From 51a9c00b4de707e0a6a1a68ca6f8e38d86c72d94 Mon Sep 17 00:00:00 2001
From: Andrew Chow <achow101-github@achow101.com>
Date: Mon, 27 Sep 2021 23:22:34 -0400
Subject: [PATCH] Return SelectionResult from SelectCoinsSRD

Changes SelectCoinsSRD to return a SelectionResult.
---
 src/wallet/coinselection.cpp | 10 ++++------
 src/wallet/coinselection.h   |  4 ++--
 src/wallet/spend.cpp         |  7 +++----
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/src/wallet/coinselection.cpp b/src/wallet/coinselection.cpp
index 97918429e0..a85547f5b2 100644
--- a/src/wallet/coinselection.cpp
+++ b/src/wallet/coinselection.cpp
@@ -166,10 +166,9 @@ std::optional<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_poo
     return result;
 }
 
-std::optional<std::pair<std::set<CInputCoin>, CAmount>> SelectCoinsSRD(const std::vector<OutputGroup>& utxo_pool, CAmount target_value)
+std::optional<SelectionResult> SelectCoinsSRD(const std::vector<OutputGroup>& utxo_pool, CAmount target_value)
 {
-    std::set<CInputCoin> out_set;
-    CAmount value_ret = 0;
+    SelectionResult result(target_value);
 
     std::vector<size_t> indexes;
     indexes.resize(utxo_pool.size());
@@ -181,10 +180,9 @@ std::optional<std::pair<std::set<CInputCoin>, CAmount>> SelectCoinsSRD(const std
         const OutputGroup& group = utxo_pool.at(i);
         Assume(group.GetSelectionAmount() > 0);
         selected_eff_value += group.GetSelectionAmount();
-        value_ret += group.m_value;
-        util::insert(out_set, group.m_outputs);
+        result.AddInput(group);
         if (selected_eff_value >= target_value) {
-            return std::make_pair(out_set, value_ret);
+            return result;
         }
     }
     return std::nullopt;
diff --git a/src/wallet/coinselection.h b/src/wallet/coinselection.h
index 23bdff73c2..aa5ec822ec 100644
--- a/src/wallet/coinselection.h
+++ b/src/wallet/coinselection.h
@@ -241,9 +241,9 @@ std::optional<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_poo
  *
  * @param[in]  utxo_pool    The positive effective value OutputGroups eligible for selection
  * @param[in]  target_value The target value to select for
- * @returns If successful, a pair of set of outputs and total selected value, otherwise, std::nullopt
+ * @returns If successful, a SelectionResult, otherwise, std::nullopt
  */
-std::optional<std::pair<std::set<CInputCoin>, CAmount>> SelectCoinsSRD(const std::vector<OutputGroup>& utxo_pool, CAmount target_value);
+std::optional<SelectionResult> SelectCoinsSRD(const std::vector<OutputGroup>& utxo_pool, CAmount target_value);
 
 // Original coin selection algorithm as a fallback
 std::optional<SelectionResult> KnapsackSolver(std::vector<OutputGroup>& groups, const CAmount& nTargetValue);
diff --git a/src/wallet/spend.cpp b/src/wallet/spend.cpp
index e953c83c10..ef8885e738 100644
--- a/src/wallet/spend.cpp
+++ b/src/wallet/spend.cpp
@@ -402,10 +402,9 @@ bool AttemptSelection(const CWallet& wallet, const CAmount& nTargetValue, const
     // We include the minimum final change for SRD as we do want to avoid making really small change.
     // KnapsackSolver does not need this because it includes MIN_CHANGE internally.
     const CAmount srd_target = nTargetValue + coin_selection_params.m_change_fee + MIN_FINAL_CHANGE;
-    auto srd_result = SelectCoinsSRD(positive_groups, srd_target);
-    if (srd_result != std::nullopt) {
-        const auto waste = GetSelectionWaste(srd_result->first, coin_selection_params.m_cost_of_change, srd_target, !coin_selection_params.m_subtract_fee_outputs);
-        results.emplace_back(std::make_tuple(waste, std::move(srd_result->first), srd_result->second));
+    if (auto srd_result{SelectCoinsSRD(positive_groups, srd_target)}) {
+        srd_result->ComputeAndSetWaste(coin_selection_params.m_cost_of_change);
+        results.emplace_back(std::make_tuple(srd_result->GetWaste(), srd_result->GetInputSet(), srd_result->GetSelectedValue()));
     }
 
     if (results.size() == 0) {