phone_num_text.rb

# Currently works with seven letter words only

phone_number = "18002435377"

last_seven_digits = phone_number.to_s[-7..-1].split(//).map(&:to_i)

def return_letters(digit)
  hash_map = {2 => ["a", "b", "c"],
    3 => ["d", "e", "f"],
    4 => ["g", "h", "i"],
    5 => ["j", "k", "l"],
    6 => ["m", "n", "o"],
    7 => ["p", "q", "r", "s"],
    8 => %w[t u v],
    9 => %w[w x y z]
  }

  hash_map[digit]
end

list1 = return_letters(last_seven_digits[0])
list2 = return_letters(last_seven_digits[1])
list3 = return_letters(last_seven_digits[2])
list4 = return_letters(last_seven_digits[3])
list5 = return_letters(last_seven_digits[4])
list6 = return_letters(last_seven_digits[5])
list7 = return_letters(last_seven_digits[6])


def return_combinations(*args)

  p "in return return_combinations"
  length = args.length
  p "length #{length}"
  tmp = []
  if length == 0
    []
  else
    list1, *rest = args
    if rest.empty?
      list1
    else
      list2 = rest[0]
      tmp = list1.product(list2).map {|x| x.join("")}

      rest.shift
      # p tmp
      # p rest
      rest.unshift(tmp)
      p rest
      if rest.empty?
        tmp
      else
        return_combinations(*rest)
      end
    end
  end
end

puts "======================="
allcombina = return_combinations(list1, list2, list3, list4, list5, list6, list7)

file_data = {}
File.open("/usr/share/dict/words", 'r') do |file|
  file.each_line do |line|
    file_data[line.chomp.downcase] = 1
  end
end

def validate_word(word, dict)
  dict.has_key?(word.downcase)
end

def possible_words(list, dict)
  list.select { |x| validate_word(x, dict) == true }
end

p possible_words( allcombina,file_data)