SPIGOT-7309: Add API for jukebox inventories

Also fixes a crash when inserting music discs into jukeboxes with a Dropper

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/block/CraftJukebox.java

@@ -1,6 +1,5 @@
 package org.bukkit.craftbukkit.block;
 
-import com.google.common.base.Preconditions;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.block.BlockJukeBox;
 import net.minecraft.world.level.block.Blocks;
@@ -11,8 +10,10 @@ import org.bukkit.Material;
 import org.bukkit.World;
 import org.bukkit.block.Jukebox;
 import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.inventory.CraftInventoryJukebox;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.craftbukkit.util.CraftMagicNumbers;
+import org.bukkit.inventory.JukeboxInventory;
 
 public class CraftJukebox extends CraftBlockEntityState<TileEntityJukeBox> implements Jukebox {
 
@@ -20,6 +21,20 @@ public class CraftJukebox extends CraftBlockEntityState<TileEntityJukeBox> imple
         super(world, tileEntity);
     }
 
+    @Override
+    public JukeboxInventory getSnapshotInventory() {
+        return new CraftInventoryJukebox(this.getSnapshot());
+    }
+
+    @Override
+    public JukeboxInventory getInventory() {
+        if (!this.isPlaced()) {
+            return this.getSnapshotInventory();
+        }
+
+        return new CraftInventoryJukebox(this.getTileEntity());
+    }
+
     @Override
     public boolean update(boolean force, boolean applyPhysics) {
         boolean result = super.update(force, applyPhysics);

paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventory.java

@@ -17,6 +17,7 @@ import net.minecraft.world.level.block.entity.TileEntityBrewingStand;
 import net.minecraft.world.level.block.entity.TileEntityDispenser;
 import net.minecraft.world.level.block.entity.TileEntityDropper;
 import net.minecraft.world.level.block.entity.TileEntityFurnace;
+import net.minecraft.world.level.block.entity.TileEntityJukeBox;
 import net.minecraft.world.level.block.entity.TileEntityLectern;
 import net.minecraft.world.level.block.entity.TileEntityShulkerBox;
 import net.minecraft.world.level.block.entity.TileEntitySmoker;
@@ -502,6 +503,8 @@ public class CraftInventory implements Inventory {
             return InventoryType.STONECUTTER;
         } else if (inventory instanceof BlockComposter.ContainerEmpty || inventory instanceof BlockComposter.ContainerInput || inventory instanceof BlockComposter.ContainerOutput) {
             return InventoryType.COMPOSTER;
+        } else if (inventory instanceof TileEntityJukeBox) {
+            return InventoryType.JUKEBOX;
         } else if (this instanceof CraftInventorySmithingNew) {
             return InventoryType.SMITHING_NEW;
         } else {

paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventoryJukebox.java

@@ -0,0 +1,32 @@
+package org.bukkit.craftbukkit.inventory;
+
+import net.minecraft.world.IInventory;
+import org.bukkit.block.Jukebox;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.JukeboxInventory;
+
+public class CraftInventoryJukebox extends CraftInventory implements JukeboxInventory {
+
+    public CraftInventoryJukebox(IInventory inventory) {
+        super(inventory);
+    }
+
+    @Override
+    public void setRecord(ItemStack item) {
+        if (item == null) {
+            inventory.removeItem(0, 0); // Second parameter is unused in TileEntityJukebox
+        } else {
+            setItem(0, item);
+        }
+    }
+
+    @Override
+    public ItemStack getRecord() {
+        return getItem(0);
+    }
+
+    @Override
+    public Jukebox getHolder() {
+        return (Jukebox) inventory.getOwner();
+    }
+}