import sys
import hashlib

progName="hashTwice_v01.py"
print("progName:",progName)
#by D@CC
#on 2023ISep25


#Hash Source: https://stackoverflow.com/questions/22058048/hashing-a-file-in-python
# compare to:
# $ md5-console -f bigfile
# $ shasum bigfile

#Snap Source:https://snapcraft.io/install/md5-console/raspbian
# $ sudo apt update
# $ sudo apt install snapd
# then reboot
# $ sudo snap install core
# $ sudo snap install snapcraft --classic
# $ sudo snap install md5-console
#  the last step took several minutes


# BUF_SIZE is totally arbitrary, change for your app!
BUF_SIZE = 65536  # lets read stuff in 64kb chunks!

md5 = hashlib.md5()
sha1 = hashlib.sha1()

md5old=sys.argv[2]
print("md5:",md5old)
with open(sys.argv[1], 'rb') as f:
    while True:
        data = f.read(BUF_SIZE)
        if not data:
            break
        md5.update(data)
        sha1.update(data)
# with end
print("MD5: {0}".format(md5.hexdigest()))
if md5old==md5.hexdigest() :
    print("md5 agrees")
else:
    print("bad md5 hash")
#if end
print("SHA1: {0}".format(sha1.hexdigest()))