1package batchbuilder
  2
  3import (
  4	"math/big"
  5
  6	ethCommon "github.com/ethereum/go-ethereum/common"
  7	"github.com/hermeznetwork/hermez-node/common"
  8	"github.com/hermeznetwork/hermez-node/db/statedb"
  9)
 10
 11// ConfigCircuit contains the circuit configuration
 12type ConfigCircuit struct {
 13	TxsMax       uint64
 14	L1TxsMax     uint64
 15	SMTLevelsMax uint64
 16}
 17
 18// BatchBuilder implements the batch builder type, which contains the
 19// functionalities
 20type BatchBuilder struct {
 21	// idx holds the current Idx that the BatchBuilder is using
 22	idx            uint64
 23	localStateDB   *statedb.LocalStateDB
 24	configCircuits []ConfigCircuit
 25}
 26
 27// ConfigBatch contains the batch configuration
 28type ConfigBatch struct {
 29	CoordinatorAddress ethCommon.Address
 30}
 31
 32// NewBatchBuilder constructs a new BatchBuilder, and executes the bb.Reset
 33// method
 34func NewBatchBuilder(synchronizerStateDB *statedb.StateDB, configCircuits []ConfigCircuit, batchNum int, idx, nLevels uint64) (*BatchBuilder, error) {
 35	localStateDB, err := statedb.NewLocalStateDB(synchronizerStateDB, true, int(nLevels))
 36	if err != nil {
 37		return nil, err
 38	}
 39
 40	bb := BatchBuilder{
 41		idx:            idx,
 42		localStateDB:   localStateDB,
 43		configCircuits: configCircuits,
 44	}
 45
 46	err = bb.Reset(batchNum, true)
 47	return &bb, err
 48}
 49
 50// Reset tells the BatchBuilder to reset it's internal state to the required
 51// `batchNum`.  If `fromSynchronizer` is true, the BatchBuilder must take a
 52// copy of the rollup state from the Synchronizer at that `batchNum`, otherwise
 53// it can just roll back the internal copy.
 54func (bb *BatchBuilder) Reset(batchNum int, fromSynchronizer bool) error {
 55	err := bb.localStateDB.Reset(batchNum, fromSynchronizer)
 56	if err != nil {
 57		return err
 58	}
 59	// bb.idx = idx // TODO idx will be obtained from the statedb reset
 60	return nil
 61}
 62
 63// BuildBatch takes the transactions and returns the common.ZKInputs of the next batch
 64func (bb *BatchBuilder) BuildBatch(configBatch ConfigBatch, l1usertxs, l1coordinatortxs []common.L1Tx, l2txs []common.L2Tx, tokenIDs []common.TokenID) (*common.ZKInputs, error) {
 65	for _, tx := range l1usertxs {
 66		err := bb.processL1Tx(tx)
 67		if err != nil {
 68			return nil, err
 69		}
 70	}
 71	for _, tx := range l1coordinatortxs {
 72		err := bb.processL1Tx(tx)
 73		if err != nil {
 74			return nil, err
 75		}
 76	}
 77	for _, tx := range l2txs {
 78		switch tx.Type {
 79		case common.TxTypeTransfer:
 80			// go to the MT account of sender and receiver, and update
 81			// balance & nonce
 82			err := bb.applyTransfer(tx.Tx)
 83			if err != nil {
 84				return nil, err
 85			}
 86		case common.TxTypeExit:
 87			// execute exit flow
 88		default:
 89		}
 90	}
 91
 92	return nil, nil
 93}
 94
 95func (bb *BatchBuilder) processL1Tx(tx common.L1Tx) error {
 96	switch tx.Type {
 97	case common.TxTypeForceTransfer, common.TxTypeTransfer:
 98		// go to the MT account of sender and receiver, and update balance
 99		// & nonce
100		err := bb.applyTransfer(tx.Tx)
101		if err != nil {
102			return err
103		}
104	case common.TxTypeCreateAccountDeposit:
105		// add new account to the MT, update balance of the MT account
106		err := bb.applyCreateAccount(tx)
107		if err != nil {
108			return err
109		}
110	case common.TxTypeDeposit: // TODO check if this type will ever exist, or will be TxTypeDepositAndTransfer with transfer 0 value
111		// update balance of the MT account
