[TASK] Support EXT:headless (Thanks to Matthias Adrowski)

Resolves: #4

Classes/Service/SpanParserService.php

 <?php
 
-namespace SGalinski\ContentReplacer\Service;
-
 /***************************************************************
  *  Copyright notice
  *
@@ -25,7 +23,10 @@ namespace SGalinski\ContentReplacer\Service;
  *  This copyright notice MUST APPEAR in all copies of the script!
  ***************************************************************/
 
+namespace SGalinski\ContentReplacer\Service;
+
 use TYPO3\CMS\Core\Log\Logger;
+use TYPO3\CMS\Core\Utility\ExtensionManagementUtility;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 
 /**
@@ -53,19 +54,33 @@ class SpanParserService extends AbstractParserService {
 	 * @param string $content
 	 * @return array
 	 */
-	public function parse($content) {
+	public function parse($content): array {
 		$matches = [];
 		$prefix = (string) ($this->extensionConfiguration['prefix'] ?? '');
-		$pattern = '/' .
-			'<span' . // This expression includes any span nodes and parses
-			'(?=[^>]+' . // any attributes of the beginning start tag.
-			'(?=(class="([^"]*?' . preg_quote($prefix, '/') . '[^"]+?)"))' .
-			')' . // Use only spans which start with the defined class prefix
-			' (.*?)\1(.*?)>' . // and stop if the closing character is reached.
-			'(.*?)<\/span>' . // Finally we fetch the span content!
-			'/is';
-		preg_match_all($pattern, $content, $matches);
+		if (ExtensionManagementUtility::isLoaded('headless')) {
+			// when headless is present, content will be escaped (JSON output), so we got to add some small details:
+			/** @noinspection RegExpRedundantEscape */
+			$pattern = '/' .
+				'<span' . // This expression includes any span nodes and parses
+				'(?=[^>]+' . // any attributes of the beginning start tag.
+				'(?=(class=\\\\"([^"]*?' . preg_quote($prefix, '/') . '[^"]+?)\\\\"))' .
+				')' . // Use only spans which start with the defined class prefix
+				' (.*?)\1(.*?)>' . // and stop if the closing character is reached.
+				'(.*?)<\\\\\\/span>' . // Finally we fetch the span content!
+				'/is';
+		} else {
+			/** @noinspection RegExpRedundantEscape */
+			$pattern = '/' .
+				'<span' . // This expression includes any span nodes and parses
+				'(?=[^>]+' . // any attributes of the beginning start tag.
+				'(?=(class="([^"]*?' . preg_quote($prefix, '/') . '[^"]+?)"))' .
+				')' . // Use only spans which start with the defined class prefix
+				' (.*?)\1(.*?)>' . // and stop if the closing character is reached.
+				'(.*?)<\/span>' . // Finally we fetch the span content!
+				'/is';
+		}
 
+		preg_match_all($pattern, $content, $matches);
 		$categories = [];
 		foreach ($matches[5] as $index => $term) {
 			$term = trim($term);
@@ -110,7 +125,7 @@ class SpanParserService extends AbstractParserService {
 	 * @return string
 	 * @throws \UnexpectedValueException
 	 */
-	public function replaceByCategory($category, array $terms, $content) {
+	public function replaceByCategory($category, array $terms, $content): string {
 		$search = $replace = [];
 		$defaultReplacement = $this->prepareFoundTerms($terms, $category);
 		foreach ($terms as $termName => $term) {
@@ -120,13 +135,24 @@ class SpanParserService extends AbstractParserService {
 			}
 
 			$searchClass = preg_quote($this->extensionConfiguration['prefix'] . $category, '/');
-			$search[$termName] = '/' .
-				'<span ' . preg_quote($term['pre'], '/') .
-				'class="([^"]*?)' . $searchClass . '([^"]*?)"' .
-				preg_quote($term['post'], '/') . '>' .
-				'\s*?' . preg_quote($term['term'], '/') . '\s*?' .
-				'<\/span>' .
-				'/i';
+			if (ExtensionManagementUtility::isLoaded('headless')) {
+				// when EXT:headless is present, content will be escaped (JSON output), so we got to add some small details:
+				$search[$termName] = '/' .
+					'<span ' . preg_quote($term['pre'], '/') .
+					'class=\\\\"([^"]*?)' . $searchClass . '([^"]*?)\\\\"' .
+					preg_quote($term['post'], '/') . '>' .
+					'\s*?' . preg_quote($term['term'], '/') . '\s*?' .
+					'<\\\\\\/span>' .
+					'/i';
+			} else {
+				$search[$termName] = '/' .
+					'<span ' . preg_quote($term['pre'], '/') .
+					'class="([^"]*?)' . $searchClass . '([^"]*?)"' .
+					preg_quote($term['post'], '/') . '>' .
+					'\s*?' . preg_quote($term['term'], '/') . '\s*?' .
+					'<\/span>' .
+					'/i';
+			}
 
 			$replace[$termName] = $this->prepareReplacementTerm(
 				$term['replacement'] ?? '',