#program GCSE coursework
#author Louis Rinaldo

allowed=set("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!$%^&*()-_=+")
lower=("abcdefghijklmnopqrstuvwxyz")
upper=("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
digit=("0123456789")
symbol=("!$%^&*()-_=+")

import random


# clear screen
def cls():
    print("\n"*60)


# introduction
def intro():
    cls()
    print("""\t\t   --- Password Checker and Generator ---
\n\n\n\nThis program will judge the strength of an inputted password or generate a strong one.""")
    menu()


# recurring menu
def menu():
    print("""\n\n\n   Please select an option:

  \t1 - Check Password

  \t2 - Generate Password

  \t3 - Quit""")

    option = input()

    while len(option) == 0:
        option = input("\nPlease select 1, 2 or 3")


    invalid = True

    while invalid == True:

        if option[0].upper() == "C" or option == "1":
            invalid = False
            checker()

        elif option[0].upper() == "G" or option == "2":
            invalid = False
            generator()

        elif option[0].upper() == "Q" or option == "3":
            invalid = False
            quitter()

        else:
            option = input("\nPlease select 1, 2 or 3")

            while len(option) == 0:
                option = input("\nPlease select 1, 2 or 3")

    invalid = False



# checker interface

def checker():
    password=input("\n\nPlease enter a password that you want checking; it may contain letters, numbers and a few allowed characters:")

    length=len(password)


    while length == 0:
        password = input("\nPlease enter a password:")
        length = len(password)


    if length < 8 and length != 0:
        input("""\nThe entered password it too short. It must contain at least 8 characters.
\nPress <Enter> to return to menu.""")
        cls()
        menu()


    if length > 24:
        input("""/nThe entered password is too long. It must not contain more than 25 characters.
\nPress <Enter> to return to menu.""")
        cls()
        menu()


    elif length > 7 and length < 25:

        if password and allowed.issuperset(password):


            score = char_check(password)
            score = triplecheck(password, score)

            print("\n\nYour password score is",score)


            if score > 20:
                print("\nYour password strength is strong!")

            elif score <= 0:
                print("\nYour password strength is weak!")

            else:
                print("\nYour password strength is medium...")


            input("\n\nPress <Enter> to return to menu.")

            cls()

            menu()


        else:
            input("""\nThe entered password contains disallowed characters.
Allowed characters are ! $ % ^ & * ( ) - _ = . +
No spaces allowed.
\n\nPress <Enter> to return to menu.""")
            cls()
            menu()







# generates a password

def generator():

    print("\nThis is password generator...")
    input("\nPress <Enter> to generate a password")

    strong = False

    while strong == False:

        lenpassword = random.randint(8,12)
        possible = lower + upper + digit + symbol
        password = ''.join(random.choice(possible) for x in range(lenpassword))

        score=char_check(password)

        score=triplecheck(password, score)


        if score > 20:
            strong = True
            print("\n\nThe generated password is:",password)
            print("\nThe score for this password is:",score)
            print("\nThis is a strong password!")


    input("\n\nPress <Enter> to return to menu.")
    cls()
    menu()




# calculates score for type of character

def char_check(password):

        lower_inside= True
        upper_inside = True
        digit_inside = True
        symbol_inside = True



        score = 0
        score = len(password)


        for i in password:


            # if contains lowercase letter

            if i in lower and lower_inside == True:
                lower_inside = False
                score = score + 5


            # if contains uppercase letter

            if i in upper and upper_inside == True:
                upper_inside = False
                score = score + 5


            # if contains number

            if i in digit and digit_inside == True:
                digit_inside = False
                score = score + 5


            # if contains symbol

            if i in symbol and symbol_inside == True:
                symbol_inside = False
                score = score + 5


        # if contains one of everything

        if lower_inside == False and upper_inside == False and digit_inside == False and symbol_inside == False:
            score = score + 10


        # if only contains letters

        if password.isalpha() == True:
            score = score - 5


        # if only contains numbers

        if password.isnumeric() == True:
            score = score - 5


        # if only contains symbols

        if lower_inside == True and upper_inside == True and digit_inside == True:
            score=score-5


        return score




# checks for 3 letters in a row and deducts 5 points every time

def triplecheck(password, score):

    row1 = "qwertyuiop"
    row2 = "asdfghjkl"
    row3 = "zxcvbnm"

    password=password.lower()

    for i in range(0,len(password)-2):
        substring = password[i]+password[i+1]+password[i+2]

        if substring in row1 or substring in row2 or substring in row3:
            score = score - 5

    return score



# quits/ends program

def quitter():

    input("\nPress <Enter> to quit")
    cls()



# main program

intro()