1 files changed, 126 insertions, 0 deletions
diff --git a/www/wiki/extensions/ConfirmEdit/MathCaptcha/MathCaptcha.class.php b/www/wiki/extensions/ConfirmEdit/MathCaptcha/MathCaptcha.class.php
new file mode 100644
index 00000000..0c7dee0a
--- /dev/null
+++ b/www/wiki/extensions/ConfirmEdit/MathCaptcha/MathCaptcha.class.php
@@ -0,0 +1,126 @@
+<?php
+
+use MediaWiki\Auth\AuthenticationRequest;
+
+class MathCaptcha extends SimpleCaptcha {
+
+	/**
+	 * Validate a captcha response
+	 * @param string $answer
+	 * @param array $info
+	 * @return bool
+	 */
+	function keyMatch( $answer, $info ) {
+		return (int)$answer == (int)$info['answer'];
+	}
+
+	/**
+	 * @param array &$resultArr
+	 */
+	function addCaptchaAPI( &$resultArr ) {
+		list( $sum, $answer ) = $this->pickSum();
+		$html = $this->fetchMath( $sum );
+		$index = $this->storeCaptcha( [ 'answer' => $answer ] );
+		$resultArr['captcha'] = $this->describeCaptchaType();
+		$resultArr['captcha']['id'] = $index;
+		$resultArr['captcha']['question'] = $html;
+	}
+
+	/**
+	 * @return array
+	 */
+	public function describeCaptchaType() {
+		return [
+			'type' => 'math',
+			'mime' => 'text/html',
+		];
+	}
+
+	/**
+	 * @param int $tabIndex
+	 * @return array
+	 */
+	function getFormInformation( $tabIndex = 1 ) {
+		list( $sum, $answer ) = $this->pickSum();
+		$index = $this->storeCaptcha( [ 'answer' => $answer ] );
+
+		$form = '<table><tr><td>' . $this->fetchMath( $sum ) . '</td>';
+		$form .= '<td>' . Html::input( 'wpCaptchaWord', false, false, [
+			'tabindex' => $tabIndex,
+			'autocomplete' => 'off',
+			'required'
+		] ) . '</td></tr></table>';
+		$form .= Html::hidden( 'wpCaptchaId', $index );
+		return [ 'html' => $form ];
+	}
+
+	/**
+	 * Pick a random sum
+	 * @return array
+	 */
+	function pickSum() {
+		$a = mt_rand( 0, 100 );
+		$b = mt_rand( 0, 10 );
+		$op = mt_rand( 0, 1 ) ? '+' : '-';
+		$sum = "{$a} {$op} {$b} = ";
+		$ans = $op == '+' ? ( $a + $b ) : ( $a - $b );
+		return [ $sum, $ans ];
+	}
+
+	/**
+	 * Fetch the math
+	 * @param int $sum
+	 * @return string
+	 */
+	function fetchMath( $sum ) {
+		if ( class_exists( 'MathRenderer' ) ) {
+			$math = MathRenderer::getRenderer( $sum, [], 'png' );
+		} else {
+			throw new LogicException(
+				'MathCaptcha requires the Math extension for MediaWiki versions 1.18 and above.' );
+		}
+		$math->render();
+		$html = $math->getHtmlOutput();
+		return preg_replace( '/alt=".*?"/', '', $html );
+	}
+
+	/**
+	 * @return array
+	 */
+	public function getCaptcha() {
+		list( $sum, $answer ) = $this->pickSum();
+		return [ 'question' => $sum, 'answer' => $answer ];
+	}
+
+	/**
+	 * @param array $captchaData
+	 * @param string $id
+	 * @return mixed
+	 */
+	public function getCaptchaInfo( $captchaData, $id ) {
+		$sum = $captchaData['question'];
+		return $this->fetchMath( $sum );
+	}
+
+	/**
+	 * @param array $requests
+	 * @param array $fieldInfo
+	 * @param array &$formDescriptor
+	 * @param string $action
+	 */
+	public function onAuthChangeFormFields( array $requests, array $fieldInfo,
+		array &$formDescriptor, $action ) {
+		/** @var CaptchaAuthenticationRequest $req */
+		$req = AuthenticationRequest::getRequestByClass(
+			$requests,
+			CaptchaAuthenticationRequest::class,
+				true
+		);
+		if ( !$req ) {
+			return;
+		}
+
+		$formDescriptor['captchaInfo']['raw'] = true;
+		$formDescriptor['captchaWord']['label-message'] = null;
+	}
+}