accounts: add functionality to update balance by given amount

.github/workflows/main.yml

@@ -253,6 +253,8 @@ jobs:
         unit_type:
           - unit-race
           - unit
+          - unit dbbackend=postgres
+          - unit dbbackend=sqlite
     steps:
       - name: git checkout
         uses: actions/checkout@v4

accounts/interface.go

@@ -1,7 +1,9 @@
 package accounts
 
 import (
+	"bytes"
 	"context"
+	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -55,6 +57,31 @@ func ParseAccountID(idStr string) (*AccountID, error) {
 	return &id, nil
 }
 
+// ToInt64 converts an AccountID to its int64 representation.
+func (a AccountID) ToInt64() (int64, error) {
+	var value int64
+	buf := bytes.NewReader(a[:])
+	if err := binary.Read(buf, byteOrder, &value); err != nil {
+		return 0, err
+	}
+
+	return value, nil
+}
+
+// AccountIDFromInt64 converts an int64 to an AccountID.
+func AccountIDFromInt64(value int64) (AccountID, error) {
+	var (
+		a   = AccountID{}
+		buf = new(bytes.Buffer)
+	)
+	if err := binary.Write(buf, binary.BigEndian, value); err != nil {
+		return a, err
+	}
+	copy(a[:], buf.Bytes())
+
+	return a, nil
+}
+
 // String returns the string representation of the AccountID.
 func (a AccountID) String() string {
 	return hex.EncodeToString(a[:])

accounts/rpcserver.go

@@ -132,6 +132,14 @@ func (s *RPCServer) UpdateAccount(ctx context.Context,
 	return marshalAccount(account), nil
 }
 
+// UpdateBalance adds or deducts an amount from an existing account in the
+// account database.
+func (s *RPCServer) UpdateBalance(ctx context.Context,
+	req *litrpc.UpdateAccountBalanceRequest) (*litrpc.Account, error) {
+
+	return nil, fmt.Errorf("not implemented")
+}
+
 // ListAccounts returns all accounts that are currently stored in the account
 // database.
 func (s *RPCServer) ListAccounts(ctx context.Context,