InventoryManager.php

<?php
 
/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
 */
 
declare(strict_types=1);
 
namespace pocketmine\network\mcpe;
 
use pocketmine\block\inventory\window\AnvilInventoryWindow;
use pocketmine\block\inventory\window\BlockInventoryWindow;
use pocketmine\block\inventory\window\BrewingStandInventoryWindow;
use pocketmine\block\inventory\window\CartographyTableInventoryWindow;
use pocketmine\block\inventory\window\CraftingTableInventoryWindow;
use pocketmine\block\inventory\window\EnchantingTableInventoryWindow;
use pocketmine\block\inventory\window\FurnaceInventoryWindow;
use pocketmine\block\inventory\window\HopperInventoryWindow;
use pocketmine\block\inventory\window\LoomInventoryWindow;
use pocketmine\block\inventory\window\SmithingTableInventoryWindow;
use pocketmine\block\inventory\window\StonecutterInventoryWindow;
use pocketmine\crafting\FurnaceType;
use pocketmine\data\bedrock\EnchantmentIdMap;
use pocketmine\inventory\Inventory;
use pocketmine\inventory\InventoryListener;
use pocketmine\inventory\transaction\action\SlotChangeAction;
use pocketmine\inventory\transaction\InventoryTransaction;
use pocketmine\item\enchantment\EnchantingOption;
use pocketmine\item\enchantment\EnchantmentInstance;
use pocketmine\item\Item;
use pocketmine\network\mcpe\cache\CreativeInventoryCache;
use pocketmine\network\mcpe\protocol\ClientboundPacket;
use pocketmine\network\mcpe\protocol\ContainerClosePacket;
use pocketmine\network\mcpe\protocol\ContainerOpenPacket;
use pocketmine\network\mcpe\protocol\ContainerSetDataPacket;
use pocketmine\network\mcpe\protocol\InventoryContentPacket;
use pocketmine\network\mcpe\protocol\InventorySlotPacket;
use pocketmine\network\mcpe\protocol\MobEquipmentPacket;
use pocketmine\network\mcpe\protocol\PlayerEnchantOptionsPacket;
use pocketmine\network\mcpe\protocol\types\BlockPosition;
use pocketmine\network\mcpe\protocol\types\Enchant;
use pocketmine\network\mcpe\protocol\types\EnchantOption as ProtocolEnchantOption;
use pocketmine\network\mcpe\protocol\types\inventory\ContainerIds;
use pocketmine\network\mcpe\protocol\types\inventory\FullContainerName;
use pocketmine\network\mcpe\protocol\types\inventory\ItemStack;
use pocketmine\network\mcpe\protocol\types\inventory\ItemStackWrapper;
use pocketmine\network\mcpe\protocol\types\inventory\NetworkInventoryAction;
use pocketmine\network\mcpe\protocol\types\inventory\UIInventorySlotOffset;
use pocketmine\network\mcpe\protocol\types\inventory\WindowTypes;
use pocketmine\network\PacketHandlingException;
use pocketmine\player\InventoryWindow;
use pocketmine\player\Player;
use pocketmine\player\PlayerInventoryWindow;
use pocketmine\utils\AssumptionFailedError;
use pocketmine\utils\Binary;
use pocketmine\utils\ObjectSet;
use function array_fill_keys;
use function array_keys;
use function array_map;
use function array_search;
use function count;
use function get_class;
use function implode;
use function is_int;
use function max;
use function spl_object_id;
 
class InventoryManager implements InventoryListener{
    private array $entries = [];
 
    private array $networkIdToWindowMap = [];
    private array $complexSlotToWindowMap = [];
 
    private int $lastWindowNetworkId = ContainerIds::FIRST;
    private int $currentWindowType = WindowTypes::CONTAINER;
 
    private int $clientSelectedHotbarSlot = -1;
 
    private ObjectSet $containerOpenCallbacks;
 
    private ?int $pendingCloseWindowId = null;
    private ?\Closure $pendingOpenWindowCallback = null;
 
    private int $nextItemStackId = 1;
    private ?int $currentItemStackRequestId = null;
 
    private bool $fullSyncRequested = false;
 
