Added finding target wallets

pkg/chain/ethereum/tbtc.go

@@ -1705,6 +1705,7 @@ func (tc *TbtcChain) ValidateHeartbeatProposal(
 }
 
 func (tc *TbtcChain) ValidateMovingFundsProposal(
+	walletPublicKeyHash [20]byte,
 	proposal *tbtc.MovingFundsProposal,
 ) error {
 	// TODO: Implement

pkg/tbtc/chain.go

@@ -188,22 +188,6 @@ type BridgeChain interface {
 	// if the wallet was not found.
 	GetWallet(walletPublicKeyHash [20]byte) (*WalletChainData, error)
 
-	// GetWalletParameters gets the current value of parameters relevant to
-	// wallet.
-	GetWalletParameters() (
-		creationPeriod uint32,
-		creationMinBtcBalance uint64,
-		creationMaxBtcBalance uint64,
-		closureMinBtcBalance uint64,
-		maxAge uint32,
-		maxBtcTransfer uint64,
-		closingPeriod uint32,
-		err error,
-	)
-
-	// GetLiveWalletsCount gets the current count of live wallets.
-	GetLiveWalletsCount() (uint32, error)
-
 	// ComputeMainUtxoHash computes the hash of the provided main UTXO
 	// according to the on-chain Bridge rules.
 	ComputeMainUtxoHash(mainUtxo *bitcoin.UnspentTransactionOutput) [32]byte
@@ -238,14 +222,6 @@ type BridgeChain interface {
 		fundingOutputIndex uint32,
 	) (*DepositChainRequest, bool, error)
 
-	// PastNewWalletRegisteredEvents fetches past new wallet registered events
-	// according to the provided filter or unfiltered if the filter is nil. Returned
-	// events are sorted by the block number in the ascending order, i.e. the
-	// latest event is at the end of the slice.
-	PastNewWalletRegisteredEvents(
-		filter *NewWalletRegisteredEventFilter,
-	) ([]*NewWalletRegisteredEvent, error)
-
 	// Submits the moving funds target wallets commitment.
 	SubmitMovingFundsCommitment(
 		walletPublicKeyHash [20]byte,
@@ -386,7 +362,10 @@ type WalletProposalValidatorChain interface {
 	// ValidateMovingFundsProposal validates the given moving funds proposal
 	// against the chain. Returns an error if the proposal is not valid or
 	// nil otherwise.
-	ValidateMovingFundsProposal(proposal *MovingFundsProposal) error
+	ValidateMovingFundsProposal(
+		walletPublicKeyHash [20]byte,
+		proposal *MovingFundsProposal,
+	) error
 }
 
 // RedemptionRequestedEvent represents a redemption requested event.

pkg/tbtc/chain_test.go

@@ -821,13 +821,6 @@ func (lc *localChain) ValidateRedemptionProposal(
 	return nil
 }
 
-func (lc *localChain) ValidateMovingFundsProposal(
-	proposal *MovingFundsProposal,
-) error {
-	// TODO: Implement
-	return nil
-}
-
 func (lc *localChain) setRedemptionProposalValidationResult(
 	walletPublicKeyHash [20]byte,
 	proposal *RedemptionProposal,
@@ -895,6 +888,14 @@ func (lc *localChain) setHeartbeatProposalValidationResult(
 	lc.heartbeatProposalValidations[proposal.Message] = result
 }
 
+func (lc *localChain) ValidateMovingFundsProposal(
+	walletPublicKeyHash [20]byte,
+	proposal *MovingFundsProposal,
+) error {
+	// TODO: Implement
+	panic("unsupported")
+}
+
 // Connect sets up the local chain.
 func Connect(blockTime ...time.Duration) *localChain {
 	operatorPrivateKey, _, err := operator.GenerateKeyPair(local_v1.DefaultCurve)

pkg/tbtcpg/chain.go

@@ -23,6 +23,22 @@ type Chain interface {
 		filter *tbtc.NewWalletRegisteredEventFilter,
 	) ([]*tbtc.NewWalletRegisteredEvent, error)
 
