module Dmp

# File lib/dmp.rb, line 18
def self.check_pwned(passphrase)
  # This module follows the k-Anonymity principle described in
  # https://haveibeenpwned.com/API/v2#PwnedPasswords
  # that allows you to search for the first 5 characters of the hash and
  # returns a list of hashes for you to search the rest of the hash locally,
  # followed by the number of times the hash appears in a data set
  # e.g: 0018A45C4D1DEF81644B54AB7F969B88D65:21
  passphrase = passphrase.join(' ') if passphrase.is_a?(Array)

  sha1_pass = Digest::SHA1.hexdigest(passphrase)
  sha1_excerpt = sha1_pass[0...5]
  sha1_to_look_for = sha1_pass[5..-1]

  api_url = URI("https://api.pwnedpasswords.com/range/#{sha1_excerpt}")
  api_request = Net::HTTP.get(api_url)

  # Response is text instead of JSON, needs to format the response
  # to a dictionary so the rest of the hash can be located easier.
  # => String '0018A45C4D1DEF81644B54AB7F969B88D65:21'
  # => Array ['0018A45C4D1DEF81644B54AB7F969B88D65:21', ...]
  # => 2D Array [['0018A45C4D1DEF81644B54AB7F969B88D65', '21'], ...]
  # => Hash {'0018A45C4D1DEF81644B54AB7F969B88D65': 21, ...}
  striped_list = api_request.split("\r\n")
  pass_list = striped_list.map { |hash| hash.split(':') }
  hash_list = Hash[*pass_list.flatten!]
  hash_list[sha1_to_look_for.upcase]
end

# File lib/dmp.rb, line 12
def self.gen_passphrase(pass_length = 7)
  wordlist = File.readlines(@eff_wordlist)
  wordlist.map(&:strip!)
  wordlist.shuffle[0...pass_length]
end