feat(op-challenger): Delayed Weth Withdrawal Request Caller (#9938)

* feat(op-challenger): Delayed Weth Withdrawal Request Caller

* fix(op-challenger): withdrawal request field ordering

* fix(op-challenger): encapsulate delayed weth behind the fault dispute game contract binding

op-challenger/game/fault/contracts/delayed_weth.go

+package contracts
+
+import (
+	"context"
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
+	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/contracts/metrics"
+	"github.com/ethereum-optimism/optimism/op-service/sources/batching"
+	"github.com/ethereum-optimism/optimism/op-service/sources/batching/rpcblock"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+var (
+	methodWithdrawals = "withdrawals"
+)
+
+type DelayedWETHContract struct {
+	metrics     metrics.ContractMetricer
+	multiCaller *batching.MultiCaller
+	contract    *batching.BoundContract
+}
+
+type WithdrawalRequest struct {
+	Amount    *big.Int
+	Timestamp *big.Int
+}
+
+func NewDelayedWETHContract(metrics metrics.ContractMetricer, addr common.Address, caller *batching.MultiCaller) (*DelayedWETHContract, error) {
+	contractAbi, err := bindings.DelayedWETHMetaData.GetAbi()
+	if err != nil {
+		return nil, fmt.Errorf("failed to load delayed weth ABI: %w", err)
+	}
+	return &DelayedWETHContract{
+		metrics:     metrics,
+		multiCaller: caller,
+		contract:    batching.NewBoundContract(contractAbi, addr),
+	}, nil
+}
+
+// GetWithdrawals returns all withdrawals made from the contract since the given block.
+func (d *DelayedWETHContract) GetWithdrawals(ctx context.Context, block rpcblock.Block, gameAddr common.Address, recipients ...common.Address) ([]*WithdrawalRequest, error) {
+	defer d.metrics.StartContractRequest("GetWithdrawals")()
+	calls := make([]batching.Call, 0, len(recipients))
+	for _, recipient := range recipients {
+		calls = append(calls, d.contract.Call(methodWithdrawals, gameAddr, recipient))
+	}
+	results, err := d.multiCaller.Call(ctx, block, calls...)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch withdrawals: %w", err)
+	}
+	withdrawals := make([]*WithdrawalRequest, len(recipients))
+	for i, result := range results {
+		withdrawals[i] = &WithdrawalRequest{
+			Amount:    result.GetBigInt(0),
+			Timestamp: result.GetBigInt(1),
+		}
+	}
+	return withdrawals, nil
+}

op-challenger/game/fault/contracts/delayed_weth_test.go

+package contracts
+
+import (
+	"context"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
+	contractMetrics "github.com/ethereum-optimism/optimism/op-challenger/game/fault/contracts/metrics"
+	"github.com/ethereum-optimism/optimism/op-service/sources/batching"
+	"github.com/ethereum-optimism/optimism/op-service/sources/batching/rpcblock"
+	batchingTest "github.com/ethereum-optimism/optimism/op-service/sources/batching/test"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	delayedWeth = common.HexToAddress("0x24112842371dFC380576ebb09Ae16Cb6B6caD7CB")
+)
+
+func TestDelayedWeth_GetWithdrawals(t *testing.T) {
+	stubRpc, weth := setupDelayedWethTest(t)
+	block := rpcblock.ByNumber(482)
+
+	addrs := []common.Address{{0x01}, {0x02}}
+	expected := [][]*big.Int{
+		[]*big.Int{big.NewInt(123), big.NewInt(456)},
+		[]*big.Int{big.NewInt(123), big.NewInt(456)},
+	}
+
+	for i, addr := range addrs {
+		stubRpc.SetResponse(delayedWeth, methodWithdrawals, block, []interface{}{fdgAddr, addr}, []interface{}{expected[i][0], expected[i][1]})
+	}
+
+	actual, err := weth.GetWithdrawals(context.Background(), block, fdgAddr, addrs...)
+	require.NoError(t, err)
+	require.Equal(t, len(expected), len(actual))
+	for i := range expected {
+		require.Zerof(t, expected[i][0].Cmp(actual[i].Amount), "expected: %v actual: %v", expected[i][1], actual[i].Amount)
+		require.Zerof(t, expected[i][1].Cmp(actual[i].Timestamp), "expected: %v actual: %v", expected[i][0], actual[i].Timestamp)
+	}
+}
+
+func setupDelayedWethTest(t *testing.T) (*batchingTest.AbiBasedRpc, *DelayedWETHContract) {
+	delayedWethAbi, err := bindings.DelayedWETHMetaData.GetAbi()
+	require.NoError(t, err)
+	stubRpc := batchingTest.NewAbiBasedRpc(t, delayedWeth, delayedWethAbi)
+	caller := batching.NewMultiCaller(stubRpc, batching.DefaultBatchSize)
+	weth, err := NewDelayedWETHContract(contractMetrics.NoopContractMetrics, delayedWeth, caller)
+	require.NoError(t, err)
+	return stubRpc, weth
+}

op-challenger/game/fault/contracts/faultdisputegame.go

@@ -231,6 +231,15 @@ func (f *FaultDisputeGameContract) addGlobalDataTx(ctx context.Context, data *ty
 	return oracle.AddGlobalDataTx(data)
 }
 
+func (f *FaultDisputeGameContract) GetDelayedWETH(ctx context.Context) (*DelayedWETHContract, error) {
+	defer f.metrics.StartContractRequest("GetDelayedWETH")()
+	result, err := f.multiCaller.SingleCall(ctx, rpcblock.Latest, f.contract.Call(methodWETH))
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch WETH addr: %w", err)
+	}
+	return NewDelayedWETHContract(f.metrics, result.GetAddress(0), f.multiCaller)
+}
+
 func (f *FaultDisputeGameContract) GetOracle(ctx context.Context) (*PreimageOracleContract, error) {
 	defer f.metrics.StartContractRequest("GetOracle")()
 	vm, err := f.vm(ctx)