From 234e9ad607f92cf150851dfeaa0ce4d9fba38244 Mon Sep 17 00:00:00 2001
From: JoeGruff <joegruffins@gmail.com>
Date: Thu, 8 Feb 2024 19:58:58 +0900
Subject: [PATCH] decred: Fix fee estimation.
---
cw_decred/lib/api/libdcrwallet.dart | 12 ++--
cw_decred/lib/transaction_priority.dart | 19 ++++++
cw_decred/lib/wallet.dart | 69 +++++++++++++++++++---
lib/entities/priority_for_wallet_type.dart | 3 +
4 files changed, 92 insertions(+), 11 deletions(-)
diff --git a/cw_decred/lib/api/libdcrwallet.dart b/cw_decred/lib/api/libdcrwallet.dart
index 12308b8ef..156ac3641 100644
--- a/cw_decred/lib/api/libdcrwallet.dart
+++ b/cw_decred/lib/api/libdcrwallet.dart
@@ -146,10 +146,14 @@ Map balance(String walletName) {
return jsonDecode(res.payload);
}
-int calculateEstimatedFeeWithFeeRate(int feeRate, int amount) {
- // Ideally we create a tx with wallet going to this amount and just return
- // the fee we get back. TODO.
- return 123000;
+String estimateFee(String walletName, int numBlocks) {
+ final cName = walletName.toCString();
+ final cNumBlocks = numBlocks.toString().toCString();
+ final res = executePayloadFn(
+ fn: () => dcrwalletApi.estimateFee(cName, cNumBlocks),
+ ptrsToFree: [cName, cNumBlocks],
+ );
+ return res.payload;
}
String createSignedTransaction(
diff --git a/cw_decred/lib/transaction_priority.dart b/cw_decred/lib/transaction_priority.dart
index f9e601539..1e1482f2f 100644
--- a/cw_decred/lib/transaction_priority.dart
+++ b/cw_decred/lib/transaction_priority.dart
@@ -52,3 +52,22 @@ class DecredTransactionPriority extends TransactionPriority {
String labelWithRate(int rate) => '${toString()} ($rate ${units}/byte)';
}
+
+class FeeCache {
+ int _feeRate;
+ DateTime stamp;
+ FeeCache(this._feeRate) : this.stamp = DateTime(0, 0, 0, 0, 0, 0, 0, 0);
+
+ bool isOld() {
+ return this.stamp.add(const Duration(minutes: 30)).isBefore(DateTime.now());
+ }
+
+ void update(int feeRate) {
+ this._feeRate = feeRate;
+ this.stamp = DateTime.now();
+ }
+
+ int feeRate() {
+ return this._feeRate;
+ }
+}
diff --git a/cw_decred/lib/wallet.dart b/cw_decred/lib/wallet.dart
index 32e7d8a48..7aec45cfb 100644
--- a/cw_decred/lib/wallet.dart
+++ b/cw_decred/lib/wallet.dart
@@ -44,11 +44,17 @@ abstract class DecredWalletBase extends WalletBase<DecredBalance,
transactionHistory = DecredTransactionHistory();
}
- final defaultFeeRate = 10000;
+ // NOTE: Hitting this max fee would be unexpected with current on chain use
+ // but this may need to be updated in the future.
+ final maxFeeRate = 100000;
+ static final defaultFeeRate = 10000;
final String _password;
final idPrefix = "decred_";
bool connecting = false;
String persistantPeer = "";
+ FeeCache feeRateFast = FeeCache(defaultFeeRate);
+ FeeCache feeRateMedium = FeeCache(defaultFeeRate);
+ FeeCache feeRateSlow = FeeCache(defaultFeeRate);
Timer? syncTimer;
Box<UnspentCoinsInfo> unspentCoinsInfo;
@@ -240,7 +246,6 @@ abstract class DecredWalletBase extends WalletBase<DecredBalance,
outputs.add(o);
}
;
- // TODO: Fix fee rate.
