import re

with open("stock.php", "r", encoding="utf-8") as f:
    content = f.read()

# Replace block from `// Handle Import CSV` to `// Handle AJAX actions`
start_marker = "// Handle Import CSV"
end_marker = "// Handle AJAX actions"
start_idx = content.find(start_marker)
end_idx = content.find(end_marker)

if start_idx == -1 or end_idx == -1:
    print("Could not find import_csv block")
    exit(1)

new_import_code = """// Handle Import CSV
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action']) && $_POST['action'] === 'import_csv') {
    if (isset($_FILES['csv_file']) && $_FILES['csv_file']['error'] === UPLOAD_ERR_OK) {
        require_once __DIR__ . '/includes/SimpleXLSX.php';
        $pdo = db();
        $file_path = $_FILES['csv_file']['tmp_name'];
        $raw_content = file_get_contents($file_path);
        
        $rows = [];
        # Check if XLSX (starts with PK)
        if (str_starts_with($raw_content, 'PK')) {
            if ( $xlsx = Shuchkin\SimpleXLSX::parse($file_path) ) {
                $rows = $xlsx->rows();
                if (count($rows) > 0) {
                    array_shift($rows); # Remove header
                }
            } else {
                header('Location: stock.php?import_error=' . urlencode('خطأ في قراءة ملف الإكسل (XLSX). يرجى التأكد من أن الملف سليم.'));
                exit;
            }
        } else {
            # Treat as CSV
            # Remove UTF-8 BOM if present
            if (str_starts_with($raw_content, "\xEF\xBB\xBF")) {
                $raw_content = substr($raw_content, 3);
            }

            # Fix encoding for Windows-1256 (common in Arabic Excel exports)
            if (!mb_check_encoding($raw_content, 'UTF-8')) {
                $raw_content = mb_convert_encoding($raw_content, 'UTF-8', 'Windows-1256');
            }

            # Determine delimiter by checking first line
            $first_line = strtok($raw_content, "\r\n");
            $delimiter = ',';
            if ($first_line !== false && substr_count($first_line, ';') > substr_count($first_line, ',')) {
                $delimiter = ';';
            }

            $clean_file = tmpfile();
            fwrite($clean_file, $raw_content);
            rewind($clean_file);
            
            $header = fgetcsv($clean_file, 0, $delimiter);
            while (($row = fgetcsv($clean_file, 0, $delimiter)) !== false) {
                $rows[] = $row;
            }
            fclose($clean_file);
        }

        $imported = 0; $updated = 0;
        $pdo->beginTransaction();
        try {
            $stmtInsert = $pdo->prepare("INSERT INTO items (sku, name, price, cost_price, base_stock, vat, category_id, supplier_id, unit_id) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)");
            $stmtUpdate = $pdo->prepare("UPDATE items SET name=?, price=?, cost_price=?, base_stock=?, vat=?, category_id=?, supplier_id=?, unit_id=? WHERE sku=?");
            $stmtCheck = $pdo->prepare("SELECT id FROM items WHERE sku=?");
            
            foreach ($rows as $row) {
                if (count($row) < 5) continue;
                $sku = trim((string)$row[0]); $name = trim((string)$row[1]);
                if ($sku === '' || $name === '') continue;
                $price = (float)($row[2] ?? 0);
                $cost_price = (float)($row[3] ?? 0);
                $base_stock = (int)($row[4] ?? 0);
                $vat = (float)($row[5] ?? 5);
                $category_id = !empty($row[6]) ? (int)$row[6] : null;
                $supplier_id = !empty($row[7]) ? (int)$row[7] : null;
                $unit_id = !empty($row[8]) ? (int)$row[8] : null;
                $stmtCheck->execute([$sku]);
                if ($stmtCheck->fetchColumn()) {
                    $stmtUpdate->execute([$name, $price, $cost_price, $base_stock, $vat, $category_id, $supplier_id, $unit_id, $sku]);
                    $updated++;
                } else {
                    $stmtInsert->execute([$sku, $name, $price, $cost_price, $base_stock, $vat, $category_id, $supplier_id, $unit_id]);
                    $imported++;
                }
            }
            $pdo->commit();
            header('Location: stock.php?import_success=1&imported='.$imported.'&updated='.$updated);
            exit;
        } catch (Exception $e) {
            $pdo->rollBack();
            header('Location: stock.php?import_error='.urlencode($e->getMessage()));
            exit;
        }
    }
    header('Location: stock.php?import_error=No+file');
    exit;
}

"""

content = content[:start_idx] + new_import_code + content[end_idx:]

# Update the modal text to reflect XLSX support
content = content.replace("ملاحظة: يدعم النظام ملفات CSV فقط. يرجى حفظ ملف Excel بصيغة (CSV UTF-8).", "ملاحظة: يدعم النظام الآن ملفات Excel (XLSX) بالإضافة إلى CSV.")
content = content.replace("Note: The system supports CSV files only. Please save your Excel file as (CSV UTF-8).", "Note: The system now supports Excel (XLSX) files in addition to CSV.")
content = content.replace('accept=".csv"', 'accept=".csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel"')

with open("stock.php", "w", encoding="utf-8") as f:
    f.write(content)

print("Patched successfully")