class Faker::Bitcoin

def address
  address_for(:main)
end

def address_for(network)
  version = PROTOCOL_VERSIONS.fetch(network)
  packed = version.chr + Faker::Config.random.bytes(20)
  checksum = Digest::SHA2.digest(Digest::SHA2.digest(packed))[0..3]
  base58(packed + checksum)
end

def base58(str)
  alphabet = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
  base = alphabet.size
  lv = 0
  str.split('').reverse.each_with_index { |v,i| lv += v.unpack('C')[0] * 256**i }
  ret = ''
  while lv > 0 do
    lv, mod = lv.divmod(base)
    ret << alphabet[mod]
  end
  npad = str.match(/^#{0.chr}*/)[0].to_s.size
  '1'*npad + ret.reverse
end

def testnet_address
  address_for(:testnet)
end