SPIGOT-3842: Add Player#fireworkBoost() and expand Firework API

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-server/nms-patches/net/minecraft/world/entity/projectile/EntityFireworks.patch

@@ -1,6 +1,6 @@
 --- a/net/minecraft/world/entity/projectile/EntityFireworks.java
 +++ b/net/minecraft/world/entity/projectile/EntityFireworks.java
-@@ -29,6 +29,8 @@
+@@ -29,15 +29,17 @@
  import net.minecraft.world.phys.MovingObjectPositionEntity;
  import net.minecraft.world.phys.Vec3D;
  
@@ -9,6 +9,17 @@
  public class EntityFireworks extends IProjectile implements ItemSupplier {
  
      public static final DataWatcherObject<ItemStack> DATA_ID_FIREWORKS_ITEM = DataWatcher.defineId(EntityFireworks.class, DataWatcherRegistry.ITEM_STACK);
+     private static final DataWatcherObject<OptionalInt> DATA_ATTACHED_TO_TARGET = DataWatcher.defineId(EntityFireworks.class, DataWatcherRegistry.OPTIONAL_UNSIGNED_INT);
+     public static final DataWatcherObject<Boolean> DATA_SHOT_AT_ANGLE = DataWatcher.defineId(EntityFireworks.class, DataWatcherRegistry.BOOLEAN);
+-    private int life;
++    public int life; // PAIL private -> public
+     public int lifetime;
+     @Nullable
+-    private EntityLiving attachedToEntity;
++    public EntityLiving attachedToEntity; // PAIL private -> public
+ 
+     public EntityFireworks(EntityTypes<? extends EntityFireworks> entitytypes, World world) {
+         super(entitytypes, world);
 @@ -144,7 +146,7 @@
          MovingObjectPosition movingobjectposition = ProjectileHelper.getHitResult(this, this::canHitEntity);
  

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftFirework.java

@@ -1,6 +1,8 @@
 package org.bukkit.craftbukkit.entity;
 
+import com.google.common.base.Preconditions;
 import java.util.Random;
+import net.minecraft.world.entity.EntityLiving;
 import net.minecraft.world.entity.projectile.EntityFireworks;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.Items;
@@ -9,6 +11,7 @@ import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.entity.EntityType;
 import org.bukkit.entity.Firework;
+import org.bukkit.entity.LivingEntity;
 import org.bukkit.inventory.meta.FireworkMeta;
 
 public class CraftFirework extends CraftProjectile implements Firework {
@@ -64,9 +67,64 @@ public class CraftFirework extends CraftProjectile implements Firework {
         getHandle().getEntityData().markDirty(EntityFireworks.DATA_ID_FIREWORKS_ITEM);
     }
 
+    @Override
+    public boolean setAttachedTo(LivingEntity entity) {
+        if (isDetonated()) {
+            return false;
+        }
+
+        getHandle().attachedToEntity = (entity != null) ? ((CraftLivingEntity) entity).getHandle() : null;
+        return true;
+    }
+
+    @Override
+    public LivingEntity getAttachedTo() {
+        EntityLiving entity = getHandle().attachedToEntity;
+        return (entity != null) ? (LivingEntity) entity.getBukkitEntity() : null;
+    }
+
+    @Override
+    public boolean setLife(int ticks) {
+        Preconditions.checkArgument(ticks >= 0, "ticks must be greater than or equal to 0");
+
+        if (isDetonated()) {
+            return false;
+        }
+
+        getHandle().life = ticks;
+        return true;
+    }
+
+    @Override
+    public int getLife() {
+        return getHandle().life;
+    }
+
+    @Override
+    public boolean setMaxLife(int ticks) {
+        Preconditions.checkArgument(ticks > 0, "ticks must be greater than 0");
+
+        if (isDetonated()) {
+            return false;
+        }
+
+        getHandle().lifetime = ticks;
+        return true;
+    }
+
+    @Override
+    public int getMaxLife() {
+        return getHandle().lifetime;
+    }
+
     @Override
     public void detonate() {
-        getHandle().lifetime = 0;
+        this.setLife(getMaxLife() + 1);
+    }
+
+    @Override
+    public boolean isDetonated() {
+        return getHandle().life > getHandle().lifetime;
     }
 
     @Override

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftHumanEntity.java

@@ -18,6 +18,7 @@ import net.minecraft.world.entity.Entity;
 import net.minecraft.world.entity.EntityTypes;
 import net.minecraft.world.entity.EnumMainHand;
 import net.minecraft.world.entity.player.EntityHuman;
+import net.minecraft.world.entity.projectile.EntityFireworks;
 import net.minecraft.world.inventory.Container;
 import net.minecraft.world.inventory.Containers;
 import net.minecraft.world.item.ItemCooldown;
@@ -49,8 +50,10 @@ import org.bukkit.craftbukkit.inventory.CraftMerchantCustom;
 import org.bukkit.craftbukkit.util.CraftChatMessage;
 import org.bukkit.craftbukkit.util.CraftMagicNumbers;
 import org.bukkit.craftbukkit.util.CraftNamespacedKey;
+import org.bukkit.entity.Firework;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Villager;
+import org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason;
 import org.bukkit.inventory.EntityEquipment;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.InventoryView;
@@ -661,4 +664,14 @@ public class CraftHumanEntity extends CraftLivingEntity implements HumanEntity {
             getHandle().setLastDeathLocation(Optional.of(CraftMemoryMapper.toNms(location)));
         }
     }
+
+    @Override
+    public Firework fireworkBoost(ItemStack fireworkItemStack) {
+        Preconditions.checkArgument(fireworkItemStack != null, "fireworkItemStack must not be null");
+        Preconditions.checkArgument(fireworkItemStack.getType() == Material.FIREWORK_ROCKET, "fireworkItemStack must be of type %s", Material.FIREWORK_ROCKET);
+
+        EntityFireworks fireworks = new EntityFireworks(getHandle().level, CraftItemStack.asNMSCopy(fireworkItemStack), getHandle());
+        boolean success = getHandle().level.addFreshEntity(fireworks, SpawnReason.CUSTOM);
+        return success ? (Firework) fireworks.getBukkitEntity() : null;
+    }
 }