Move logic to extend til blocks to til

Previously, the synchronizer test was extending the output from til to
precalculate many fields to compare it with the synchronizer and BD output.
Since this is useful outside of the syncrhonizer testing: move this
functionality to til via a function that extends the output
(til.Context.FillBlocksExtra).

Also, add new functionality: calculate fee idxs dynamically by setting a user
name, and calculate collected fees.

test/til/txs.go

@@ -21,7 +21,10 @@ func newBatchData(batchNum int) common.BatchData {
 		L2Txs:            []common.L2Tx{},
 		Batch: common.Batch{
 			BatchNum:  common.BatchNum(batchNum),
-			StateRoot: big.NewInt(0), ExitRoot: big.NewInt(0)},
+			StateRoot: big.NewInt(0), ExitRoot: big.NewInt(0),
+			FeeIdxsCoordinator: make([]common.Idx, 0),
+			CollectedFees:      make(map[common.TokenID]*big.Int),
+		},
 	}
 }
 
@@ -36,13 +39,22 @@ func newBlock(blockNum int64) common.BlockData {
 	}
 }
 
+type contextExtra struct {
+	openToForge     int64
+	toForgeL1TxsNum int64
+	nonces          map[common.Idx]common.Nonce
+	idx             int
+}
+
 // Context contains the data of the test
 type Context struct {
 	Instructions          []instruction
 	userNames             []string
-	Users                 map[string]*User
+	Users                 map[string]*User // Name -> *User
+	usersByIdx            map[int]*User
+	accountsByIdx         map[int]*Account
 	LastRegisteredTokenID common.TokenID
-	l1CreatedAccounts     map[string]*Account
+	l1CreatedAccounts     map[string]*Account // (Name, TokenID) -> *Account
 
 	// rollupConstMaxL1UserTx Maximum L1-user transactions allowed to be queued in a batch
 	rollupConstMaxL1UserTx int
@@ -59,6 +71,8 @@ type Context struct {
 		l2Txs            []L2Tx
 	}
 	blockNum int64
+
+	extra contextExtra
 }
 
 // NewContext returns a new Context
@@ -67,6 +81,8 @@ func NewContext(rollupConstMaxL1UserTx int) *Context {
 	return &Context{
 		Users:                 make(map[string]*User),
 		l1CreatedAccounts:     make(map[string]*Account),
+		usersByIdx:            make(map[int]*User),
+		accountsByIdx:         make(map[int]*Account),
 		LastRegisteredTokenID: 0,
 
 		rollupConstMaxL1UserTx: rollupConstMaxL1UserTx,
@@ -82,17 +98,26 @@ func NewContext(rollupConstMaxL1UserTx int) *Context {
 		openToForge: 1,
 		//nolint:gomnd
 		blockNum: 2, // rollup genesis blockNum
+		extra: contextExtra{
+			openToForge:     0,
+			toForgeL1TxsNum: 0,
+			nonces:          make(map[common.Idx]common.Nonce),
+			idx:             common.UserThreshold,
+		},
 	}
 }
 
 // Account contains the data related to the account for a specific TokenID of a User
 type Account struct {
-	Idx   common.Idx
-	Nonce common.Nonce
+	Idx      common.Idx
+	TokenID  common.TokenID
+	Nonce    common.Nonce
+	BatchNum int
 }
 
 // User contains the data related to a testing user
 type User struct {
+	Name     string
 	BJJ      *babyjub.PrivateKey
 	Addr     ethCommon.Address
 	Accounts map[common.TokenID]*Account
@@ -361,10 +386,14 @@ func (tc *Context) calculateIdxForL1Txs(isCoordinatorTxs bool, txs []L1Tx) error
 				return fmt.Errorf("Can not create same account twice (same User (%s) & same TokenID (%d)) (this is a design property of Til)", tx.fromIdxName, tx.L1Tx.TokenID)
 			}
 			tc.Users[tx.fromIdxName].Accounts[tx.L1Tx.TokenID] = &Account{
-				Idx:   common.Idx(tc.idx),
-				Nonce: common.Nonce(0),
+				Idx:      common.Idx(tc.idx),
+				TokenID:  tx.L1Tx.TokenID,
+				Nonce:    common.Nonce(0),
+				BatchNum: tc.currBatchNum,
 			}
 			tc.l1CreatedAccounts[idxTokenIDToString(tx.fromIdxName, tx.L1Tx.TokenID)] = tc.Users[tx.fromIdxName].Accounts[tx.L1Tx.TokenID]
+			tc.accountsByIdx[tc.idx] = tc.Users[tx.fromIdxName].Accounts[tx.L1Tx.TokenID]
+			tc.usersByIdx[tc.idx] = tc.Users[tx.fromIdxName]
 			tc.idx++
 		}
 		if isCoordinatorTxs {
@@ -606,6 +635,7 @@ func (tc *Context) generateKeys(userNames []string) {
 		addr := ethCrypto.PubkeyToAddress(key.PublicKey)
 
