module ShortHash

# File lib/short_hash.rb, line 6
def self.gen num = 0
  v = self.raw_gen62
  if num > 0
    v = v[0, num]
  end
  v
end

# File lib/short_hash.rb, line 14
def self.gen36 num = 0
  v = self.raw_gen36
  if num > 0
    v = v[0, num]
  end
  v
end

# File lib/short_hash.rb, line 22
def self.gen_number num = 0
  self.raw_gen_number num
end

# File lib/short_hash.rb, line 46
def self.raw_gen36
  charlist = '0123456789abcdefghijklmnopqrstuvwxyz'
  charlen = charlist.length()

  val = rand().to_s + ':' + Time.now.to_f.to_s
  u = Digest::MD5.hexdigest(val)

  digit = []

  no = u.hex
  begin
    no, c = no.divmod charlen
    digit << charlist[c]
  end while no > 0

  digit.join ''
end

# File lib/short_hash.rb, line 28
def self.raw_gen62
  charlist = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
  charlen = charlist.length()

  val = rand().to_s + ':' + Time.now.to_f.to_s
  u = Digest::MD5.hexdigest(val)

  digit = []

  no = u.hex
  begin
    no, c = no.divmod charlen
    digit << charlist[c]
  end while no > 0

  digit.join ''
end

# File lib/short_hash.rb, line 64
def self.raw_gen_number num = 0
  s = [*0..9]
  r = s.sample num
  r.join ''
end