Adds proper checking and odd case catching before teleporting players through artificial end portals

Adds a proper permission check to make sure players are allowed to teleport through the artificial portal
Adds a teleportation back to the entrance as the teleportation event cannot be properly cancelled
Adds a proper class for storing info about the teleportation

src/main/java/net/knarcraft/stargate/container/FromTheEndTeleportation.java

@@ -0,0 +1,43 @@
+package net.knarcraft.stargate.container;
+
+import net.knarcraft.stargate.portal.Portal;
+import org.bukkit.entity.Player;
+
+/**
+ * This class represents a player teleporting from the end to the over-world using an artificial end portal
+ */
+public class FromTheEndTeleportation {
+
+    private final Player teleportingPlayer;
+    private final Portal exitPortal;
+
+    /**
+     * Instantiates a new teleportation from the end
+     *
+     * @param teleportingPlayer <p>The teleporting player</p>
+     * @param exitPortal        <p>The portal to exit from</p>
+     */
+    public FromTheEndTeleportation(Player teleportingPlayer, Portal exitPortal) {
+        this.teleportingPlayer = teleportingPlayer;
+        this.exitPortal = exitPortal;
+    }
+
+    /**
+     * Gets the teleporting player
+     *
+     * @return <p>The teleporting player</p>
+     */
+    public Player getPlayer() {
+        return this.teleportingPlayer;
+    }
+
+    /**
+     * Gets the portal to exit from
+     *
+     * @return <p>The portal to exit from</p>
+     */
+    public Portal getExit() {
+        return this.exitPortal;
+    }
+
+}

src/main/java/net/knarcraft/stargate/listener/PlayerEventListener.java

@@ -5,8 +5,6 @@ import net.knarcraft.stargate.container.BlockLocation;
 import net.knarcraft.stargate.portal.Portal;
 import net.knarcraft.stargate.portal.PortalHandler;
 import net.knarcraft.stargate.utility.BungeeHelper;
-import net.knarcraft.stargate.utility.EconomyHandler;
-import net.knarcraft.stargate.utility.EconomyHelper;
 import net.knarcraft.stargate.utility.MaterialHelper;
 import net.knarcraft.stargate.utility.PermissionHelper;
 import org.bukkit.GameMode;
@@ -127,7 +125,7 @@ public class PlayerEventListener implements Listener {
         Portal destination = entrancePortal.getDestination(player);
 
         //Decide if the anything stops the player from teleport
-        if (!playerCanTeleport(entrancePortal, destination, player, event)) {
+        if (PermissionHelper.playerCannotTeleport(entrancePortal, destination, player, event)) {
             return false;
         }
 
@@ -322,47 +320,4 @@ public class PlayerEventListener implements Listener {
         return true;
     }
 
-    /**
-     * Decide of the player can teleport through a portal
-     *
-     * @param entrancePortal <p>The portal the player is entering from</p>
-     * @param destination    <p>The destination of the portal the player is inside</p>
-     * @param player         <p>The player wanting to teleport</p>
-     * @param event          <p>The move event causing the teleportation</p>
-     * @return <p>True if the player can teleport. False otherwise</p>
-     */
-    private boolean playerCanTeleport(Portal entrancePortal, Portal destination, Player player, PlayerMoveEvent event) {
-        // No portal or not open
-        if (entrancePortal == null || !entrancePortal.isOpen()) {
-            return false;
-        }
-
-        // Not open for this player
-        if (!entrancePortal.isOpenFor(player)) {
-            Stargate.sendErrorMessage(player, Stargate.getString("denyMsg"));
-            entrancePortal.teleport(player, entrancePortal, event);
-            return false;
-        }
-
-        //No destination
-        if (!entrancePortal.getOptions().isBungee() && destination == null) {
-            return false;
-        }
-
-        //Player cannot access portal
-        if (PermissionHelper.cannotAccessPortal(player, entrancePortal, destination)) {
-            Stargate.sendErrorMessage(player, Stargate.getString("denyMsg"));
-            entrancePortal.teleport(player, entrancePortal, event);
-            entrancePortal.close(false);
-            return false;
-        }
-
-        //Player cannot pay for teleportation
-        int cost = EconomyHandler.getUseCost(player, entrancePortal, destination);
-        if (cost > 0) {
-            return EconomyHelper.payTeleportFee(entrancePortal, player, cost);
-        }
-        return true;
-    }
-
 }

src/main/java/net/knarcraft/stargate/listener/PortalEventListener.java

@@ -1,8 +1,9 @@
 package net.knarcraft.stargate.listener;
 
-import net.knarcraft.stargate.container.TwoTuple;
+import net.knarcraft.stargate.container.FromTheEndTeleportation;
 import net.knarcraft.stargate.portal.Portal;
 import net.knarcraft.stargate.portal.PortalHandler;
+import net.knarcraft.stargate.utility.PermissionHelper;
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.World;
@@ -23,7 +24,7 @@ import java.util.List;
  */
 public class PortalEventListener implements Listener {
 
