// Clientul x402 al unui agent AI (2026-09-29, punctele 23, 25): cumpara o resursa HTTP care cere plata (402), scriind INTAI plata in
// registrul agentului, apoi cerand portofelului (wallet.mjs) semnatura, apoi reluand cererea cu antetul PAYMENT-SIGNATURE. Numele
// antetelor si forma lor sunt ale specificatiei x402 v2 (transportul HTTP): PAYMENT-REQUIRED, PAYMENT-SIGNATURE, PAYMENT-RESPONSE, toate
// JSON in base64. Daca politica refuza plata, clientul se opreste inainte de portofel (si portofelul ar refuza oricum).
import { x402Action } from './wallet.mjs';

export const b64json = (o) => Buffer.from(JSON.stringify(o), 'utf8').toString('base64');
export function dinB64json(s) { try { return JSON.parse(Buffer.from(String(s), 'base64').toString('utf8')); } catch { return null; } }

/** portofelul prin HTTP (serviciul wallet.mjs serve), cu aceeasi forma ca obiectul din createWallet */
export function walletOverHttp(baseUrl, fetchImpl = fetch) {
  const b = String(baseUrl).replace(/\/+$/, '');
  return {
    async status() { const r = await fetchImpl(b + '/status'); return r.json(); },
    async authorize(body) { const r = await fetchImpl(b + '/authorize', { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify(body) }); return r.json(); },
  };
}

/**
 * @param {object} o
 * @param {string} o.url            resursa
 * @param {object} o.ledger         registrul agentului (openLedger / resumeLedger)
 * @param {object} o.wallet         portofelul (createWallet sau walletOverHttp)
 * @param {Array}  [o.approvals]    aprobari umane pentru aceasta plata, cand politica le cere
 * @param {Function} [o.fetchImpl]
 * @returns {Promise<{paid:boolean, status:number, reason?:string, body?:string, settlement?:object, entry?:object, receipt?:object, decision?:object}>}
 */
export async function payWithAgent({ url, ledger, wallet, approvals = [], fetchImpl = fetch }) {
  const r0 = await fetchImpl(url);
  if (r0.status !== 402) return { paid: false, status: r0.status, body: await r0.text(), reason: r0.ok ? 'no payment was required' : `the resource answered ${r0.status}` };
  const pr = dinB64json(r0.headers.get('payment-required')) || (await r0.json().catch(() => null));
  if (!pr || pr.x402Version !== 2 || !Array.isArray(pr.accepts)) return { paid: false, status: 402, reason: 'the 402 response carries no x402 v2 PaymentRequired' };
  const w = await wallet.status();
  const req = pr.accepts.find((a) => a.scheme === 'exact' && a.network === w.network && String(a.asset).toLowerCase() === String(w.asset).toLowerCase());
  if (!req) return { paid: false, status: 402, reason: `no accepted payment is in this wallet's asset on ${w.network}` };
  // 1. plata, in registru, inainte de orice semnatura
  const r = ledger.record(x402Action(w.address, pr.resource || null, req), { approvals });
  if (!r.allowed) return { paid: false, status: 402, reason: `the agent's policy refused the payment: ${r.reason}`, entry: r.entry };
  // 2. semnatura portofelului, care judeca din nou tot registrul
  const a = await wallet.authorize({ requirements: req, resource: pr.resource || null, ledger: ledger.export() });
  if (!a.ok) return { paid: false, status: 402, reason: `the wallet refused: ${a.error}`, entry: r.entry, equivocation: a.equivocation };
  // 3. cererea reluata, cu plata
  const r1 = await fetchImpl(url, { headers: { 'PAYMENT-SIGNATURE': a.header } });
  const settlement = dinB64json(r1.headers.get('payment-response'));
  const body = await r1.text();
  return { paid: r1.ok && !!(settlement && settlement.success), status: r1.status, body, settlement, entry: r.entry, receipt: a.receipt, decision: a.decision,
    ...(r1.ok ? {} : { reason: `the resource answered ${r1.status} after payment: ${body.slice(0, 160)}` }) };
}