Risk Auto Roller — Source Code

<?php
	// the maximum number of dice that can be used by each side
	define("ATTACKER_MAX_DICE", 3);
	define("DEFENDER_MAX_DICE", 2);

 
	// number of troops allowed on each side in a battle. To protect server.
	define("TROOP_LIMIT", 200);
 
	// values of inputs to save for HTML page

	$attackerSave = "";
	$defenderSave = "";
	$attackerStopSave = "";

	$aboveCount = NULL;
	$belowCount = NULL;
 

	// set up attacker stop strategy
	$stopMethod = "none";
	$stopOptions = array("fixed" => false, "less" => false, "more" => false,

				 "equal" => false, "none" => false);
 

	// assume everything is OK
	$valid = true;
 
	// only show results if form has been submitted
	if ($_SERVER['REQUEST_METHOD'] == "POST")

	{
		// make sure our input is good
		if (isset($_POST['attackers'], $_POST['defenders']) && (int)$_POST['attackers'] > 1 && (int)$_POST['defenders'] > 0)

		{	
			$attackers = $attackerSave = (int)$_POST['attackers'];

			$defenders = $defenderSave = (int)$_POST['defenders'];

 
			// check our stopping strategy. If it's not set, default to
			// 'bitter end.'
			if (isset($_POST['stopMethod']) && array_key_exists($_POST['stopMethod'], $stopOptions))

			{
				$stopMethod = $_POST['stopMethod'];
 
				// get fixed number of troops for attacker to stop at. Make sure it's in legal range

				if ($stopMethod == "fixed" && isset($_POST['attackerStop']) && trim($_POST['attackerStop']) != "" && is_numeric($_POST['attackerStop']) && (int)$_POST['attackerStop'] < $attackers)

				{
					$attackerStop = (int)$_POST['attackerStop'];

					$attackerStopSave = $attackerStop;
				}
				// get variable number of troops above defender count
				else if ($stopMethod == "more" && isset($_POST['aboveCount']) && trim($_POST['aboveCount']) != "" && (int)$_POST['aboveCount'] >= 0 && $attackers - $defenders > (int)$_POST['aboveCount'])

				{
					$aboveCount = (int)$_POST['aboveCount'];

				}
				// get variable number of troops below defender count
				else if ($stopMethod == "less" && isset($_POST['belowCount']) && trim($_POST['belowCount']) != "" && (int)$_POST['belowCount'] >= 0 && $defenders - $attackers < (int)$_POST['belowCount'])

				{
					$belowCount = (int)$_POST['belowCount'];

				}
				// stop case for when the troop counts are equal. Sneakily, we
				// just pick the 'above' method, with an input of zero.
				else if ($stopMethod == "equal" && $attackers != $defenders)

				{
					$aboveCount = 0;
				}
				// now, if there was something wrong and all the conditions weren't right

				// for the given stop method, decide the correct error message
				else if ($stopMethod != "none")
				{

					$valid = false;
					switch ($stopMethod)
					{

						case "fixed":
							$error = "The number of troops the attacker stops at must be less than the number he attacks with.";
						break;

						case "more":
							$error = "Attacker already have fewer than " . $_POST['aboveCount'] . " troops more than the defender.";

						break;
						case "less":
							$error = "Attacker already have more than " . $_POST['belowCount'] . " troops less than the defender.";

						break;
						case "equal":
							$error = "The number of troops is already equal.";

						break;
					}
				} // end if input for stop strategy wasn't correct
 
				// if the stop strategy is none at all
				if ($valid && $stopMethod == "none")

				{
					$stopMethod = "none";
					$valid = true;

				}
 
			} // end if stop strategy is defined
 
			// set the attacker stopping value into a legal range
			$attackerStop = max(1, $attackerStop);

			$attackerStop = min($attackers - 1, $attackerStop);

 
			// set up array to track each roll and troop totals
			$rollTrack = array();			
 
			// set up total track array

			$totalTrack [] = array('attackers' => $attackers, 'defenders' => $defenders);

 
 
			// check for huge inputs
			if ($attackers > TROOP_LIMIT || $defenders > TROOP_LIMIT)

			{
				$error = "Sorry, I only allow up to " . TROOP_LIMIT . " troops on this page to reduce server load. Although a battle of 1,000,000 soldiers would be cool, it would hit the server pretty hard.";

				$valid = false;
			}
 
			$roll = 0;

 
			// now, loop until we hit a stop condition
			while ($valid && $attackers > $attackerStop && $defenders > 0)

			{
				$roll++;
 
				// dynamically update above or below defender counts, for the
				// attacker stop condition
				if (!is_null($aboveCount))

				{
					$attackerStop = $defenders + $aboveCount;
					if ($attackers < $attackerStop)

					{
						break;
					}
				}
				else if (!is_null($belowCount))

