanta: true)).with_index do |(direction, grid), i|
    if i.even?
      grid.move_santa direction
    else
      grid.move_robosanta direction
    end
  end.houses_count
end

puts "=== Part 1 ==="
puts part1
puts "=== Part 2 ==="
puts part2(Input.new(__dir__).readlines.join)