    private array $enchantingTableOptions = [];
    //TODO: this should be based on the total number of crafting recipes - if there are ever 100k recipes, this will
    //conflict with regular recipes
    private int $nextEnchantingTableOptionId = 100000;
 
    public function __construct(
        private Player $player,
        private NetworkSession $session
    ){
        $this->containerOpenCallbacks = new ObjectSet();
        $this->containerOpenCallbacks->add(self::createContainerOpen(...));
 
        foreach($this->player->getPermanentWindows() as $window){
            match($window->getType()){
                PlayerInventoryWindow::TYPE_INVENTORY => $this->add(ContainerIds::INVENTORY, $window),
                PlayerInventoryWindow::TYPE_OFFHAND => $this->add(ContainerIds::OFFHAND, $window),
                PlayerInventoryWindow::TYPE_ARMOR => $this->add(ContainerIds::ARMOR, $window),
                PlayerInventoryWindow::TYPE_CURSOR => $this->addComplex(UIInventorySlotOffset::CURSOR, $window),
                PlayerInventoryWindow::TYPE_CRAFTING => $this->addComplex(UIInventorySlotOffset::CRAFTING2X2_INPUT, $window),
                default => throw new AssumptionFailedError("Unknown permanent window type " . $window->getType())
            };
        }
 
        $this->player->getHotbar()->getSelectedIndexChangeListeners()->add($this->syncSelectedHotbarSlot(...));
    }
 
    private function associateIdWithInventory(int $id, InventoryWindow $window) : void{
        $this->networkIdToWindowMap[$id] = $window;
    }
 
    private function getNewWindowId() : int{
        $this->lastWindowNetworkId = max(ContainerIds::FIRST, ($this->lastWindowNetworkId + 1) % ContainerIds::LAST);
        return $this->lastWindowNetworkId;
    }
 
    private function getEntry(Inventory $inventory) : ?InventoryManagerEntry{
        return $this->entries[spl_object_id($inventory)] ?? null;
    }
 
    private function getEntryByWindow(InventoryWindow $window) : ?InventoryManagerEntry{
        return $this->getEntry($window->getInventory());
    }
 
    public function getInventoryWindow(Inventory $inventory) : ?InventoryWindow{
        return $this->getEntry($inventory)?->window;
    }
 
    private function add(int $id, InventoryWindow $window) : void{
        $k = spl_object_id($window->getInventory());
        if(isset($this->entries[$k])){
            throw new \InvalidArgumentException("Inventory " . get_class($window->getInventory()) . " is already tracked (open in two different windows?)");
        }
        $this->entries[$k] = new InventoryManagerEntry($window);
        $window->getInventory()->getListeners()->add($this);
        $this->associateIdWithInventory($id, $window);
    }
 
    private function addDynamic(InventoryWindow $inventory) : int{
        $id = $this->getNewWindowId();
        $this->add($id, $inventory);
        return $id;
    }
 
    private function addComplex(array|int $slotMap, InventoryWindow $window) : void{
        $k = spl_object_id($window->getInventory());
        if(isset($this->entries[$k])){
            throw new \InvalidArgumentException("Inventory " . get_class($window) . " is already tracked");
        }
        $complexSlotMap = new ComplexWindowMapEntry($window, is_int($slotMap) ? [$slotMap => 0] : $slotMap);
        $this->entries[$k] = new InventoryManagerEntry(
            $window,
            $complexSlotMap
        );
        $window->getInventory()->getListeners()->add($this);
        foreach($complexSlotMap->getSlotMap() as $netSlot => $coreSlot){
            $this->complexSlotToWindowMap[$netSlot] = $complexSlotMap;
        }
    }
 
    private function addComplexDynamic(array|int $slotMap, InventoryWindow $inventory) : int{
        $this->addComplex($slotMap, $inventory);
        $id = $this->getNewWindowId();
        $this->associateIdWithInventory($id, $inventory);
        return $id;
    }
 
