feat(participation): isolate opted-out combat

src/main/java/games/dmg/spigottyrant/ParticipationCombatListener.java

@@ -0,0 +1,64 @@
+package games.dmg.spigottyrant;
+
+import java.util.Map;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.ChatColor;
+import org.bukkit.entity.Player;
+import org.bukkit.entity.Projectile;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.entity.EntityDamageByEntityEvent;
+
+public final class ParticipationCombatListener implements Listener {
+    public static final String OPTED_OUT_MESSAGE =
+        "That player has chosen not to take part in the Tyrant event.";
+
+    private final TyrantStateManager stateManager;
+    private final ParticipationCombatService combat;
+
+    public ParticipationCombatListener(
+        TyrantStateManager stateManager,
+        ParticipationCombatService combat
+    ) {
+        this.stateManager = stateManager;
+        this.combat = combat;
+    }
+
+    @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
+    public void onDamage(EntityDamageByEntityEvent event) {
+        if (!(event.getEntity() instanceof Player target)) {
+            return;
+        }
+        Optional<Player> attacker = attackingPlayer(event);
+        if (attacker.isEmpty()) {
+            return;
+        }
+        Player source = attacker.orElseThrow();
+        Map<UUID, PlayerState> players = stateManager.players();
+        PlayerState attackerState = players.getOrDefault(
+            source.getUniqueId(),
+            PlayerState.newPlayer(source.getUniqueId(), source.getName())
+        );
+        PlayerState targetState = players.getOrDefault(
+            target.getUniqueId(),
+            PlayerState.newPlayer(target.getUniqueId(), target.getName())
+        );
+        if (combat.blocks(stateManager.game(), attackerState, targetState)) {
+            event.setCancelled(true);
+            source.sendMessage(ChatColor.YELLOW + OPTED_OUT_MESSAGE);
+        }
+    }
+
+    private static Optional<Player> attackingPlayer(EntityDamageByEntityEvent event) {
+        if (event.getDamager() instanceof Player player) {
+            return Optional.of(player);
+        }
+        if (event.getDamager() instanceof Projectile projectile
+                && projectile.getShooter() instanceof Player player) {
+            return Optional.of(player);
+        }
+        return Optional.empty();
+    }
+}

src/main/java/games/dmg/spigottyrant/ParticipationCombatService.java

@@ -0,0 +1,24 @@
+package games.dmg.spigottyrant;
+
+public final class ParticipationCombatService {
+    public boolean blocks(
+        GameState game,
+        PlayerState attacker,
+        PlayerState target
+    ) {
+        if (game.lifecycle() != GameLifecycle.RUNNING) {
+            return false;
+        }
+        boolean attackerOptedOut = attacker.optedOutUntil().isPresent();
+        boolean targetOptedOut = target.optedOutUntil().isPresent();
+        boolean attackerTyrantSide = isTyrantSide(game, attacker);
+        boolean targetTyrantSide = isTyrantSide(game, target);
+        return (attackerTyrantSide && targetOptedOut)
+            || (attackerOptedOut && targetTyrantSide);
+    }
+
+    private static boolean isTyrantSide(GameState game, PlayerState player) {
+        return game.tyrantId().filter(player.playerId()::equals).isPresent()
+            || player.tyrantClass() != TyrantClass.NONE;
+    }
+}

src/main/java/games/dmg/spigottyrant/SpigotTyrantPlugin.java

@@ -122,6 +122,12 @@ public final class SpigotTyrantPlugin extends JavaPlugin {
             ),
             this
         );
+        getServer().getPluginManager().registerEvents(
+            new ParticipationCombatListener(
+                stateManager, new ParticipationCombatService()
+            ),
+            this
+        );
         getServer().getPluginManager().registerEvents(
             new VigilanteCombatListener(
                 stateManager, combatTracker, clock, settings.vigilanteCombatDuration()