import { Client, ConfigBuilder, X402Flow } from "@4mica/sdk";

const cfg = new ConfigBuilder().walletPrivateKey("0x...").build();
const client = await Client.connect(cfg);
const flow = X402Flow.fromClient(client);

import type { PaymentRequirementsV1 } from "@4mica/sdk";

type ResourceResponse = {
  x402Version: number;
  accepts: PaymentRequirementsV1[];
  error?: string;
};

// 1) GET the protected endpoint and parse the JSON body
const res = await fetch("https://resource-url/resource");
const body = (await res.json()) as ResourceResponse;

// 2) Select a payment option
const requirements = body.accepts[0];

// 3) Build the X-PAYMENT header
const payment = await flow.signPayment(requirements);

// 4) Call the protected resource with the header
await fetch("https://resource-url/resource", {
  headers: { "X-PAYMENT": payment.header },
});

import { X402PaymentRequired } from "@4mica/sdk";

// 1) GET the protected endpoint and read the payment-required header
const res = await fetch("https://resource-url/resource");
const header = res.headers.get("payment-required");
if (!header) throw new Error("Missing payment-required header");

// 2) Decode and parse the challenge
const decoded = Buffer.from(header, "base64").toString("utf8");
const paymentRequired = X402PaymentRequired.fromRaw(JSON.parse(decoded));

// 3) Select a payment option
const accepted = paymentRequired.accepts[0];

// 4) Build the PAYMENT-SIGNATURE header
const signed = await flow.signPaymentV2(paymentRequired, accepted);

// 5) Call the protected resource with the header
await fetch("https://resource-url/resource", {
  headers: { "PAYMENT-SIGNATURE": signed.header },
});

import type { PaymentRequirementsV1, X402SignedPayment } from "@4mica/sdk";

async function settle(
  facilitatorUrl: string,
  paymentRequirements: PaymentRequirementsV1,
  payment: X402SignedPayment,
) {
  const settled = await flow.settlePayment(
    payment,
    paymentRequirements,
    facilitatorUrl,
  );
  if (!settled.settlement.success) {
    // errorReason is a code such as invalid_4mica_credit_checkpoint_required;
    // retryable and details say whether and how the payer can act on it.
    console.error(
      "settlement rejected:",
      settled.settlement.errorReason,
      settled.settlement.errorMessage,
    );
    return;
  }
  // settled.settlement.receipt is the operator's GuaranteeReceipt, read from
  // the facilitator's extra.receipt
}