Add Decred fee calculation (#613)

* Add decred fee estimation * Fix old issue template * Fix codacy warning
trustwallet · Sep 1, 2019 · 4689c20 · 4689c20
1 parent ad355b3
commit 4689c20
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Showing 6 changed files with 45 additions and 47 deletions.
diff --git a/.github/ISSUE_TEMPLATE/new_blockchain.md b/.github/ISSUE_TEMPLATE/new_blockchain.md
@@ -1,7 +1,13 @@
-<!--- Thank you for requesting new blockchain support -->
+---
+name: New blockchain
+about: Request a new blockchain support
+title: ''
+labels: chain-integration
+assignees: ''
 
-<!--- Before submitting please check to see if this coin was already requested -->
+---
 
+<!--- Before submitting please check to see if this coin was already requested -->
 <!--- Provide as many relevant details about the coin -->
 ## Description
 

diff --git a/src/Bitcoin/TransactionBuilder.h b/src/Bitcoin/TransactionBuilder.h
@@ -16,7 +16,8 @@
 
 namespace TW::Bitcoin {
 
-struct TransactionBuilder {
+class TransactionBuilder {
+public:
     /// Plans a transaction by selecting UTXOs and calculating fees.
     static TransactionPlan plan(const Bitcoin::Proto::SigningInput& input) {
         auto plan = TransactionPlan();

diff --git a/src/Bitcoin/UnspentCalculator.cpp b/src/Bitcoin/UnspentCalculator.cpp
@@ -16,6 +16,16 @@ UnspentCalculator UnspentCalculator::getCalculator(TWCoinType coinType) {
         auto calcInput = [](int64_t byteFee) -> int64_t { return 0; };
         return UnspentCalculator(calc, calcInput);
     }
+    case TWCoinTypeDecred: {
+        auto calc = [](size_t inputs, size_t outputs, int64_t byteFee) -> int64_t { 
+            const auto txsize = ((166 * inputs) + (38 * outputs) + 12);
+            return int64_t(txsize) * byteFee;
+        };
+        auto calcInput = [](int64_t byteFee) -> int64_t { 
+            return int64_t(166) * byteFee;
+        };
+        return UnspentCalculator(calc, calcInput);
+    }
     default:
         return UnspentCalculator();
     }

diff --git a/src/Decred/Signer.h b/src/Decred/Signer.h
@@ -46,7 +46,10 @@ class Signer {
     Signer() = default;
 
     /// Initializes a transaction signer with signing input.
-    explicit Signer(Bitcoin::Proto::SigningInput&& input) : input(input) {}
+    explicit Signer(Bitcoin::Proto::SigningInput&& input) 
+      : input(input), plan(TransactionBuilder::plan(input)) {
+        transaction = TransactionBuilder::build(plan, input.to_address(), input.change_address());
+    }
 
     /// Initializes a transaction signer with signing input, a transaction, and
     /// a hash type.

diff --git a/src/Decred/TransactionBuilder.h b/src/Decred/TransactionBuilder.h
@@ -8,6 +8,7 @@
 
 #include "Transaction.h"
 #include "../Bitcoin/TransactionPlan.h"
+#include "../Bitcoin/TransactionBuilder.h"
 #include "../Bitcoin/UnspentSelector.h"
 #include "../proto/Bitcoin.pb.h"
 #include "../proto/Decred.pb.h"
@@ -21,45 +22,7 @@ namespace TW::Decred {
 struct TransactionBuilder {
     /// Plans a transaction by selecting UTXOs and calculating fees.
     static Bitcoin::TransactionPlan plan(const Bitcoin::Proto::SigningInput& input) {
-        auto plan = Bitcoin::TransactionPlan();
-        plan.amount = input.amount();
-
-        auto output_size = 2;
-        auto calculator =
-            Bitcoin::UnspentCalculator::getCalculator(static_cast<TWCoinType>(input.coin_type()));
-        auto unspentSelector = Bitcoin::UnspentSelector(calculator);
-        if (input.use_max_amount() && Bitcoin::UnspentSelector::sum(input.utxo()) == plan.amount) {
-            output_size = 1;
-            int64_t newAmount = 0;
-            auto input_size = 0;
-
-            for (auto utxo : input.utxo()) {
-                if (utxo.amount() >
-                    unspentSelector.calculator.calculateSingleInput(input.byte_fee())) {
-                    input_size++;
-                    newAmount += utxo.amount();
-                }
-            }
-
-            plan.amount = newAmount - unspentSelector.calculator.calculate(input_size, output_size,
-                                                                           input.byte_fee());
-            plan.amount = std::max(Bitcoin::Amount(0), plan.amount);
-        }
-
-        plan.utxos =
-            unspentSelector.select(input.utxo(), plan.amount, input.byte_fee(), output_size);
-        plan.fee =
-            unspentSelector.calculator.calculate(plan.utxos.size(), output_size, input.byte_fee());
-
-        plan.availableAmount = Bitcoin::UnspentSelector::sum(plan.utxos);
-
-        if (plan.amount > plan.availableAmount - plan.fee) {
-            plan.amount = std::max(Bitcoin::Amount(0), plan.availableAmount - plan.fee);
-        }
-
-        plan.change = plan.availableAmount - plan.amount - plan.fee;
-
-        return plan;
+        return Bitcoin::TransactionBuilder::plan(input);
     }
 
