[Quest API] Add Parcel Sending to Perl/Lua (#4287)

common/repositories/character_parcels_repository.h

@@ -78,6 +78,37 @@ public:
 
 		return all_entries;
 	}
+
+	static int GetNextFreeParcelSlot(Database& db, const uint32 character_id, const uint32 max_slots)
+	{
+		const auto& l = CharacterParcelsRepository::GetWhere(
+			db,
+			fmt::format(
+				"char_id = '{}' ORDER BY slot_id ASC",
+				character_id
+			)
+		);
+
+		if (l.empty()) {
+			return PARCEL_BEGIN_SLOT;
+		}
+
+		for (uint32 i = PARCEL_BEGIN_SLOT; i <= max_slots; i++) {
+			auto it = std::find_if(
+				l.cbegin(),
+				l.cend(),
+				[&](const auto &x) {
+					return x.slot_id == i;
+				}
+			);
+
+			if (it == l.end()) {
+				return i;
+			}
+		}
+
+		return INVALID_INDEX;
+	}
 };
 
 #endif //EQEMU_CHARACTER_PARCELS_REPOSITORY_H