//**********
//SimpleCalculator.java
//John Purcell EID: 824479727
//CS 160: HW6
//November 3, 2008
//This is a game of rock-paper-scissors.  The user inputs their choice
//and the computer "rolls" it's choice and returns who wins.
//**********


import java.util.Scanner;
import java.util.Random;

public class RockPaperScissors {
	public static int Checker (String r){
		String v = r.toLowerCase();
		if (v.equals("rock")){
			return 0;
		}
		if (v.equals("paper")){
			return 1;
		}
		if (v.equals("scissors")){
			return 2;
		}
		else{
			return 3;
		}
	}
	//the method "Checker(r)" first converts the input to lower case
	//then tests it against the three choices.  The "3" output then
	//becomes the "invalid entry" value.
	public static void main (String[] args){
		Scanner S = new Scanner(System.in);
		System.out.println("Let's play Rock-Paper-Scissors.");
		System.out.println("Your choice?");
		String x = S.next();
		Random R = new Random();
		int y = R.nextInt(2);
		//R.nextInt is 2 because that will return either 0, 1 or 2
		//the switch/catch tree will then try all 3 of the possible 
		//outputs.
		switch (y){
		case 0://computer chooses rock
			if (Checker(x)==0){
				System.out.println("I chose Rock");
				System.out.println("The game was a tie");
				break;
			}
			if (Checker(x)==1){
				System.out.println("I chose Rock");
				System.out.println("You won");
				break;
			}
			if (Checker(x)==2){
				System.out.println("I chose Rock");
				System.out.println("I won");
				break;
			}
			else{
				System.out.println("Invalid choice");
				//The only else case is Checker==3, but since else 
				//would handle the outcome and allow proper compiling, 
				//if (checker(x)==3) is not used.
				break;
			}
			
		
		case 1://computer chooses paper
			if (Checker(x)==0){
				System.out.println("I chose Paper");
				System.out.println("I won");
				break;
			}
			if (Checker(x)==1){
				System.out.println("I chose Paper");
				System.out.println("The game was a tie");
				break;
			}
			if (Checker(x)==2){
				System.out.println("I chose Paper");
				System.out.println("You won");
				break;
			}
			else{
				System.out.println("Invalid choice");
				break;
			}
			
		case 2://computer chooses scissors
			if (Checker(x)==0){
				System.out.println("I chose Scissors");
				System.out.println("You win");
				break;
			}
			if (Checker(x)==1){
				System.out.println("I chose Scissors");
				System.out.println("I win");
				break;
			}
			if (Checker(x)==2){
				System.out.println("I chose Scissors");
				System.out.println("The game was a tie");
				break;
			}
			else{
				System.out.println("Invalid choice");
				break;
			}
			
		}
		
	}
}