    private function remove(int $id) : void{
        $window = $this->networkIdToWindowMap[$id];
        $inventory = $window->getInventory();
        unset($this->networkIdToWindowMap[$id]);
        if($this->getWindowId($window) === null){
            $inventory->getListeners()->remove($this);
            unset($this->entries[spl_object_id($inventory)]);
            foreach($this->complexSlotToWindowMap as $netSlot => $entry){
                if($entry->getWindow() === $window){
                    unset($this->complexSlotToWindowMap[$netSlot]);
                }
            }
        }
    }
 
    public function getWindowId(InventoryWindow $window) : ?int{
        return ($id = array_search($window, $this->networkIdToWindowMap, true)) !== false ? $id : null;
    }
 
    public function getCurrentWindowId() : int{
        return $this->lastWindowNetworkId;
    }
 
    public function locateWindowAndSlot(int $windowId, int $netSlotId) : ?array{
        if($windowId === ContainerIds::UI){
            $entry = $this->complexSlotToWindowMap[$netSlotId] ?? null;
            if($entry === null){
                return null;
            }
            $window = $entry->getWindow();
            $coreSlotId = $entry->mapNetToCore($netSlotId);
            return $coreSlotId !== null && $window->getInventory()->slotExists($coreSlotId) ? [$window, $coreSlotId] : null;
        }
        $window = $this->networkIdToWindowMap[$windowId] ?? null;
        if($window !== null && $window->getInventory()->slotExists($netSlotId)){
            return [$window, $netSlotId];
        }
        return null;
    }
 
    private function addPredictedSlotChangeInternal(InventoryWindow $window, int $slot, ItemStack $item) : void{
        //TODO: does this need a null check?
        $entry = $this->getEntryByWindow($window) ?? throw new AssumptionFailedError("Assume this should never be null");
        $entry->predictions[$slot] = $item;
    }
 
    public function addPredictedSlotChange(InventoryWindow $window, int $slot, Item $item) : void{
        $typeConverter = $this->session->getTypeConverter();
        $itemStack = $typeConverter->coreItemStackToNet($item);
        $this->addPredictedSlotChangeInternal($window, $slot, $itemStack);
    }
 
    public function addTransactionPredictedSlotChanges(InventoryTransaction $tx) : void{
        foreach($tx->getActions() as $action){
            if($action instanceof SlotChangeAction){
                //TODO: ItemStackRequestExecutor can probably build these predictions with much lower overhead
                $this->addPredictedSlotChange(
                    $action->getInventoryWindow(),
                    $action->getSlot(),
                    $action->getTargetItem()
                );
            }
        }
    }
 
    public function addRawPredictedSlotChanges(array $networkInventoryActions) : void{
        foreach($networkInventoryActions as $action){
            if($action->sourceType !== NetworkInventoryAction::SOURCE_CONTAINER){
                continue;
            }
            if($action->windowId === null){
                throw new PacketHandlingException("Window ID should always be set for SOURCE_CONTAINER");
            }
 
            //legacy transactions should not modify or predict anything other than these inventories, since these are
            //the only ones accessible when not in-game (ItemStackRequest is used for everything else)
            if(match($action->windowId){
                ContainerIds::INVENTORY, ContainerIds::OFFHAND, ContainerIds::ARMOR => false,
                default => true
            }){
                throw new PacketHandlingException("Legacy transactions cannot predict changes to inventory with ID " . $action->windowId);
            }
            $info = $this->locateWindowAndSlot($action->windowId, $action->inventorySlot);
            if($info === null){
                continue;
            }
 
            [$window, $slot] = $info;
            $this->addPredictedSlotChangeInternal($window, $slot, $action->newItem->getItemStack());
        }
    }
 
    public function setCurrentItemStackRequestId(?int $id) : void{
        $this->currentItemStackRequestId = $id;
    }
 
    private function openWindowDeferred(\Closure $func) : void{
        if($this->pendingCloseWindowId !== null){
            $this->session->getLogger()->debug("Deferring opening of new window, waiting for close ack of window $this->pendingCloseWindowId");
            $this->pendingOpenWindowCallback = $func;
        }else{
            $func();
        }
    }
 
