const libsodium          = require('libsodium-wrappers');
const concat_typed_array = require("concat-typed-array");
const nonce_length       = libsodium.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES;

(async () => {
    await libsodium.ready;
}).then(function(){
    module.exports = class Sodium {
        constructor(key){
             if(key === null) {
                 throw "Sodium: Private key not set."
             }

            this.key = libsodium.from_hex(key);
        }

        encrypt(plaintext){
            var nonce      = libsodium.randombytes_buf(nonce_length),
                ciphertext = libsodium.crypto_aead_xchacha20poly1305_ietf_encrypt(plaintext, null, nonce, nonce, this.key);

            console.log("nonce", nonce);
            console.log("ciphertext", ciphertext);

            return concat_typed_array(Uint8Array, nonce, ciphertext);
        }

        decrypt(encryption){
            var nonce      = encryption.slice(0, nonce_length),
                ciphertext = encryption.slice(nonce_length);

            console.log("nonce", nonce);
            console.log("ciphertext", ciphertext);

            return libsodium.crypto_aead_xchacha20poly1305_ietf_decrypt(nonce, ciphertext, null, nonce, this.key, "text");
        }
    }
});