wallet: remove fetch pre-selected-inputs responsibility from SelectCoins

so if there is an error in any of the pre-set coins, we can fail right away
without computing the wallet available coins set (calling `AvailableCoins`)
which is a slow operation as it goes through the entire wallet's txes map.

----------------------

And to make the Coin Selection flow cleared, have decoupled SelectCoins in two functions:

1) AutomaticCoinSelection.
2) SelectCoins.

1) AutomaticCoinSelection:
   Receives a set of coins and selects the best subset of them to
   cover the target amount.

2) SelectCoins
   In charge of select all the user manually selected coins first ("pre-set inputs"), and
   if coin_control 'm_allow_other_inputs=true', call 'AutomaticCoinSelection' to select a
   subset of coins owned by the wallet to cover for the target - preset_inputs.total_amount
   remaining value.

1 files changed, 19 insertions, 8 deletions

diff --git a/src/wallet/test/coinselector_tests.cpp b/src/wallet/test/coinselector_tests.cpp
index 23f024247d..f9c8c8ee9d 100644
--- a/src/wallet/test/coinselector_tests.cpp
+++ b/src/wallet/test/coinselector_tests.cpp
@@ -338,9 +338,13 @@ BOOST_AUTO_TEST_CASE(bnb_search_test)
         add_coin(available_coins, *wallet, 2 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
         CCoinControl coin_control;
         coin_control.m_allow_other_inputs = true;
-        coin_control.Select(available_coins.All().at(0).outpoint);
+        COutput select_coin = available_coins.All().at(0);
+        coin_control.Select(select_coin.outpoint);
+        PreSelectedInputs selected_input;
+        selected_input.Insert(select_coin, coin_selection_params_bnb.m_subtract_fee_outputs);
+        available_coins.coins[OutputType::BECH32].erase(available_coins.coins[OutputType::BECH32].begin());
         coin_selection_params_bnb.m_effective_feerate = CFeeRate(0);
-        const auto result10 = SelectCoins(*wallet, available_coins, 10 * CENT, coin_control, coin_selection_params_bnb);
+        const auto result10 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
         BOOST_CHECK(result10);
     }
     {
@@ -363,7 +367,7 @@ BOOST_AUTO_TEST_CASE(bnb_search_test)
         expected_result.Clear();
         add_coin(10 * CENT, 2, expected_result);
         CCoinControl coin_control;
-        const auto result11 = SelectCoins(*wallet, available_coins, 10 * CENT, coin_control, coin_selection_params_bnb);
+        const auto result11 = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, 10 * CENT, coin_control, coin_selection_params_bnb);
         BOOST_CHECK(EquivalentResult(expected_result, *result11));
         available_coins.Clear();
 
@@ -378,7 +382,7 @@ BOOST_AUTO_TEST_CASE(bnb_search_test)
         expected_result.Clear();
         add_coin(9 * CENT, 2, expected_result);
         add_coin(1 * CENT, 2, expected_result);
-        const auto result12 = SelectCoins(*wallet, available_coins, 10 * CENT, coin_control, coin_selection_params_bnb);
+        const auto result12 = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, 10 * CENT, coin_control, coin_selection_params_bnb);
         BOOST_CHECK(EquivalentResult(expected_result, *result12));
         available_coins.Clear();
 
@@ -394,8 +398,12 @@ BOOST_AUTO_TEST_CASE(bnb_search_test)
         add_coin(9 * CENT, 2, expected_result);
         add_coin(1 * CENT, 2, expected_result);
         coin_control.m_allow_other_inputs = true;
-        coin_control.Select(available_coins.All().at(1).outpoint); // pre select 9 coin
-        const auto result13 = SelectCoins(*wallet, available_coins, 10 * CENT, coin_control, coin_selection_params_bnb);
+        COutput select_coin = available_coins.All().at(1); // pre select 9 coin
+        coin_control.Select(select_coin.outpoint);
+        PreSelectedInputs selected_input;
+        selected_input.Insert(select_coin, coin_selection_params_bnb.m_subtract_fee_outputs);
+        available_coins.coins[OutputType::BECH32].erase(++available_coins.coins[OutputType::BECH32].begin());
+        const auto result13 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
         BOOST_CHECK(EquivalentResult(expected_result, *result13));
     }
 }
@@ -783,7 +791,7 @@ BOOST_AUTO_TEST_CASE(SelectCoins_test)
         cs_params.m_cost_of_change = 1;
         cs_params.min_viable_change = 1;
         CCoinControl cc;
-        const auto result = SelectCoins(*wallet, available_coins, target, cc, cs_params);
+        const auto result = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, target, cc, cs_params);
         BOOST_CHECK(result);
         BOOST_CHECK_GE(result->GetSelectedValue(), target);
     }
@@ -965,7 +973,10 @@ BOOST_AUTO_TEST_CASE(SelectCoins_effective_value_test)
     cc.SetInputWeight(output.outpoint, 148);
     cc.SelectExternal(output.outpoint, output.txout);
 
-    const auto result = SelectCoins(*wallet, available_coins, target, cc, cs_params);
+    const auto preset_inputs = *Assert(FetchSelectedInputs(*wallet, cc, cs_params));
+    available_coins.coins[OutputType::BECH32].erase(available_coins.coins[OutputType::BECH32].begin());
+
+    const auto result = SelectCoins(*wallet, available_coins, preset_inputs, target, cc, cs_params);
     BOOST_CHECK(!result);
 }