Fix to Nether Portal traps. See #928

src/com/massivecraft/factions/engine/EngineExploit.java

@@ -1,13 +1,18 @@
 package com.massivecraft.factions.engine;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.UUID;
 
 import org.bukkit.block.Block;
+import org.bukkit.entity.Player;
 import org.bukkit.entity.TNTPrimed;
 import org.bukkit.event.block.BlockFromToEvent;
 import org.bukkit.event.entity.EntityExplodeEvent;
+import org.bukkit.event.player.PlayerMoveEvent;
 import org.bukkit.event.player.PlayerTeleportEvent;
+import org.bukkit.event.player.PlayerTeleportEvent.TeleportCause;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority; 
 import org.bukkit.plugin.Plugin;
@@ -17,6 +22,8 @@ import org.bukkit.Material;
 import com.massivecraft.factions.Factions;
 import com.massivecraft.factions.entity.MConf;
 import com.massivecraft.massivecore.EngineAbstract;
+import com.massivecraft.massivecore.ps.PS;
+import com.massivecraft.massivecore.util.MUtil;
 
 
 public class EngineExploit extends EngineAbstract
@@ -137,4 +144,121 @@ public class EngineExploit extends EngineAbstract
 		}
 	}
 	
+
+	// -------------------------------------------- //
+	// NETHER PORTAL TRAP 
+	// -------------------------------------------- //
+	// A nether portal trap can be created by the destination portal being enclosed (trapped) - resulting in the player not being able to run commands.
+	// This fix removes the portal blocks (client side) from the destination until they are away from the portal.
+	
+	private int NETHER_TRAP_RADIUS_CHECK = 5;
+	private int NETHER_TRAP_RESET_RADIUS = 3;
+	
+	private HashMap<UUID, List<Block>> netherTrapBlockSet = new HashMap<UUID, List<Block>>();
+	
+	// Detect teleport from a nether portal and remove animation if required 
+	@EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+	public void netherportalTrapRemoveAnimation(PlayerTeleportEvent event)
+	{
+		if ( ! MConf.get().handleNetherPortalTrap) return;
+
+		if (event.getCause() != TeleportCause.NETHER_PORTAL) return;
+
+		// If they can build at the target destination then we will not do any further checks 
+		if (EngineMain.canPlayerBuildAt(event.getPlayer(), PS.valueOf(event.getTo()), false)) return;
+				
+		final Player player = event.getPlayer();
+		final UUID uuid = player.getUniqueId();
+		
+		Block from = event.getTo().getBlock();
+				
+		// If a list exists, then we're dealing with a new portal - so revert the old portal blocks
+		this.netherportalReset(player);
+		
+		// Store some temporary data 
+		this.netherTrapBlockSet.put(uuid, this.getPortalBlocks(from));
+		
+		// Send the air update
+		this.netherportalSendAir(player);
+
+	}
+	
+	// When they leave the portal we will update it, otherwise send the updates again
+	@EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+	public void netherportalTrapUpdate(PlayerMoveEvent event)
+	{
+		if ( ! MConf.get().handleNetherPortalTrap) return;
+		
+		// Only check if we're changing blocks
+		if (MUtil.isSameBlock(event)) return;
+		
+		Player player = event.getPlayer();
+		UUID uuid = player.getUniqueId();
+		
+		// Check if we're sending updates to this player
+		if ( ! this.netherTrapBlockSet.containsKey(uuid)) return;
+		
+		// If they've changed worlds we don't bother checking this
+		if (event.getTo().getWorld() != this.netherTrapBlockSet.get(uuid).get(0).getWorld())
+		{
+			this.netherportalReset(player);
+			return;
+		}
+			
+		// When the player moves away from the portal, we put it back to normal
+		if (event.getTo().distance(this.netherTrapBlockSet.get(uuid).get(0).getLocation()) > NETHER_TRAP_RESET_RADIUS)
+		{
+			this.netherportalReset(player);
+		}
+		else
+		{
+			// Send updates as air
+			this.netherportalSendAir(player);
+		}
+	}
+	
+	// Sends block update to player with original blocks (if required) 
+	@SuppressWarnings("deprecation")
+	public void netherportalReset(Player player)
+	{
+		UUID uuid = player.getUniqueId();
+		
+		if ( ! this.netherTrapBlockSet.containsKey(uuid)) return;
+		
+		// Only send updates if they're in the same world
+		if (this.netherTrapBlockSet.get(uuid).get(0).getWorld() == player.getWorld()) for (Block block : this.netherTrapBlockSet.get(uuid)) player.sendBlockChange(block.getLocation(), block.getType(), block.getData());
+		
+		// Remove the block set 
+		this.netherTrapBlockSet.remove(uuid);
+	}
+	
+	// Send air block updates to player 
+	@SuppressWarnings("deprecation")
+	public void netherportalSendAir(Player player) 
+	{
+		for (Block block : this.netherTrapBlockSet.get(player.getUniqueId())) player.sendBlockChange(block.getLocation(), Material.AIR, (byte) 0);
+	}
+	
+	// Get portal blocks near a block 
+	public List<Block> getPortalBlocks(Block from) {
+		List<Block> blocks = new ArrayList<Block>();
+		
+		// Check in a radius of the block to find the portal blocks
+		for (int x = -(NETHER_TRAP_RADIUS_CHECK); x <= NETHER_TRAP_RADIUS_CHECK; x ++)
+		{
+			for (int y = -(NETHER_TRAP_RADIUS_CHECK); y <= NETHER_TRAP_RADIUS_CHECK; y ++)
+			{
+				for (int z = -(NETHER_TRAP_RADIUS_CHECK); z <= NETHER_TRAP_RADIUS_CHECK; z ++)
+				{
+					if (from.getRelative(x, y, z).getType() == Material.PORTAL)
+					{
+						// Store block
+						blocks.add(from.getRelative(x, y, z));
+					}
+				}
+			}
+		}
+		
+		return blocks;
+	}
 }

src/com/massivecraft/factions/entity/MConf.java

@@ -441,6 +441,7 @@ public class MConf extends Entity<MConf>
 	public boolean handleExploitObsidianGenerators = true;
 	public boolean handleExploitEnderPearlClipping = true;
 	public boolean handleExploitTNTWaterlog = false;
+	public boolean handleNetherPortalTrap = true;
 	
 	// -------------------------------------------- //
 	// SEE CHUNK