import { encodeJSONAsBinary, decodeJSONFromBinary } from "encoding/json/index";
import { JSONValue } from "encoding/json/types";
import { AESEncryptor } from "encryption/low-level/symmetric/aes/data";
import { b64Encode, b64Decode } from "encoding/base64";

export interface EncryptedData {
    iv: string;
    data: string;
    algorithm: AesKeyAlgorithm;
}

export interface SymmetricDataEncryptorI {
    encrypt(jsonableInput: JSONValue): Promise<EncryptedData>;
    decrypt(encryptedObject: EncryptedData): Promise<JSONValue>;
}

export function SymmetricDataEncryptor(
    dek: CryptoKey
): SymmetricDataEncryptorI {
    const aes = AESEncryptor(dek);

    return {
        async encrypt(jsonableInput: JSONValue): Promise<EncryptedData> {
            const { iv, data } = await aes.encryptBinary(
                encodeJSONAsBinary(jsonableInput)
            );

            return {
                iv: b64Encode(iv),
                // TODO: Decide if length of encrypted data could give anything away
                data: b64Encode(data),
                // While we don't actually use the algorithm at the moment, we may want to
                // change this one day
                algorithm: aes.getAlgorithm()
            };
        },
        async decrypt(encryptedObject: EncryptedData): Promise<JSONValue> {
            const { iv, data } = encryptedObject;
            return decodeJSONFromBinary(
                await aes.decryptBinary(b64Decode(iv), b64Decode(data))
            );
        }
    };
}
SymmetricDataEncryptor.getDefaultAlgorithm = AESEncryptor.getDefaultAlgorithm;
SymmetricDataEncryptor.generateKey = AESEncryptor.generateKey;