Implement basic entity pick

src/main/java/cn/nukkit/Player.java

@@ -2755,59 +2755,40 @@ public void onCompletion(Server server) {
 
                     PlayerBlockPickEvent pickEvent = new PlayerBlockPickEvent(this, block, item);
                     if (this.isSpectator()) {
-                        log.debug("Got block-pick request from " + this.getName() + " when in spectator mode");
                         pickEvent.setCancelled();
                     }
-
                     this.server.getPluginManager().callEvent(pickEvent);
-
                     if (!pickEvent.isCancelled()) {
-                        boolean itemExists = false;
-                        int itemSlot = -1;
-                        for (int slot = 0; slot < this.inventory.getSize(); slot++) {
-                            if (this.inventory.getItem(slot).equals(pickEvent.getItem())) {
-                                if (slot < this.inventory.getHotbarSize()) {
-                                    this.inventory.setHeldItemSlot(slot);
-                                } else {
-                                    itemSlot = slot;
-                                }
-                                itemExists = true;
-                                break;
-                            }
-                        }
+                        this.pickItem(pickEvent.getItem());
+                    }
+                    break;
+                case ProtocolInfo.ENTITY_PICK_REQUEST_PACKET:
+                    EntityPickRequestPacket entityPickRequestPacket = (EntityPickRequestPacket) packet;
+                    targetEntity = this.level.getEntity(entityPickRequestPacket.entityId);
+                    if (!(targetEntity instanceof EntityPickable)) {
+                        break;
+                    }
 
-                        for (int slot = 0; slot < this.inventory.getHotbarSize(); slot++) {
-                            if (this.inventory.getItem(slot).isNull()) {
-                                if (!itemExists && this.isCreative()) {
-                                    this.inventory.setHeldItemSlot(slot);
-                                    this.inventory.setItemInHand(pickEvent.getItem());
-                                    break packetswitch;
-                                } else if (itemSlot > -1) {
-                                    this.inventory.setHeldItemSlot(slot);
-                                    this.inventory.setItemInHand(this.inventory.getItem(itemSlot));
-                                    this.inventory.clear(itemSlot, true);
-                                    break packetswitch;
-                                }
-                            }
-                        }
+                    if (this.distanceSquared(targetEntity) > 1000) {
+                        this.getServer().getLogger().debug(this.getName() + ": Entity pick request for a entity too far away");
+                        break;
+                    }
 
-                        if (!itemExists && this.isCreative()) {
-                            Item itemInHand = this.inventory.getItemInHand();
-                            this.inventory.setItemInHand(pickEvent.getItem());
-                            if (!this.inventory.isFull()) {
-                                for (int slot = 0; slot < this.inventory.getSize(); slot++) {
-                                    if (this.inventory.getItem(slot).isNull()) {
-                                        this.inventory.setItem(slot, itemInHand);
-                                        break;
-                                    }
-                                }
-                            }
-                        } else if (itemSlot > -1) {
-                            Item itemInHand = this.inventory.getItemInHand();
-                            this.inventory.setItemInHand(this.inventory.getItem(itemSlot));
-                            this.inventory.setItem(itemSlot, itemInHand);
-                        }
+                    item = ((EntityPickable) targetEntity).toItem();
+                    if (item == null || item.isNull()) {
+                        break;
+                    }
+
+                    PlayerEntityPickEvent entityPickEvent = new PlayerEntityPickEvent(this, targetEntity, item);
+                    if (this.isSpectator()) {
+                        entityPickEvent.setCancelled();
+                    }
+                    this.server.getPluginManager().callEvent(entityPickEvent);
+                    if (entityPickEvent.isCancelled()) {
+                        break;
                     }
+
+                    this.pickItem(entityPickEvent.getItem());
                     break;
                 case ProtocolInfo.ANIMATE_PACKET:
                     if (!this.spawned || !this.isAlive()) {
@@ -5324,4 +5305,65 @@ public int getTimeSinceRest() {
     public void setTimeSinceRest(int timeSinceRest) {
         this.timeSinceRest = timeSinceRest;
     }
+
+    protected void pickItem(Item item) {
+        if (item == null || item.isNull()) {
+            return;
+        }
+
+        int existingSlot = -1;
+        for (int slot = 0; slot < this.inventory.getSize(); slot++) {
+            if (!this.inventory.getItem(slot).equals(item)) {
+                continue;
+            }
+
+            if (slot < this.inventory.getHotbarSize()) {
+                this.inventory.setHeldItemSlot(slot);
+                return;
+            }
+
+            existingSlot = slot;
+            break;
+        }
+
+        if (existingSlot == -1 && !this.isCreative()) {
+            return;
+        }
+
+        for (int slot = 0; slot < this.inventory.getHotbarSize(); slot++) {
+            if (!this.inventory.getItem(slot).isNull()) {
+                continue;
+            }
+
+            this.inventory.setHeldItemSlot(slot);
+            if (existingSlot == -1) {
+                this.inventory.setItemInHand(item);
+            } else {
+                this.inventory.setItemInHand(this.inventory.getItem(existingSlot));
+                this.inventory.clear(existingSlot, true);
+            }
+            return;
+        }
+
+        Item itemInHand = this.inventory.getItemInHand();
+        if (existingSlot != -1) {
+            this.inventory.setItemInHand(this.inventory.getItem(existingSlot));
+            this.inventory.setItem(existingSlot, itemInHand);
+            return;
+        }
+
+        this.inventory.setItemInHand(item);
+        if (this.inventory.isFull()) {
+            return;
+        }
+
+        for (int slot = 0; slot < this.inventory.getSize(); slot++) {
+            if (!this.inventory.getItem(slot).isNull()) {
+                continue;
+            }
+
+            this.inventory.setItem(slot, itemInHand);
+            break;
+        }
+    }
 }

