import bcrypt
import pickle

def create_user(username, password, users, user_salts):
    if not username in users:
        user_salts[username] = create_salt(username, user_salts)
        users[username] = bcrypt.hashpw(str.encode(password), user_salts[username])
        return users, user_salts
    else:
        return False

def update_user(username, password, newpassword, users, user_salts):
    if username in users and bcrypyt.hashpw(password, user_salts[username]) == users[username]:
        user_salts[username] = bcrypt.gensalt()
        users[username] = bcrypt.hashpw(newpassword, user_salts[username])
        return users, user_salts

def check_pass(username, password, users, user_salts):
    password = str.encode(password)
    try:
        return users[username] == bcrypt.hashpw(password, user_salts[username])
    except: return False

def create_salt(username, user_salts):
    return bcrypt.gensalt()

def save_salt(user_salts, user_salts_db):
    pickle.dump(user_salts, user_salts_db)

def load_salts(user_salts_db):
    return pickle.load(user_salts_db)

def save_users(users, userdb):
    pickle.dump(users, userdb)

def load_users(userdb):
    return pickle.load(userdb)

def login(users, user_salts):
    uname = input("Enter your username: ")
    pword = input("Enter your password: ")
    if check_pass(uname, pword, users, user_salts):
        print("Success!")
    else:
        print("Failure.")
        main()

def newuser(users, user_salts):
    uname = input("Enter your desired username: ")
    pword = input("Enter your password: ")
    pword2 = input("Confirm password: ")
    if not pword == pword2:
        print("Try again.")
        newuser(users)
    else:
        b = create_user(uname, pword, users, user_salts)
        if not b:
            print("Username already exists.")
        else:
            print("Success")
            users, user_salts = b
    with open("userdb.pickle", "wb") as userdb:
        save_users(users, userdb)
    with open("user_salts_db.pickle", "wb") as user_salts_db:
        save_users(user_salts, user_salts_db)

def main():
    try:
        with open("userdb.pickle", "rb") as userdb:
            users = load_users(userdb)
    except: users = {}
    try:
        with open("user_salts_db.pickle", "rb") as user_salts_db:
            user_salts = load_salts(user_salts_db)
    except: user_salts = {}

    purpose = input("Log in, register, or change password?")
    if purpose.lower() == "log in":
        login(users, user_salts)
    elif purpose.lower() == "register":
        newuser(users, user_salts)
    else:
        uname = input("Username: ")
        pword = input("Old password: ")
        newp = input("New password: ")
        newp2 = input("Confirm new password: ")
        if newp == newp2:
            users, user_salts = update_user(uname, pword, newpassord, users, user_salts)
            save_users(users)
            save_salts(user_salts)
        else:
            print("Passwords do not match")
            main()

if __name__ == "__main__":
    main()