				{
					$attackerStop = $defenders - $belowCount;
					if ($attackers < $attackerStop)

					{
						break;
					}
				}
 
				// figure out how many dice each combatant gets this round		

				$dice['attackers'] = min(ATTACKER_MAX_DICE, $attackers - 1, $attackers - $attackerStop);

				$dice['defenders'] = min(DEFENDER_MAX_DICE, $defenders);

 
				// if attacker has zero dice, then the battle is over
				if ($dice['attackers'] < 1)

					break;
 
				// array for each combatant's rolls
				$rolls = array();

 
				// shake those dice
				for ($i = 0; $i < $dice['attackers']; $i++)

					$rolls['attackers'][] = rand(1, 6);

				for ($i = 0; $i < $dice['defenders']; $i++)

					$rolls['defenders'][] = rand(1, 6);

 
				// sort in reverse, for comparing
				rsort($rolls['attackers']);
				rsort($rolls['defenders']);

 
				// we only compare the same number of dice. Since the arrays of roll are
				// sorted, this is OK.
				for ($i = 0; $i < min($dice['attackers'], $dice['defenders']); $i++)

				{
					if ($rolls['attackers'][$i] <= $rolls['defenders'][$i])

						$attackers--;
					else
						$defenders--;
				}
 
				// save tracking data

				$totalTrack [] = array('attackers' => $attackers, 'defenders' => $defenders);

				$rollTrack [] = $rolls;
 
			} // end main battle loop

 
			// figure out WHY we stopped
			if (!isset($stopBecause))
			{

				if ($defenders <= 0)
					$stopBecause = "Defender was annihilated.";

				else if ($stopMethod == "more")
					$stopBecause = "Attacker troop count reached limit above defender count.";

				else if ($stopMethod == "less")
					$stopBecause = "Attacker troop count reached limit below defender count.";

				else if ($stopMethod == "equal" && $attackers == $defenders)

					$stopBecause = "Attacker count equals defender count.";
				else if ($stopMethod == "fixed" && $attackerStop != 1)

					$stopBecause = "Attacker count reached fixed limit.";
				else
					$stopBecause = "Attacker cannot continue battle because only one troop remains.";

			} // end block of code to figure out reason for stopping
 
		}
		else // Troop counts were bad or too low
		{

			$error = "Bad numbers assigned to attacking and defending troops. Attackers must have at least two troops, and defenders must have at least one.";
			$valid = false;
		}

 
	} // end if form was submitted
 
?>
 
<h2>Risk Auto Roller</h2>
<?php if ($valid && isset($totalTrack, $rollTrack)): ?>

 
	<h3>Results</h3>
	<p>
		<strong>Attackers: </strong><?php echo $attackers ?><br />

		<strong>Defenders: </strong><?php echo $defenders ?>
	</p>

 
	<h3>Rolls</h3>
	<table class="rolls">
		<tr>
			<th style="width: 8%;">Roll</th>

			<th style="width: 8%;">Attackers</th>
			<th style="width: 8%;">Defenders</th>
			<th style="width: 38%;">Attacker Rolls</th>

			<th style="width: 38%;">Defender Rolls</th>
		</tr>
		<?php for ($i = 0; $i < count($totalTrack); $i++): ?>

		<tr<?php if ($i >= count($rollTrack)): ?> style="height: 36px;"<?php endif; ?>>

			<td><?php echo ($i < count($rollTrack) ? $i + 1 : '-') ?></td>

			<td>
				<?php echo $totalTrack[$i]['attackers'] ?>

				<?php if ($i > 0 && $totalTrack[$i-1]['attackers'] > $totalTrack[$i]['attackers']): ?><span class="change">(-<?= $totalTrack[$i-1]['attackers'] - $totalTrack[$i]['attackers'] ?>)</span><?php endif; ?>

			</td>
			<td>
				<?php echo $totalTrack[$i]['defenders'] ?>

				<?php if ($i > 0 && $totalTrack[$i-1]['defenders'] > $totalTrack[$i]['defenders']): ?><span class="change">(-<?= $totalTrack[$i-1]['defenders'] - $totalTrack[$i]['defenders'] ?>)</span><?php endif; ?>

			</td>
			<?php if ($i < count($rollTrack)): ?>

			<td>
				<?php for ($j = 0; $i < count($rollTrack) && $j < count($rollTrack[$i]['attackers']); $j++): ?><img src="img/attacker-dice-<?php echo $rollTrack[$i]['attackers'][$j] ?>.png" alt="<?php echo $rollTrack[$i]['attackers'][$j] ?><?php echo ($j + 1 < count($rollTrack[$j]['attackers']) ? ', ' : '') ?>" />

