require 'debug'

# Generic FileHandler
class FileHandler
  def initialize(file_path)
    @file_path = file_path
  end

  # Usage:
  # FileHandler.new('/path_to_file').read_lines do |line|
  #   # process line
  # end
  def read_lines
    File.foreach(@file_path, chomp: true).map do |line|
      yield(line)
    end
  end

  # Usage:
  # file_content = FileHandler.new('/path_to_file').read_file(
  def read_file
    File.read(@file_path, chomp: true)
  end
end

class PuzzleSolver
  def initialize(file_handler, debug: false)
    @handler = file_handler
    @debug = debug
  end

  def debug(message)
    puts message if @debug
  end

  def print_debug(message)
    print message if @debug
  end

  def solve
    raise NotImplementedError, 'Please implement this method in subclasses.'
  end
end

class FreshnessDatabase
  # @param [<Range>] list of ranges of fresh IDs
  def initialize(fresh_ranges)
    @fresh_ranges = fresh_ranges
  end

  def fresh_id?(id)
    @fresh_ranges.any? {|range| range.include?(id)}
  end
end

class Solver < PuzzleSolver
  # @param [String] e.g., "11-22"
  # @return [Range] e.g., 11..22 (inclusive)
  def to_range(string)
    boundaries = string.split('-').map(&:to_i)
    raise "Invalid boundaries for #{string}, got #{boundaries.inspect}" if boundaries.length != 2
    Range.new(boundaries[0], boundaries[1])
  end

  # @param [String] full input e.g., "11-22\n33-604\n..."
  # @return [<Range>] e.g., [11..22, 33..604, ...]
  def parse_ranges(input)
    input.split("\n").map {|range| to_range(range)}
  end

  # @param [String] ids_str e.g., "1\n5\n8\n11\n17\n32"
  # @return [<Integer>] e.g., [1, 5, 8, 11, 17, 32]
  def parse_ids(ids_str)
    ids_str.split("\n").map(&:to_i)
  end

  def solve
    two_parts = @handler.read_file.split("\n\n")
    raise "Invalid file format: #{two_parts.inpsect}" if two_parts.length != 2

    db = FreshnessDatabase.new(parse_ranges(two_parts[0]))
    ids = parse_ids(two_parts[1])

    fresh_ids = ids.select {|id| db.fresh_id?(id)}
    fresh_ids.length
  end
end


if ARGV[0].nil? || ARGV[0].empty?
  puts "Usage: ruby #{__FILE__} <file_name> [debug]"
  exit 1
end
file_path = ARGV[0]
debug = (ARGV[1] == "debug")
file_handler = FileHandler.new(file_path)

## Puzzle-specific
cls = Solver
##

puts "The answer is: #{cls.new(file_handler, debug:).solve}"