deviant/scripts/chipnet-asm-batch.mjs

#!/usr/bin/env node
/**
 * chipnet-asm-batch.mjs — Wallet C batches N small ASM transfers in one tx.
 *
 * Env vars:
 *   BATCH=100   (number of output transfers; default 100)
 *   PER=7       (ASM per output; default 7 — the dust minimum at rate 100)
 *   TO=a|b|c    (recipient for all outputs; default 'a')
 *
 * Demonstrates the "100 transactions in one tx fee" property. Each of
 * the BATCH outputs is a complete CashTokens FT transfer that, if sent
 * individually, would consume one tx fee each (BATCH × ~2K = ~200K sats
 * for 100). Bundled into a single transaction, the entire batch shares
 * one miner fee (~8K sats for a 100-output tx, plus the per-output dust
 * which is the same in either case).
 *
 * Net saving for 100 outputs: ~190K sats in miner fees not paid.
 */
import { readFileSync } from 'node:fs';
import { join } from 'node:path';
import { TestNetWallet } from 'mainnet-js';
import {
  ElectrumNetworkProvider,
  TransactionBuilder,
  SignatureTemplate,
} from 'cashscript';

const ROOT = join(import.meta.dirname, '..');
const ASM_FILE = join(ROOT, 'ChipnetTests', '.chipnet-asm-token.json');
const KEYS_C = join(ROOT, '.chipnet-keys-c.json');

const BATCH = parseInt(process.env.BATCH ?? '100', 10);
const PER = BigInt(process.env.PER ?? '7');
const TO = (process.env.TO ?? 'a').toLowerCase();

const KEYS = {
  a: join(ROOT, '.chipnet-keys.json'),
  b: join(ROOT, '.chipnet-keys-b.json'),
  c: join(ROOT, '.chipnet-keys-c.json'),
};
if (!KEYS[TO]) throw new Error(`TO must be a/b/c`);

function divider() { console.log('='.repeat(72)); }

async function main() {
  const asm = JSON.parse(readFileSync(ASM_FILE, 'utf8'));
  const { wif } = JSON.parse(readFileSync(KEYS_C, 'utf8'));
  const { tokenaddr: toTokenaddr } = JSON.parse(readFileSync(KEYS[TO], 'utf8'));

  const sender = await TestNetWallet.fromWIF(wif);
  const provider = new ElectrumNetworkProvider('chipnet');
  const sigTemplate = new SignatureTemplate(sender.privateKey);
  const rateSats = BigInt(asm.rateSats);

  const perOutputBacking = PER * rateSats;
  if (perOutputBacking < 700n) {
    throw new Error(`PER × rate (${perOutputBacking} sats) below CashTokens dust ~675`);
  }

  const totalAsmSent = BigInt(BATCH) * PER;
  const totalSendBacking = BigInt(BATCH) * perOutputBacking;

  // Source FT UTXO must have enough ASM.
  const senderUtxos = await provider.getUtxos(sender.cashaddr);
  const ftUtxos = senderUtxos.filter(
    (u) => u.token?.category === asm.categoryId && !u.token?.nft && u.token?.amount > 0n,
  );
  ftUtxos.sort((a, b) => Number(b.token.amount - a.token.amount));
  const sourceFt = ftUtxos.find((u) => u.token.amount >= totalAsmSent);
  if (!sourceFt) {
    throw new Error(`Wallet C has no ASM UTXO with ≥ ${totalAsmSent} ASM. Claim more first.`);
  }

  const bchUtxos = senderUtxos.filter((u) => !u.token).sort((a, b) => Number(b.satoshis) - Number(a.satoshis));
  if (bchUtxos.length === 0) throw new Error('Wallet C has no plain BCH UTXO for fee');
  const feeInput = bchUtxos[0];

  // Miner fee estimate: each output ~40 bytes (P2PKH locking + token bitfield + amount).
  // Each P2PKH input ~150 bytes. Tx header ~10. So for BATCH+1 outputs + 1 change FT
  // output + 1 BCH change output + 2 inputs:
  //   ~(BATCH + 3) * 40 + 2 * 150 + 10 ≈ BATCH*40 + 430
  // For BATCH=100: ~4430 bytes. At 1.5 sat/byte safety margin: ~6700 sats.
  const txByteEstimate = BigInt(BATCH) * 40n + 600n;
  const minerFee = txByteEstimate * 2n; // 2 sats/byte safety
  const sourceAmount = sourceFt.token.amount;
  const ftChangeAmount = sourceAmount - totalAsmSent;
  const ftChangeBacking = ftChangeAmount * rateSats;

  const bchAvailable = BigInt(sourceFt.satoshis) + BigInt(feeInput.satoshis);
  const bchUsed = totalSendBacking + (ftChangeAmount > 0n ? ftChangeBacking : 0n) + minerFee;
  const bchChange = bchAvailable - bchUsed;
  if (bchChange < 546n) {
    throw new Error(
      `BCH change ${bchChange} below dust. avail=${bchAvailable} used=${bchUsed}`,
    );
  }

  divider();
  console.log(`Wallet C batches ${BATCH} ASM transfers in ONE tx`);
  divider();
  console.log(`  Source FT:           ${sourceFt.txid.slice(0, 16)}:${sourceFt.vout} (${sourceAmount} ASM)`);
  console.log(`  Fee BCH input:       ${feeInput.txid.slice(0, 16)}:${feeInput.vout} (${feeInput.satoshis} sat)`);
  console.log(`  Per-output payload:  ${PER} ASM + ${perOutputBacking} sat backing`);
  console.log(`  Outputs in batch:    ${BATCH}`);
  console.log(`  Total ASM sent:      ${totalAsmSent}`);
  console.log(`  All to recipient:    ${toTokenaddr.slice(0, 30)}...`);
  console.log(`  Estimated tx bytes:  ${txByteEstimate}`);
  console.log(`  Miner fee:           ${minerFee} sat (single fee for ${BATCH} transfers)`);
  console.log(`  Equivalent N-tx fee: ${BigInt(BATCH) * 2_000n} sat (if sent individually)`);
  console.log(`  Saving:              ~${BigInt(BATCH) * 2_000n - minerFee} sat`);
  console.log(`  FT change to C:      ${ftChangeAmount} ASM`);
  console.log(`  BCH change to C:     ${bchChange} sat`);
  divider();

  const tb = new TransactionBuilder({ provider });
  tb.addInput(sourceFt, sigTemplate.unlockP2PKH());
  tb.addInput(feeInput, sigTemplate.unlockP2PKH());

  for (let i = 0; i < BATCH; i++) {
    tb.addOutput({
      to: toTokenaddr,
      amount: perOutputBacking,
      token: { amount: PER, category: asm.categoryId },
    });
  }
  if (ftChangeAmount > 0n) {
    tb.addOutput({
      to: sender.tokenaddr,
      amount: ftChangeBacking,
      token: { amount: ftChangeAmount, category: asm.categoryId },
    });
  }
  tb.addOutput({ to: sender.cashaddr, amount: bchChange });

  const sent = await tb.send();
  const txid = typeof sent === 'string' ? sent : sent?.txid ?? sent?.txId;
  console.log('');
  console.log(`Batch TXID: ${txid}`);
  console.log(`Verify on chipnet: each of ${BATCH} recipients now holds one ${PER}-ASM UTXO.`);
}

main().catch((err) => {
  console.error('FAILED:', err?.message ?? err);
  if (err?.stack) console.error(err.stack);
  process.exit(1);
});