A colleague set a task of creating a Rock, Paper, Scissors game for our junior developers to tackle, and I thought I'd give it a shot.

gistfile1.php

<?php

$pieces = ['r' => 'Rock', 'p' => 'Paper', 's' => 'Scissors'];
$stack = [[['p','r'],'p'],[['r','s'],'r'],[['s','p'],'s']];
$takes = 5;

function request_player_piece() {
	global $pieces;
	echo "\nChoose piece: ";
	$playerPiece = strtolower(trim(fgets(STDIN)));
	if (!in_array($playerPiece, array_keys($pieces))) {
		echo "Invalid choice, please choose from " . implode(', ', array_keys($pieces)) . ".\n";
		request_player_piece();
	}
	return $playerPiece;
};

$computerPlay = function() use($pieces) {
	return array_keys($pieces)[rand(0, count($pieces) - 1)];
};

$playerIsWinner = function($playerPiece, $computerPiece) use ($stack) {

	if ($playerPiece == $computerPiece) return false;

	$played = [$playerPiece, $computerPiece];
	foreach ($stack as $config) {
		$combination = $config[0];
		$winner = $config[1];
		if (count(array_diff($played, $combination)) == 0) {
			$won = $winner == $playerPiece;
			$retval = [
				'won' => $won, 
				'winningPiece' => $won ? $playerPiece : $computerPiece, 
				'losingPiece' => $won ? $computerPiece : $playerPiece
			];
			break;
		}
	}
	return $retval;
};

while (true) {
	
	$gameTotal = ['Player' => 0, 'Computer' => 0];

	$taken = 0;
	while ($taken < $takes) {
		echo "\nTake " . ($taken + 1) . ' of ' . $takes . "\n";
		echo 'Player has chosen ' . $pieces[($playerPiece = request_player_piece())] . "\n";
		echo 'Computer has chosen ' . $pieces[($computerPiece = $computerPlay())] . "\n";
		$result = $playerIsWinner($playerPiece, $computerPiece);
		if ($result == false) {
			echo "It's a draw!\n";
			continue;
		}
		$winner = $result['won'] ? 'Player' : 'Computer';
		$gameTotal[$winner]++;
		echo sprintf('%s beats %s, %s wins', $pieces[$result['winningPiece']], $pieces[$result['losingPiece']], $winner);
		$taken++;
	}

	if ($gameTotal['Player'] == $gameTotal['Computer']) {
		echo 'Nobody wins, score is level';
	} else if ($gameTotal['Player'] > $gameTotal['Computer']) {
		echo sprintf("\n\nPlayer wins with a ratio of %s wins to %s\n", $gameTotal['Player'], $gameTotal['Computer']);
	} else {
		echo sprintf("\n\nComputer wins with a ratio of %s wins to %s\n", $gameTotal['Computer'], $gameTotal['Player']);
	}

	$gameTotal['Player'] = $gameTotal['Computer'] = 0;
}