Avoid saved WorldGuard regions during allocation

src/main/java/com/majinnaibu/bukkitplugins/metropolis/MetropolisPlugin.java

@@ -90,6 +90,7 @@ public class MetropolisPlugin extends JavaPlugin {
   private HashMap<UUID, UserOverride> _userOverrides;
   private List<HomePermissionOverride> _permissionOverrides;
   private HashMap<UUID, Integer> _currentHomes;
+  private List<Cuboid> _savedWorldGuardBounds = List.of();
 
   private PlayerJoinListener _playerJoinListener = null;
 
@@ -891,7 +892,7 @@ public class MetropolisPlugin extends JavaPlugin {
       return true;
     }
 
-    return false;
+    return WorldGuardRegionOccupancy.overlapsAny(cuboid, _savedWorldGuardBounds);
   }
 
   private boolean areBlocksOccupied(int row, int col, int i) {
@@ -911,6 +912,8 @@ public class MetropolisPlugin extends JavaPlugin {
   }
 
   private Cuboid findNextUnownedHomeRegion(int plotMultiplier) {
+    refreshSavedWorldGuardBounds();
+
     int row = 0;
     int col = 0;
     int ring = 0;
@@ -995,6 +998,11 @@ public class MetropolisPlugin extends JavaPlugin {
     return null;
   }
 
+  private void refreshSavedWorldGuardBounds() {
+    _savedWorldGuardBounds =
+        WorldGuardRegionOccupancy.boundsToAvoid(regionManager.getRegions().values());
+  }
+
   private boolean isAvailableSupportedPlot(int row, int col, int plotMultiplier, int level) {
     return !areBlocksOccupied(row, col, plotMultiplier, level)
         && PlotLevelSupport.hasCompleteSupport(

src/main/java/com/majinnaibu/bukkitplugins/metropolis/WorldGuardRegionOccupancy.java

@@ -0,0 +1,44 @@
+/*
+This file is part of Metropolis.
+
+Metropolis is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Metropolis is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with Metropolis. If not, see <https://www.gnu.org/licenses/agpl-3.0.txt>.
+*/
+
+package com.majinnaibu.bukkitplugins.metropolis;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import com.sk89q.worldguard.protection.regions.ProtectedRegion;
+
+public final class WorldGuardRegionOccupancy {
+  private WorldGuardRegionOccupancy() {}
+
+  public static List<Cuboid> boundsToAvoid(Collection<ProtectedRegion> regions) {
+    List<Cuboid> bounds = new ArrayList<>();
+    for (ProtectedRegion region : regions) {
+      String id = region.getId();
+      if (id.equalsIgnoreCase("city") || id.equalsIgnoreCase("__global__")) {
+        continue;
+      }
+      bounds.add(new Cuboid(region.getMinimumPoint(), region.getMaximumPoint()));
+    }
+    return List.copyOf(bounds);
+  }
+
+  public static boolean overlapsAny(Cuboid candidate, Collection<Cuboid> occupiedBounds) {
+    return occupiedBounds.stream().anyMatch(candidate::intersects);
+  }
+}

src/test/java/com/majinnaibu/bukkitplugins/metropolis/WorldGuardRegionOccupancyTest.java

@@ -0,0 +1,60 @@
+/*
+This file is part of Metropolis.
+
+Metropolis is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Metropolis is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with Metropolis. If not, see <https://www.gnu.org/licenses/agpl-3.0.txt>.
+*/
+
+package com.majinnaibu.bukkitplugins.metropolis;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldguard.protection.regions.ProtectedRegion;
+
+import org.junit.jupiter.api.Test;
+
+class WorldGuardRegionOccupancyTest {
+  @Test
+  void treatsArbitrarySavedRegionBoundsAsOccupiedButIgnoresCityAndGlobalRegions() {
+    ProtectedRegion market =
+        region("market", BlockVector3.at(40, 62, 40), BlockVector3.at(70, 90, 70));
+    ProtectedRegion city =
+        region("City", BlockVector3.at(-100, 0, -100), BlockVector3.at(100, 320, 100));
+    ProtectedRegion global =
+        region(
+            "__global__",
+            BlockVector3.at(-30_000_000, -64, -30_000_000),
+            BlockVector3.at(30_000_000, 320, 30_000_000));
+
+    List<Cuboid> occupied = WorldGuardRegionOccupancy.boundsToAvoid(List.of(market, city, global));
+
+    assertEquals(1, occupied.size());
+    assertTrue(WorldGuardRegionOccupancy.overlapsAny(new Cuboid(60, 70, 60, 80, 75, 80), occupied));
+    assertFalse(WorldGuardRegionOccupancy.overlapsAny(new Cuboid(0, 62, 0, 31, 71, 31), occupied));
+  }
+
+  private static ProtectedRegion region(String id, BlockVector3 minimum, BlockVector3 maximum) {
+    ProtectedRegion region = mock(ProtectedRegion.class);
+    when(region.getId()).thenReturn(id);
+    when(region.getMinimumPoint()).thenReturn(minimum);
+    when(region.getMaximumPoint()).thenReturn(maximum);
+    return region;
+  }
+}