// Igneum light client, version zero, browser driver. Fetches /api/checkpoint and verifies it in this tab with
// core.js, then fills the homepage card. Everything is computed here; the server only ships data.
// Libraries, pinned: BLAKE2b from @noble/hashes 2.4.0, BLS12-381 from @noble/curves 2.4.0 (pure JavaScript,
// served by jsdelivr as ES modules).
import { blake2b } from 'https://cdn.jsdelivr.net/npm/@noble/hashes@2.4.0/blake2.js/+esm';
import { bls12_381 } from 'https://cdn.jsdelivr.net/npm/@noble/curves@2.4.0/bls12-381.js/+esm';
import { verifyCheckpoint } from './core.js';

export const LIBRARIES = { '@noble/hashes': '2.4.0', '@noble/curves': '2.4.0' };
const deps = { blake2b, bls: bls12_381 };

export async function fetchCheckpoint(url = '/api/checkpoint') {
  const r = await fetch(url, { cache: 'no-store' });
  let body = null;
  try { body = await r.json(); } catch { body = null; }
  if (!body) return { ok: false, error: `api answered ${r.status}` };
  return body;
}

export function verify(data) { return verifyCheckpoint(data, deps); }

// The homepage card. Cells carry data-lc="..." so the layout and classes stay as they are.
const $ = sel => document.querySelector(sel);
const pct = x => `${(x * 100).toFixed(1)}%`;

export function renderCard(result, data) {
  const badge = $('[data-lc="badge"]'), badgeText = $('[data-lc="badge-text"]');
  const cp = $('[data-lc="checkpoint"]'), proof = $('[data-lc="proof"]'), sys = $('[data-lc="system"]'), tab = $('[data-lc="tab"]');
  const line = $('[data-lc="line"]');
  if (!cp) return;
  if (proof) proof.textContent = 'not yet';
  if (sys) sys.textContent = 'BLS aggregate, version 1';
  if (result.verified) {
    const count = (window.__igneumVerified = (window.__igneumVerified || 0) + 1);
    cp.textContent = `${count} verified in this tab`;
    cp.title = `checkpoint ${result.index} on ${result.network}, block ${String(result.hash).slice(0, 12)}, ${result.headers_checked} headers checked`;
    tab.textContent = `${result.ms} ms · ${pct(result.weight_fraction_total)} of weight`;
    tab.title = `${result.signers} of ${result.voters} voters signed: ${pct(result.weight_fraction_active)} of active weight, ${pct(result.weight_fraction_total)} of total${result.weights_exact ? '' : ` (weights read at checkpoint ${result.weights_at_index})`}`;
    tab.style.color = '';
    if (badgeText) badgeText.textContent = data.source === 'test' ? 'LIVE · test network' : 'LIVE';
    if (badge) badge.classList.add('on');
    if (line) line.textContent = data.source === 'test'
      ? `Checkpoint ${result.index} of the test network, certified by ${result.signers} miners. Verified here.`
      : `Checkpoint ${result.index}, certified by ${result.signers} miners. Verified here.`;
  } else {
    cp.textContent = 'could not verify';
    cp.title = result.reason || '';
    tab.textContent = result.reason ? result.reason : 'could not verify';
    tab.style.color = 'var(--molten)';
    if (badgeText) badgeText.textContent = 'PREVIEW';
    if (badge) badge.classList.remove('on');
  }
}

export async function run(url) {
  const data = await fetchCheckpoint(url);
  const result = verify(data);
  window.__igneumLightClient = { result, data };
  renderCard(result, data);
  return result;
}

if (typeof document !== 'undefined' && document.querySelector('[data-lc="checkpoint"]')) {
  const start = () => run().catch(e => renderCard({ verified: false, reason: String(e.message || e) }, {}));
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', start); else start();
}