func lookupInputAccount(dbtx walletdb.ReadTx, w *Wallet, details *wtxmgr.TxDetails, deb wtxmgr.DebitRecord) uint32 {
	addrmgrNs := dbtx.ReadBucket(waddrmgrNamespaceKey)
	txmgrNs := dbtx.ReadBucket(wtxmgrNamespaceKey)

	// TODO: Debits should record which account(s?) they
	// debit from so this doesn't need to be looked up.
	prevOP := &details.MsgTx.TxIn[deb.Index].PreviousOutPoint
	prev, err := w.TxStore.TxDetails(txmgrNs, &prevOP.Hash)
	if err != nil {
		log.Errorf("Cannot query previous transaction details for %v: %v", prevOP.Hash, err)
		return 0
	}
	if prev == nil {
		log.Errorf("Missing previous transaction %v", prevOP.Hash)
		return 0
	}
	prevOut := prev.MsgTx.TxOut[prevOP.Index]
	_, addrs, _, err := txscript.ExtractPkScriptAddrs(prevOut.Version, prevOut.PkScript, w.chainParams)
	var inputAcct uint32
	if err == nil && len(addrs) > 0 {
		inputAcct, err = w.Manager.AddrAccount(addrmgrNs, addrs[0])
	}
	if err != nil {
		log.Errorf("Cannot fetch account for previous output %v: %v", prevOP, err)
		inputAcct = 0
	}
	return inputAcct
}

// MakeSecp256k1MultiSigScript creates a multi-signature script that can be
// redeemed with nRequired signatures of the passed keys and addresses.  If the
// address is a P2PKH address, the associated pubkey is looked up by the wallet
// if possible, otherwise an error is returned for a missing pubkey.
//
// This function only works with secp256k1 pubkeys and P2PKH addresses derived
// from them.
func (w *Wallet) MakeSecp256k1MultiSigScript(secp256k1Addrs []dcrutil.Address, nRequired int) ([]byte, error) {
	secp256k1PubKeys := make([]*dcrutil.AddressSecpPubKey, len(secp256k1Addrs))

	var dbtx walletdb.ReadTx
	var addrmgrNs walletdb.ReadBucket
	defer func() {
		if dbtx != nil {
			dbtx.Rollback()
		}
	}()

	// The address list will made up either of addreseses (pubkey hash), for
	// which we need to look up the keys in wallet, straight pubkeys, or a
	// mixture of the two.
	for i, addr := range secp256k1Addrs {
		switch addr := addr.(type) {
		default:
			return nil, errors.New("cannot make multisig script for " +
				"a non-secp256k1 public key or P2PKH address")

		case *dcrutil.AddressSecpPubKey:
			secp256k1PubKeys[i] = addr

		case *dcrutil.AddressPubKeyHash:
			if addr.DSA(w.chainParams) != chainec.ECTypeSecp256k1 {
				return nil, errors.New("cannot make multisig " +
					"script for a non-secp256k1 P2PKH address")
			}

			if dbtx == nil {
				var err error
				dbtx, err = w.db.BeginReadTx()
				if err != nil {
					return nil, err
				}
				addrmgrNs = dbtx.ReadBucket(waddrmgrNamespaceKey)
			}
			addrInfo, err := w.Manager.Address(addrmgrNs, addr)
			if err != nil {
				return nil, err
			}
			serializedPubKey := addrInfo.(waddrmgr.ManagedPubKeyAddress).
				PubKey().Serialize()

			pubKeyAddr, err := dcrutil.NewAddressSecpPubKey(
				serializedPubKey, w.chainParams)
			if err != nil {
				return nil, err
			}
			secp256k1PubKeys[i] = pubKeyAddr
		}
	}

	return txscript.MultiSigScript(secp256k1PubKeys, nRequired)
}

func lookupOutputChain(dbtx walletdb.ReadTx, w *Wallet, details *wtxmgr.TxDetails,
	cred wtxmgr.CreditRecord) (account uint32, internal bool) {

	addrmgrNs := dbtx.ReadBucket(waddrmgrNamespaceKey)

	output := details.MsgTx.TxOut[cred.Index]
	_, addrs, _, err := txscript.ExtractPkScriptAddrs(output.Version, output.PkScript, w.chainParams)
	var ma waddrmgr.ManagedAddress
	if err == nil && len(addrs) > 0 {
		ma, err = w.Manager.Address(addrmgrNs, addrs[0])
	}
	if err != nil {
		log.Errorf("Cannot fetch account for wallet output: %v", err)
	} else {
		account = ma.Account()
		internal = ma.Internal()
	}
	return
}