src/main/java/cn/nukkit/entity/EntityPickable.java

@@ -0,0 +1,8 @@
+package cn.nukkit.entity;
+
+import cn.nukkit.item.Item;
+
+public interface EntityPickable {
+
+    Item toItem();
+}

src/main/java/cn/nukkit/entity/item/EntityBoat.java

@@ -5,6 +5,7 @@
 import cn.nukkit.block.BlockWater;
 import cn.nukkit.entity.Entity;
 import cn.nukkit.entity.EntityLiving;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.entity.data.ByteEntityData;
 import cn.nukkit.entity.data.FloatEntityData;
 import cn.nukkit.entity.passive.EntityWaterAnimal;
@@ -29,7 +30,7 @@
 /**
  * Created by yescallop on 2016/2/13.
  */
-public class EntityBoat extends EntityVehicle {
+public class EntityBoat extends EntityVehicle implements EntityPickable {
 
     public static final int NETWORK_ID = 90;
 
@@ -433,4 +434,9 @@ public boolean isFull() {
     public String getInteractButtonText() {
         return !this.isFull() ? "action.interact.ride.boat" : "";
     }
+
+    @Override
+    public Item toItem() {
+        return Item.get(Item.BOAT, this.woodID);
+    }
 }

src/main/java/cn/nukkit/entity/item/EntityEndCrystal.java

@@ -2,7 +2,9 @@
 
 import cn.nukkit.entity.Entity;
 import cn.nukkit.entity.EntityExplosive;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.event.entity.EntityDamageEvent;
+import cn.nukkit.item.Item;
 import cn.nukkit.level.Explosion;
 import cn.nukkit.level.GameRule;
 import cn.nukkit.level.Position;
@@ -12,7 +14,7 @@
 /**
  * Created by PetteriM1
  */
-public class EntityEndCrystal extends Entity implements EntityExplosive {
+public class EntityEndCrystal extends Entity implements EntityExplosive, EntityPickable {
 
     public static final int NETWORK_ID = 71;
 
@@ -93,6 +95,11 @@ public boolean canCollideWith(Entity entity) {
         return false;
     }
 
+    @Override
+    public Item toItem() {
+        return Item.get(Item.END_CRYSTAL);
+    }
+
     public boolean showBase() {
         return this.getDataFlag(DATA_FLAGS, DATA_FLAG_SHOWBASE);
     }

src/main/java/cn/nukkit/entity/item/EntityMinecartChest.java

@@ -3,6 +3,7 @@
 import cn.nukkit.Player;
 import cn.nukkit.block.Block;
 import cn.nukkit.entity.Entity;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.inventory.InventoryHolder;
 import cn.nukkit.inventory.MinecartChestInventory;
 import cn.nukkit.item.Item;
@@ -17,7 +18,7 @@
  * Created by Snake1999 on 2016/1/30.
  * Package cn.nukkit.entity.item in project Nukkit.
  */
-public class EntityMinecartChest extends EntityMinecartAbstract implements InventoryHolder {
+public class EntityMinecartChest extends EntityMinecartAbstract implements InventoryHolder, EntityPickable {
 
     public static final int NETWORK_ID = 98;
 
