// simulate.js, migration cost estimator. Given a set of accounts and a target
// post-quantum scheme, estimate the gas to migrate and to authorize, using the
// MEASURED PQC verify costs from the Aere benchmark report. Zero dependencies.
//
// All per-scheme gas is [CITED: AERE-BENCHMARK-REPORT.md Part C.1] (native
// precompile marginal gas + the verify-and-record tx gasUsed receipt). The
// deployed-account Falcon path is [CITED: pqc-account.json] (Solidity verifier,
// ~10.5M gas). This estimator does not invent numbers; it composes the cited
// ones and is explicit about which path each figure represents.

import {
  PQC, HYBRID_MARGINAL_GAS, CLASSICAL,
  AERE_PQC_ACCOUNT_MEASURED_USEROP_GAS, FALCON512_SOLIDITY_VERIFIER_GAS,
} from './precompiles.js';

// One-time CREATE2 deploy of an AerePQCAccount. [CITED: pqc-account.json createGasUsed]
export const ACCOUNT_DEPLOY_GAS = 1493084;

// The live 1 Gwei base-fee floor on chain 2800. [CITED: EIP-COMPATIBILITY-MATRIX EIP-1559 row]
export const GAS_PRICE_GWEI = 1;

// Per-scheme model. `verifyTxGas` is the realistic on-chain verify-and-record
// receipt via the NATIVE precompile. `note` records path caveats.
const SCHEME_MODEL = {
  falcon512:  { label: 'Falcon-512 (native precompile)',  verifyTxGas: PQC.falcon512.verifyAndRecordTxGas, marginal: PQC.falcon512.marginalGas },
  falcon1024: { label: 'Falcon-1024 (native precompile)', verifyTxGas: PQC.falcon1024.verifyAndRecordTxGas, marginal: PQC.falcon1024.marginalGas },
  mldsa44:    { label: 'ML-DSA-44 (native precompile)',   verifyTxGas: PQC.mldsa44.verifyAndRecordTxGas, marginal: PQC.mldsa44.marginalGas },
  slhdsa128s: { label: 'SLH-DSA-128s (native precompile)', verifyTxGas: PQC.slhdsa128s.verifyAndRecordTxGas, marginal: PQC.slhdsa128s.marginalGas },
  hybrid:     { label: 'Hybrid ECDSA + Falcon-512 (native)', verifyTxGas: PQC.falcon512.verifyAndRecordTxGas + CLASSICAL.ecrecover.marginalGas, marginal: HYBRID_MARGINAL_GAS },
  // The path an ACTUALLY-DEPLOYED AerePQCAccount takes today (Solidity verifier).
  falcon512_solidity: { label: 'Falcon-512 (deployed AerePQCAccount, Solidity verifier)', verifyTxGas: AERE_PQC_ACCOUNT_MEASURED_USEROP_GAS, marginal: FALCON512_SOLIDITY_VERIFIER_GAS },
};

export function schemeList() {
  return Object.keys(SCHEME_MODEL);
}

function gasToAere(gas, gweiPrice = GAS_PRICE_GWEI) {
  // gas * price(Gwei) * 1e-9 AERE/Gwei-gas
  return gas * gweiPrice * 1e-9;
}

/**
 * Estimate migration cost for a set of accounts.
 * @param {Array<{address?:string, scheme?:string, deployAccount?:boolean, authsPerAccount?:number}>} accounts
 * @param {object} opts
 * @param {string} opts.defaultScheme default scheme when an account omits one
 * @param {number} opts.defaultAuths default authorizations/account to project
 * @param {number} opts.gweiPrice gas price in Gwei (default 1, the live floor)
 */
export function simulateMigration(accounts, opts = {}) {
  const defaultScheme = opts.defaultScheme || 'falcon512';
  const defaultAuths = opts.defaultAuths ?? 1;
  const gweiPrice = opts.gweiPrice ?? GAS_PRICE_GWEI;

  const rows = [];
  let totalDeployGas = 0;
  let totalAuthGas = 0;

  for (const acc of accounts) {
    const scheme = acc.scheme || defaultScheme;
    const model = SCHEME_MODEL[scheme];
    if (!model) throw new Error(`unknown scheme "${scheme}". Known: ${schemeList().join(', ')}`);
    const deployAccount = acc.deployAccount !== false; // default: deploy a smart account
    const auths = acc.authsPerAccount ?? defaultAuths;

    const deployGas = deployAccount ? ACCOUNT_DEPLOY_GAS : 0;
    const authGas = model.verifyTxGas * auths;
    totalDeployGas += deployGas;
    totalAuthGas += authGas;

    rows.push({
      address: acc.address || '(counterfactual)',
      scheme,
      schemeLabel: model.label,
      deployGas,
      authsProjected: auths,
      perAuthGas: model.verifyTxGas,
      authGas,
      totalGas: deployGas + authGas,
    });
  }

  const totalGas = totalDeployGas + totalAuthGas;
  return {
    accounts: rows,
    totals: {
      count: accounts.length,
      totalDeployGas,
      totalAuthGas,
      totalGas,
      gweiPrice,
      estimatedAere: gasToAere(totalGas, gweiPrice),
    },
    assumptions: [
      `Account deploy gas = ${ACCOUNT_DEPLOY_GAS.toLocaleString()} (CREATE2 AerePQCAccount, [CITED: pqc-account.json]).`,
      `Per-auth gas is the native-precompile verify-and-record receipt [CITED: AERE-BENCHMARK-REPORT.md Part C.1]; the scheme "falcon512_solidity" instead models the CURRENTLY-DEPLOYED AerePQCAccount path (~10.5M gas, [CITED: pqc-account.json]).`,
      `Gas price = ${gweiPrice} Gwei (the live 1 Gwei base-fee floor on chain 2800).`,
      `SCOPE: these costs are for ACCOUNT/APPLICATION authentication. They do not make Aere consensus post-quantum.`,
    ],
  };
}

/** Render a simulation result as a plain-text table for the CLI. */
export function formatSimulation(sim) {
  const lines = [];
  const pad = (s, n) => String(s).padEnd(n);
  const padL = (s, n) => String(s).padStart(n);
  lines.push(pad('ADDRESS', 26) + pad('SCHEME', 20) + padL('DEPLOY', 12) + padL('AUTHS', 7) + padL('PER-AUTH', 12) + padL('TOTAL', 14));
  lines.push('-'.repeat(91));
  for (const r of sim.accounts) {
    const a = r.address.length > 24 ? r.address.slice(0, 10) + '..' + r.address.slice(-8) : r.address;
    lines.push(
      pad(a, 26) + pad(r.scheme, 20) + padL(r.deployGas.toLocaleString(), 12) +
      padL(r.authsProjected, 7) + padL(r.perAuthGas.toLocaleString(), 12) + padL(r.totalGas.toLocaleString(), 14),
    );
  }
  lines.push('-'.repeat(91));
  const t = sim.totals;
  lines.push(pad(`TOTAL (${t.count} accounts)`, 46) + padL(t.totalDeployGas.toLocaleString(), 12) + padL('', 7) + padL(t.totalAuthGas.toLocaleString(), 12) + padL(t.totalGas.toLocaleString(), 14));
  lines.push('');
  lines.push(`Estimated cost at ${t.gweiPrice} Gwei: ${t.estimatedAere.toFixed(6)} AERE total.`);
  lines.push('');
  lines.push('Assumptions:');
  for (const a of sim.assumptions) lines.push('  - ' + a);
  return lines.join('\n');
}