From d6c923b525a510c6c7675714b6286c53db3a89c4 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Fri, 7 Apr 2023 22:33:30 +0100
Subject: [PATCH] ExperienceOrb: add get/setDespawnDelay closes #5645

the code for this is borrowed from ItemEntity. I didn't feel like a base class was appropriate, and we can't (yet) declare constants in traits.
---
 src/entity/object/ExperienceOrb.php | 36 ++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/src/entity/object/ExperienceOrb.php b/src/entity/object/ExperienceOrb.php
index 2b5932e9c..b2db15642 100644
--- a/src/entity/object/ExperienceOrb.php
+++ b/src/entity/object/ExperienceOrb.php
@@ -32,6 +32,7 @@ use pocketmine\network\mcpe\protocol\types\entity\EntityIds;
 use pocketmine\network\mcpe\protocol\types\entity\EntityMetadataCollection;
 use pocketmine\network\mcpe\protocol\types\entity\EntityMetadataProperties;
 use pocketmine\player\Player;
+use function max;
 use function sqrt;
 
 class ExperienceOrb extends Entity{
@@ -48,6 +49,10 @@ class ExperienceOrb extends Entity{
 	/** Split sizes used for dropping experience orbs. */
 	public const ORB_SPLIT_SIZES = [2477, 1237, 617, 307, 149, 73, 37, 17, 7, 3, 1]; //This is indexed biggest to smallest so that we can return as soon as we found the biggest value.
 
+	public const DEFAULT_DESPAWN_DELAY = 6000;
+	public const NEVER_DESPAWN = -1;
+	public const MAX_DESPAWN_DELAY = 32767 + self::DEFAULT_DESPAWN_DELAY; //max value storable by mojang NBT :(
+
 	/**
 	 * Returns the largest size of normal XP orb that will be spawned for the specified amount of XP. Used to split XP
 	 * up into multiple orbs when an amount of XP is dropped.
@@ -82,7 +87,10 @@ class ExperienceOrb extends Entity{
 	public $gravity = 0.04;
 	public $drag = 0.02;
 
-	/** @var int */
+	/**
+	 * @var int
+	 * @deprecated
+	 */
 	protected $age = 0;
 
 	/**
@@ -100,6 +108,8 @@ class ExperienceOrb extends Entity{
 	/** @var int */
 	protected $xpValue;
 
+	private int $despawnDelay = self::DEFAULT_DESPAWN_DELAY;
+
 	public function __construct(Location $location, int $xpValue, ?CompoundTag $nbt = null){
 		$this->xpValue = $xpValue;
 		parent::__construct($location, $nbt);
@@ -111,12 +121,22 @@ class ExperienceOrb extends Entity{
 		parent::initEntity($nbt);
 
 		$this->age = $nbt->getShort(self::TAG_AGE, 0);
+		if($this->age === -32768){
+			$this->despawnDelay = self::NEVER_DESPAWN;
+		}else{
+			$this->despawnDelay = max(0, self::DEFAULT_DESPAWN_DELAY - $this->age);
+		}
 	}
 
 	public function saveNBT() : CompoundTag{
 		$nbt = parent::saveNBT();
 
-		$nbt->setShort(self::TAG_AGE, $this->age);
+		if($this->despawnDelay === self::NEVER_DESPAWN){
+			$age = -32768;
+		}else{
+			$age = self::DEFAULT_DESPAWN_DELAY - $this->despawnDelay;
+		}
+		$nbt->setShort(self::TAG_AGE, $age);
 
 		$nbt->setShort(self::TAG_VALUE_PC, $this->getXpValue());
 		$nbt->setInt(self::TAG_VALUE_PE, $this->getXpValue());
@@ -124,6 +144,15 @@ class ExperienceOrb extends Entity{
 		return $nbt;
 	}
 
+	public function getDespawnDelay() : int{ return $this->despawnDelay; }
+
+	public function setDespawnDelay(int $despawnDelay) : void{
+		if(($despawnDelay < 0 || $despawnDelay > self::MAX_DESPAWN_DELAY) && $despawnDelay !== self::NEVER_DESPAWN){
+			throw new \InvalidArgumentException("Despawn ticker must be in range 0 ... " . self::MAX_DESPAWN_DELAY . " or " . self::NEVER_DESPAWN . ", got $despawnDelay");
+		}
+		$this->despawnDelay = $despawnDelay;
+	}
+
 	public function getXpValue() : int{
 		return $this->xpValue;
 	}
@@ -161,7 +190,8 @@ class ExperienceOrb extends Entity{
 		$hasUpdate = parent::entityBaseTick($tickDiff);
 
 		$this->age += $tickDiff;
-		if($this->age > 6000){
+		$this->despawnDelay -= $tickDiff;
+		if($this->despawnDelay <= 0){
 			$this->flagForDespawn();
 			return true;
 		}