feat: implement 5 new advanced WCAG rules (ColorContrast, DuplicateId, TabindexOrder, AriaRole, IframeTitle)

src/Rules/DuplicateId.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace YakNet\AccessibilityConsole\Rules;
+
+use YakNet\AccessibilityConsole\Core\AbstractRule;
+use YakNet\AccessibilityConsole\Core\Severity;
+use YakNet\AccessibilityConsole\Core\WCAGStandard;
+
+class DuplicateId extends AbstractRule
+{
+    public function check(\DOMDocument $doc): array
+    {
+        $violations = [];
+        $xpath = new \DOMXPath($doc);
+        $elements = $xpath->query('//*[@id]');
+        
+        $ids = [];
+        foreach ($elements as $el) {
+            if (!$el instanceof \DOMElement) {
+                continue;
+            }
+            $id = $el->getAttribute('id');
+            if ($id === '') {
+                continue;
+            }
+            if (!isset($ids[$id])) {
+                $ids[$id] = [];
+            }
+            $ids[$id][] = $el;
+        }
+
+        foreach ($ids as $id => $elementsWithId) {
+            if (count($elementsWithId) > 1) {
+                foreach ($elementsWithId as $el) {
+                    $violations[] = $this->createViolation(
+                        "Duplicate ID \"{$id}\" found. Element ID attribute must be unique across the document.",
+                        $el
+                    );
+                }
+            }
+        }
+
+        return $violations;
+    }
+
+    public function getStandard(): WCAGStandard { return WCAGStandard::A; }
+    public function getSeverity(): Severity { return Severity::ERROR; }
+}