+	// GetWalletParameters gets the current value of parameters relevant to
+	// wallet.
+	GetWalletParameters() (
+		creationPeriod uint32,
+		creationMinBtcBalance uint64,
+		creationMaxBtcBalance uint64,
+		closureMinBtcBalance uint64,
+		maxAge uint32,
+		maxBtcTransfer uint64,
+		closingPeriod uint32,
+		err error,
+	)
+
+	// GetLiveWalletsCount gets the current count of live wallets.
+	GetLiveWalletsCount() (uint32, error)
+
 	// BuildDepositKey calculates a deposit key for the given funding transaction
 	// which is a unique identifier for a deposit on-chain.
 	BuildDepositKey(fundingTxHash bitcoin.Hash, fundingOutputIndex uint32) *big.Int
@@ -111,4 +127,12 @@ type Chain interface {
 		walletPublicKeyHash [20]byte,
 		proposal *tbtc.HeartbeatProposal,
 	) error
+
+	// ValidateMovingFundsProposal validates the given moving funds proposal
+	// against the chain. Returns an error if the proposal is not valid or
+	// nil otherwise.
+	ValidateMovingFundsProposal(
+		walletPublicKeyHash [20]byte,
+		proposal *tbtc.MovingFundsProposal,
+	) error
 }

pkg/tbtcpg/chain_test.go

@@ -616,6 +616,22 @@ func (lc *LocalChain) SetHeartbeatProposalValidationResult(
 	lc.heartbeatProposalValidations[proposal.Message] = result
 }
 
+func (lc *LocalChain) ValidateMovingFundsProposal(
+	walletPublicKeyHash [20]byte,
+	proposal *tbtc.MovingFundsProposal,
+) error {
+	// TODO: Implement
+	panic("unsupported")
+}
+
+func (lc *LocalChain) SetMovingFundsProposalValidationResult(
+	proposal *tbtc.MovingFundsProposal,
+	result bool,
+) {
+	// TODO: Implement
+	panic("unsupported")
+}
+
 func buildRedemptionProposalValidationKey(
 	walletPublicKeyHash [20]byte,
 	proposal *tbtc.RedemptionProposal,

pkg/tbtcpg/moving_funds.go

@@ -2,6 +2,8 @@ package tbtcpg
 
 import (
 	"fmt"
+	"math/big"
+	"sort"
 
 	"go.uber.org/zap"
 
@@ -38,14 +40,30 @@ func (mft *MovingFundsTask) Run(request *tbtc.CoordinationProposalRequest) (
 		zap.String("walletPKH", fmt.Sprintf("0x%x", walletPublicKeyHash)),
 	)
 
-	liveWalletsCount, err := mft.chain.GetLiveWalletsCount()
+	// Check if the wallet is eligible for moving funds.
+	walletChainData, err := mft.chain.GetWallet(walletPublicKeyHash)
 	if err != nil {
 		return nil, false, fmt.Errorf(
-			"cannot get Live wallets count: [%w]",
+			"cannot get source wallet's chain data: [%w]",
 			err,
 		)
 	}
 
+	if walletChainData.State != tbtc.StateMovingFunds {
+		taskLogger.Infof("source wallet not in MoveFunds state")
+		return nil, false, nil
+	}
+
+	if walletChainData.PendingRedemptionsValue > 0 {
+		taskLogger.Infof("source wallet has pending redemptions")
+		return nil, false, nil
+	}
+
+	if walletChainData.PendingMovedFundsSweepRequestsCount > 0 {
+		taskLogger.Infof("source wallet has pending moved funds sweep requests")
+		return nil, false, nil
+	}
+
 	walletMainUtxo, err := tbtc.DetermineWalletMainUtxo(
 		walletPublicKeyHash,
 		mft.chain,
@@ -63,35 +81,32 @@ func (mft *MovingFundsTask) Run(request *tbtc.CoordinationProposalRequest) (
 		walletBalance = walletMainUtxo.Value
 	}
 