 		u := User{
+			Name:     userNames[i-1],
 			BJJ:      &sk,
 			Addr:     addr,
 			Accounts: make(map[common.TokenID]*Account),
@@ -622,3 +652,205 @@ func L1TxsToCommonL1Txs(l1 []L1Tx) []common.L1Tx {
 	}
 	return r
 }
+
+// ConfigExtra is the configuration used in FillBlocksExtra to extend the
+// blocks returned by til.
+type ConfigExtra struct {
+	// Address to set as forger for each batch
+	BootCoordAddr ethCommon.Address
+	// Coordinator user name used to select the corresponding accounts to
+	// collect coordinator fees
+	CoordUser string
+}
+
+// FillBlocksExtra fills extra fields not generated by til in each block, so
+// that the blockData is closer to what the HistoryDB stores.  The filled fields are:
+// - blocks[].Rollup.L1UserTxs[].BatchNum
+// - blocks[].Rollup.Batch.EthBlockNum
+// - blocks[].Rollup.Batch.ForgerAddr
+// - blocks[].Rollup.Batch.ForgeL1TxsNum
+// - blocks[].Rollup.Batch.L1CoordinatorTxs[].TxID
+// - blocks[].Rollup.Batch.L1CoordinatorTxs[].BatchNum
+// - blocks[].Rollup.Batch.L1CoordinatorTxs[].EthBlockNum
+// - blocks[].Rollup.Batch.L1CoordinatorTxs[].Position
+// - blocks[].Rollup.Batch.L2Txs[].TxID
+// - blocks[].Rollup.Batch.L2Txs[].Position
+// - blocks[].Rollup.Batch.L2Txs[].Nonce
+// - blocks[].Rollup.Batch.ExitTree
+// - blocks[].Rollup.Batch.CreatedAccounts
+// - blocks[].Rollup.Batch.FeeIdxCoordinator
+// - blocks[].Rollup.Batch.CollectedFees
+func (tc *Context) FillBlocksExtra(blocks []common.BlockData, cfg *ConfigExtra) error {
+	// Fill extra fields not generated by til in til block
+	for i := range blocks {
+		block := &blocks[i]
+		for j := range block.Rollup.Batches {
+			batch := &block.Rollup.Batches[j]
+			if batch.L1Batch {
+				// Set BatchNum for forged L1UserTxs to til blocks
+				bn := batch.Batch.BatchNum
+				for k := range blocks {
+					block := &blocks[k]
+					for l := range block.Rollup.L1UserTxs {
+						tx := &block.Rollup.L1UserTxs[l]
+						if *tx.ToForgeL1TxsNum == tc.extra.openToForge {
+							tx.BatchNum = &bn
+						}
+					}
+				}
+				tc.extra.openToForge++
+			}
+
+			batch.Batch.EthBlockNum = block.Block.EthBlockNum
+			// til doesn't fill the batch forger addr
+			batch.Batch.ForgerAddr = cfg.BootCoordAddr
+			if batch.L1Batch {
+				toForgeL1TxsNumCpy := tc.extra.toForgeL1TxsNum
+				// til doesn't fill the ForgeL1TxsNum
+				batch.Batch.ForgeL1TxsNum = &toForgeL1TxsNumCpy
+				tc.extra.toForgeL1TxsNum++
+			}
+
+			batchNum := batch.Batch.BatchNum
+			for k := range batch.L1CoordinatorTxs {
+				tx := &batch.L1CoordinatorTxs[k]
+				tx.BatchNum = &batchNum
+				tx.EthBlockNum = batch.Batch.EthBlockNum
+			}
+		}
+	}
+
+	// Fill CreatedAccounts
+	for i := range blocks {
+		block := &blocks[i]
+		for j := range block.Rollup.Batches {
+			batch := &block.Rollup.Batches[j]
+			l1Txs := []common.L1Tx{}
+			if batch.L1Batch {
+				for _, tx := range tc.Queues[*batch.Batch.ForgeL1TxsNum] {
+					l1Txs = append(l1Txs, tx.L1Tx)
+				}
+			}
+			l1Txs = append(l1Txs, batch.L1CoordinatorTxs...)
+			for k := range l1Txs {
+				tx := &l1Txs[k]
+				if tx.Type == common.TxTypeCreateAccountDeposit ||
+					tx.Type == common.TxTypeCreateAccountDepositTransfer {
+					user, ok := tc.usersByIdx[tc.extra.idx]