     /// Builds a transaction by selecting UTXOs and calculating fees.

diff --git a/tests/Bitcoin/TransactionPlanTests.cpp b/tests/Bitcoin/TransactionPlanTests.cpp
@@ -10,6 +10,7 @@
 #include "Bitcoin/TransactionPlan.h"
 #include "Bitcoin/TransactionBuilder.h"
 #include "proto/Bitcoin.pb.h"
+#include <TrustWalletCore/TWCoinType.h>
 
 #include <gtest/gtest.h>
 
@@ -34,11 +35,12 @@ inline auto buildUTXO(const OutPoint& outPoint, Amount amount) {
     return utxo;
 }
 
-inline auto buildSigningInput(Amount amount, int byteFee, const std::vector<Proto::UnspentTransaction> utxos, bool useMaxAmount) {
+inline auto buildSigningInput(Amount amount, int byteFee, const std::vector<Proto::UnspentTransaction>& utxos, bool useMaxAmount, enum TWCoinType coin) {
     Proto::SigningInput input;
     input.set_amount(amount);
     input.set_byte_fee(byteFee);
     input.set_use_max_amount(useMaxAmount);
+    input.set_coin_type(coin);
     *input.mutable_utxo() = { utxos.begin(), utxos.end() };
     return input;
 }
@@ -52,7 +54,7 @@ TEST(TransactionPlan, NonMaxAmount) {
     utxos.push_back(buildUTXO(txOutPoint, 50000));
     utxos.push_back(buildUTXO(txOutPoint, 120000));
 
-    auto sigingInput = buildSigningInput(10000, 1, utxos, false);
+    auto sigingInput = buildSigningInput(10000, 1, utxos, false, TWCoinTypeBitcoin);
     auto txPlan = TransactionBuilder::plan(sigingInput);
 
     ASSERT_EQ(txPlan.amount, 10000);
@@ -70,7 +72,7 @@ TEST(TransactionPlan, MaxAmount) {
 
     ASSERT_EQ(sum(utxos), 39200);
 
-    auto sigingInput = buildSigningInput(39200, 32, utxos, true);
+    auto sigingInput = buildSigningInput(39200, 32, utxos, true, TWCoinTypeBitcoin);
     auto txPlan = TransactionBuilder::plan(sigingInput);
 
     ASSERT_EQ(txPlan.availableAmount, 30000);
@@ -87,11 +89,24 @@ TEST(TransactionPlan, MaxAmountDoge) {
 
     ASSERT_EQ(sum(utxos), Amount(2300000000));
 
-    auto sigingInput = buildSigningInput(Amount(2300000000), 100, utxos, true);
+    auto sigingInput = buildSigningInput(Amount(2300000000), 100, utxos, true, TWCoinTypeDogecoin);
     auto txPlan = TransactionBuilder::plan(sigingInput);
 
     ASSERT_EQ(txPlan.availableAmount, Amount(2300000000));
     ASSERT_EQ(txPlan.amount, Amount(2299951200));
     ASSERT_EQ(txPlan.change, 0);
     ASSERT_EQ(txPlan.fee, 48800);
 }
+
+TEST(TransactionPlan, AmountDecred) {
+    auto utxos = std::vector<Proto::UnspentTransaction>();
+    utxos.push_back(buildUTXO(txOutPoint, Amount(39900000)));
+
+    auto sigingInput = buildSigningInput(Amount(10000000), 10, utxos, false, TWCoinTypeDecred);
+    auto txPlan = TransactionBuilder::plan(sigingInput);
+
+    ASSERT_EQ(txPlan.availableAmount, Amount(39900000));
+    ASSERT_EQ(txPlan.amount, Amount(10000000));
+    ASSERT_EQ(txPlan.change, 29897460);
+    ASSERT_EQ(txPlan.fee, 2540);
+}