Match profanity words case-insensitively and across punctuation

app/Rules/ProfanityCheck.php

@@ -9,10 +9,20 @@ class ProfanityCheck implements Rule
 {
     public function passes($attribute, $value)
     {
-        $words = explode(' ', $value);
+        if (! is_string($value)) {
+            return true;
+        }
+
+        foreach (app(GeneralSettings::class)->profanity_words as $profanityWord) {
+            $terms = preg_split('/\s+/u', trim((string) $profanityWord), -1, PREG_SPLIT_NO_EMPTY);
+
+            if (empty($terms)) {
+                continue;
+            }
+
+            $phrase = implode('\s+', array_map(fn (string $term) => preg_quote($term, '/'), $terms));
 
-        foreach ($words as $word) {
-            if (in_array($word, app(GeneralSettings::class)->profanity_words)) {
+            if (preg_match('/(?<![\p{L}\p{N}])' . $phrase . '(?![\p{L}\p{N}])/iu', $value) === 1) {
                 return false;
             }
         }

tests/Unit/Rules/ProfanityCheckTest.php

@@ -0,0 +1,36 @@
+<?php
+
+use App\Rules\ProfanityCheck;
+use App\Settings\GeneralSettings;
+
+beforeEach(function () {
+    GeneralSettings::fake([
+        'profanity_words' => ['fuck', 'asshole', 'dick', 'screw you'],
+    ]);
+});
+
+test('content containing a profanity word fails', function (string $content) {
+    expect((new ProfanityCheck())->passes('content', $content))->toBeFalse();
+})->with([
+    'exact word' => 'fuck',
+    'different casing' => 'Fuck this feature',
+    'trailing punctuation' => 'What the fuck!',
+    'surrounded by punctuation' => '(asshole)',
+    'separated by a newline' => "Nice idea\ndick",
+    'multi word entry' => 'Screw you',
+    'multi word entry across whitespace' => "screw\n  you, really",
+]);
+
+test('content without a profanity word passes', function (string $content) {
+    expect((new ProfanityCheck())->passes('content', $content))->toBeTrue();
+})->with([
+    'clean sentence' => 'Please add dark mode',
+    'word containing a profanity word' => 'I love reading Dickens',
+    'multi word entry split by other words' => 'Screw the lid on, thank you',
+]);
+
+test('empty profanity entries are ignored', function () {
+    GeneralSettings::fake(['profanity_words' => ['', '  ']]);
+
+    expect((new ProfanityCheck())->passes('content', 'Please add dark mode'))->toBeTrue();
+});