package {
    import com.hurlant.util.Base64;
    import com.hurlant.crypto.symmetric.PKCS5;
    import com.hurlant.crypto.symmetric.ECBMode;
    import com.hurlant.crypto.symmetric.BlowFishKey;
    import com.hurlant.crypto.symmetric.ICipher;
    import com.hurlant.crypto.symmetric.IPad;
    import flash.utils.ByteArray;

    public class BFHelper {
        /**
        * Encrypts a string.
        * @param text  The text string to encrypt.
        * @param key  A cipher key to encrypt the text with.
        */
        static public function encrypt($text:String, $key:String=""):String {
            try {
                var $output:ByteArray = new ByteArray();
                $output.writeUTF($text);
                var $pad:IPad = new PKCS5();
                var $cipher:ICipher = _getCipher( $key, $pad );
                $pad.setBlockSize( $cipher.getBlockSize() );
                $cipher.encrypt( $output );
                $cipher.dispose();
                return Base64.encodeByteArray( $output );
            }
            catch ($error:Error) {
                trace("An encryption error occured.");
            }
            return null;
        }

        /**
        * Decrypts an encrypted string.
        * @param text  The text string to decrypt.
        * @param key  The key used while originally encrypting the text.
        */
        static public function decrypt($text:String, $key:String=""):String {
            try {
                var $input:ByteArray = Base64.decodeToByteArray( $text );
                var $pad:IPad = new PKCS5();
                var $cipher:ICipher = _getCipher( $key, $pad );
                $pad.setBlockSize( $cipher.getBlockSize() );
                $cipher.decrypt( $input );
                $cipher.dispose();
                $input.position = 0;
                return $input.readUTF();
            }
            catch ($error:Error) {
                trace("A decryption error occured.");
            }
            return null;
        }

        /** @private builds a Blowfish cipher algorithm. */
        private static function _getCipher( $key:String, $pad:IPad ):ICipher {
            return new ECBMode( new BlowFishKey(Base64.decodeToByteArray( $key )), $pad );
        }
    }
}