ItemStackRequestExecutor.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\handler;
 
use pocketmine\block\inventory\EnchantInventory;
use pocketmine\inventory\Inventory;
use pocketmine\inventory\transaction\action\CreateItemAction;
use pocketmine\inventory\transaction\action\DestroyItemAction;
use pocketmine\inventory\transaction\action\DropItemAction;
use pocketmine\inventory\transaction\CraftingTransaction;
use pocketmine\inventory\transaction\EnchantingTransaction;
use pocketmine\inventory\transaction\InventoryTransaction;
use pocketmine\inventory\transaction\TransactionBuilder;
use pocketmine\inventory\transaction\TransactionBuilderInventory;
use pocketmine\item\Item;
use pocketmine\network\mcpe\InventoryManager;
use pocketmine\network\mcpe\protocol\types\inventory\ContainerUIIds;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\CraftingConsumeInputStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\CraftingCreateSpecificResultStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\CraftRecipeAutoStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\CraftRecipeStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\CreativeCreateStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\DeprecatedCraftingResultsStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\DestroyStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\DropStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\ItemStackRequest;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\ItemStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\ItemStackRequestSlotInfo;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\PlaceStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\SwapStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackrequest\TakeStackRequestAction;
use pocketmine\network\mcpe\protocol\types\inventory\stackresponse\ItemStackResponse;
use pocketmine\network\mcpe\protocol\types\inventory\UIInventorySlotOffset;
use pocketmine\player\Player;
use pocketmine\utils\AssumptionFailedError;
use function array_key_first;
use function count;
use function spl_object_id;
 
class ItemStackRequestExecutor{
    private TransactionBuilder $builder;
 
    private array $requestSlotInfos = [];
 
    private ?InventoryTransaction $specialTransaction = null;
 
    private array $craftingResults = [];
 
    private ?Item $nextCreatedItem = null;
    private bool $createdItemFromCreativeInventory = false;
    private int $createdItemsTakenCount = 0;
 
    public function __construct(
        private Player $player,
        private InventoryManager $inventoryManager,
        private ItemStackRequest $request
    ){
        $this->builder = new TransactionBuilder();
    }
 
    protected function prettyInventoryAndSlot(Inventory $inventory, int $slot) : string{
        if($inventory instanceof TransactionBuilderInventory){
            $inventory = $inventory->getActualInventory();
        }
        return (new \ReflectionClass($inventory))->getShortName() . "#" . spl_object_id($inventory) . ", slot: $slot";
    }
 
    private function matchItemStack(Inventory $inventory, int $slotId, int $clientItemStackId) : void{
        $info = $this->inventoryManager->getItemStackInfo($inventory, $slotId);
        if($info === null){
            throw new AssumptionFailedError("The inventory is tracked and the slot is valid, so this should not be null");
        }
 
        if(!($clientItemStackId < 0 ? $info->getRequestId() === $clientItemStackId : $info->getStackId() === $clientItemStackId)){
            throw new ItemStackRequestProcessException(
                $this->prettyInventoryAndSlot($inventory, $slotId) . ": " .
                "Mismatched expected itemstack, " .
                "client expected: $clientItemStackId, server actual: " . $info->getStackId() . ", last modified by request: " . ($info->getRequestId() ?? "none")
            );
        }
    }
 
    protected function getBuilderInventoryAndSlot(ItemStackRequestSlotInfo $info) : array{
        [$windowId, $slotId] = ItemStackContainerIdTranslator::translate($info->getContainerName()->getContainerId(), $this->inventoryManager->getCurrentWindowId(), $info->getSlotId());
        $windowAndSlot = $this->inventoryManager->locateWindowAndSlot($windowId, $slotId);
        if($windowAndSlot === null){
            throw new ItemStackRequestProcessException("No open inventory matches container UI ID: " . $info->getContainerName()->getContainerId() . ", slot ID: " . $info->getSlotId());
        }
        [$inventory, $slot] = $windowAndSlot;
        if(!$inventory->slotExists($slot)){
            throw new ItemStackRequestProcessException("No such inventory slot :" . $this->prettyInventoryAndSlot($inventory, $slot));
        }
 
        if($info->getStackId() !== $this->request->getRequestId()){ //the itemstack may have been modified by the current request
            $this->matchItemStack($inventory, $slot, $info->getStackId());
        }
 
        return [$this->builder->getInventory($inventory), $slot];
    }
 
    protected function transferItems(ItemStackRequestSlotInfo $source, ItemStackRequestSlotInfo $destination, int $count) : void{
        $removed = $this->removeItemFromSlot($source, $count);
        $this->addItemToSlot($destination, $removed, $count);
    }
 