    private function createComplexSlotMapping(InventoryWindow $inventory) : ?array{
        //TODO: make this dynamic so plugins can add mappings for stuff not implemented by PM
        return match(true){
            $inventory instanceof AnvilInventoryWindow => UIInventorySlotOffset::ANVIL,
            $inventory instanceof EnchantingTableInventoryWindow => UIInventorySlotOffset::ENCHANTING_TABLE,
            $inventory instanceof LoomInventoryWindow => UIInventorySlotOffset::LOOM,
            $inventory instanceof StonecutterInventoryWindow => [UIInventorySlotOffset::STONE_CUTTER_INPUT => StonecutterInventoryWindow::SLOT_INPUT],
            $inventory instanceof CraftingTableInventoryWindow => UIInventorySlotOffset::CRAFTING3X3_INPUT,
            $inventory instanceof CartographyTableInventoryWindow => UIInventorySlotOffset::CARTOGRAPHY_TABLE,
            $inventory instanceof SmithingTableInventoryWindow => UIInventorySlotOffset::SMITHING_TABLE,
            default => null,
        };
    }
 
    public function onCurrentWindowChange(InventoryWindow $window) : void{
        $this->onCurrentWindowRemove();
 
        $this->openWindowDeferred(function() use ($window) : void{
            if(($slotMap = $this->createComplexSlotMapping($window)) !== null){
                $windowId = $this->addComplexDynamic($slotMap, $window);
            }else{
                $windowId = $this->addDynamic($window);
            }
 
            foreach($this->containerOpenCallbacks as $callback){
                $pks = $callback($windowId, $window);
                if($pks !== null){
                    $windowType = null;
                    foreach($pks as $pk){
                        if($pk instanceof ContainerOpenPacket){
                            //workaround useless bullshit in 1.21 - ContainerClose requires a type now for some reason
                            $windowType = $pk->windowType;
                        }
                        $this->session->sendDataPacket($pk);
                    }
                    $this->currentWindowType = $windowType ?? WindowTypes::CONTAINER;
                    $this->syncContents($window);
                    return;
                }
            }
            throw new \LogicException("Unsupported inventory type");
        });
    }
 
    public function getContainerOpenCallbacks() : ObjectSet{ return $this->containerOpenCallbacks; }
 
    protected static function createContainerOpen(int $id, InventoryWindow $window) : ?array{
        //TODO: we should be using some kind of tagging system to identify the types. Instanceof is flaky especially
        //if the class isn't final, not to mention being inflexible.
        if($window instanceof BlockInventoryWindow){
            $blockPosition = BlockPosition::fromVector3($window->getHolder());
            $windowType = match(true){
                $window instanceof LoomInventoryWindow => WindowTypes::LOOM,
                $window instanceof FurnaceInventoryWindow => match($window->getFurnaceType()){
                        FurnaceType::FURNACE => WindowTypes::FURNACE,
                        FurnaceType::BLAST_FURNACE => WindowTypes::BLAST_FURNACE,
                        FurnaceType::SMOKER => WindowTypes::SMOKER,
                        FurnaceType::CAMPFIRE, FurnaceType::SOUL_CAMPFIRE => throw new \LogicException("Campfire inventory cannot be displayed to a player")
                    },
                $window instanceof EnchantingTableInventoryWindow => WindowTypes::ENCHANTMENT,
                $window instanceof BrewingStandInventoryWindow => WindowTypes::BREWING_STAND,
                $window instanceof AnvilInventoryWindow => WindowTypes::ANVIL,
                $window instanceof HopperInventoryWindow => WindowTypes::HOPPER,
                $window instanceof CraftingTableInventoryWindow => WindowTypes::WORKBENCH,
                $window instanceof StonecutterInventoryWindow => WindowTypes::STONECUTTER,
                $window instanceof CartographyTableInventoryWindow => WindowTypes::CARTOGRAPHY,
                $window instanceof SmithingTableInventoryWindow => WindowTypes::SMITHING_TABLE,
                default => WindowTypes::CONTAINER
            };
            return [ContainerOpenPacket::blockInv($id, $windowType, $blockPosition)];
        }
        return null;
    }
 
    public function onClientOpenMainInventory() : void{
        $this->onCurrentWindowRemove();
 
