Support for swapping two creatures on a side.

Signed-off-by: Deukhoofd <Deukhoofd@gmail.com>

CInterface/Battling/BattleSide.cpp

@@ -38,3 +38,7 @@ export uint8_t CreatureLib_BattleSide_MarkSlotAsUnfillable(BattleSide* p, Creatu
 export bool CreatureLib_BattleSide_IsDefeated(BattleSide* p) { return p->IsDefeated(); }
 export bool CreatureLib_BattleSide_HasFled(BattleSide* p) { return p->HasFled(); }
 export void CreatureLib_BattleSide_MarkAsFled(BattleSide* p) { p->MarkAsFled(); }
+
+export u8 CreatureLib_BattleSide_SwapPositions(u8& out, BattleSide* p, u8 a, u8 b) {
+    Try(out = p->SwapPositions(a, b);)
+}

src/Battling/Models/BattleSide.cpp

@@ -90,3 +90,35 @@ uint8_t BattleSide::GetRandomCreatureIndex() {
     // TODO: Consider adding parameter to only get index for available creatures.
     return _battle->GetRandom()->Get(_creaturesPerSide);
 }
+bool BattleSide::SwapPositions(u8 a, u8 b) {
+    // If out of range, don't allow swapping.
+    if (a >= _creaturesPerSide || b >= _creaturesPerSide) {
+        return false;
+    }
+
+    // If the two indices are the same, don't allow swapping.
+    if (a == b) {
+        return false;
+    }
+
+    // Fetch parties for the two indices.
+    BattleParty* partyA = nullptr;
+    BattleParty* partyB = nullptr;
+    for (auto* party : this->_battle->GetParties()) {
+        if (party->IsResponsibleForIndex(_index, a)) {
+            partyA = party;
+        }
+        if (party->IsResponsibleForIndex(_index, b)) {
+            partyB = party;
+        }
+    }
+    // Don't allow swapping if different parties are responsible for the indices.
+    if (partyA != partyB) {
+        return false;
+    }
+
+    auto creatureA = _creatures[a];
+    _creatures[a] = _creatures[b];
+    _creatures[b] = creatureA;
+    return true;
+}

src/Battling/Models/BattleSide.hpp

@@ -85,6 +85,8 @@ namespace CreatureLib::Battling {
         void MarkAsFled() noexcept { _hasFled = true; }
 
         uint8_t GetRandomCreatureIndex();
+
+        bool SwapPositions(u8 a, u8 b);
     };
 }