st-really-simple-captcha.php

<?php
/**
 * Plugin Name: Really Simple Captcha for Strong Testimonials
 * Plugin URI: https://strongtestimonials.com
 * Description: Add Really Simple Captcha to Strong Testimonials.
 * Author: MachoThemes
 * Author URI: https://www.machothemes.com/
 * Version: 1.0.0
 * Requires: 4.6 or higher
 * License: GPLv3 or later
 * License URI: http://www.gnu.org/licenses/gpl-3.0.html
 * Requires PHP: 5.6
 */

/**
 * Print form catpcha.
 */
function strsc_wpmtst_form_captcha() {
	$form_options = get_option( 'wpmtst_form_options' );
	if ( ! isset( $form_options['captcha'] ) || ! $form_options['captcha'] ) {
		return;
	}

	if ( 'really-simple-captcha' !== $form_options['captcha'] ) {
		return;
	}

	/**
	 * Only display Captcha label if properly configured.
	 */
	$captcha_html = apply_filters( 'wpmtst_add_captcha', $form_options['captcha'] );
	if ( ! $captcha_html ) {
		return;
	}
	$invisible = wpmtst_form_captcha_invisible();
	$errors    = WPMST()->form->get_form_errors();
	/**
	 * To display or not to display.
	 */
	if ( $invisible && 'captcha-pro' == $form_options['captcha'] ) {
		echo '<div class="form-field wpmtst-captcha">';
		echo $captcha_html;
		echo '</div>';
	} elseif ( $invisible ) {
		echo $captcha_html;
	} else {
		?>
		<div class="form-field wpmtst-captcha">
			<?php if ( wpmtst_get_form_message( 'captcha' ) ) : ?>
			<label for="wpmtst_captcha"><?php wpmtst_form_message( 'captcha' ); ?></label><span class="required symbol"></span>
			<?php endif; ?>
			<div>
				<?php echo $captcha_html; ?>
				<?php if ( isset( $errors['captcha'] ) ) : ?>
					<p><label class="error"><?php echo esc_html( $errors['captcha'] ); ?></label></p>
				<?php endif; ?>
			</div>
		</div>
		<?php
	}
}
add_action( 'wpmtst_form_after_fields', 'strsc_wpmtst_form_captcha', 11 );