#!/usr/bin/env node
// Sign and submit a Nano forecast ladder entry.
//   node client/sign-and-submit.js --key <64 hex private key> --round 0 --forecasts '{"btc_usd":0.4,...}'
//   node client/sign-and-submit.js --seed <64 hex seed> [--index 0] --round 0 --forecasts-file f.json
// Options: --url http://127.0.0.1:3002  --nonce <string>  --stake-hash <64 hex>  --dry-run (print, do not POST)
//          --work-rpc http://127.0.0.1:7076 (ask a Nano node for work instead of computing it here)
//          --threads N (default: all CPUs; in-process work takes ~2^29 hashes, roughly 25-100 s on 4 cores)
// Needs: npm i nanocurrency blakejs   (run from the ladder dir, or install those two packages)
'use strict';
const { Worker, isMainThread, parentPort, workerData } = require('worker_threads');
const os = require('os');
const fs = require('fs');
const nc = require('nanocurrency');
const { blake2b } = require('blakejs');
const THRESHOLD = 'fffffff800000000';

if (!isMainThread) {              // worker: search one slice of the nonce space
  nc.computeWork(workerData.hash, { workThreshold: THRESHOLD, workerIndex: workerData.index, workerCount: workerData.count })
    .then(w => parentPort.postMessage(w));
  return;
}

function canonical(v) {
  if (v === null || typeof v !== 'object') return JSON.stringify(v);
  if (Array.isArray(v)) return '[' + v.map(canonical).join(',') + ']';
  return '{' + Object.keys(v).sort().map(k => JSON.stringify(k) + ':' + canonical(v[k])).join(',') + '}';
}
const blake256 = s => Buffer.from(blake2b(Buffer.from(s, 'utf8'), undefined, 32)).toString('hex').toUpperCase();

function computeWorkLocal(hash, threads) {
  return new Promise((resolve, reject) => {
    const started = Date.now(), workers = [];
    const timer = setInterval(() => process.stderr.write('  working... ' + Math.round((Date.now() - started) / 1000) + ' s elapsed (expected ~' + Math.round(100 / threads) + '-' + Math.round(200 / threads) + ' s on ~5 MH/s/thread)\n'), 5000);
    const done = w => { clearInterval(timer); workers.forEach(x => x.terminate()); w ? resolve(w) : reject(new Error('no work found')); };
    for (let i = 0; i < threads; i++) {
      const w = new Worker(__filename, { workerData: { hash, index: i, count: threads } });
      w.on('message', done); w.on('error', reject); workers.push(w);
    }
  });
}
async function computeWorkRpc(hash, url) {
  const r = await fetch(url, { method: 'POST', body: JSON.stringify({ action: 'work_generate', hash, difficulty: THRESHOLD }) });
  const j = await r.json(); if (j.error) throw new Error('work_generate: ' + j.error); return j.work;
}

(async () => {
  const a = {}; const argv = process.argv.slice(2);
  for (let i = 0; i < argv.length; i++) if (argv[i].startsWith('--')) a[argv[i].slice(2)] = argv[i + 1] && !argv[i + 1].startsWith('--') ? argv[++i] : true;
  let sk = a.key;
  if (a.seed) sk = nc.deriveSecretKey(a.seed.toUpperCase(), Number(a.index || 0));
  if (!sk || !/^[0-9a-fA-F]{64}$/.test(sk) || a.round === undefined || !(a.forecasts || a['forecasts-file'])) {
    console.error('usage: --key <64hex> | --seed <64hex> [--index N]  --round <id>  --forecasts <json> | --forecasts-file <file>  [--url U] [--nonce S] [--stake-hash H] [--work-rpc U] [--threads N] [--dry-run]');
    process.exit(2);
  }
  sk = sk.toUpperCase();
  const address = nc.deriveAddress(nc.derivePublicKey(sk), { useNanoPrefix: true });
  const forecasts = JSON.parse(a.forecasts || fs.readFileSync(a['forecasts-file'], 'utf8'));
  const url = a.url || 'http://127.0.0.1:3002';
  const nonce = a.nonce || Date.now().toString(36) + Math.random().toString(36).slice(2, 8);
  const fields = { round: Number(a.round), address, forecasts, nonce };
  const canon = canonical(fields), hash = blake256(canon);
  console.error('address  ' + address + '\ncanonical ' + canon + '\nmessage  ' + hash);
  const threads = Number(a.threads || os.cpus().length);
  const t0 = Date.now();
  const work = a['work-rpc'] ? await computeWorkRpc(hash, a['work-rpc']) : await computeWorkLocal(hash, threads);
  console.error('work     ' + work + ' (' + Math.round((Date.now() - t0) / 1000) + ' s)');
  const signature = nc.signBlock({ hash, secretKey: sk });
  const body = { ...fields, work, signature };
  if (a['stake-hash']) body.stake_hash = a['stake-hash'];
  console.log(JSON.stringify(body, null, 1));
  if (a['dry-run']) return;
  const r = await fetch(url + '/v1/entries', { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify(body) });
  const text = await r.text();
  console.error('HTTP ' + r.status + ' ' + text);
  process.exit(r.ok ? 0 : 1);
})().catch(e => { console.error(e.message); process.exit(1); });