verdant-system

byEast Los

Act as a Principal MEV (Maximal Extractable Value) R&D Engineer and a Senior Solidity Security Auditor specializing in low-latency EVM arbitrage systems on high-throughput networks. I want to build a highly competitive, production-grade cross-DEX flash loan arbitrage bot for Polygon Mainnet. The architecture must be heavily inspired by the core structural philosophy of the 'pmuens/midas' framework but radically modernized to compete in today's cutthroat MEV environment. Generate the code base according to the exact architectural specifications, structural parameters, and execution protocols outlined below. --- ### 1. SYSTEM PARAMETERS & ENVIRONMENTAL BOUNDS - Network: Polygon Mainnet (Gas asset: POL / Base trading asset: Native USDC) - Flash Loan Source: Balancer V2 Vault (Address: 0xBA12222222228d8Ba445958a75a0704d566BF2C8) for 0% fee asset borrowing. - Target DEX Liquidity Pools: QuickSwap V2 (Uniswap V2 Clone) and SushiSwap V2. - Development Framework: Foundry (Solidity ^0.8.20) for the smart contracts; TypeScript (ethers.js v6) for the off-chain orchestration engine. --- ### 2. CORE COMPONENTS REQUIRED #### COMPONENT A: The Smart Contract ('MidasPolygonEngine.sol') Write a highly gas-optimized, production-ready Solidity contract that implements the Balancer V2 Flash Loan receiver interface ('IFlashLoanRecipient'). - Gas Optimization Rules: Optimize for bytecode compactness and minimal runtime overhead. Use custom errors instead of string require statements. Use 'unchecked {}' blocks for arithmetic loops and balance changes where overflow is mathematically impossible. Avoid high-level abstractions like routers. - Direct Pool Routing: The contract must execute swaps by calling the liquidity pool pair contracts directly via '.swap()' instead of using high-level router contracts (like QuickSwapRouter). - Strict Execution Safety: Implement a bulletproof safeguard. At the end of the callback function—immediately before the Balancer Vault pulls back the loan principal—the contract must verify that the ending balance of the profit token (USDC) is greater than the starting balance plus an off-chain parameterized 'minProfitThreshold'. If this condition fails, the contract must explicitly revert the entire transaction transaction string to prevent capital loss. - Access Control: Secure the trigger mechanism so that only the owner's monitoring bot address can call the execution entry point, completely preventing external actors from frontrunning or hijacking the execution. #### COMPONENT B: The Node Engine ('monitor.ts') Write a highly optimized TypeScript orchestration script that acts as the real-time data ingestion and calculations hub. - Event-Driven Architecture: Do not use interval JSON-RPC block polling. Use a high-fidelity WebSocket provider ('wss://') to subscribe directly to the 'Sync(uint112,uint112)' or 'Swap' event logs emitted directly by the target QuickSwap and SushiSwap pair contracts. - Math Engine (Optimal Input Calculation): Implement the standard AMM optimal input amount formula for two constant-product (x * y = k) Uniswap V2 pairs to calculate the mathematically perfect input amount (A_in) that maximizes arbitrage yield given the exact reserves extracted from the latest 'Sync' logs. The equation must natively factor in the standard 0.3% fee modifier (gamma = 0.997). - MEV Guardrail & Private Relaying: Structure the transaction submission logic to bypass the public Polygon mempool entirely to prevent frontrunning and sandwich attacks. Integrate the transaction dispatch code with the FastLane Protocol API or Flashbots Polygon Builder endpoint, sending the execution payload as a private bundle. --- ### 3. OUTPUT SPECIFICATION Please provide the complete, functional code for both 'MidasPolygonEngine.sol' and 'monitor.ts'. Include explicit inline comments detailing the low-level data handoff between the off-chain TypeScript script and the contract's flash loan callback payload. Do not use placeholders or omit complex logic loops.