    protected function removeItemFromSlot(ItemStackRequestSlotInfo $slotInfo, int $count) : Item{
        if($slotInfo->getContainerName()->getContainerId() === ContainerUIIds::CREATED_OUTPUT && $slotInfo->getSlotId() === UIInventorySlotOffset::CREATED_ITEM_OUTPUT){
            //special case for the "created item" output slot
            //TODO: do we need to send a response for this slot info?
            return $this->takeCreatedItem($count);
        }
        $this->requestSlotInfos[] = $slotInfo;
        [$inventory, $slot] = $this->getBuilderInventoryAndSlot($slotInfo);
        if($count < 1){
            //this should be impossible at the protocol level, but in case of buggy core code this will prevent exploits
            throw new ItemStackRequestProcessException($this->prettyInventoryAndSlot($inventory, $slot) . ": Cannot take less than 1 items from a stack");
        }
 
        $existingItem = $inventory->getItem($slot);
        if($existingItem->getCount() < $count){
            throw new ItemStackRequestProcessException($this->prettyInventoryAndSlot($inventory, $slot) . ": Cannot take $count items from a stack of " . $existingItem->getCount());
        }
 
        $removed = $existingItem->pop($count);
        $inventory->setItem($slot, $existingItem);
 
        return $removed;
    }
 
    protected function addItemToSlot(ItemStackRequestSlotInfo $slotInfo, Item $item, int $count) : void{
        $this->requestSlotInfos[] = $slotInfo;
        [$inventory, $slot] = $this->getBuilderInventoryAndSlot($slotInfo);
        if($count < 1){
            //this should be impossible at the protocol level, but in case of buggy core code this will prevent exploits
            throw new ItemStackRequestProcessException($this->prettyInventoryAndSlot($inventory, $slot) . ": Cannot take less than 1 items from a stack");
        }
 
        $existingItem = $inventory->getItem($slot);
        if(!$existingItem->isNull() && !$existingItem->canStackWith($item)){
            throw new ItemStackRequestProcessException($this->prettyInventoryAndSlot($inventory, $slot) . ": Can only add items to an empty slot, or a slot containing the same item");
        }
 
        //we can't use the existing item here; it may be an empty stack
        $newItem = clone $item;
        $newItem->setCount($existingItem->getCount() + $count);
        $inventory->setItem($slot, $newItem);
    }
 
    protected function dropItem(Item $item, int $count) : void{
        if($count < 1){
            throw new ItemStackRequestProcessException("Cannot drop less than 1 of an item");
        }
        $this->builder->addAction(new DropItemAction((clone $item)->setCount($count)));
    }
 
    protected function setNextCreatedItem(?Item $item, bool $creative = false) : void{
        if($item !== null && $item->isNull()){
            $item = null;
        }
        if($this->nextCreatedItem !== null){
            //while this is more complicated than simply adding the action when the item is taken, this ensures that
            //plugins can tell the difference between 1 item that got split into 2 slots, vs 2 separate items.
            if($this->createdItemFromCreativeInventory && $this->createdItemsTakenCount > 0){
                $this->nextCreatedItem->setCount($this->createdItemsTakenCount);
                $this->builder->addAction(new CreateItemAction($this->nextCreatedItem));
            }elseif($this->createdItemsTakenCount < $this->nextCreatedItem->getCount()){
                throw new ItemStackRequestProcessException("Not all of the previous created item was taken");
            }
        }
        $this->nextCreatedItem = $item;
        $this->createdItemFromCreativeInventory = $creative;
        $this->createdItemsTakenCount = 0;
    }
 
    protected function beginCrafting(int $recipeId, int $repetitions) : void{
        if($this->specialTransaction !== null){
            throw new ItemStackRequestProcessException("Another special transaction is already in progress");
        }
        if($repetitions < 1){
            throw new ItemStackRequestProcessException("Cannot craft a recipe less than 1 time");
        }
        if($repetitions > 256){
            //TODO: we can probably lower this limit to 64, but I'm unsure if there are cases where the client may
            //request more than 64 repetitions of a recipe.
            //It's already hard-limited to 256 repetitions in the protocol, so this is just a sanity check.
            throw new ItemStackRequestProcessException("Cannot craft a recipe more than 256 times");
        }
        $craftingManager = $this->player->getServer()->getCraftingManager();
        $recipe = $craftingManager->getCraftingRecipeFromIndex($recipeId);
        if($recipe === null){
            throw new ItemStackRequestProcessException("No such crafting recipe index: $recipeId");
        }
 
        $this->specialTransaction = new CraftingTransaction($this->player, $craftingManager, [], $recipe, $repetitions);
 
