# purpose
# - write function
# - local and global --> accumulate
#
# activity:
# - Create a python module (i.e., python file)
#   that has multiple functions to maintain balance in
#   a checking account and a saving account
#   and; and to retrieve the balance information.
# - Let's say, there are 4 functions:
#   -- deposit(amt, to_which_acct)
#   -- withdraw(amt, from_which_acct)
#   -- transfer(amt, from_which_acct, to_which_acct)
#   -- get_total_fund()   --> return avai_checking + avai_saving
# - hint: use global to keep track of available balance
#   in checking and saving, avai_checking, avai_saving
# - to test your functions,
#   write test cases to call these functions
#   -- in addition to happy paths, always consider edge cases
#      (later the semester, we'll discuss how to handle
#      exception; therefore, we'll leave exception cases for now)


def deposit(amt, to_which_acct):
    """
    Add amount to given account
    :param amt:
    :param to_which_acct:
    :return:
    """

    global saving
    global checking

    if to_which_acct == "saving":
        saving += float(amt)
    if to_which_acct == "checking":
        checking += float(amt)


def withdraw(amt, from_which_acct):
    """
    Withdraw amount from the specified account
    :param amt:
    :param from_which_acct:
    :return:
    """
    global saving
    global checking

    if from_which_acct == "saving":
        saving -= float(amt)
    if from_which_acct == "checking":
        checking -= float(amt)


def transfer(amt, from_which_acct, to_which_acct):
    """
    Transfer amount from from_which_acct to to_which_acct

    note: normally, banking transaction requires user
            to specify "from" and "to" account.
            However, for this exercise and for simplicity,
            since there are only 2 accounts and
            transferring from saving to saving does not make sense,
            we only check which is the "from" account.

    :param amt:
    :param from_which_acct:
    :param to_which_acct:
    :return:
    """
    global saving, checking    # multiple variables can be written in the same line

    if from_which_acct == "saving":
        saving -= amt
        checking += amt
    elif from_which_acct == "checking":
        checking -= amt
        saving += amt


# def get_total_fund():
#
#     """
#     return the sum of saving and checking
#     :param:
#     :param:
#     :return: total_fund
#     """
#     # global saving     # not needed as we don't expect to update it
#     # global checking   # not needed as we don't expect to update it
#
#     return saving + checking


# what if instead we want get_total_fund() to simply print
# the total fund, let's modify the function
def get_total_fund():
    """
    return the sum of saving and checking
    :param:
    :param:
    :return: total_fund
    """

    # global saving     # not needed as we don't expect to update it
    # global checking   # not needed as we don't expect to update it
    print('in get_total_fund() :', saving + checking)


saving = 0
checking = 0

deposit(20, "saving")
print('1. deposit 20 to saving, saving =', saving)

deposit(25, "checking")
print('2. deposit 25 to checking, checking =', checking)

withdraw(10, "saving")
print('3. withdraw 10 from saving, saving =', saving)

withdraw(5, "saving")
print('4. withdraw 5 from saving, saving =', saving)

withdraw(5, "checking")
print('5. withdraw 5 from checking, checking =', checking)

deposit(10, "saving")
print('6. deposit 10 to saving, saving =', saving)

# print(get_total_fund())
get_total_fund()

transfer(10, "saving", "checking")
print('7. transfer 10 from saving to checking: balance saving, checking =', saving, checking)