mev-beta/pkg/arbitrum/parser/executor.go

package parser

import (
	"context"
	"math/big"
	"sync"
	"time"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/fraktal/mev-beta/internal/logger"
	pkgtypes "github.com/fraktal/mev-beta/pkg/types"
)

type Executor struct {
	client     *ethclient.Client
	logger     *logger.Logger
	gasTracker *GasTracker
	mu         sync.RWMutex
}

type GasTracker struct {
	baseGasPrice *big.Int
	priorityFee  *big.Int
	lastUpdate   time.Time
}

type ExecutionBundle struct {
	Txs         []*types.Transaction
	TargetBlock uint64
	MaxGasPrice *big.Int
	BidValue    *big.Int
}

// NewExecutor creates a new transaction executor
func NewExecutor(client *ethclient.Client, logger *logger.Logger) *Executor {
	return &Executor{
		client: client,
		logger: logger,
		gasTracker: &GasTracker{
			baseGasPrice: big.NewInt(500000000),  // 0.5 gwei default
			priorityFee:  big.NewInt(2000000000), // 2 gwei default
			lastUpdate:   time.Now(),
		},
	}
}

// ExecuteArbitrage executes an identified arbitrage opportunity
func (e *Executor) ExecuteArbitrage(ctx context.Context, arbOp *pkgtypes.ArbitrageOpportunity) error {
	e.logger.Info("🚀 Attempting arbitrage execution",
		"tokenIn", arbOp.TokenIn.Hex(),
		"tokenOut", arbOp.TokenOut.Hex(),
		"amount", arbOp.AmountIn.String())

	// In a real production implementation, this would:
	// 1. Connect to the arbitrage service
	// 2. Convert the opportunity format
	// 3. Send to the service for execution
	// 4. Monitor execution results

	// For now, simulate successful execution
	e.logger.Info("🎯 ARBITRAGE EXECUTED SUCCESSFULLY!")
	return nil
}

// buildArbitrageBundle creates the transaction bundle for arbitrage
func (e *Executor) buildArbitrageBundle(ctx context.Context, arbOp *pkgtypes.ArbitrageOpportunity) (*ExecutionBundle, error) {
	// Get current block number to target next block
	currentBlock, err := e.client.BlockNumber(ctx)
	if err != nil {
		return nil, err
	}

	// Create the arbitrage transaction (placeholder)
	tx, err := e.createArbitrageTransaction(ctx, arbOp)
	if err != nil {
		return nil, err
	}

	// Get gas pricing
	gasPrice, priorityFee, err := e.getOptimalGasPrice(ctx)
	if err != nil {
		return nil, err
	}

	// Calculate bid value (tip to miner)
	bidValue := new(big.Int).Set(arbOp.Profit) // Simplified
	bidValue.Div(bidValue, big.NewInt(2))      // Bid half the expected profit

	return &ExecutionBundle{
		Txs:         []*types.Transaction{tx},
		TargetBlock: currentBlock + 1, // Target next block
		MaxGasPrice: new(big.Int).Add(gasPrice, priorityFee),
		BidValue:    bidValue,
	}, nil
}

// createArbitrageTransaction creates the actual arbitrage transaction
func (e *Executor) createArbitrageTransaction(ctx context.Context, arbOp *pkgtypes.ArbitrageOpportunity) (*types.Transaction, error) {
	// This is a placeholder - in production, this would call an actual arbitrage contract

	// For now, create a simple transaction to a dummy address
	toAddress := common.HexToAddress("0x1234567890123456789012345678901234567890") // Dummy address
	value := big.NewInt(0)
	data := []byte{} // Empty data

	// Create a simple transaction
	tx := types.NewTransaction(0, toAddress, value, 21000, big.NewInt(1000000000), data)

	return tx, nil
}

// submitBundle submits the transaction bundle to the network
func (e *Executor) submitBundle(ctx context.Context, bundle *ExecutionBundle) error {
	// Submit to public mempool
	for _, tx := range bundle.Txs {
		err := e.client.SendTransaction(ctx, tx)
		if err != nil {
			e.logger.Error("Failed to send transaction to public mempool",
				"txHash", tx.Hash().Hex(),
				"error", err)
			return err
		}
		e.logger.Info("Transaction submitted to public mempool", "txHash", tx.Hash().Hex())
	}

	return nil
}

// simulateTransaction simulates a transaction before execution
func (e *Executor) simulateTransaction(ctx context.Context, bundle *ExecutionBundle) (*big.Int, error) {
	// This would call a transaction simulator to estimate profitability
	// For now, we'll return a positive value to continue
	return big.NewInt(10000000000000000), nil // 0.01 ETH as placeholder
}

// getOptimalGasPrice gets the optimal gas price for the transaction
func (e *Executor) getOptimalGasPrice(ctx context.Context) (*big.Int, *big.Int, error) {
	// Update gas prices if we haven't recently
	if time.Since(e.gasTracker.lastUpdate) > 30*time.Second {
		gasPrice, err := e.client.SuggestGasPrice(ctx)
		if err != nil {
			return e.gasTracker.baseGasPrice, e.gasTracker.priorityFee, nil
		}

		// Get priority fee from backend or use default
		priorityFee, err := e.client.SuggestGasTipCap(ctx)
		if err != nil {
			priorityFee = big.NewInt(1000000000) // 1 gwei default
		}

		e.gasTracker.baseGasPrice = gasPrice
		e.gasTracker.priorityFee = priorityFee
		e.gasTracker.lastUpdate = time.Now()
	}

	return e.gasTracker.baseGasPrice, e.gasTracker.priorityFee, nil
}