+					if !ok {
+						return fmt.Errorf("Created account with idx: %v not found", tc.extra.idx)
+					}
+					batch.CreatedAccounts = append(batch.CreatedAccounts,
+						common.Account{
+							Idx:       common.Idx(tc.extra.idx),
+							TokenID:   tx.TokenID,
+							BatchNum:  batch.Batch.BatchNum,
+							PublicKey: user.BJJ.Public(),
+							EthAddr:   user.Addr,
+							Nonce:     0,
+							Balance:   big.NewInt(0),
+						})
+					tc.extra.idx++
+				}
+			}
+		}
+	}
+
+	// Fill expected positions in L1CoordinatorTxs and L2Txs
+	for i := range blocks {
+		block := &blocks[i]
+		for j := range block.Rollup.Batches {
+			batch := &block.Rollup.Batches[j]
+			position := 0
+			if batch.L1Batch {
+				position = len(tc.Queues[*batch.Batch.ForgeL1TxsNum])
+			}
+			for k := range batch.L1CoordinatorTxs {
+				tx := &batch.L1CoordinatorTxs[k]
+				tx.Position = position
+				position++
+				nTx, err := common.NewL1Tx(tx)
+				if err != nil {
+					return err
+				}
+				*tx = *nTx
+			}
+			for k := range batch.L2Txs {
+				tx := &batch.L2Txs[k]
+				tx.Position = position
+				position++
+				tc.extra.nonces[tx.FromIdx]++
+				tx.Nonce = tc.extra.nonces[tx.FromIdx]
+				nTx, err := common.NewL2Tx(tx)
+				if err != nil {
+					return err
+				}
+				*tx = *nTx
+			}
+		}
+	}
+
+	// Fill ExitTree (only AccountIdx and Balance)
+	for i := range blocks {
+		block := &blocks[i]
+		for j := range block.Rollup.Batches {
+			batch := &block.Rollup.Batches[j]
+			if batch.L1Batch {
+				for _, _tx := range tc.Queues[*batch.Batch.ForgeL1TxsNum] {
+					tx := _tx.L1Tx
+					if tx.Type == common.TxTypeForceExit {
+						batch.ExitTree =
+							append(batch.ExitTree,
+								common.ExitInfo{
+									AccountIdx: tx.FromIdx,
+									Balance:    tx.Amount,
+								})
+					}
+				}
+			}
+			for k := range batch.L2Txs {
+				tx := &batch.L2Txs[k]
+				if tx.Type == common.TxTypeExit {
+					batch.ExitTree = append(batch.ExitTree, common.ExitInfo{
+						AccountIdx: tx.FromIdx,
+						Balance:    tx.Amount,
+					})
+				}
+				fee, err := common.CalcFeeAmount(tx.Amount, tx.Fee)
+				if err != nil {
+					return err
+				}
+
+				// Find the TokenID of the tx
+				fromAcc, ok := tc.accountsByIdx[int(tx.FromIdx)]
+				if !ok {
+					return fmt.Errorf("L2tx.FromIdx idx: %v not found", tx.FromIdx)
+				}
+
+				// Find the idx of the CoordUser for the
+				// TokenID, and if it exists, add the fee to
+				// the collectedFees.  Only consider the
+				// coordinator account to receive fee if it was
+				// created in this or a previous batch
+				if acc, ok := tc.l1CreatedAccounts[idxTokenIDToString(cfg.CoordUser, fromAcc.TokenID)]; ok &&
+					common.BatchNum(acc.BatchNum) <= batch.Batch.BatchNum {
+					found := false
+					for _, idx := range batch.Batch.FeeIdxsCoordinator {
+						if idx == common.Idx(acc.Idx) {
+							found = true
+							break
+						}
+					}
+					if !found {
+						batch.Batch.FeeIdxsCoordinator = append(batch.Batch.FeeIdxsCoordinator,
+							common.Idx(acc.Idx))
+						batch.Batch.CollectedFees[fromAcc.TokenID] = big.NewInt(0)
+					}
+					collected := batch.Batch.CollectedFees[fromAcc.TokenID]
+					collected.Add(collected, fee)
+				}
+			}
+		}
+	}
+	return nil
+}