func totalBalances(dbtx walletdb.ReadTx, w *Wallet, m map[uint32]dcrutil.Amount) error {
	addrmgrNs := dbtx.ReadBucket(waddrmgrNamespaceKey)
	unspent, err := w.TxStore.UnspentOutputs(dbtx.ReadBucket(wtxmgrNamespaceKey))
	if err != nil {
		return err
	}
	for i := range unspent {
		output := unspent[i]
		var outputAcct uint32
		_, addrs, _, err := txscript.ExtractPkScriptAddrs(
			txscript.DefaultScriptVersion, output.PkScript, w.chainParams)
		if err == nil && len(addrs) > 0 {
			outputAcct, err = w.Manager.AddrAccount(addrmgrNs, addrs[0])
		}
		if err == nil {
			_, ok := m[outputAcct]
			if ok {
				m[outputAcct] += output.Amount
			}
		}
	}
	return nil
}

func (s *NotificationServer) notifyUnminedTransaction(dbtx walletdb.ReadTx, details *wtxmgr.TxDetails) {
	// Sanity check: should not be currently coalescing a notification for
	// mined transactions at the same time that an unmined tx is notified.
	if s.currentTxNtfn != nil {
		log.Tracef("Notifying unmined tx notification while creating notification for blocks")
	}

	defer s.mu.Unlock()
	s.mu.Lock()
	clients := s.transactions
	if len(clients) == 0 {
		return
	}

	unminedTxs := []TransactionSummary{makeTxSummary(dbtx, s.wallet, details)}
	unminedHashes, err := s.wallet.TxStore.UnminedTxHashes(dbtx.ReadBucket(wtxmgrNamespaceKey))
	if err != nil {
		log.Errorf("Cannot fetch unmined transaction hashes: %v", err)
		return
	}
	bals := make(map[uint32]dcrutil.Amount)
	relevantAccounts(s.wallet, bals, unminedTxs)
	err = totalBalances(dbtx, s.wallet, bals)
	if err != nil {
		log.Errorf("Cannot determine balances for relevant accounts: %v", err)
		return
	}
	n := &TransactionNotifications{
		UnminedTransactions:      unminedTxs,
		UnminedTransactionHashes: unminedHashes,
		NewBalances:              flattenBalanceMap(bals),
	}
	for _, c := range clients {
		c <- n
	}
}

func (s *NotificationServer) notifyAttachedBlock(dbtx walletdb.ReadTx, block *wtxmgr.BlockMeta) {
	if s.currentTxNtfn == nil {
		s.currentTxNtfn = &TransactionNotifications{}
	}

	// Add block details if it wasn't already included for previously
	// notified mined transactions.
	n := len(s.currentTxNtfn.AttachedBlocks)
	if n == 0 || *s.currentTxNtfn.AttachedBlocks[n-1].Hash != block.Hash {
		s.currentTxNtfn.AttachedBlocks = append(s.currentTxNtfn.AttachedBlocks, Block{
			Hash:      &block.Hash,
			Height:    block.Height,
			Timestamp: block.Time.Unix(),
		})
	}

	// For now (until notification coalescing isn't necessary) just use
	// chain length to determine if this is the new best block.
	if s.wallet.ChainSynced() {
		if len(s.currentTxNtfn.DetachedBlocks) >= len(s.currentTxNtfn.AttachedBlocks) {
			return
		}
	}

	defer s.mu.Unlock()
	s.mu.Lock()
	clients := s.transactions
	if len(clients) == 0 {
		s.currentTxNtfn = nil
		return
	}

	// The UnminedTransactions field is intentionally not set.  Since the
	// hashes of all detached blocks are reported, and all transactions
	// moved from a mined block back to unconfirmed are either in the
	// UnminedTransactionHashes slice or don't exist due to conflicting with
	// a mined transaction in the new best chain, there is no possiblity of
	// a new, previously unseen transaction appearing in unconfirmed.

	txmgrNs := dbtx.ReadBucket(wtxmgrNamespaceKey)
	unminedHashes, err := s.wallet.TxStore.UnminedTxHashes(txmgrNs)
	if err != nil {
		log.Errorf("Cannot fetch unmined transaction hashes: %v", err)
		return
	}
	s.currentTxNtfn.UnminedTransactionHashes = unminedHashes

	bals := make(map[uint32]dcrutil.Amount)
	for _, b := range s.currentTxNtfn.AttachedBlocks {
		relevantAccounts(s.wallet, bals, b.Transactions)
	}
	err = totalBalances(dbtx, s.wallet, bals)
	if err != nil {
		log.Errorf("Cannot determine balances for relevant accounts: %v", err)
		return
	}
	s.currentTxNtfn.NewBalances = flattenBalanceMap(bals)

	for _, c := range clients {
		c <- s.currentTxNtfn
	}
	s.currentTxNtfn = nil
}