// CS7 - Solution to RPS
// Spring 2004
//
// This program plays Rock, Paper, Scissors with the user.  It asks how
// long of a match is desired, and then plays until a majority of those
// games are won.  For example, a 5 game match is over when either player
// (the person or the computer) reaches 3 wins.  The user's win/loss record
// is displayed after each game.
//
// Game choices are represented by integers, but constants are available 
// to make the code more readable.  The computer's choice is determined
// randomly.

import tio.*;    // using JBD's input package

class rps2 {

	// Constants for all to use
	static final int ROCK = 1;
	static final int PAPER = 2;
	static final int SCISSORS = 3;

	// the main steps of the algorithm are in main(), with methods handling
	// most of the details
	public static void main(String [] args) {
		
		int userChoice, compChoice;   // the "hands" of each player
		int outcome;                  // holds the result of the game

		// get the two picks and display them
		userChoice = getUserChoice();
		compChoice = getCompChoice();
		System.out.print("Your choice: ");
		printGameChoice(userChoice);
		System.out.print("Compuer choice: ");
		printGameChoice(compChoice);

		// find out the result (two game choices are input) - this method
		// returns a -1 if the user lost, 0 on a tie, and 1 is the user wins.
		outcome = determineWinner(userChoice, compChoice);

		// print result and update counters
		if (outcome < 0) {     // user loses
			System.out.println("The Computer wins.");
		} else if (outcome > 0) {    // user wins
			System.out.println("You win!");
		} else
			System.out.println("The game is a tie.");
	}

	// ask the user for a game choice
	static int getUserChoice() {
		System.out.print("Enter (1) for Rock, (2) for Paper, or (3) for Scissors: ");
		int choice = Console.in.readInt();
		while (choice < 1 || choice > 3) {
			System.out.println("Try again: ");
			choice = Console.in.readInt();
		}
		return choice;
	}

	// returns a random number between 1 and 3 for the three possible choices
	static int getCompChoice() {
		return (int)(Math.random() * 3) + 1;
	}

	// prints a choice on the screen (as a string)
	static void printGameChoice(int c) {
		switch (c) {
			case ROCK:  
				System.out.println("Rock");
				break;
			case PAPER:
				System.out.println("Paper");
				break;
			case SCISSORS:
				System.out.println("Scissors");
				break;
			default:
				System.out.println("!!");
		}
	}

	// determineWinner() accepts two RPS game choices and returns the result
	// of the game.  A game can end with a player win (1), a tie (0), or a
	// player loss (-1).  The first argument should be the player's choice.
	static int determineWinner(int uc, int cc) {
		// when the choices are the same, the result is a tie.
		if (uc == cc) 
			return 0;
		
		// there are 3 ways the user can win
		else if ( (uc == ROCK && cc == SCISSORS) ||
				    (uc == SCISSORS && cc == PAPER) ||
					 (uc == PAPER && cc == ROCK) )
			return 1;

		// the only other possibility is a user loss
		return -1;
	}
}