        $this->openWindowDeferred(function() : void{
            $windowId = $this->getNewWindowId();
            $window = $this->getInventoryWindow($this->player->getInventory()) ?? throw new AssumptionFailedError("This should never be null");
            $this->associateIdWithInventory($windowId, $window);
            $this->currentWindowType = WindowTypes::INVENTORY;
 
            $this->session->sendDataPacket(ContainerOpenPacket::entityInv(
                $windowId,
                $this->currentWindowType,
                $this->player->getId()
            ));
        });
    }
 
    public function onCurrentWindowRemove() : void{
        if(isset($this->networkIdToWindowMap[$this->lastWindowNetworkId])){
            $this->remove($this->lastWindowNetworkId);
            $this->session->sendDataPacket(ContainerClosePacket::create($this->lastWindowNetworkId, $this->currentWindowType, true));
            if($this->pendingCloseWindowId !== null){
                throw new AssumptionFailedError("We should not have opened a new window while a window was waiting to be closed");
            }
            $this->pendingCloseWindowId = $this->lastWindowNetworkId;
            $this->enchantingTableOptions = [];
        }
    }
 
    public function onClientRemoveWindow(int $id) : void{
        if(Binary::signByte($id) === ContainerIds::NONE){ //TODO: REMOVE signByte() once BedrockProtocol + ext-encoding are implemented
            //TODO: HACK! Since 1.21.100 (and probably earlier), the client will send -1 to close windows that it can't
            //view for some reason, e.g. if the chat window was already open. This is pretty awkward, since it means
            //that we can only assume it refers to the most recently sent window, and if we don't handle it,
            //InventoryManager will never get the green light to send subsequent windows, which breaks inventory UIs.
            //Fortunately, we already wait for close acks anyway, so the window ID is technically useless...?
            $this->session->getLogger()->debug("Client rejected opening of a window, assuming it was $this->lastWindowNetworkId");
            $id = $this->lastWindowNetworkId;
        }
        if($id === $this->lastWindowNetworkId){
            if(isset($this->networkIdToWindowMap[$id]) && $id !== $this->pendingCloseWindowId){
                $this->remove($id);
                $this->player->removeCurrentWindow();
            }
        }else{
            $this->session->getLogger()->debug("Attempted to close inventory with network ID $id, but current is $this->lastWindowNetworkId");
        }
 
        //Always send this, even if no window matches. If we told the client to close a window, it will behave as if it
        //initiated the close and expect an ack.
        $this->session->sendDataPacket(ContainerClosePacket::create($id, $this->currentWindowType, false));
 
        if($this->pendingCloseWindowId === $id){
            $this->pendingCloseWindowId = null;
            if($this->pendingOpenWindowCallback !== null){
                $this->session->getLogger()->debug("Opening deferred window after close ack of window $id");
                ($this->pendingOpenWindowCallback)();
                $this->pendingOpenWindowCallback = null;
            }
        }
    }
 
    private function itemStackExtraDataEqual(ItemStack $left, ItemStack $right) : bool{
        if($left->getRawExtraData() === $right->getRawExtraData()){
            return true;
        }
 
        $typeConverter = $this->session->getTypeConverter();
        $leftExtraData = $typeConverter->deserializeItemStackExtraData($left->getRawExtraData(), $left->getId());
        $rightExtraData = $typeConverter->deserializeItemStackExtraData($right->getRawExtraData(), $right->getId());
 
        $leftNbt = $leftExtraData->getNbt();
        $rightNbt = $rightExtraData->getNbt();
        return
            $leftExtraData->getCanPlaceOn() === $rightExtraData->getCanPlaceOn() &&
            $leftExtraData->getCanDestroy() === $rightExtraData->getCanDestroy() && (
                $leftNbt === $rightNbt || //this covers null === null and fast object identity
                ($leftNbt !== null && $rightNbt !== null && $leftNbt->equals($rightNbt))
            );
    }
 
    private function itemStacksEqual(ItemStack $left, ItemStack $right) : bool{
        return
            $left->getId() === $right->getId() &&
            $left->getMeta() === $right->getMeta() &&
            $left->getBlockRuntimeId() === $right->getBlockRuntimeId() &&
            $left->getCount() === $right->getCount() &&
            $this->itemStackExtraDataEqual($left, $right);
    }
 
