InvisibleWrapper.php

<?php

class InvisibleWrapper
{
    // Invisible characters used for encoding
    const INVISIBLE_CHARACTERS = ["\u{200C}", "\u{200D}"];
    const MESSAGE_END = "\x0A";


    /**
     * Converts string to byte array
     *
     * @param string $text The text to convert to bytes
     * @return array Array of bytes
     */
    private function toBytes($text)
    {
        // PHP equivalent of TextEncoder.encode
        return array_values(unpack('C*', $text));
    }

    /**
     * Pads binary string to 8 bits
     *
     * @param string $binary The binary string to pad
     * @return string Padded binary string
     */
    private function padToWholeBytes($binary)
    {
        $needsToAdd = 8 - strlen($binary);
        return str_repeat('0', $needsToAdd) . $binary;
    }

    /**
     * Encodes text to invisible characters
     *
     * @param string $text The text to encode
     * @return string Text encoded with invisible characters
     */
    public function encodeMessage($text)
    {
        // Convert text to bytes
        $bytes = $this->toBytes($text);

        // Convert bytes to binary string with padding and separator
        $binary = '';
        foreach ($bytes as $byte) {
            $binary .= $this->padToWholeBytes(decbin($byte)) . '0';
        }

        // Convert binary to invisible characters
        $result = '';
        for ($i = 0; $i < strlen($binary); $i++) {
            $result .= self::INVISIBLE_CHARACTERS[(int)$binary[$i]];
        }

        return $result;
    }

    /**
     * Encodes a message with separator
     *
     * @param string $message The message to encode
     * @return string Encoded message with separator
     */
    function encodeWithSeparator($message)
    {
        return self::encodeMessage($message . self::MESSAGE_END);
    }

    /**
     * Wraps a translation with invisible encoded key data
     *
     * @param string $key The translation key
     * @param string|null $ns The namespace (optional)
     * @param string $translation The translated text
     * @return string Translation with appended invisible characters
     */
    function wrapWithFullKeyEncode($key, $ns, $translation)
    {
        // Create the data structure to encode
        $data = [
            'k' => $key,
            'n' => $ns ?: ''
        ];

        // Convert to JSON
        $encodedValue = json_encode($data);

        // Encode with invisible characters
        $invisibleMark = self::encodeWithSeparator($encodedValue);

        // Append invisible characters to the translation
        return $translation . $invisibleMark;
    }

}