Client & helpers

# Prefer env vars — never hardcode secrets in source control
export AVRIX_API_KEY="avrix_sk_sbx_your_key_here"
export AVRIX_BASE_URL="https://api.avrix.io"

async function sellerFetch(
  path: string,
  init: RequestInit & { idempotencyKey?: string } = {},
): Promise<Response> {
  const headers = new Headers(init.headers);
  headers.set("Authorization", `Bearer ${apiKey}`);
  if (init.idempotencyKey) headers.set("Idempotency-Key", init.idempotencyKey);
  if (init.body && !headers.has("Content-Type")) {
    headers.set("Content-Type", "application/json");
  }

  let attempt = 0;
  while (true) {
    const res = await fetch(`https://api.avrix.io${path}`, { ...init, headers });
    if (res.status !== 429 && res.status < 500) return res;
    attempt += 1;
    if (attempt > 5) return res;
    const retryAfter = Number(res.headers.get("Retry-After") ?? "1");
    await new Promise((r) => setTimeout(r, Math.min(30, retryAfter) * 1000));
  }
}

await sellerFetch("/api/seller/v1/whoami");

const previewRes = await sellerFetch("/api/seller/v1/orders/preview", {
  method: "POST",
  body: JSON.stringify({
    skuCode: "SANDBOX-ALWAYS-001",
    quantity: 1,
    countryCode: "US",
  }),
});
const previewJson = await previewRes.json();
if (!previewJson.data?.canFulfill) {
  throw new Error("Do not charge — Avrix cannot fulfil");
}

// Charge at your PSP, then:
const orderRes = await sellerFetch("/api/seller/v1/orders", {
  method: "POST",
  idempotencyKey: "ik_store_10432",
  body: JSON.stringify({
    skuCode: "SANDBOX-ALWAYS-001",
    quantity: 1,
    orderReference: "store-order-10432",
    countryCode: "US",
    expectedUnitPriceCents: previewJson.data.unitPriceCents,
    priceCommitmentToken: previewJson.data.priceCommitmentToken,
    integrationOrderContext: {
      schemaVersion: 1,
      salesCountryCode: "US",
      currencyCode: "USD",
      salesPriceGrossMinor: 1999,
      salesPriceNetMinor: 1999,
      priceIncludesTax: true,
      salesTaxAmountMinor: 0,
      salesTaxRatePercent: 0,
      salesChannel: "web",
      consumerIp: "203.0.113.42",
      paymentMethodFamily: "card",
      paymentProcessorReference: "psp_txn_10432",
      checkoutSessionId: "cs_store_10432",
    },
  }),
});