    public function onSlotChange(Inventory $inventory, int $slot, Item $oldItem) : void{
        $window = $this->getInventoryWindow($inventory);
        if($window === null){
            //this can happen when an inventory changed during InventoryCloseEvent, or when a temporary inventory
            //is cleared before removal.
            return;
        }
        $this->requestSyncSlot($window, $slot);
    }
 
    public function requestSyncSlot(InventoryWindow $window, int $slot) : void{
        $inventoryEntry = $this->getEntryByWindow($window);
        if($inventoryEntry === null){
            //this can happen when an inventory changed during InventoryCloseEvent, or when a temporary inventory
            //is cleared before removal.
            return;
        }
 
        $currentItem = $this->session->getTypeConverter()->coreItemStackToNet($window->getInventory()->getItem($slot));
        $clientSideItem = $inventoryEntry->predictions[$slot] ?? null;
        if($clientSideItem === null || !$this->itemStacksEqual($currentItem, $clientSideItem)){
            //no prediction or incorrect - do not associate this with the currently active itemstack request
            $this->trackItemStack($inventoryEntry, $slot, $currentItem, null);
            $inventoryEntry->pendingSyncs[$slot] = $currentItem;
        }else{
            //correctly predicted - associate the change with the currently active itemstack request
            $this->trackItemStack($inventoryEntry, $slot, $currentItem, $this->currentItemStackRequestId);
        }
 
        unset($inventoryEntry->predictions[$slot]);
    }
 
    private function sendInventorySlotPackets(int $windowId, int $netSlot, ItemStackWrapper $itemStackWrapper) : void{
        /*
         * TODO: HACK!
         * As of 1.20.12, the client ignores change of itemstackID in some cases when the old item == the new item.
         * Notably, this happens with armor, offhand and enchanting tables, but not with main inventory.
         * While we could track the items previously sent to the client, that's a waste of memory and would
         * cost performance. Instead, clear the slot(s) first, then send the new item(s).
         * The network cost of doing this is fortunately minimal, as an air itemstack is only 1 byte.
         */
        if($itemStackWrapper->getStackId() !== 0){
            $this->session->sendDataPacket(InventorySlotPacket::create(
                $windowId,
                $netSlot,
                null,
                null,
                new ItemStackWrapper(0, ItemStack::null())
            ));
        }
        //now send the real contents
        $this->session->sendDataPacket(InventorySlotPacket::create(
            $windowId,
            $netSlot,
            null,
            null,
            $itemStackWrapper
        ));
    }
 
    private function sendInventoryContentPackets(int $windowId, array $itemStackWrappers) : void{
        /*
         * TODO: HACK!
         * As of 1.20.12, the client ignores change of itemstackID in some cases when the old item == the new item.
         * Notably, this happens with armor, offhand and enchanting tables, but not with main inventory.
         * While we could track the items previously sent to the client, that's a waste of memory and would
         * cost performance. Instead, clear the slot(s) first, then send the new item(s).
         * The network cost of doing this is fortunately minimal, as an air itemstack is only 1 byte.
         */
        $this->session->sendDataPacket(InventoryContentPacket::create(
            $windowId,
            array_fill_keys(array_keys($itemStackWrappers), new ItemStackWrapper(0, ItemStack::null())),
            new FullContainerName(0, null),
            new ItemStackWrapper(0, ItemStack::null())
        ));
        //now send the real contents
        $this->session->sendDataPacket(InventoryContentPacket::create($windowId, $itemStackWrappers, new FullContainerName(0, null), new ItemStackWrapper(0, ItemStack::null())));
    }
 
    private function syncSlot(InventoryWindow $window, int $slot, ItemStack $itemStack) : void{
        $entry = $this->getEntryByWindow($window) ?? throw new \LogicException("Cannot sync an untracked inventory");
        $itemStackInfo = $entry->itemStackInfos[$slot];
        if($itemStackInfo === null){
            throw new \LogicException("Cannot sync an untracked inventory slot");
        }
        if($entry->complexSlotMap !== null){
            $windowId = ContainerIds::UI;
            $netSlot = $entry->complexSlotMap->mapCoreToNet($slot) ?? throw new AssumptionFailedError("We already have an ItemStackInfo, so this should not be null");
        }else{
            $windowId = $this->getWindowId($window) ?? throw new AssumptionFailedError("We already have an ItemStackInfo, so this should not be null");
            $netSlot = $slot;
        }
 
