# program to play rock, paper scissors
#
# Matt Bishop, MHI 289I, Winter 2021
#
# final version
#
import random

# list of objects
things = ( "rock", "paper", "scissors" )
# list of legal commands
cmdlist = ( "rock", "paper", "scissors", "quit" )
# list of winning pairs (first dominates second)
winlist = ( ("rock", "scissors"), ("paper", "rock"), ("scissors", "paper") )
# scores
score = { "user" : 0, "computer" : 0, "tie" : 0 }

# get user input
def getuser():
    while True:
        # get string input, and look for problems
        try:
            n = input("Human: enter rock, paper, scissors, quit: ")
        except (EOFError, KeyboardInterrupt):
            n = "quit"
        except Exception as msg:
            print("Unknown exception:", msg, "-- quitting")
            n = "quit"
            break
        # it's a good string; compain if not a command, or return it
        if n not in cmdlist:
            print("Bad input; try again")
        else:
            break
    return n

# function to generate computer selection pseudo-randomly
# returns: "rock", "paper", "scissors"
def getcomp():
    pick = random.choice(things)
    print("Computer picks", pick)
    return pick

# function to determine who wins
# parameters: user: user's selection
#             computer's selection
# returns: "user" if user won
#          "computer" if computer won
#          "tie" if tie
def whowins(user, comp):
	if user == comp:
		win = "tie"
	elif (user, comp) in winlist:
		win = "user"
	else:
		win = "computer"
	return win

# pulling it all together
# calls: getuser(), getcomp(), whowins()
def main():
    # initialize the pseudorandom number generator
    random.seed()
    # now we play
    while True:
        # get the user's choice
        userchoice = getuser();
        if userchoice == "quit":
            break
        # get the computer's choice
        compchoice = getcomp();
        # figure out who won
        winner = whowins(userchoice, compchoice)
        # announce it to the world!
        if winner == "user":
            print("You win")
        elif winner == "computer":
            print("Computer wins")
        elif winner == "tie":
            print("Tie")
        else:
            print("*** INTERNAL ERROR *** winner is", winner)
            break
        # track the new score
        score[winner] += 1;

    #
    # announce the final score, with good grammar
    #
    print("You won", end='')
    if score["user"] == 1:
        print("1 game, the computer won",end=' ')
    else:
        print(score["user"], "games, the computer won", end=' ')
    if score["computer"] == 1:
        print("1 game, and you two tied", end=' ')
    else:
        print(score["computer"], "games, and you two tied", end=' ')
    if score["tie"] == 1:
        print("1 game.")
    else:
        print(score["tie"], "games.")

main()