@@ -113,4 +114,9 @@ public void saveNBT() {
     public String getInteractButtonText() {
         return "action.interact.opencontainer";
     }
+
+    @Override
+    public Item toItem() {
+        return Item.get(Item.MINECART_WITH_CHEST);
+    }
 }

src/main/java/cn/nukkit/entity/item/EntityMinecartEmpty.java

@@ -3,9 +3,11 @@
 import cn.nukkit.Player;
 import cn.nukkit.entity.Entity;
 import cn.nukkit.entity.EntityLiving;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.entity.passive.EntityWaterAnimal;
 import cn.nukkit.event.entity.EntityDamageByBlockEvent;
 import cn.nukkit.event.entity.EntityDamageEvent.DamageCause;
+import cn.nukkit.item.Item;
 import cn.nukkit.level.format.FullChunk;
 import cn.nukkit.nbt.tag.CompoundTag;
 import cn.nukkit.utils.MinecartType;
@@ -14,7 +16,7 @@
  * Created by Snake1999 on 2016/1/30.
  * Package cn.nukkit.entity.item in project Nukkit.
  */
-public class EntityMinecartEmpty extends EntityMinecartAbstract {
+public class EntityMinecartEmpty extends EntityMinecartAbstract implements EntityPickable {
 
     public static final int NETWORK_ID = 84;
 
@@ -74,4 +76,9 @@ public boolean onUpdate(int currentTick) {
     public String getInteractButtonText() {
         return this.passengers.isEmpty() ? "action.interact.ride.minecart" : "";
     }
+
+    @Override
+    public Item toItem() {
+        return Item.get(Item.MINECART);
+    }
 }

src/main/java/cn/nukkit/entity/item/EntityMinecartHopper.java

@@ -3,6 +3,7 @@
 import cn.nukkit.Player;
 import cn.nukkit.block.Block;
 import cn.nukkit.entity.Entity;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.inventory.InventoryHolder;
 import cn.nukkit.inventory.MinecartHopperInventory;
 import cn.nukkit.item.Item;
@@ -13,7 +14,7 @@
 import cn.nukkit.nbt.tag.ListTag;
 import cn.nukkit.utils.MinecartType;
 
-public class EntityMinecartHopper extends EntityMinecartAbstract implements InventoryHolder {
+public class EntityMinecartHopper extends EntityMinecartAbstract implements InventoryHolder, EntityPickable {
 
     public static final int NETWORK_ID = 96;
 
@@ -109,4 +110,9 @@ public void saveNBT() {
     public String getInteractButtonText() {
         return "action.interact.opencontainer";
     }
+
+    @Override
+    public Item toItem() {
+        return Item.get(Item.MINECART_WITH_HOPPER);
+    }
 }

src/main/java/cn/nukkit/entity/item/EntityMinecartTNT.java

@@ -5,6 +5,7 @@
 import cn.nukkit.block.BlockID;
 import cn.nukkit.entity.Entity;
 import cn.nukkit.entity.EntityExplosive;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.entity.data.IntEntityData;
 import cn.nukkit.event.entity.EntityExplosionPrimeEvent;
 import cn.nukkit.item.Item;
@@ -24,7 +25,7 @@
  * <p>
  * Nukkit Project.
  */
-public class EntityMinecartTNT extends EntityMinecartAbstract implements EntityExplosive {
+public class EntityMinecartTNT extends EntityMinecartAbstract implements EntityExplosive, EntityPickable {
 
     public static final int NETWORK_ID = 97;
     private int fuse;
@@ -156,6 +157,11 @@ public boolean onInteract(Player player, Item item, Vector3 clickedPos) {
         return interact;
     }
 
+    @Override
+    public Item toItem() {
+        return Item.get(Item.MINECART_WITH_TNT);
+    }
+
     @Override
     public boolean mountEntity(Entity entity, byte mode) {
         return false;

src/main/java/cn/nukkit/entity/item/EntityPainting.java

@@ -3,8 +3,10 @@
 import cn.nukkit.Player;
 import cn.nukkit.entity.Entity;
 import cn.nukkit.entity.EntityHanging;
+import cn.nukkit.entity.EntityPickable;
 import cn.nukkit.event.entity.EntityDamageByEntityEvent;
 import cn.nukkit.event.entity.EntityDamageEvent;
+import cn.nukkit.item.Item;
 import cn.nukkit.item.ItemPainting;
 import cn.nukkit.level.GameRule;
 import cn.nukkit.level.format.FullChunk;
@@ -19,7 +21,7 @@
  * author: MagicDroidX
  * Nukkit Project
  */
-public class EntityPainting extends EntityHanging {
+public class EntityPainting extends EntityHanging implements EntityPickable {
 
     public static final int NETWORK_ID = 83;
 
@@ -88,6 +90,11 @@ public Motive getMotive() {
         return Motive.BY_NAME.get(namedTag.getString("Motive"));
     }
 
+    @Override
+    public Item toItem() {
+        return Item.get(Item.PAINTING);
+    }
+
     public enum Motive {
         KEBAB("Kebab", 1, 1),
         AZTEC("Aztec", 1, 1),