Find Deep Differences Between Two Associative PHP Arrays

function array_deep_diff(array $array1, array $array2): array
{
    $diff = [];

    // Check for removed keys from array1
    foreach ($array1 as $key => $value) {
        if (!array_key_exists($key, $array2)) {
            $diff['removed'][$key] = $value;
        }
    }

    // Check for added or modified keys in array2
    foreach ($array2 as $key => $value) {
        if (!array_key_exists($key, $array1)) {
            $diff['added'][$key] = $value;
        } elseif (is_array($value) && is_array($array1[$key])) {
            $subDiff = array_deep_diff($array1[$key], $value);
            if (!empty($subDiff)) {
                $diff['modified'][$key] = $subDiff;
            }
        } elseif ($value !== $array1[$key]) {
            $diff['modified'][$key] = [
                'old' => $array1[$key],
                'new' => $value
            ];
        }
    }
    return $diff;
}

$originalConfig = [
    'database' => [
        'host' => 'localhost',
        'port' => 3306,
        'user' => 'root',
        'password' => 'old_pass',
        'options' => ['charset' => 'utf8']
    ],
    'app_name' => 'MyApp',
    'debug_mode' => true,
    'features' => ['login', 'register', 'dashboard']
];

$newConfig = [
    'database' => [
        'host' => '127.0.0.1', // Changed
        'port' => 3306,
        'user' => 'admin',    // Changed
        'password' => 'new_pass', // Changed
        'timeout' => 5        // Added
    ],
    'app_name' => 'MyNewApp', // Changed
    // 'debug_mode' removed
    'environment' => 'production', // Added
    'features' => ['login', 'dashboard', 'settings'] // 'register' removed, 'settings' added
];

$configDiff = array_deep_diff($originalConfig, $newConfig);
print_r($configDiff);