#
# Purpose: Write 2 new JPG image files => PicSeal JPG Files
#
# Data: public key, private key, image hash, image signature
# Has: JPG fingerprint
#
# Big-endian
# Pub: [app15:2|size:2|'picseal':7|type:1|sig:512|pubkey:550]
# Pvt: [app15:2|size:2|'picseal':7|type:1|sig:512|pvtkey:2347]
#
import struct
import logging
from Crypto.PublicKey import RSA
from libs.crypto_sig import Signature


class JpgPicSeal:

  app15_marker   = b'\xff\xef'
  # ascii code for "picseal"
  picseal_marker = b'\x70\x69\x63\x73\x65\x61\x6C'
  pub_marker = b'\x01'
  pvt_marker = b'\x02'


  def __init__(self):
    pass    

  #
  # READ
  #

  def isPicSeal(buf):
    if (buf == JpgPicSeal.picseal_marker):
      return True
    return False

  #
  # [size:2|picseal:7|type:1|sig:512|key:550] == 1072
  #
  def deserialize(buf):
    sig = Signature()
    retval = False

    # read type 0x01 is public key, 0x02 private key
    try:
      if (buf[9] == ord(JpgPicSeal.pub_marker)):
        sig.importPubKey(buf[522:])
        print("*** *** ***")
        print("*** Public Key Import Sucessful")
        print("*** *** ***")
      else:
        sig.importPvtKey(buf[522:])
        print("*** *** ***")
        print("*** Private Key Import Sucessful")
        print("*** *** ***")
      return sig
    except Exception as ex:
      logging.debug(ex)

    return None


  #
  def readPub(self):
    pass

  def readPvt(self):
    pass



  #
  # WRITE
  #

  #
  def serilize(fname):
    pass
  #
  # input is the Crypto Sig class
  #
  def writePub(fhw, sig):
    JpgPicSeal.__writeData(fhw, sig.sig_data, sig.getPubKeyDER(), JpgPicSeal.pub_marker)

  #
  # input is the Crypto Sig class
  #
  def writePvt(fhw, sig):
    JpgPicSeal.__writeData(fhw, sig.sig_data, sig.getPvtKeyDER(), JpgPicSeal.pvt_marker)


  #
  def __writeData(fhw, sig_data, keyder, pubpvt):
    # must include 2 bytes for length too, plus 1 for the key type
    size = 3
    size += len(JpgPicSeal.picseal_marker)
    size += len(sig_data)
    size += len(keyder)

    logging.debug("3+{}+{}+{}=={} | picseal, sig, key".format(str(len(JpgPicSeal.picseal_marker)), str(len(sig_data)), str(len(keyder)), str(size) ))
    #
    # write header
    # write app marker
    fhw.write(JpgPicSeal.app15_marker)
    # write the size of picseal record
    fhw.write(size.to_bytes(2, byteorder='big'))

    #
    # write picseal data
    # write picseal marker
    fhw.write(JpgPicSeal.picseal_marker)
    fhw.write(pubpvt)
    # write signature of image
    fhw.write(sig_data)  
    # write the key data
    fhw.write(keyder)