final signReq = {
"inputs": inputs,
"ignoreInputs": ignoreInputs,
@@ -264,17 +269,67 @@ abstract class DecredWalletBase extends WalletBase<DecredBalance,
}
int feeRate(TransactionPriority priority) {
- // TODO
- return 1000;
+ if (!(priority is DecredTransactionPriority)) {
+ return defaultFeeRate;
+ }
+ int Function(int nb) feeForNb = (int nb) {
+ try {
+ final feeStr = libdcrwallet.estimateFee(walletInfo.name, nb);
+ var fee = int.parse(feeStr);
+ if (fee > maxFeeRate) {
+ throw "dcr fee returned from estimate fee was over max";
+ } else if (fee <= 0) {
+ throw "dcr fee returned from estimate fee was zero";
+ }
+ return fee;
+ } catch (e) {
+ print(e);
+ return defaultFeeRate;
+ }
+ };
+ final p = priority as DecredTransactionPriority;
+ switch (p) {
+ case DecredTransactionPriority.slow:
+ if (feeRateSlow.isOld()) {
+ feeRateSlow.update(feeForNb(4));
+ }
+ return feeRateSlow.feeRate();
+ case DecredTransactionPriority.medium:
+ if (feeRateMedium.isOld()) {
+ feeRateMedium.update(feeForNb(2));
+ }
+ return feeRateMedium.feeRate();
+ case DecredTransactionPriority.fast:
+ if (feeRateFast.isOld()) {
+ feeRateFast.update(feeForNb(1));
+ }
+ return feeRateFast.feeRate();
+ }
+ return defaultFeeRate;
}
@override
int calculateEstimatedFee(TransactionPriority priority, int? amount) {
if (priority is DecredTransactionPriority) {
- return libdcrwallet.calculateEstimatedFeeWithFeeRate(
- this.feeRate(priority), amount ?? 0);
- }
+ final P2PKHOutputSize =
+ 36; // 8 bytes value + 2 bytes version + at least 1 byte varint script size + P2PKHPkScriptSize
+ // MsgTxOverhead is 4 bytes version (lower 2 bytes for the real transaction
+ // version and upper 2 bytes for the serialization type) + 4 bytes locktime
+ // + 4 bytes expiry + 3 bytes of varints for the number of transaction
+ // inputs (x2 for witness and prefix) and outputs
+ final MsgTxOverhead = 15;
+ // TxInOverhead is the overhead for a wire.TxIn with a scriptSig length <
+ // 254. prefix (41 bytes) + ValueIn (8 bytes) + BlockHeight (4 bytes) +
+ // BlockIndex (4 bytes) + sig script var int (at least 1 byte)
+ final TxInOverhead = 57;
+ final P2PKHInputSize = TxInOverhead +
+ 109; // TxInOverhead (57) + var int (1) + P2PKHSigScriptSize (108)
+ // Estimate using a transaction consuming three inputs and paying to one
+ // address with change.
+ return this.feeRate(priority) *
+ (MsgTxOverhead + P2PKHInputSize * 3 + P2PKHOutputSize * 2);
+ }
return 0;
}
diff --git a/lib/entities/priority_for_wallet_type.dart b/lib/entities/priority_for_wallet_type.dart
index 534287494..3dd85c92c 100644
--- a/lib/entities/priority_for_wallet_type.dart
+++ b/lib/entities/priority_for_wallet_type.dart
@@ -5,6 +5,7 @@ import 'package:cake_wallet/haven/haven.dart';
import 'package:cake_wallet/monero/monero.dart';
import 'package:cake_wallet/polygon/polygon.dart';
import 'package:cake_wallet/wownero/wownero.dart';
+import 'package:cake_wallet/decred/decred.dart';
import 'package:cw_core/transaction_priority.dart';
import 'package:cw_core/wallet_type.dart';
@@ -32,6 +33,8 @@ List<TransactionPriority> priorityForWalletType(WalletType type) {
case WalletType.solana:
case WalletType.tron:
return [];
+ case WalletType.decred:
+ return decred!.getTransactionPriorities();
default:
return [];
}