-	walletChainData, err := mft.chain.GetWallet(walletPublicKeyHash)
-	if err != nil {
-		return nil, false, fmt.Errorf(
-			"cannot get source wallet's chain data: [%w]",
-			err,
-		)
+	if walletBalance <= 0 {
+		// The wallet's balance cannot be `0`. Since we are dealing with
+		// a signed integer we also check it's not negative just in case.
+		taskLogger.Infof("source wallet does not have a positive balance")
+		return nil, false, nil
 	}
 
-	ok, err := mft.CheckEligibility(
-		taskLogger,
-		liveWalletsCount,
-		walletBalance,
-		walletChainData,
-	)
+	liveWalletsCount, err := mft.chain.GetLiveWalletsCount()
 	if err != nil {
 		return nil, false, fmt.Errorf(
-			"cannot check wallet eligibility: [%w]",
+			"cannot get Live wallets count: [%w]",
 			err,
 		)
 	}
 
-	if !ok {
-		taskLogger.Info("wallet not eligible for moving funds")
+	if liveWalletsCount == 0 {
+		taskLogger.Infof("there are no Live wallets available")
 		return nil, false, nil
 	}
 
 	targetWallets, commitmentSubmitted, err := mft.FindTargetWallets(
 		taskLogger,
+		walletPublicKeyHash,
 		walletChainData,
+		uint64(walletBalance),
+		liveWalletsCount,
 	)
 	if err != nil {
 		return nil, false, fmt.Errorf("cannot find target wallets: [%w]", err)
@@ -117,52 +132,133 @@ func (mft *MovingFundsTask) Run(request *tbtc.CoordinationProposalRequest) (
 
 func (mft *MovingFundsTask) FindTargetWallets(
 	taskLogger log.StandardLogger,
+	sourceWalletPublicKeyHash [20]byte,
 	walletChainData *tbtc.WalletChainData,
+	walletBalance uint64,
+	liveWalletsCount uint32,
 ) ([][20]byte, bool, error) {
 	if walletChainData.MovingFundsTargetWalletsCommitmentHash == [32]byte{} {
-		taskLogger.Infof("Move funds commitment has not been submitted yet")
-		// TODO: Find the target wallets among Live wallets.
-	} else {
-		taskLogger.Infof("Move funds commitment has already been submitted")
-		// TODO: Find the target wallets from the emitted event.
+		return mft.findNewTargetWallets(
+			taskLogger,
+			sourceWalletPublicKeyHash,
+			walletBalance,
+			liveWalletsCount,
+		)
 	}
-	return nil, false, nil
+
+	return mft.retrieveCommittedTargetWallets(taskLogger)
 }
 
-func (mft *MovingFundsTask) CheckEligibility(
+func (mft *MovingFundsTask) findNewTargetWallets(
 	taskLogger log.StandardLogger,
+	sourceWalletPublicKeyHash [20]byte,
+	walletBalance uint64,
 	liveWalletsCount uint32,
-	walletBalance int64,
-	walletChainData *tbtc.WalletChainData,
-) (bool, error) {
-	if liveWalletsCount == 0 {
-		taskLogger.Infof("there are no Live wallets available")
-		return false, nil
+) ([][20]byte, bool, error) {
+	taskLogger.Infof(
+		"commitment not submitted yet; looking for new target wallets",
+	)
+
+	_, _, _, _, _, walletMaxBtcTransfer, _, err := mft.chain.GetWalletParameters()
+	if err != nil {
+		return nil, false, fmt.Errorf("cannot get wallet parameters: [%w]", err)
 	}
 
