import random


# Check that users have entered a valid
# option based on a list
def string_checker(question, valid_ans=("yes", "no")):
    while True:

        error = f"Enter a valid option from {valid_ans}"

        user_response = input(question).lower()

        for item in valid_ans:
            # check if the user response is a valid answer
            if item == user_response:
                return item

            elif user_response == item[0]:
                return item

        print(error)
        print()


def instructions():
    print('''
    
            **** Instructions ****
            
            To begin, choose the number of rounds (or press <enter> for infinite mode).
            
            Then play against the computer, You enter R (rock), P (paper) or S (scissors),
            
            The rules are:
            Paper beats rock
            Rock beats scissors
            Scissors beats paper
            
            Press xxx to end the game at any time
            
            '''
          )

# compare the comp selection v the user input
# result - win, lose or tie


def rps_compare(user, comp):

    if user == comp:
        result = "tie"
    elif user == "paper" and comp == "rock":
        result = "win"
    elif user == "rock" and comp == "scissors":
        result = "win"
    elif user == "scissors" and comp == "paper":
        result = "win"
    else:
        result = "lose"

    return result

# checks the input is an integer

def int_check(question):

    while True:
        error = "Enter an integer more than 1"

        to_check = input(question)

        if to_check == "":
            return "infinite"

        try:
            response = int(to_check)

            # check the number is more than 1
            if response >= 1:
                return response

            else:
                print(error)

        except ValueError:
            print(error)


# Main routine


# game variables
mode = "regular"
rounds_played = 0
rps_list = ["rock", "paper", "scissors", "xxx"]


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


# instructions

want_instructions = string_checker("Do you want to see the instructions? ")

if want_instructions == "yes":
    instructions()

num_rounds = int_check("Enter the number of rounds or press enter for unlimited ")


# game loop starts here

while rounds_played < num_rounds:
    # infinite mode
    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)

    user_choice = string_checker("Choose: ", rps_list)
    print("You selected: ", user_choice)

    if user_choice == "xxx":
        break

    # Random computer choice
    comp_choice = random.choice(rps_list[:-1])
    print(comp_choice)

    result = rps_compare(user_choice, comp_choice)
    print(f"{user_choice} vs {comp_choice}, {result}")

    rounds_played += 1

    # infinite mode - increase number of rounds
    if num_rounds == "infinite":
        num_rounds += 1


print("The program has ended")