step 1: minimize timecomplexity

plugin/src/main/java/com/craftmend/openaudiomc/spigot/modules/voicechat/tasks/PlayerProximityTicker.java

@@ -12,6 +12,7 @@
 import com.craftmend.openaudiomc.generic.networking.interfaces.NetworkingService;
 import com.craftmend.openaudiomc.generic.utils.data.Filter;
 import com.craftmend.openaudiomc.spigot.modules.voicechat.filters.PeerFilter;
+import com.craftmend.openaudiomc.spigot.modules.voicechat.utils.CombinationChecker;
 import lombok.Setter;
 import org.bukkit.entity.Player;
 
@@ -76,6 +77,8 @@ public void run() {
                 .filter((c) -> c.getRtcSessionManager().isReady())
                 .toArray(ClientConnection[]::new);
 
+        CombinationChecker combinationChecker = new CombinationChecker();
+
         for (ClientConnection client : allClients) {
 
             // am I valid? no? do nothing.
@@ -92,19 +95,21 @@ public void run() {
             // clear the applicable players if i'm disabled myself
             if (!client.getRtcSessionManager().getBlockReasons().isEmpty()) applicableClients.clear();
 
-            // remove moderators, if I'm not moderating myself
-            if (!client.getSession().isModerating()) {
-                applicableClients.removeIf(other -> other.getSession().isModerating());
-            }
-
             // find players that we don't have yet
             applicableClients
                     .stream()
+                    .filter(peer -> {
+                        if (combinationChecker.hasChecked(client.getUser().getUniqueId(), peer.getUser().getUniqueId())) return false;
+                        return client.getSession().isModerating() && other.getSession().isModerating();
+                    })
                     .filter(peer -> !client.getRtcSessionManager().getCurrentProximityPeers().contains(peer.getOwner().getUniqueId()))
                     .filter(peer -> !peer.getSession().isResetVc()) // they are already resetting, give it a sec
                     .filter(peer -> (client.isModerating() || !peer.isModerating())) // ignore moderators
 
                     .forEach(peer -> {
+                        // register check
+                        combinationChecker.registerCheck(client.getUser().getUniqueId(), peer.getUser().getUniqueId());
+
                         // am I moderating compared to this peer?
                         boolean isModerating = client.isModerating() && !peer.isModerating();
 

plugin/src/main/java/com/craftmend/openaudiomc/spigot/modules/voicechat/utils/CombinationChecker.java

@@ -0,0 +1,35 @@
+package com.craftmend.openaudiomc.spigot.modules.voicechat.utils;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+public class CombinationChecker {
+
+    /**
+     * This is a small utility class that helps with the combination of two UUIDs.
+     * We use it to cut down on iterations during proximity checks, where we want to
+     * register AA-AA-AA>BB-BB-BB and exempt BB-BB-BB>AA-AA-AA.
+     * This implementation has some room for error, because the hashcode method of UUID
+     * does not guarantee a unique hash for each UUID, but it's good enough for our use case.
+     * https://stackoverflow.com/questions/24876188/how-big-is-the-chance-to-get-a-java-uuid-randomuuid-collision
+     * If this ever happens then well, guess some minecraft has worse odds than winning the lottery but we'll have to fix it
+     */
+
+    private Set<Integer> checkedCombinations = new HashSet<>();
+
+    public boolean contains(UUID player1, UUID player2) {
+        int hashCode = getCombinedHashCode(player1, player2);
+        return checkedCombinations.contains(hashCode);
+    }
+
+    public void mark(UUID player1, UUID player2) {
+        int hashCode = getCombinedHashCode(player1, player2);
+        checkedCombinations.add(hashCode);
+    }
+
+    private int getCombinedHashCode(UUID player1, UUID player2) {
+        return player1.hashCode() ^ player2.hashCode();
+    }
+
+}