class Json

final class Json {
    
    /**
     * @throws InvalidJsonException
     */
    public static function prettify(string $json) : string {
        $decodedJson = json_decode($json, false);
        if (json_last_error()) {
            throw new InvalidJsonException();
        }
        return json_encode($decodedJson, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
    }
    
    /**
     * To allow comparison of JSON strings, first process them into a consistent
     * format so that they can be compared as strings.
     *
     * @return array ($error, $canonicalized_json)  The $error parameter is used
     *               to indicate an error decoding the json. This is used to avoid ambiguity
     *               with JSON strings consisting entirely of 'null' or 'false'.
     */
    public static function canonicalize(string $json) : array {
        $decodedJson = json_decode($json);
        if (json_last_error()) {
            return [
                true,
                null,
            ];
        }
        self::recursiveSort($decodedJson);
        $reencodedJson = json_encode($decodedJson);
        return [
            false,
            $reencodedJson,
        ];
    }
    
    /**
     * JSON object keys are unordered while PHP array keys are ordered.
     *
     * Sort all array keys to ensure both the expected and actual values have
     * their keys in the same order.
     */
    private static function recursiveSort(mixed &$json) : void {
        // Nulls, empty arrays, and scalars need no further handling.
        if (!$json || is_scalar($json)) {
            return;
        }
        $isObject = is_object($json);
        if ($isObject) {
            // Objects need to be sorted during canonicalization to ensure
            // correct comparsion since JSON objects are unordered. It must be
            // kept as an object so that the value correctly stays as a JSON
            // object instead of potentially being converted to an array. This
            // approach ensures that numeric string JSON keys are preserved and
            // don't risk being flattened due to PHP's array semantics.
            // See #2919, #4584, #4674
            $json = (array) $json;
            ksort($json, SORT_STRING);
        }
        foreach ($json as &$value) {
            self::recursiveSort($value);
        }
        if ($isObject) {
            $json = (object) $json;
        }
    }

}