FCM 83 - How to program in Python #53

from random import randint, seed
import sys

localvalid1 = "abcdefghijklmnopqrstuvwxyz"
localvalid2 = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
localvalid3 = "!#$%&'*+-/=?^_`{|}~."
Offset = 0

def IsValidEmail(s,debug=0):
    email = s
    pos = email.rfind("@")
    local = email[:pos]
    domain = email[pos+1:]
    if debug == 1:
        print local
        print domain
    isgood = False
    localvalid = localvalid1 + localvalid2 + localvalid3
    # Check Local Part
    for cntr in range(0,len(local)):
        if local[cntr] in localvalid:
            if debug == 1:
                print local[cntr],ord(local[cntr]),"True"
            isgood = True
        else:
            if debug == 1:
                print local[cntr],ord(local[cntr]),"False"
            isgood = False
            break
    r = email.find("..")
    if r > -1:
        isgood = False
    return isgood

def CheckSum(s,debug = 0):
    sum = 0
    email = s.upper()
    for cntr in range(0,len(email)):
        if debug == 1:
            print email[cntr],ord(email[cntr])
        sum += ord(email[cntr])
    cs = sum/len(email)
    if debug == 1:
        print('Sum = %d' % sum)
        print('ChkSum = %d' % cs)
        print('ChkSum = %s' % chr(cs))
    return cs,chr(cs)

def EncodeKey(s, csum, debug = 0):
    global Offset
    email = s
    Offset = csum - 68
    if debug == 1:
        print("Offset is %d" % Offset)
    NewEmail = ""
    for cntr in range(0,len(email)):
        ch = ord(email[cntr]) + Offset
        if cntr == 1:
            NewEmail = NewEmail + (chr(len(email)+68)) + chr(ch)
        elif cntr == 2:
            NewEmail = NewEmail + chr(csum) + chr(ch)
        else:
            NewEmail = NewEmail + chr(ch)
    if debug == 1:
        print cntr, NewEmail
    return NewEmail

def DecodeKey(s,debug = 0):
    global Offset
    eml = ""
    for cntr in range(0,len(s)):
        if debug != 0:
            print cntr,s[cntr],ord(s[cntr])-Offset,chr(ord(s[cntr])-Offset)
        if cntr == 0:
            eml = eml + chr(ord(s[cntr])-Offset)
        elif cntr == 1:
            emllen = ord(s[cntr])-Offset
        elif cntr == 3:
            csumchr=s[cntr]
        else:
            eml = eml + chr(ord(s[cntr])-Offset)
    if debug == 1:
        print eml
    return eml

def DoIt():
    email = raw_input("Please enter email address -> ")
    isok = IsValidEmail(email,0)
    if isok == True:
        csum,csumchr = CheckSum(email)
        ke = EncodeKey(email,csum,0)
        print("License Key    = %s" % ke)
        print("Original email = %s" % DecodeKey(ke,0))

if __name__ == "__main__":
    DoIt()