# Быстрый smoke-test: AES-256-GCM конверт через openssl + curl.
# openssl ниже работает с GCM на 1.1.1+; для прод-интеграции используйте
# библиотечный пример (Python / JS / Rust) — там tag и nonce обрабатываются явно.

KEY_B64="your_base64_encryption_key"
BODY='{"public_user_id":"DPPU-X9Y8Z7W6V5","qr_payload":"00020101021230740016A000000677010111011300660000000000021700000000000000000530376454031500802TH91047CBC","external_user_id":"user_456","callback_url":"https://your.domain/webhooks/payments"}'

# 1) Сгенерировать случайный 12-байтный nonce
NONCE=$(openssl rand 12 | base64)
NONCE_HEX=$(echo "$NONCE" | base64 -d | xxd -p -c 256)
KEY_HEX=$(echo "$KEY_B64" | base64 -d | xxd -p -c 256)

# 2) Зашифровать (ciphertext + GCM tag) и base64-кодировать
CIPHERTEXT=$(echo -n "$BODY" | openssl enc -aes-256-gcm -K "$KEY_HEX" -iv "$NONCE_HEX" -nopad | base64)

# 3) Завернуть в конверт и отправить
curl -X POST https://api.doverkapay.com/api/v1/payments/transactions \
  -H "Authorization: Bearer dpm_your_token_here" \
  -H "Idempotency-Key: pay-20260520-inv-0042" \
  -H "Content-Type: application/json" \
  -d "{\"data\":\"$CIPHERTEXT\",\"nonce\":\"$NONCE\"}"

import os, json, base64
from cryptography.hazmat.primitives.ciphers.aead import AESGCM

def encrypt_envelope(key: bytes, payload: dict) -> dict:
    nonce = os.urandom(12)
    ct = AESGCM(key).encrypt(nonce, json.dumps(payload).encode(), None)
    return {
        "data": base64.b64encode(ct).decode(),
        "nonce": base64.b64encode(nonce).decode(),
    }

def decrypt_envelope(key: bytes, envelope: dict) -> dict:
    nonce = base64.b64decode(envelope["nonce"])
    ct = base64.b64decode(envelope["data"])
    return json.loads(AESGCM(key).decrypt(nonce, ct, None))

// Node 18+: WebCrypto API (crypto.subtle). For browser code it is identical.
export async function encryptEnvelope(key, payload) {
  const nonce = crypto.getRandomValues(new Uint8Array(12));
  const pt = new TextEncoder().encode(JSON.stringify(payload));
  const ct = new Uint8Array(
    await crypto.subtle.encrypt({ name: "AES-GCM", iv: nonce }, key, pt)
  );
  const b64 = (u8) => Buffer.from(u8).toString("base64");
  return { data: b64(ct), nonce: b64(nonce) };
}

<?php
// PHP 7.2+: AES-256-GCM через openssl_encrypt с параметром tag.
// $key — это 32 сырых байта (ваш encryption_key, после base64-decode).

function encryptEnvelope(string $key, array $payload): array {
    $nonce = random_bytes(12);
    $tag = '';
    $ciphertext = openssl_encrypt(
        json_encode($payload, JSON_UNESCAPED_UNICODE),
        'aes-256-gcm',
        $key,
        OPENSSL_RAW_DATA,
        $nonce,
        $tag,
        '',
        16
    );
    return [
        'data'  => base64_encode($ciphertext . $tag),
        'nonce' => base64_encode($nonce),
    ];
}

function decryptEnvelope(string $key, array $envelope): array {
    $blob = base64_decode($envelope['data']);
    $nonce = base64_decode($envelope['nonce']);
    $tag = substr($blob, -16);
    $ciphertext = substr($blob, 0, -16);
    $plaintext = openssl_decrypt(
        $ciphertext,
        'aes-256-gcm',
        $key,
        OPENSSL_RAW_DATA,
        $nonce,
        $tag
    );
    return json_decode($plaintext, true);
}

// Cargo.toml: aes-gcm = "0.10"; rand = "0.8"; base64 = "0.22"; serde_json = "1"
use aes_gcm::{Aes256Gcm, KeyInit, Nonce, aead::Aead};
use base64::{Engine, engine::general_purpose::STANDARD};
use rand::RngCore;
use serde_json::Value;

type BoxError = Box<dyn std::error::Error + Send + Sync>;

pub fn encrypt_envelope(key: &[u8; 32], payload: &Value) -> Result<Value, BoxError> {
    let cipher = Aes256Gcm::new(key.into());
    let mut nonce_bytes = [0u8; 12];
    rand::thread_rng().fill_bytes(&mut nonce_bytes);
    let ct = cipher
        .encrypt(Nonce::from_slice(&nonce_bytes), serde_json::to_vec(payload)?.as_ref())
        .map_err(|e| format!("encrypt: {e}"))?;
    Ok(serde_json::json!({
        "data": STANDARD.encode(&ct),
        "nonce": STANDARD.encode(&nonce_bytes),
    }))
}