Accept payments

import crypto from 'node:crypto';
import { htp } from './htp.js';

export async function startCheckout(order, user) {
  // Persist the key with the order so retries reuse it
  order.idempotencyKey ??= crypto.randomBytes(16).toString('hex');
  const payment = await htp(
    'POST',
    '/open/v1/payments',
    {
      out_order_no: order.number,
      amount: order.total, // "40.00" — a string
      currency: 'USDT',
      description: order.title,
      payer_sub: user.htpSub,
    },
    order.idempotencyKey,
  );
  await db.orders.update(order.id, { htpPaymentId: payment.id, status: 'AWAITING_PAYMENT' });
  return payment.checkout_url;
}

import secrets
from htp import htp

def start_checkout(order, user):
    order.idempotency_key = order.idempotency_key or secrets.token_hex(16)
    payment = htp("POST", "/open/v1/payments", {
        "out_order_no": order.number,
        "amount": order.total,          # "40.00" — a string
        "currency": "USDT",
        "description": order.title,
        "payer_sub": user.htp_sub,
    }, order.idempotency_key)
    order.htp_payment_id = payment["id"]
    order.status = "AWAITING_PAYMENT"
    order.save()
    return payment["checkout_url"]

type Order struct {
	ID          string `json:"id"`
	Status      string `json:"status"`
	CheckoutURL string `json:"checkout_url"`
}

func StartCheckout(ctx context.Context, c *htp.Client, o *MyOrder, payerSub string) (string, error) {
	var p Order
	err := c.Do(ctx, "POST", "/open/v1/payments", map[string]any{
		"out_order_no": o.Number,
		"amount":       o.Total, // "40.00"
		"currency":     "USDT",
		"description":  o.Title,
		"payer_sub":    payerSub,
	}, o.IdempotencyKey, &p)
	if err != nil {
		return "", err
	}
	o.HTPPaymentID = p.ID
	return p.CheckoutURL, saveOrder(ctx, o)
}

// HtpClient from /docs/authentication; JSON with Jackson
private final ObjectMapper mapper = new ObjectMapper();

public String startCheckout(MyOrder order, String payerSub) throws Exception {
    if (order.idempotencyKey == null) {
        // Persist the key with the order so retries reuse it
        order.idempotencyKey = UUID.randomUUID().toString().replace("-", "");
    }
    String body = mapper.writeValueAsString(Map.of(
        "out_order_no", order.number,
        "amount", order.total,          // "40.00" — a string
        "currency", "USDT",
        "description", order.title,
        "payer_sub", payerSub));

    HttpResponse<String> res = htp.send("POST", "/open/v1/payments", body, order.idempotencyKey);
    JsonNode json = mapper.readTree(res.body());
    if (res.statusCode() != 200) {
        throw new IllegalStateException(json.path("error_code").asText() + " (trace " + json.path("trace_id").asText() + ")");
    }
    JsonNode payment = json.get("data");
    order.htpPaymentId = payment.get("id").asText();
    order.status = "AWAITING_PAYMENT";
    orders.save(order);
    return payment.get("checkout_url").asText();
}