import random

def play_round():
    choices = ["rock", "paper", "scissors"]
    computer_choice = random.choice(choices)

    while True:
        user_choice = input("Enter rock, paper, or scissors: ").lower()
        if user_choice in choices:
            break
        else:
            print("Invalid choice. Please enter rock, paper, or scissors.")

    print(f"You chose: {user_choice}")
    print(f"Computer chose: {computer_choice}")

    if user_choice == computer_choice:
        print("It's a tie!")
        return 0
    elif (
        (user_choice == "rock" and computer_choice == "scissors")
        or (user_choice == "paper" and computer_choice == "rock")
        or (user_choice == "scissors" and computer_choice == "paper")
    ):
        print("You win!")
        return 1
    else:
        print("You lose!")
        return -1

def main():
    user_score = 0
    computer_score = 0

    print("Welcome to Rock, Paper, Scissors!")

    while True:
        result = play_round()
        if result == 1:
            user_score += 1
        elif result == -1:
            computer_score += 1

        print(f"Your score: {user_score}, Computer score: {computer_score}")

        play_again = input("Play again? (yes/no): ").lower()
        if play_again != "yes":
            break

    print("Thanks for playing!")
    print(f"Final score. Your score: {user_score}, Computer score: {computer_score}")

if __name__ == "__main__":
    main()