/* CSCI 261 A02: Rock, Paper, Scissors
 *
 * Author: _INSERT_YOUR_NAME_HERE_ (original code by Dr. Paone)
 *
 * This program allows a human to play a game of Rock, Paper, Scissors
 * against the computer.  The computer makes a random choice of what
 * to throw.
 */

#include <cctype>		// for tolower()
#include <cstdlib>		// for srand() and rand()
#include <ctime>		// for time()
#include <iostream>		// for cout, cin, endl
using namespace std;

int main() {
	
	// seed our RNG with the current time
	srand( time(0) );
		
	// variables to hold the player's and computer's choice to throw
	// initialize them both to rock.  trusty old rock, nothing beats rock
	char playerChoice = 'r', computerChoice = 'r';
	
	cout << "Welcome one and all to a round of Rock, Paper, Scissors! (Enter P, R, or S)" << endl;
	
	// prompt the user to enter their choice
	cout << "Player one: ";
	cin >> playerChoice;
	
	// force the user's choice to be lower case
	playerChoice = tolower( playerChoice );
	
	// generate a random number in the range [0, 2] inclusive
	int computerRandomValue = rand() % 3;
	
	// check the random value and assign the appropriate value to the computer's choice
	if( computerRandomValue == 0 ) {			// if the random value is 0
		computerChoice = 'r';						// then the computer chose rock
	} else if( computerRandomValue == 1 ) {		// if the random value is 1
		computerChoice = 'p';						// then the computer chose paper
	} else {									// otherwise the random value is 2
		computerChoice = 's';						// and the computer chose scissors
	}
	
	// print computer's choice
	cout << "Computer: " << computerChoice << endl;
	
	// check our various win conditions
	
	// Player One win scenarios
	if( playerChoice == 'r' && computerChoice == 's' ) {
		cout << "Rock beats Scissors.  Player one wins!" << endl;
	} else if( playerChoice == 's' && computerChoice == 'p' ) {
		cout << "Scissors beats Paper.  Player one wins!" << endl;
	} else if( playerChoice == 'p' && computerChoice == 'r' ) {
		cout << "Paper beats Rock.  Player one wins!" << endl;
	} 
	// Computer win scenarios
	else if( playerChoice == 'r' && computerChoice == 'p' ) {
		cout << "Paper beats Rock.  Computer wins!" << endl;
	} else if( playerChoice == 's' && computerChoice == 'r' ) {
		cout << "Rock beats Scissors.  Computer wins!" << endl;
	} else if( playerChoice == 'p' && computerChoice == 's' ) {
		cout << "Scissors beats Paper.  Computer wins!" << endl;
	} 
	// Tie scenario
	else {
		// unless we want to print "Rock ties Rock", we don't need to check all three draw scenarios
		cout << "It's a draw!" << endl;
	}
	
	return EXIT_SUCCESS;						// signals the operating system that our program ended OK
}