const { ethers } = require("ethers");

const RPC_URL = (process.env.BASE_SEPOLIA_RPC_URL || "").trim();
const MEMBERSHIP_GAS = Number.parseInt((process.env.SMOKE_MEMBERSHIP_GAS || "160000").trim(), 10);
const CHECKOUT_GAS = Number.parseInt((process.env.SMOKE_CHECKOUT_GAS || "220000").trim(), 10);
const SAFETY_BPS = Number.parseInt((process.env.SMOKE_SAFETY_BPS || "15000").trim(), 10); // 1.5x
const MIN_GAS_PRICE_WEI = (process.env.SMOKE_MIN_GAS_PRICE_WEI || "1000000000").trim(); // 1 gwei floor

function required(name, value) {
  if (!value) {
    throw new Error(`Missing required env: ${name}`);
  }
  return value;
}

function validatePositiveInt(name, value) {
  if (!Number.isFinite(value) || value <= 0) {
    throw new Error(`${name} must be a positive integer`);
  }
  return value;
}

function maxBigInt(values) {
  let out = values[0];
  for (let i = 1; i < values.length; i += 1) {
    if (values[i].gt(out)) {
      out = values[i];
    }
  }
  return out;
}

function applySafety(valueWei) {
  return valueWei.mul(SAFETY_BPS).add(9999).div(10000);
}

async function main() {
  required("BASE_SEPOLIA_RPC_URL", RPC_URL);
  validatePositiveInt("SMOKE_MEMBERSHIP_GAS", MEMBERSHIP_GAS);
  validatePositiveInt("SMOKE_CHECKOUT_GAS", CHECKOUT_GAS);
  validatePositiveInt("SMOKE_SAFETY_BPS", SAFETY_BPS);
  const minGasPrice = ethers.BigNumber.from(required("SMOKE_MIN_GAS_PRICE_WEI", MIN_GAS_PRICE_WEI));
  if (minGasPrice.lte(0)) {
    throw new Error("SMOKE_MIN_GAS_PRICE_WEI must be > 0");
  }

  const provider = new ethers.providers.JsonRpcProvider(RPC_URL);
  const feeData = await provider.getFeeData();
  const feeCandidates = [feeData.gasPrice, feeData.maxFeePerGas, minGasPrice].filter(Boolean);
  if (feeCandidates.length === 0) {
    throw new Error("Unable to resolve gas price from provider");
  }
  const gasPrice = maxBigInt(feeCandidates);

  const membershipWei = gasPrice.mul(MEMBERSHIP_GAS);
  const checkoutWei = gasPrice.mul(CHECKOUT_GAS);
  const freshWalletBaseWei = membershipWei.add(checkoutWei);
  const activeWalletBaseWei = checkoutWei;
  const freshWalletRecommendedWei = applySafety(freshWalletBaseWei);
  const activeWalletRecommendedWei = applySafety(activeWalletBaseWei);

  const report = {
    chain: "base-sepolia",
    gas_price_sources: {
      provider_gas_price_wei: feeData.gasPrice ? feeData.gasPrice.toString() : null,
      provider_max_fee_per_gas_wei: feeData.maxFeePerGas ? feeData.maxFeePerGas.toString() : null,
      floor_gas_price_wei: minGasPrice.toString(),
    },
    gas_price_wei: gasPrice.toString(),
    gas_price_gwei: ethers.utils.formatUnits(gasPrice, "gwei"),
    gas_budgets: {
      membership: MEMBERSHIP_GAS,
      checkout: CHECKOUT_GAS,
    },
    safety_multiplier: `${(SAFETY_BPS / 10000).toFixed(2)}x`,
    thresholds: {
      fresh_wallet_membership_plus_checkout: {
        base_wei: freshWalletBaseWei.toString(),
        base_eth: ethers.utils.formatEther(freshWalletBaseWei),
        recommended_wei: freshWalletRecommendedWei.toString(),
        recommended_eth: ethers.utils.formatEther(freshWalletRecommendedWei),
      },
      active_wallet_checkout_only: {
        base_wei: activeWalletBaseWei.toString(),
        base_eth: ethers.utils.formatEther(activeWalletBaseWei),
        recommended_wei: activeWalletRecommendedWei.toString(),
        recommended_eth: ethers.utils.formatEther(activeWalletRecommendedWei),
      },
    },
  };

  console.log(JSON.stringify(report, null, 2));
}

main().catch((err) => {
  console.error(err.message || err);
  process.exit(1);
});