# functions
def make_statement(statement, decoration):
    """"emphasises headings by adding decoration on the start and end"""

    print(f"{decoration * 3} {statement} {decoration * 3}")


def string_check(question, valid_ans_list=('yes', 'no'), num_letters=1):
    """checks that users enter the full word
    or the 'n' letter/s of the word from a list of valid responses"""

    while True:

        response = input(question).lower()

        for item in valid_ans_list:

            # check if response is the entire word
            if response == item:
                return item

            # check if it's the "n" letters
            elif response == item[:num_letters]:
                return item

        print(f"Please choose an option from {valid_ans_list}")


def instructions():
    make_statement("Instructions", "🔍")

    print('''
    
    For each ticket holder, enter:
    - Their name
    - Their age
    - Their payment method (cash / credit)
    
    The program will record the ticket sale and calculate the cost (and the profit).
    
    Once you have either sold all the tickets or entered the exit code ('xxx'), the program will display the sales information and write the data to a text file.
    
    It will also choose one lucky ticket holder who wins the draw (their ticket is free).
    
    ''')


def not_blank(question):
    """checks that user response isn't blank"""

    while True:
        response = input(question)

        if response != "":
            return response

        print("Sorry, this can't be blank. Please try again\n")


def int_check(question):
    """checks users enter an integer"""

    error = "Oops - please enter an integer."

    while True:

        try:
            # return response if it's an integer
            response = int(input(question))

            return response

        except ValueError:
            print(error)


# main routine

# initialise variables / non-default options for string checker
payment_ans = ('cash', 'credit')

# ticket price list
CHILD_PRICE = 7.50
ADULT_PRICE = 10.50
SENIOR_PRICE = 6.50

# credit card surcharge (currently 5%)
CREDIT_SURCHARGE = 0.05

while True:
    name = input("Name: ")

    # if name is exit code, break the loop
    if name == "xxx":
        break

    # ask for their age and check it's between 12 and 120
    age = int_check("Age: ")

    # output error and success message
    if age < 12:
        print(f"{name} is too young.")
        continue

    # child ticket price ($7.50)
    elif 12 <= age < 16:
        ticket_price = CHILD_PRICE

    # adult ticket ($10.50)
    elif 16 <= age < 65:
        ticket_price = ADULT_PRICE

    #senior citizen ticket ($6.50)
    elif 65 <= age < 121:
        ticket_price = SENIOR_PRICE

    else:
        print(f"{name} is too old.")
        continue

    # ask user for payment method (cash or credit, ca or cr)
    pay_method = string_check("Payment method: ", payment_ans, 2)

    if pay_method == "cash":
        surcharge = 0

    # if paying by credit, calculate surcharge
    else:
        surcharge = ticket_price * CREDIT_SURCHARGE

    # calculate total payable
    total_to_pay = ticket_price + surcharge

    print(f"{name}'s ticket cost is ${ticket_price:.2f}, and they paid by {pay_method}, "
          f"so the surcharge is ${surcharge:.2f}.\n"
          f"The total payable is ${total_to_pay:.2f}.\n")