"""
*******************************************************************************
*   Ledger Blue
*   (c) 2016 Ledger
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
********************************************************************************
"""

import argparse

def get_argparser():
	parser = argparse.ArgumentParser("""Verify that the provided signature is a valid signature of the provided
application.""")
	parser.add_argument("--hex", help="The hex file of the signed application")
	parser.add_argument("--key", help="The Custom CA public key with which to verify the signature (hex encoded)")
	parser.add_argument("--signature", help="The signature to be verified (hex encoded)")
	return parser

def auto_int(x):
	return int(x, 0)

if __name__ == '__main__':
	from .hexParser import IntelHexParser
	from .hexParser import IntelHexPrinter
	from .ecWrapper import PublicKey
	import hashlib
	import binascii

	args = get_argparser().parse_args()

	if args.hex == None:
		raise Exception("Missing hex filename to verify")
	if args.key == None:
		raise Exception("Missing public key")
	if args.signature == None:
		raise Exception("Missing signature")

	# parse
	parser = IntelHexParser(args.hex)

	# prepare data
	m = hashlib.sha256()
	# consider areas are ordered by ascending address and non-overlaped
	for a in parser.getAreas():
		m.update(a.data)
	dataToSign = m.digest()

	publicKey = PublicKey(bytes(bytearray.fromhex(args.key)), raw=True)
	signature = publicKey.ecdsa_deserialize(bytes(bytearray.fromhex(args.signature)))
	if not publicKey.ecdsa_verify(bytes(dataToSign), signature, raw=True):
		raise Exception("Signature not verified")

	print("Signature verified")