        $itemStackWrapper = new ItemStackWrapper($itemStackInfo->getStackId(), $itemStack);
        if($windowId === ContainerIds::OFFHAND){
            //TODO: HACK!
            //The client may sometimes ignore the InventorySlotPacket for the offhand slot.
            //This can cause a lot of problems (totems, arrows, and more...).
            //The workaround is to send an InventoryContentPacket instead
            //BDS (Bedrock Dedicated Server) also seems to work this way.
            $this->sendInventoryContentPackets($windowId, [$itemStackWrapper]);
        }else{
            $this->sendInventorySlotPackets($windowId, $netSlot, $itemStackWrapper);
        }
        unset($entry->predictions[$slot], $entry->pendingSyncs[$slot]);
    }
 
    public function onContentChange(Inventory $inventory, array $oldContents) : void{
        //this can be null when an inventory changed during InventoryCloseEvent, or when a temporary inventory
        //is cleared before removal.
        $window = $this->getInventoryWindow($inventory);
        if($window !== null){
            $this->syncContents($window);
        }
    }
 
    private function syncContents(InventoryWindow $window) : void{
        $entry = $this->getEntryByWindow($window);
        if($entry === null){
            //this can happen when an inventory changed during InventoryCloseEvent, or when a temporary inventory
            //is cleared before removal.
            return;
        }
        if($entry->complexSlotMap !== null){
            $windowId = ContainerIds::UI;
        }else{
            $windowId = $this->getWindowId($window);
        }
        if($windowId !== null){
            $entry->predictions = [];
            $entry->pendingSyncs = [];
            $contents = [];
            $typeConverter = $this->session->getTypeConverter();
            foreach($window->getInventory()->getContents(true) as $slot => $item){
                $itemStack = $typeConverter->coreItemStackToNet($item);
                $info = $this->trackItemStack($entry, $slot, $itemStack, null);
                $contents[] = new ItemStackWrapper($info->getStackId(), $itemStack);
            }
            if($entry->complexSlotMap !== null){
                foreach($contents as $slotId => $info){
                    $packetSlot = $entry->complexSlotMap->mapCoreToNet($slotId) ?? null;
                    if($packetSlot === null){
                        continue;
                    }
                    $this->sendInventorySlotPackets($windowId, $packetSlot, $info);
                }
            }else{
                $this->sendInventoryContentPackets($windowId, $contents);
            }
        }
    }
 
    public function syncAll() : void{
        foreach($this->entries as $entry){
            $this->syncContents($entry->window);
        }
    }
 
    public function requestSyncAll() : void{
        $this->fullSyncRequested = true;
    }
 
    public function syncMismatchedPredictedSlotChanges() : void{
        $typeConverter = $this->session->getTypeConverter();
        foreach($this->entries as $entry){
            $inventory = $entry->window->getInventory();
            foreach($entry->predictions as $slot => $expectedItem){
                if(!$inventory->slotExists($slot) || $entry->itemStackInfos[$slot] === null){
                    continue; //TODO: size desync ???
                }
 
                //any prediction that still exists at this point is a slot that was predicted to change but didn't
                $this->session->getLogger()->debug("Detected prediction mismatch in inventory " . get_class($inventory) . "#" . spl_object_id($inventory) . " slot $slot");
                $entry->pendingSyncs[$slot] = $typeConverter->coreItemStackToNet($inventory->getItem($slot));
            }
 
