Fix ISBN detection and language filter bugs

**ISBN Detection Fix:**
- Fix regex pattern to correctly detect 10 and 13 digit ISBNs
- Remove hyphens and spaces before checking ISBN format
- Now correctly identifies: 3551354030, 978-3-551-35403-0, etc.
- Support manual prefixes: isbn:, intitle:, inauthor: (Google)
- Support manual prefixes: isbn:, author:, title: (OpenLibrary)

**Language Filter Fix:**
- Fix Google Books language filter (was concatenating to query string)
- Now correctly passes langRestrict as separate parameter
- German books (de) will no longer show Dutch (nl) results

**Pattern Improvements:**
- Simplified author name detection (2+ words, capitalized)
- More robust ISBN cleaning (removes hyphens AND spaces)
- Consistent behavior across both search providers

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: roberteinsle

app/Services/GoogleBooksService.php

@@ -23,18 +23,20 @@ public function search(string $query, int $maxResults = 20, string $language = n
         // Detect query type and build appropriate search query
         $searchQuery = $this->buildSearchQuery($query);
 
+        $params = [
+            'q' => $searchQuery,
+            'key' => $this->apiKey,
+            'maxResults' => $maxResults,
+            'orderBy' => 'relevance',
+        ];
+
         // Add language filter if specified
         if ($language) {
-            $searchQuery .= '&langRestrict=' . $language;
+            $params['langRestrict'] = $language;
         }
 
         try {
-            $response = Http::get("{$this->baseUrl}/volumes", [
-                'q' => $searchQuery,
-                'key' => $this->apiKey,
-                'maxResults' => $maxResults,
-                'orderBy' => 'relevance',
-            ]);
+            $response = Http::get("{$this->baseUrl}/volumes", $params);
 
             if ($response->successful()) {
                 return $this->formatResults($response->json());
@@ -89,13 +91,21 @@ protected function buildSearchQuery(string $query): string
     {
         $query = trim($query);
 
-        // ISBN-10 or ISBN-13 (with or without hyphens)
-        if (preg_match('/^(\d{10}|\d{13}|\d{1,5}-\d{1,7}-\d{1,7}-[\dX])$/i', str_replace('-', '', $query))) {
-            return 'isbn:' . str_replace('-', '', $query);
+        // Remove any existing prefix if user added it manually
+        if (preg_match('/^(isbn|intitle|inauthor):/i', $query)) {
+            return $query; // Already formatted, return as-is
+        }
+
+        // Clean query for ISBN check (remove hyphens and spaces)
+        $cleanQuery = str_replace(['-', ' '], '', $query);
+
+        // ISBN-10 (10 digits) or ISBN-13 (13 digits)
+        if (preg_match('/^\d{10}$|^\d{13}$/', $cleanQuery)) {
+            return 'isbn:' . $cleanQuery;
         }
 
-        // Check if query looks like an author name (2+ words with capitalization)
-        if (preg_match('/^[A-Z][a-z]+\s+[A-Z][a-z]+/', $query)) {
+        // Check if query looks like an author name (2+ words, first letters capitalized)
+        if (preg_match('/^[A-Z][a-z]+\s+[A-Z]/', $query)) {
             return 'inauthor:' . $query;
         }
 

app/Services/OpenLibraryService.php

@@ -185,18 +185,22 @@ protected function buildSearchQuery(string $query): string
         $query = trim($query);
 
         // Remove 'isbn:', 'author:', 'title:' prefixes if user added them manually
-        if (preg_match('/^(isbn|author|title):\s*(.+)$/i', $query, $matches)) {
+}
+        // Remove 'isbn:', 'author:', 'title:' prefixes if user added them manually
+        if (preg_match('/^(isbn|author|title):/i', $query)) {
             return $query; // Already formatted, return as-is
         }
 
-        // ISBN-10 or ISBN-13 (with or without hyphens)
-        $cleanQuery = str_replace('-', '', $query);
+        // Clean query for ISBN check (remove hyphens and spaces)
+        $cleanQuery = str_replace(['-', ' '], '', $query);
+
+        // ISBN-10 (10 digits) or ISBN-13 (13 digits)
         if (preg_match('/^\d{10}$|^\d{13}$/', $cleanQuery)) {
             return 'isbn:' . $cleanQuery;
         }
 
-        // Check if query looks like an author name (2+ words with capitalization)
-        if (preg_match('/^[A-Z][a-z]+\s+[A-Z][a-z]+/', $query)) {
+        // Check if query looks like an author name (2+ words, first letters capitalized)
+        if (preg_match('/^[A-Z][a-z]+\s+[A-Z]/', $query)) {
             return 'author:' . $query;
         }