-	if walletBalance <= 0 {
-		// The wallet's balance cannot be `0`. Since we are dealing with
-		// a signed integer we also check it's not negative just in case.
-		taskLogger.Infof("source wallet does not have a positive balance")
-		return false, nil
+	if walletMaxBtcTransfer == 0 {
+		return nil, false, fmt.Errorf(
+			"wallet max BTC transfer must be positive: [%w]", err,
+		)
 	}
 
-	if walletChainData.State != tbtc.StateMovingFunds {
-		taskLogger.Infof("source wallet not in MoveFunds state")
-		return false, nil
+	ceilingDivide := func(x, y uint64) uint64 {
+		// The divisor must be positive, but we do not need to check it as
+		// this function will be executed with wallet max BTC transfer as
+		// the divisor and we already ensured it is positive.
+		return (x + y - 1) / y
+	}
+	min := func(x, y uint64) uint64 {
+		if x < y {
+			return x
+		}
+		return y
 	}
 
-	if walletChainData.PendingRedemptionsValue > 0 {
-		taskLogger.Infof("source wallet has pending redemptions")
-		return false, nil
+	targetWalletsCount := min(
+		uint64(liveWalletsCount),
+		ceilingDivide(walletBalance, walletMaxBtcTransfer),
+	)
+
+	// Prepare a list of target wallets using the new wallets registration
+	// events. Retrieve only the necessary number of live wallets.
+	// The iteration is started from the end of the list as the newest wallets
+	// are located there and have highest the chance of being Live.
+	events, err := mft.chain.PastNewWalletRegisteredEvents(nil)
+	if err != nil {
+		return nil, false, fmt.Errorf(
+			"failed to get past new wallet registered events: [%v]",
+			err,
+		)
 	}
 
-	if walletChainData.PendingMovedFundsSweepRequestsCount > 0 {
-		taskLogger.Infof("source wallet has pending moved funds sweep requests")
-		return false, nil
+	targetWallets := make([][20]byte, 0)
+
+	for i := len(events) - 1; i >= 0; i-- {
+		walletPubKeyHash := events[i].WalletPublicKeyHash
+		if walletPubKeyHash == sourceWalletPublicKeyHash {
+			// Just in case make sure not to include the source wallet
+			// itself.
+			continue
+		}
+
+		wallet, err := mft.chain.GetWallet(walletPubKeyHash)
+		if err != nil {
+			taskLogger.Errorf(
+				"failed to get wallet data for wallet with PKH [0x%x]: [%v]",
+				walletPubKeyHash,
+				err,
+			)
+			continue
+		}
+
+		if wallet.State == tbtc.StateLive {
+			targetWallets = append(targetWallets, walletPubKeyHash)
+		}
+		if len(targetWallets) == int(targetWalletsCount) {
+			// Stop the iteration if enough live wallets have been gathered.
+			break
+		}
 	}
 
-	return true, nil
+	if len(targetWallets) != int(targetWalletsCount) {
+		return nil, false, fmt.Errorf(
+			"failed to get enough target wallets: required [%v]; gathered [%v]",
+			targetWalletsCount,
+			len(targetWallets),
+		)
+	}
+
+	// Sort the target wallets according to their numerical representation
+	// as the on-chain contract expects.
+	sort.Slice(targetWallets, func(i, j int) bool {
+		bigIntI := new(big.Int).SetBytes(targetWallets[i][:])
+		bigIntJ := new(big.Int).SetBytes(targetWallets[j][:])
+		return bigIntI.Cmp(bigIntJ) < 0
+	})
+
+	logger.Infof("gathered [%v] target wallets", len(targetWallets))
+
+	return targetWallets, false, nil
+}
+
+func (mft *MovingFundsTask) retrieveCommittedTargetWallets(
+	taskLogger log.StandardLogger,
+) ([][20]byte, bool, error) {
+	taskLogger.Infof(
+		"commitment already submitted; retrieving committed target wallets",
+	)
+
+	// TODO: Implement
+	return nil, false, nil
 }
 
 func (mft *MovingFundsTask) SubmitMovingFundsCommitment() ([][20]byte, error) {