Flash Loan Arbitrage

import { encodeFunctionData, encodeAbiParameters } from 'viem'
import { sendRawTransactionSync } from 'shreds/viem'
 
// Flash loan ABI (simplified)
const flashLoanAbi = [
  {
    inputs: [
      { name: 'receiverAddress', type: 'address' },
      { name: 'assets', type: 'address[]' },
      { name: 'amounts', type: 'uint256[]' },
      { name: 'modes', type: 'uint256[]' },
      { name: 'onBehalfOf', type: 'address' },
      { name: 'params', type: 'bytes' },
      { name: 'referralCode', type: 'uint16' }
    ],
    name: 'flashLoan',
    outputs: [],
    type: 'function'
  }
] as const
 
async function executeArbitrage(
  token: `0x${string}`,
  amount: bigint,
  targetDex1: `0x${string}`,
  targetDex2: `0x${string}`
) {
  const flashLoanProvider = '0x...' // Aave lending pool
  const arbitrageContract = '0x...' // Your deployed contract
  
  console.log('[FLASH] Starting flash loan arbitrage...')
  
  try {
    // Encode arbitrage parameters
    const params = encodeAbiParameters(
      [{ type: 'address' }, { type: 'address' }],
      [targetDex1, targetDex2]
    )
    
    // Prepare and sign flash loan transaction
    const request = await walletClient.prepareTransactionRequest({
      to: flashLoanProvider,
      data: encodeFunctionData({
        abi: flashLoanAbi,
        functionName: 'flashLoan',
        args: [
          arbitrageContract,
          [token],
          [amount],
          [0n], // modes
          arbitrageContract,
          params,
          0 // referral code
        ]
      }),
      gas: 500000n // Higher gas for complex operation
    })
    
    const serializedTransaction = await walletClient.signTransaction(request)
    
    // Execute flash loan (triggers arbitrage)
    const receipt = await sendRawTransactionSync(publicClient, {
      serializedTransaction
    })
    
    console.log('[SUCCESS] Arbitrage executed in milliseconds!')
    console.log('Gas used:', receipt.gasUsed)
    
    // Parse logs to calculate profit...
    
    return receipt.transactionHash
  } catch (error) {
    console.error('[ERROR] Arbitrage failed:', error)
    throw error
  }
}

contract FlashArbitrage {
    function executeOperation(
        address[] calldata assets,
        uint256[] calldata amounts,
        uint256[] calldata premiums,
        address initiator,
        bytes calldata params
    ) external returns (bool) {
        // Decode DEX addresses
        (address dex1, address dex2) = abi.decode(params, (address, address));
        
        // Execute arbitrage
        uint256 amountIn = amounts[0];
        
        // Trade on DEX 1 (buy)
        uint256 amountOut = buyOnDex(dex1, assets[0], amountIn);
        
        // Trade on DEX 2 (sell)
        uint256 finalAmount = sellOnDex(dex2, assets[0], amountOut);
        
        // Calculate profit
        uint256 totalDebt = amountIn + premiums[0];
        require(finalAmount > totalDebt, "No profit");
        
        // Approve and repay flash loan
        IERC20(assets[0]).approve(msg.sender, totalDebt);
        
        return true;
    }
}