Advent Of Code - Day 4 (Part two) - Ruby

aoc_day_4_part_two.rb

passports = File.open('input.txt').read.split("\n\n")

class Passport
  REQUIRED_FIELDS = %w[
    byr
    iyr
    eyr
    hgt
    hcl
    ecl
    pid
  ].freeze

  def initialize(passport_string)
    @passport_string = passport_string
    convert_passport_string_to_hash!
  end

  def valid?
    puts ""
    puts ""

    REQUIRED_FIELDS.all? do |field|
      puts "#{field}: #{@parts[field]} = #{ send("#{field}_valid?") if @parts[field]}"

      @parts[field] && send("#{field}_valid?")
    end
  end

  private

  def convert_passport_string_to_hash!
    @parts = @passport_string
      .split("\n")
      .join(' ')
      .split(' ')
      .collect { |part| part.split(':') }
      .to_h
  end

  # four digits; at least 1920 and at most 2002.
  def byr_valid?
    byr = @parts['byr'].to_i

    @parts['byr'].length == 4 && byr >= 1920 && byr <= 2002
  end

  # four digits; at least 2010 and at most 2020.
  def iyr_valid?
    iyr = @parts['iyr'].to_i
    @parts['iyr'].length == 4 && iyr >= 2010 && iyr <= 2020
  end

  # four digits; at least 2020 and at most 2030.
  def eyr_valid?
    eyr = @parts['eyr'].to_i
    @parts['eyr'].length == 4 && eyr >= 2020 && eyr <= 2030
  end

  # If cm, the number must be at least 150 and at most 193.
  # If in, the number must be at least 59 and at most 76.
  def hgt_valid?
    hgt_value = @parts['hgt'].sub(/in|cm/, '').to_i

    if @parts['hgt'].include?('cm')
      hgt_value >= 150 && hgt_value <= 193
    else
      hgt_value >= 59 && hgt_value <= 76
    end
  end

  # a # followed by exactly six characters 0-9 or a-f.
  def hcl_valid?
    @parts['hcl'].match?(/^#[0-9a-f]{6}$/i)
  end

  # exactly one of: amb blu brn gry grn hzl oth.
  def ecl_valid?
    ['amb', 'blu', 'brn', 'gry', 'grn', 'hzl', 'oth'].include?(@parts['ecl'])
  end

  # a nine-digit number, including leading zeroes.
  def pid_valid?
    @parts['pid'].length == 9
  end
end

puts passports
  .collect { |passport_string| Passport.new(passport_string) }
  .select(&:valid?)
  .count