mev-beta/pkg/uniswap/multicall.go

package uniswap

import (
	"context"
	"fmt"
	"strings"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/ethclient"
)

// Multicall3 address on Arbitrum
var Multicall3Address = common.HexToAddress("0xcA11bde05977b3631167028862bE2a173976CA11")

// Multicall3 ABI (simplified - only aggregate3 function)
const Multicall3ABI = `[{
	"inputs": [{
		"components": [{
			"internalType": "address",
			"name": "target",
			"type": "address"
		}, {
			"internalType": "bool",
			"name": "allowFailure",
			"type": "bool"
		}, {
			"internalType": "bytes",
			"name": "callData",
			"type": "bytes"
		}],
		"internalType": "struct Multicall3.Call3[]",
		"name": "calls",
		"type": "tuple[]"
	}],
	"name": "aggregate3",
	"outputs": [{
		"components": [{
			"internalType": "bool",
			"name": "success",
			"type": "bool"
		}, {
			"internalType": "bytes",
			"name": "returnData",
			"type": "bytes"
		}],
		"internalType": "struct Multicall3.Result[]",
		"name": "returnData",
		"type": "tuple[]"
	}],
	"stateMutability": "payable",
	"type": "function"
}]`

// Call3 represents a single call in Multicall3
type Call3 struct {
	Target       common.Address
	AllowFailure bool
	CallData     []byte
}

// Result3 represents the result of a Multicall3 call
type Result3 struct {
	Success    bool
	ReturnData []byte
}

// MulticallBatcher batches multiple RPC calls into a single Multicall3 transaction
type MulticallBatcher struct {
	client      *ethclient.Client
	multicallABI abi.ABI
}

// NewMulticallBatcher creates a new multicall batcher
func NewMulticallBatcher(client *ethclient.Client) (*MulticallBatcher, error) {
	parsedABI, err := abi.JSON(strings.NewReader(Multicall3ABI))
	if err != nil {
		return nil, fmt.Errorf("failed to parse Multicall3 ABI: %w", err)
	}

	return &MulticallBatcher{
		client:      client,
		multicallABI: parsedABI,
	}, nil
}

// ExecuteMulticall executes multiple calls in a single transaction
func (m *MulticallBatcher) ExecuteMulticall(ctx context.Context, calls []Call3) ([]Result3, error) {
	if len(calls) == 0 {
		return []Result3{}, nil
	}

	// Pack the aggregate3 call
	data, err := m.multicallABI.Pack("aggregate3", calls)
	if err != nil {
		return nil, fmt.Errorf("failed to pack multicall data: %w", err)
	}

	// Create the call message
	msg := ethereum.CallMsg{
		To:   &Multicall3Address,
		Data: data,
	}

	// Execute the call
	result, err := m.client.CallContract(ctx, msg, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to execute multicall: %w", err)
	}

	// Unpack the results
	var results []Result3
	err = m.multicallABI.UnpackIntoInterface(&results, "aggregate3", result)
	if err != nil {
		return nil, fmt.Errorf("failed to unpack multicall results: %w", err)
	}

	return results, nil
}

// BatchPoolDataCalls batches slot0, liquidity, token0, token1, and fee calls for a pool
func (m *MulticallBatcher) BatchPoolDataCalls(ctx context.Context, poolAddress common.Address, poolABI abi.ABI) (
	slot0Data []byte,
	liquidityData []byte,
	token0Data []byte,
	token1Data []byte,
	feeData []byte,
	err error,
) {
	// Prepare call data for each function
	slot0CallData, err := poolABI.Pack("slot0")
	if err != nil {
		return nil, nil, nil, nil, nil, fmt.Errorf("failed to pack slot0: %w", err)
	}

	liquidityCallData, err := poolABI.Pack("liquidity")
	if err != nil {
		return nil, nil, nil, nil, nil, fmt.Errorf("failed to pack liquidity: %w", err)
	}

	token0CallData, err := poolABI.Pack("token0")
	if err != nil {
		return nil, nil, nil, nil, nil, fmt.Errorf("failed to pack token0: %w", err)
	}

	token1CallData, err := poolABI.Pack("token1")
	if err != nil {
		return nil, nil, nil, nil, nil, fmt.Errorf("failed to pack token1: %w", err)
	}

	feeCallData, err := poolABI.Pack("fee")
	if err != nil {
		return nil, nil, nil, nil, nil, fmt.Errorf("failed to pack fee: %w", err)
	}

	// Create multicall calls
	calls := []Call3{
		{Target: poolAddress, AllowFailure: true, CallData: slot0CallData},
		{Target: poolAddress, AllowFailure: true, CallData: liquidityCallData},
		{Target: poolAddress, AllowFailure: true, CallData: token0CallData},
		{Target: poolAddress, AllowFailure: true, CallData: token1CallData},
		{Target: poolAddress, AllowFailure: true, CallData: feeCallData},
	}

	// Execute multicall
	results, err := m.ExecuteMulticall(ctx, calls)
	if err != nil {
		return nil, nil, nil, nil, nil, err
	}

	// Extract results
	if len(results) != 5 {
		return nil, nil, nil, nil, nil, fmt.Errorf("expected 5 results, got %d", len(results))
	}

	// Return raw data (caller will unpack based on success flags)
	return results[0].ReturnData,
		results[1].ReturnData,
		results[2].ReturnData,
		results[3].ReturnData,
		results[4].ReturnData,
		nil
}

// BatchMultiplePoolData batches pool data calls for multiple pools
func (m *MulticallBatcher) BatchMultiplePoolData(ctx context.Context, pools []common.Address, poolABI abi.ABI) (
	results map[common.Address]map[string][]byte,
	err error,
) {
	results = make(map[common.Address]map[string][]byte)

	if len(pools) == 0 {
		return results, nil
	}

	// Prepare all calls
	var allCalls []Call3
	callMap := make(map[int]struct {
		poolAddr common.Address
		funcName string
	})

	functions := []string{"slot0", "liquidity", "token0", "token1", "fee"}

	callIndex := 0
	for _, poolAddr := range pools {
		for _, funcName := range functions {
			callData, err := poolABI.Pack(funcName)
			if err != nil {
				// Skip this call if packing fails
				continue
			}

			allCalls = append(allCalls, Call3{
				Target:       poolAddr,
				AllowFailure: true,
				CallData:     callData,
			})

			callMap[callIndex] = struct {
				poolAddr common.Address
				funcName string
			}{poolAddr, funcName}
			callIndex++
		}
	}

	// Execute multicall
	multicallResults, err := m.ExecuteMulticall(ctx, allCalls)
	if err != nil {
		return nil, fmt.Errorf("failed to execute multicall: %w", err)
	}

	// Parse results
	for i, result := range multicallResults {
		if info, ok := callMap[i]; ok {
			if _, exists := results[info.poolAddr]; !exists {
				results[info.poolAddr] = make(map[string][]byte)
			}
			if result.Success {
				results[info.poolAddr][info.funcName] = result.ReturnData
			}
		}
	}

	return results, nil
}