				<?php endfor; ?>
			</td>
			<td>
				<?php for ($j = 0;  $i < count($rollTrack) && $j < count($rollTrack[$i]['defenders']); $j++): ?><img src="img/defender-dice-<?php echo $rollTrack[$i]['defenders'][$j] ?>.png" alt="<?php echo $rollTrack[$i]['defenders'][$j] ?><?php echo ($j + 1 < count($rollTrack[$j]['defenders']) ? ', ' : '') ?>" />

				<?php endfor; ?>
			</td>
			<?php else: ?>

			<td colspan="2" class="reason">
				<strong>Battle ended: </strong><?php echo $stopBecause ?>
			</td>

			<?php endif; ?>
		</tr>
		<?php endfor; ?>

	</table>
	<h3>Roll Again</h3>
<?php elseif (!$valid): ?>

	<h3>Invalid Input</h3>
	<?php if (isset($error)): ?>

		<p><?php echo $error ?></p>
	<?php endif; ?>

	<p>Please double-check your input.</p>
	<h3>Roll Again</h3>
<?php else: ?>

	<h3>Roll</h3>
<?php endif; ?>
 
<form action="riskRoller.php" method="post" class="roll">
	<fieldset>

		<legend>Troops</legend>
		<div class="item">
			<label for="attackers">Attackers:</label>
			<input name="attackers" id="attackers" value="<?php echo $attackerSave ?>" class="short" />

		</div>
		<div class="item">
			<label for="defenders">Defenders:</label>
			<input name="defenders" id="defenders" value="<?php echo $defenderSave ?>" class="short" />

		</div>
	</fieldset>
	<fieldset>
		<legend>Attacker Stops</legend>
		<div class="option">

			<input type="radio" class="radio" name="stopMethod" value="none" id="stopNone" <?php if ($stopMethod == "none"): ?>checked="checked"<?php endif; ?>/>

			<label for="stopNone"><strong>Bitter End: </strong>Stop when I cannot continue attacking</label>
		</div>
		<div class="option">
			<label for="attackerStop">

				<input type="radio" class="radio" name="stopMethod" value="fixed" id="stopFixed" <?php if ($stopMethod == "fixed"): ?>checked="checked"<?php endif; ?> />

			</label>
			<label for="stopFixed">
			<strong>Fixed Number: </strong>Stop when I have </label>
			<input name="attackerStop" id="attackerStop" value="<?php echo $attackerStopSave ?>" class="short" /> 
			<label for="stopFixed">units left</label>

		</div>
		<div class="option">
			<label for="aboveCount">
				<input type="radio" class="radio" name="stopMethod" value="more" id="stopMore" <?php if ($stopMethod == "more"): ?>checked="checked"<?php endif; ?> />

			</label>
			<label for="stopMore"><strong>More Than Defender: </strong>Stop if I have exactly </label>
			<input name="aboveCount" id="aboveCount" <?php if (!is_null($aboveCount)): ?>value="<?php echo $aboveCount ?>"<?php endif; ?> class="short" /> 
			<label for="stopMore">more units than the defender</label>

		</div>
		<div class="option">
			<input type="radio" class="radio" name="stopMethod" value="equal" id="stopEqual" <?php if ($stopMethod == "equal"): ?>checked="checked"<?php endif; ?> />

			<label for="stopEqual"><strong>Equal to Defender: </strong>
			Stop when I have the same number of units as the defender</label>
		</div>
		<div class="option">
			<label for="belowCount">

				<input type="radio" class="radio" name="stopMethod" value="less" id="stopLess" <?php if ($stopMethod == "less"): ?>checked="checked"<?php endif; ?> />

			</label>
			<label for="stopLess">
			<strong>Less Than Defender: </strong>Stop if I have exactly</label>
			<input name="belowCount" id="belowCount" <?php if (!is_null($belowCount)): ?>value="<?php echo $belowCount ?>"<?php endif; ?> class="short" />

			<label for="stopLess">fewer units than the defender</label>
		</div>
	</fieldset>
	<fieldset class="buttons">
		<button type="submit">Run Battle</button>

	</fieldset>
</form>
How to Use

Attackers: The number of troops in the attacking country. Make sure to count every one (the Auto Roller will ensure that you have at least one troop left if your attack fails, as per the Risk Rules).
Defenders: The number of troops in the country being attacked.
Attack Methods

The attack methods allow you to choose whether or not the attacker should give up.
Bitter End: The default value. The attack will continue until either the attacker destroys the defending troops or the attacker cannot continue the battle (because he is left with one troop in the attacking country).
Fixed Number: The battle will continue until the attacker's troops fall to this number. The attacker will adjust the number of dice to ensure that his troop count never falls below this value.
More Than Defender: The attack will continue until the attacker has this many more troops than the defender.
Equal To Defender: The attack will proceed until the number of troops in both countries are equal.
Less Than Defender: The attack will continue until the attacker has this many fewer troops than the attacking country.
Dave Short
