#open a file in read mode
file = open("data.txt","r")
#read each line of data to a vairble
FileData = file.readlines()
#close the file
file.close()
#set correct password to false as no true password found yet
CorrectPassword = False
while CorrectPassword == False:
    #ask the user for username and password
    print("input your username?")
    UserName = input()
    print("input your password?")
    UserPassword = input()
    #go through each line of the file
    for line in  FileData:
        #split the line in to first and second section
        LineUserName = line.split(":")[0]
        LineUserPassword = line.split(":")[1]
        #check if the username is the same as the one in this line
        if  UserName == LineUserName :
            #now check if thepassword is correct
            if UserPassword == LineUserPassword:
                CorrectPassword=True
        if CorrectPassword == False:
            print("Your usernam or password is incorrect")
            print("")
print("This is a secret message")

print("choose an option: 1 - Add user ,2 - delete user ,  3 - change password")
UserChoice = input()
if UserChoice == "1":
    PassMatch = False
    while PassMatch == False:
        print("please type the new username")
        NewUserName = input()
        print("please type the new password")
        NewUserPassword = input()
        print("please retype the new password")
        PasswordCheck = input()
        if NewUserPassword == PasswordCheck:
            PassMatch=True
        else:
            print("passwords don't match")
    file = open("data.txt","a")
    print("\n" + NewUserName+ ":" +  NewUserPassword)
    file.write("\n" + NewUserName+ ":" +  NewUserPassword)
    file.close()
elif UserChoice == "2":
     print("please type the user name of the user to remove?")
     UserName=input()
     file = open("data.txt","r")
     FileData = file.readlines()
     file.close()
     file = open("data.txt","w")
     for line in FileData:
          LineUserName = line.split(":")[0]
          LineUserPassword = line.split(":")[1]
          if Uername != LineUserName :
              file.write(line)
     file.close()
if UserChoice == "3":
    PassMatch = False
    while PassMatch== False:
        print("please type the new password")
        NewUserPassword = input()
        print("please retype the new password")
        PasswordCheck = input()
        if NewUserPassword == PasswordCheck:
            PassMatch=True
        else:
            print("passwords don't match")
    file = open("data.txt","r")
    FileData = file.readlines()
    file.close()
    file = open("data.txt","w")
    LineNumber+ 0
    for line in FileData:
        LineUserName = line.split(":")[0]
        LineUserPassword = line.split(":")[1]
        if Uername != LineUserName :
            file.write(LineUserName + ":" + LinePassword + ":")
        else:
            file.write("\n"+ LineUserName + ":" + LinePassword + ":")
    file.close()