import random


# Check that the users entered a valid
# option based on a list


def string_checker(question, valid_ans=("yes", "no")):
    while True:


        user_response = input(question).lower()

        for item in valid_ans:
            if item == user_response:
                return item

            elif user_response == item[0]:
                return item

def instructions():
    """prints instructions"""

    print("""
*** Instructions ***

To begin, choose the number of rounds (or infinite mode).

Then play against the computer, with either R (rock), P 
(paper), or S (scissors).

The rules are as follows:

Paper beats rock
Rock beats scissors
Scissors beats paper

Win the majority of rounds to win overall!
    """)

def int_check(question):
    while True:
        error = "Please enter an integer that is 1 or more."

        to_check = input(question)

        if to_check == "":
            return "infinite"

        try:
            response = int(to_check)

            if response < 1:
                print(error)
                return "invalid"
            else:
                return response

        except ValueError:
            print(error)


# Main Routine goes here

# Initialise game variables
mode = "regular"
rounds_played = 0

rps_list = ["rock", "paper", "scissors", "xxx"]

print(" Rock / Paper / Scissors Game")
print()

#ask the user if they want to see the instructions
want_instructions = string_checker("Do you want to see the instructions? ")

#Display the instructions if the user responded with yes
if want_instructions == 'yes':
    instructions()

# Ask user for number of rounds / infinite mode
num_rounds = int_check("How many rounds would you like? press <enter> for infinite mode: ")

if num_rounds == "infinite":
    mode = "infinite"
    num_rounds = 5

# game loop starts here
while rounds_played < num_rounds:

    if mode == "infinite":
        rounds_heading = f"\n Round {rounds_played + 1} (Infinite) Mode"
    else:
        rounds_heading = f"\n Round {rounds_played + 1} of {num_rounds}"

    print(rounds_heading)
    print()

    user_choice = string_checker("Choose: ", rps_list)
    print("you chose", user_choice)

    if user_choice == "xxx":
        break

    comp_choice = random.choice(rps_list[:-1])

    rounds_played += 1

    if mode == "infinite":
        num_rounds += 1

# game loop ends here

# game history / statistic area