112		err := bb.applyDeposit(tx, false)
113		if err != nil {
114			return err
115		}
116	case common.TxTypeDepositAndTransfer:
117		// update balance in MT account, update balance & nonce of sender
118		// & receiver
119		err := bb.applyDeposit(tx, true)
120		if err != nil {
121			return err
122		}
123	case common.TxTypeCreateAccountDepositAndTransfer:
124		// add new account to the merkletree, update balance in MT account,
125		// update balance & nonce of sender & receiver
126		err := bb.applyCreateAccount(tx)
127		if err != nil {
128			return err
129		}
130		err = bb.applyTransfer(tx.Tx)
131		if err != nil {
132			return err
133		}
134	case common.TxTypeExit:
135		// execute exit flow
136	default:
137	}
138
139	return nil
140}
141
142// applyCreateAccount creates a new account in the account of the depositer, it stores
143// the deposit value
144func (bb *BatchBuilder) applyCreateAccount(tx common.L1Tx) error {
145	account := &common.Account{
146		TokenID:   tx.TokenID,
147		Nonce:     0,
148		Balance:   tx.LoadAmount,
149		PublicKey: &tx.FromBJJ,
150		EthAddr:   tx.FromEthAddr,
151	}
152
153	err := bb.localStateDB.CreateAccount(common.Idx(bb.idx+1), account)
154	if err != nil {
155		return err
156	}
157
158	bb.idx = bb.idx + 1
159	return nil
160}
161
162// applyDeposit updates the balance in the account of the depositer, if
163// andTransfer parameter is set to true, the method will also apply the
164// Transfer of the L1Tx/DepositAndTransfer
165func (bb *BatchBuilder) applyDeposit(tx common.L1Tx, transfer bool) error {
166	// deposit the tx.LoadAmount into the sender account
167	accSender, err := bb.localStateDB.GetAccount(tx.FromIdx)
168	if err != nil {
169		return err
170	}
171	accSender.Balance = new(big.Int).Add(accSender.Balance, tx.LoadAmount)
172
173	// in case that the tx is a L1Tx>DepositAndTransfer
174	if transfer {
175		accReceiver, err := bb.localStateDB.GetAccount(tx.ToIdx)
176		if err != nil {
177			return err
178		}
179		// substract amount to the sender
180		accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Tx.Amount)
181		// add amount to the receiver
182		accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Tx.Amount)
183		// update receiver account in localStateDB
184		err = bb.localStateDB.UpdateAccount(tx.ToIdx, accReceiver)
185		if err != nil {
186			return err
187		}
188	}
189	// update sender account in localStateDB
190	err = bb.localStateDB.UpdateAccount(tx.FromIdx, accSender)
191	if err != nil {
192		return err
193	}
194	return nil
195}
196
197// applyTransfer updates the balance & nonce in the account of the sender, and
198// the balance in the account of the receiver
199func (bb *BatchBuilder) applyTransfer(tx common.Tx) error {
200	// get sender and receiver accounts from localStateDB
201	accSender, err := bb.localStateDB.GetAccount(tx.FromIdx)
202	if err != nil {
203		return err
204	}
205	accReceiver, err := bb.localStateDB.GetAccount(tx.ToIdx)
206	if err != nil {
207		return err
208	}
209
210	// substract amount to the sender
211	accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount)
212	// add amount to the receiver
213	accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount)
214
215	// update receiver account in localStateDB
216	err = bb.localStateDB.UpdateAccount(tx.ToIdx, accReceiver)
217	if err != nil {
218		return err
219	}
220	// update sender account in localStateDB
221	err = bb.localStateDB.UpdateAccount(tx.FromIdx, accSender)
222	if err != nil {
223		return err
224	}
225
226	return nil
227}