import { createWalletClient, createPublicClient, http, parseAbi, formatUnits } from 'viem';
import { base } from 'viem/chains';
import { privateKeyToAccount } from 'viem/accounts';

const USDC = '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913' as const;
const ERC20_ABI = parseAbi([
  'function transfer(address to, uint256 amount) returns (bool)',
  'function balanceOf(address account) view returns (uint256)',
]);

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const publicClient = createPublicClient({ chain: base, transport: http() });
const walletClient = createWalletClient({ account, chain: base, transport: http() });

async function sendUSDC(to: `0x${string}`, amountUsdc: number): Promise<`0x${string}`> {
  const raw = BigInt(Math.round(amountUsdc * 1e6));

  // Check balance
  const balance = await publicClient.readContract({
    address: USDC, abi: ERC20_ABI, functionName: 'balanceOf', args: [account.address],
  });
  if (balance < raw) {
    throw new Error(`Insufficient USDC. Have: ${formatUnits(balance, 6)}, Need: ${amountUsdc}`);
  }

  // Transfer
  const txHash = await walletClient.writeContract({
    address: USDC, abi: ERC20_ABI, functionName: 'transfer', args: [to, raw],
  });

  await publicClient.waitForTransactionReceipt({ hash: txHash });
  return txHash;
}

// Usage
const tx = await sendUSDC('0xRecipientAddress...' as `0x${string}`, 50); // 50 USDC
console.log(`https://basescan.org/tx/${tx}`);