-    private static final List<TwoTuple<Player, Portal>> playersFromTheEnd = new ArrayList<>();
+    private static final List<FromTheEndTeleportation> playersFromTheEnd = new ArrayList<>();
 
     /**
      * Listen for and abort vanilla portal creation caused by stargate creation
@@ -55,12 +56,18 @@ public class PortalEventListener implements Listener {
         World world = location.getWorld();
         Entity entity = event.getEntity();
         //Block normal portal teleportation if teleporting from a stargate
-        if (entity instanceof Player && location.getBlock().getType() == Material.END_PORTAL && world != null &&
+        if (entity instanceof Player player && location.getBlock().getType() == Material.END_PORTAL && world != null &&
                 world.getEnvironment() == World.Environment.THE_END) {
             Portal portal = PortalHandler.getByAdjacentEntrance(location);
-            if (portal != null) {
+
-                playersFromTheEnd.add(new TwoTuple<>((Player) entity, portal.getDestination()));
+            //Remove any old player teleportations in case weird things happen
+            playersFromTheEnd.removeIf((teleportation -> teleportation.getPlayer() == player));
+            //Decide if the anything stops the player from teleporting
+            if (PermissionHelper.playerCannotTeleport(portal, portal.getDestination(), player, null)) {
+                //Teleport the player back to the portal they came in, just in case
+                playersFromTheEnd.add(new FromTheEndTeleportation(player, portal));
             }
+            playersFromTheEnd.add(new FromTheEndTeleportation(player, portal.getDestination()));
         }
     }
 
@@ -72,14 +79,10 @@ public class PortalEventListener implements Listener {
     @EventHandler
     public void onRespawn(PlayerRespawnEvent event) {
         Player respawningPlayer = event.getPlayer();
-        playersFromTheEnd.forEach((tuple) -> {
+        playersFromTheEnd.forEach((teleportation) -> {
             //Check if player is actually teleporting from the end
-            if (tuple.getFirstValue() == respawningPlayer) {
+            if (teleportation.getPlayer() == respawningPlayer) {
-                Portal exitPortal = tuple.getSecondValue();
+                Portal exitPortal = teleportation.getExit();
-                //Need to make sure the player is allowed to exit from the portal
-                if (!exitPortal.isOpenFor(respawningPlayer)) {
-                    return;
-                }
                 //Overwrite respawn location to respawn in front of the portal
                 event.setRespawnLocation(exitPortal.getExit(respawningPlayer, respawningPlayer.getLocation()));
                 //Properly close the portal to prevent it from staying in a locked state until it times out

src/main/java/net/knarcraft/stargate/utility/PermissionHelper.java

@@ -5,6 +5,7 @@ import net.knarcraft.stargate.event.StargateAccessEvent;
 import net.knarcraft.stargate.portal.Portal;
 import net.knarcraft.stargate.portal.PortalOption;
 import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerMoveEvent;
 
 /**
  * Helper class for deciding which actions a player is allowed to perform
@@ -368,4 +369,47 @@ public final class PermissionHelper {
         return portal.isOwner(player) && hasPermission(player, "stargate.destroy.personal");
     }
 
+    /**
+     * Decide of the player can teleport through a portal
+     *
+     * @param entrancePortal <p>The portal the player is entering from</p>
+     * @param destination    <p>The destination of the portal the player is inside</p>
+     * @param player         <p>The player wanting to teleport</p>
+     * @param event          <p>The move event causing the teleportation</p>
+     * @return <p>True if the player cannot teleport. False otherwise</p>
+     */
+    public static boolean playerCannotTeleport(Portal entrancePortal, Portal destination, Player player, PlayerMoveEvent event) {
+        // No portal or not open
+        if (entrancePortal == null || !entrancePortal.isOpen()) {
+            return true;
+        }
+
+        // Not open for this player
+        if (!entrancePortal.isOpenFor(player)) {
+            Stargate.sendErrorMessage(player, Stargate.getString("denyMsg"));
+            entrancePortal.teleport(player, entrancePortal, event);
+            return true;
+        }
+
+        //No destination
+        if (!entrancePortal.getOptions().isBungee() && destination == null) {
+            return true;
+        }
+
+        //Player cannot access portal
+        if (PermissionHelper.cannotAccessPortal(player, entrancePortal, destination)) {
+            Stargate.sendErrorMessage(player, Stargate.getString("denyMsg"));
+            entrancePortal.teleport(player, entrancePortal, event);
+            entrancePortal.close(false);
+            return true;
+        }
+
+        //Player cannot pay for teleportation
+        int cost = EconomyHandler.getUseCost(player, entrancePortal, destination);
+        if (cost > 0) {
+            return !EconomyHelper.payTeleportFee(entrancePortal, player, cost);
+        }
+        return false;
+    }
+
 }