            $entry->predictions = [];
        }
    }
 
    public function flushPendingUpdates() : void{
        if($this->fullSyncRequested){
            $this->fullSyncRequested = false;
            $this->session->getLogger()->debug("Full inventory sync requested, sending contents of " . count($this->entries) . " inventories");
            $this->syncAll();
        }else{
            foreach($this->entries as $entry){
                if(count($entry->pendingSyncs) === 0){
                    continue;
                }
                $inventory = $entry->window;
                $this->session->getLogger()->debug("Syncing slots " . implode(", ", array_keys($entry->pendingSyncs)) . " in inventory " . get_class($inventory) . "#" . spl_object_id($inventory));
                foreach($entry->pendingSyncs as $slot => $itemStack){
                    $this->syncSlot($inventory, $slot, $itemStack);
                }
                $entry->pendingSyncs = [];
            }
        }
    }
 
    public function syncData(Inventory $inventory, int $propertyId, int $value) : void{
        //TODO: the handling of this data has always kinda sucked. Probably ought to route it through InventoryWindow
        //somehow, but I'm not sure exactly how that should look.
        $window = $this->getInventoryWindow($inventory);
        if($window === null){
            return;
        }
        $windowId = $this->getWindowId($window);
        if($windowId !== null){
            $this->session->sendDataPacket(ContainerSetDataPacket::create($windowId, $propertyId, $value));
        }
    }
 
    public function onClientSelectHotbarSlot(int $slot) : void{
        $this->clientSelectedHotbarSlot = $slot;
    }
 
    public function syncSelectedHotbarSlot() : void{
        $playerInventory = $this->player->getInventory();
        $selected = $this->player->getHotbar()->getSelectedIndex();
        if($selected !== $this->clientSelectedHotbarSlot){
            $inventoryEntry = $this->getEntry($playerInventory) ?? throw new AssumptionFailedError("Player inventory should always be tracked");
            $itemStackInfo = $inventoryEntry->itemStackInfos[$selected] ?? null;
            if($itemStackInfo === null){
                throw new AssumptionFailedError("Untracked player inventory slot $selected");
            }
 
            $this->session->sendDataPacket(MobEquipmentPacket::create(
                $this->player->getId(),
                new ItemStackWrapper($itemStackInfo->getStackId(), $this->session->getTypeConverter()->coreItemStackToNet($playerInventory->getItem($selected))),
                $selected,
                $selected,
                ContainerIds::INVENTORY
            ));
            $this->clientSelectedHotbarSlot = $selected;
        }
    }
 
    public function syncCreative() : void{
        $this->session->sendDataPacket(CreativeInventoryCache::getInstance()->buildPacket($this->player->getCreativeInventory(), $this->session));
    }
 
    public function syncEnchantingTableOptions(array $options) : void{
        $protocolOptions = [];
 
        foreach($options as $index => $option){
            $optionId = $this->nextEnchantingTableOptionId++;
            $this->enchantingTableOptions[$optionId] = $index;
 
            $protocolEnchantments = array_map(
                fn(EnchantmentInstance $e) => new Enchant(EnchantmentIdMap::getInstance()->toId($e->getType()), $e->getLevel()),
                $option->getEnchantments()
            );
            // We don't pay attention to the $slotFlags, $heldActivatedEnchantments and $selfActivatedEnchantments
            // as everything works fine without them (perhaps these values are used somehow in the BDS).
            $protocolOptions[] = new ProtocolEnchantOption(
                $option->getRequiredXpLevel(),
                0, $protocolEnchantments,
                [],
                [],
                $option->getDisplayName(),
                $optionId
            );
        }
 
        $this->session->sendDataPacket(PlayerEnchantOptionsPacket::create($protocolOptions));
    }
 
    public function getEnchantingTableOptionIndex(int $recipeId) : ?int{
        return $this->enchantingTableOptions[$recipeId] ?? null;
    }
 
    private function newItemStackId() : int{
        return $this->nextItemStackId++;
    }
 
    public function getItemStackInfo(InventoryWindow $window, int $slot) : ?ItemStackInfo{
        return $this->getEntryByWindow($window)?->itemStackInfos[$slot] ?? null;
    }
 
    private function trackItemStack(InventoryManagerEntry $entry, int $slotId, ItemStack $itemStack, ?int $itemStackRequestId) : ItemStackInfo{
        //TODO: ItemStack->isNull() would be nice to have here
        $info = new ItemStackInfo($itemStackRequestId, $itemStack->getId() === 0 ? 0 : $this->newItemStackId());
        return $entry->itemStackInfos[$slotId] = $info;
    }
}