Lightning Payments

const quote = await client.getPayLightningWithTokenQuote(
  "lnbc50u1p55pfnq...", // BOLT11 invoice
  "btkn1xgrvjwey..."    // Your token address (bech32m or hex)
);

console.log('Invoice amount:', quote.invoiceAmountSats, 'sats');
console.log('Lightning fee:', quote.estimatedLightningFee, 'sats');
console.log('Total BTC needed:', quote.btcAmountRequired, 'sats');
console.log('Token required:', quote.tokenAmountRequired);
console.log('AMM fee:', quote.estimatedAmmFee);
console.log('Price impact:', quote.priceImpactPct, '%');

const result = await client.payLightningWithToken({
  invoice: "lnbc50u1p55pfnq...",
  tokenAddress: "btkn1xgrvjwey...",
  // All options below are optional with sensible defaults
});

if (result.success) {
  console.log('Payment successful!');
  console.log('Lightning payment ID:', result.lightningPaymentId);
  console.log('Token spent:', result.tokenAmountSpent);
  console.log('BTC received from swap:', result.btcAmountReceived, 'sats');
  console.log('AMM fee paid:', result.ammFeePaid);
} else {
  console.log('Payment failed:', result.error);
}

import { SparkWallet } from "@buildonspark/spark-sdk";
import { FlashnetClient } from "@flashnet/sdk";

async function payInvoiceWithUSDB() {
  // Initialize wallet
  const { wallet } = await SparkWallet.initialize({
    mnemonicOrSeed: "your-mnemonic",
    options: { network: "MAINNET" },
  });

  // Initialize Flashnet client
  const client = new FlashnetClient(wallet);
  await client.initialize();

  // Get wallet balance and find USDB token
  const balance = await client.getBalance();
  let usdbAddress: string | null = null;
  let usdbBalance = 0n;

  for (const [tokenPubkey, tokenData] of balance.tokenBalances.entries()) {
    const symbol = tokenData.tokenInfo?.tokenSymbol || "";
    if (symbol.toUpperCase().includes("USDB")) {
      usdbAddress = tokenData.tokenInfo?.tokenAddress || tokenPubkey;
      usdbBalance = tokenData.balance;
      console.log(`Found USDB: ${usdbBalance} (${tokenData.tokenInfo?.tokenDecimals} decimals)`);
    }
  }

  if (!usdbAddress) {
    throw new Error("No USDB token found in wallet");
  }

  // Lightning invoice to pay
  const invoice = "lnbc50u1p55pfnqpp5...";

  // Step 1: Get quote
  const quote = await client.getPayLightningWithTokenQuote(invoice, usdbAddress);
  
  console.log(`Paying ${quote.invoiceAmountSats} sats invoice`);
  console.log(`Requires ${quote.tokenAmountRequired} USDB (smallest units)`);
  console.log(`Price impact: ${quote.priceImpactPct}%`);

  // Check sufficient balance
  if (usdbBalance < BigInt(quote.tokenAmountRequired)) {
    throw new Error(`Insufficient USDB: need ${quote.tokenAmountRequired}, have ${usdbBalance}`);
  }

  // Step 2: Execute payment (with optional rollback on failure)
  const result = await client.payLightningWithToken({
    invoice,
    tokenAddress: usdbAddress,
    rollbackOnFailure: true, // Recover tokens if Lightning payment fails
  });

  if (result.success) {
    console.log('✅ Payment successful!');
    console.log('Lightning payment ID:', result.lightningPaymentId);
    console.log('Token spent:', result.tokenAmountSpent);
    console.log('BTC received:', result.btcAmountReceived, 'sats');
  } else {
    console.log('❌ Payment failed:', result.error);
  }

  await wallet.cleanupConnections();
}

Invoice amount:     5,000 sats
Lightning fee:     +   14 sats  
BTC adjustment:    +   42 sats (rounds to next multiple of 64)
─────────────────────────────
Total BTC needed:   5,056 sats

Token input calculated via AMM:
  amount_in_effective = (reserve_token × 5056) / (reserve_btc - 5056)
  amount_in = amount_in_effective × (1 + 0.002)  // 20 bps fee

const result = await client.payLightningWithToken({
  invoice,
  tokenAddress,
  useExistingBtcBalance: true, // Pay instantly if BTC available
});

const result = await client.payLightningWithToken({
  invoice,
  tokenAddress,
  rollbackOnFailure: true, // Swap BTC back to token if Lightning fails
});

if (!result.success) {
  // Check if funds were rolled back
  if (result.error?.includes('Funds rolled back')) {
    console.log('Payment failed but tokens were recovered');
  } else if (result.error?.includes('BTC remains in wallet')) {
    console.log('Payment failed, BTC needs manual handling');
  }
}

try {
  const result = await client.payLightningWithToken({
    invoice,
    tokenAddress,
  });
  
  if (!result.success) {
    console.error('Payment failed:', result.error);
  }
} catch (error) {
  if (error.message.includes('Invoice amount too small')) {
    console.error('Invoice below minimum (1000 sats)');
  } else if (error.message.includes('Insufficient liquidity')) {
    console.error('Pool lacks liquidity for this swap');
  } else if (error.message.includes('Insufficient token balance')) {
    console.error('Not enough tokens in wallet');
  } else {
    console.error('Unexpected error:', error);
  }
}