rpc: break down wallet balance by accounts

lnrpc/rpc.proto

@@ -2254,8 +2254,17 @@ message ChannelEventUpdate {
     UpdateType type = 5;
 }
 
+message WalletAccountBalance {
+    // The confirmed balance of the account (with >= 1 confirmations).
+    int64 confirmed_balance = 1;
+
+    // The unconfirmed balance of the account (with 0 confirmations).
+    int64 unconfirmed_balance = 2;
+}
+
 message WalletBalanceRequest {
 }
+
 message WalletBalanceResponse {
     // The balance of the wallet
     int64 total_balance = 1;
@@ -2265,6 +2274,9 @@ message WalletBalanceResponse {
 
     // The unconfirmed balance of a wallet(with 0 confirmations)
     int64 unconfirmed_balance = 3;
+
+    // A mapping of each wallet account's name to its balance.
+    map<string, WalletAccountBalance> account_balance = 4;
 }
 
 message Amount {

lnrpc/rpc.swagger.json

@@ -5770,6 +5770,21 @@
         }
       }
     },
+    "lnrpcWalletAccountBalance": {
+      "type": "object",
+      "properties": {
+        "confirmed_balance": {
+          "type": "string",
+          "format": "int64",
+          "description": "The confirmed balance of the account (with \u003e= 1 confirmations)."
+        },
+        "unconfirmed_balance": {
+          "type": "string",
+          "format": "int64",
+          "description": "The unconfirmed balance of the account (with 0 confirmations)."
+        }
+      }
+    },
     "lnrpcWalletBalanceResponse": {
       "type": "object",
       "properties": {
@@ -5787,6 +5802,13 @@
           "type": "string",
           "format": "int64",
           "title": "The unconfirmed balance of a wallet(with 0 confirmations)"
+        },
+        "account_balance": {
+          "type": "object",
+          "additionalProperties": {
+            "$ref": "#/definitions/lnrpcWalletAccountBalance"
+          },
+          "description": "A mapping of each wallet account's name to its balance."
         }
       }
     },

rpcserver.go

@@ -25,6 +25,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcutil/psbt"
+	"github.com/btcsuite/btcwallet/waddrmgr"
 	"github.com/btcsuite/btcwallet/wallet/txauthor"
 	"github.com/davecgh/go-spew/spew"
 	proxy "github.com/grpc-ecosystem/grpc-gateway/runtime"
@@ -2769,34 +2770,80 @@ func (r *rpcServer) SubscribePeerEvents(req *lnrpc.PeerEventSubscription,
 func (r *rpcServer) WalletBalance(ctx context.Context,
 	in *lnrpc.WalletBalanceRequest) (*lnrpc.WalletBalanceResponse, error) {
 
-	// Get total balance, from txs that have >= 0 confirmations.
-	totalBal, err := r.server.cc.Wallet.ConfirmedBalance(
-		0, lnwallet.DefaultAccountName,
-	)
+	// Retrieve all existing wallet accounts. We'll compute the confirmed
+	// and unconfirmed balance for each and tally them up.
+	accounts, err := r.server.cc.Wallet.ListAccounts("", nil)
 	if err != nil {
 		return nil, err
 	}
 
-	// Get confirmed balance, from txs that have >= 1 confirmations.
-	// TODO(halseth): get both unconfirmed and confirmed balance in one
-	// call, as this is racy.
-	confirmedBal, err := r.server.cc.Wallet.ConfirmedBalance(
-		1, lnwallet.DefaultAccountName,
+	var totalBalance, confirmedBalance, unconfirmedBalance btcutil.Amount
+	rpcAccountBalances := make(
+		map[string]*lnrpc.WalletAccountBalance, len(accounts),
 	)
-	if err != nil {
-		return nil, err
-	}
+	for _, account := range accounts {
+		// There are two default accounts, one for NP2WKH outputs and
+		// another for P2WKH outputs. The balance will be computed for
+		// both given one call to ConfirmedBalance with the default
+		// wallet and imported account, so we'll skip the second
+		// instance to avoid inflating the balance.
+		switch account.AccountName {
+		case waddrmgr.ImportedAddrAccountName:
+			// Omit the imported account from the response unless we
+			// actually have any keys imported.
+			if account.ImportedKeyCount == 0 {
+				continue
+			}
 
-	// Get unconfirmed balance, from txs with 0 confirmations.
-	unconfirmedBal := totalBal - confirmedBal
+			fallthrough
+
+		case lnwallet.DefaultAccountName:
+			if _, ok := rpcAccountBalances[account.AccountName]; ok {
+				continue
+			}
+
+		default:
+		}
+
+		// Get total balance, from txs that have >= 0 confirmations.
+		totalBal, err := r.server.cc.Wallet.ConfirmedBalance(
+			0, account.AccountName,
+		)
+		if err != nil {
+			return nil, err
+		}
+		totalBalance += totalBal
+
+		// Get confirmed balance, from txs that have >= 1 confirmations.
+		// TODO(halseth): get both unconfirmed and confirmed balance in
+		// one call, as this is racy.
+		confirmedBal, err := r.server.cc.Wallet.ConfirmedBalance(
+			1, account.AccountName,
+		)
+		if err != nil {
+			return nil, err
+		}
+		confirmedBalance += confirmedBal
+
+		// Get unconfirmed balance, from txs with 0 confirmations.
+		unconfirmedBal := totalBal - confirmedBal
+		unconfirmedBalance += unconfirmedBal
+
+		rpcAccountBalances[account.AccountName] = &lnrpc.WalletAccountBalance{
+			ConfirmedBalance:   int64(confirmedBal),
+			UnconfirmedBalance: int64(unconfirmedBal),
+		}
+	}
 
 	rpcsLog.Debugf("[walletbalance] Total balance=%v (confirmed=%v, "+
-		"unconfirmed=%v)", totalBal, confirmedBal, unconfirmedBal)
+		"unconfirmed=%v)", totalBalance, confirmedBalance,
+		unconfirmedBalance)
 
 	return &lnrpc.WalletBalanceResponse{
-		TotalBalance:       int64(totalBal),
-		ConfirmedBalance:   int64(confirmedBal),
-		UnconfirmedBalance: int64(unconfirmedBal),
+		TotalBalance:       int64(totalBalance),
+		ConfirmedBalance:   int64(confirmedBalance),
+		UnconfirmedBalance: int64(unconfirmedBalance),
+		AccountBalance:     rpcAccountBalances,
 	}, nil
 }