        //TODO: Since the system assumes that crafting can only be done in the crafting grid, we have to give it a
        //crafting grid to make the API happy. No implementation of getResultsFor() actually uses the crafting grid
        //right now, so this will work, but this will become a problem in the future for things like shulker boxes and
        //custom crafting recipes.
        $craftingResults = $recipe->getResultsFor($this->player->getCraftingGrid());
        foreach($craftingResults as $k => $craftingResult){
            $craftingResult->setCount($craftingResult->getCount() * $repetitions);
            $this->craftingResults[$k] = $craftingResult;
        }
        if(count($this->craftingResults) === 1){
            //for multi-output recipes, later actions will tell us which result to create and when
            $this->setNextCreatedItem($this->craftingResults[array_key_first($this->craftingResults)]);
        }
    }
 
    protected function takeCreatedItem(int $count) : Item{
        if($count < 1){
            //this should be impossible at the protocol level, but in case of buggy core code this will prevent exploits
            throw new ItemStackRequestProcessException("Cannot take less than 1 created item");
        }
        $createdItem = $this->nextCreatedItem;
        if($createdItem === null){
            throw new ItemStackRequestProcessException("No created item is waiting to be taken");
        }
 
        if(!$this->createdItemFromCreativeInventory){
            $availableCount = $createdItem->getCount() - $this->createdItemsTakenCount;
            if($count > $availableCount){
                throw new ItemStackRequestProcessException("Not enough created items available to be taken (have $availableCount, tried to take $count)");
            }
        }
 
        $this->createdItemsTakenCount += $count;
        $takenItem = clone $createdItem;
        $takenItem->setCount($count);
        if(!$this->createdItemFromCreativeInventory && $this->createdItemsTakenCount >= $createdItem->getCount()){
            $this->setNextCreatedItem(null);
        }
        return $takenItem;
    }
 
    private function assertDoingCrafting() : void{
        if(!$this->specialTransaction instanceof CraftingTransaction && !$this->specialTransaction instanceof EnchantingTransaction){
            if($this->specialTransaction === null){
                throw new ItemStackRequestProcessException("Expected CraftRecipe or CraftRecipeAuto action to precede this action");
            }else{
                throw new ItemStackRequestProcessException("A different special transaction is already in progress");
            }
        }
    }
 
    protected function processItemStackRequestAction(ItemStackRequestAction $action) : void{
        if(
            $action instanceof TakeStackRequestAction ||
            $action instanceof PlaceStackRequestAction
        ){
            $this->transferItems($action->getSource(), $action->getDestination(), $action->getCount());
        }elseif($action instanceof SwapStackRequestAction){
            $this->requestSlotInfos[] = $action->getSlot1();
            $this->requestSlotInfos[] = $action->getSlot2();
 
            [$inventory1, $slot1] = $this->getBuilderInventoryAndSlot($action->getSlot1());
            [$inventory2, $slot2] = $this->getBuilderInventoryAndSlot($action->getSlot2());
 
            $item1 = $inventory1->getItem($slot1);
            $item2 = $inventory2->getItem($slot2);
            $inventory1->setItem($slot1, $item2);
            $inventory2->setItem($slot2, $item1);
        }elseif($action instanceof DropStackRequestAction){
            //TODO: this action has a "randomly" field, I have no idea what it's used for
            $dropped = $this->removeItemFromSlot($action->getSource(), $action->getCount());
            $this->builder->addAction(new DropItemAction($dropped));
 
        }elseif($action instanceof DestroyStackRequestAction){
            $destroyed = $this->removeItemFromSlot($action->getSource(), $action->getCount());
            $this->builder->addAction(new DestroyItemAction($destroyed));
 
        }elseif($action instanceof CreativeCreateStackRequestAction){
            $item = $this->player->getCreativeInventory()->getItem($action->getCreativeItemId());
            if($item === null){
                throw new ItemStackRequestProcessException("No such creative item index: " . $action->getCreativeItemId());
            }
 
            $this->setNextCreatedItem($item, true);
        }elseif($action instanceof CraftRecipeStackRequestAction){
            $window = $this->player->getCurrentWindow();
            if($window instanceof EnchantInventory){
                $optionId = $this->inventoryManager->getEnchantingTableOptionIndex($action->getRecipeId());
                if($optionId !== null && ($option = $window->getOption($optionId)) !== null){
                    $this->specialTransaction = new EnchantingTransaction($this->player, $option, $optionId + 1);
                    $this->setNextCreatedItem($window->getOutput($optionId));
                }
            }else{
                $this->beginCrafting($action->getRecipeId(), $action->getRepetitions());
            }
        }elseif($action instanceof CraftRecipeAutoStackRequestAction){
            $this->beginCrafting($action->getRecipeId(), $action->getRepetitions());
        }elseif($action instanceof CraftingConsumeInputStackRequestAction){
            $this->assertDoingCrafting();
            $this->removeItemFromSlot($action->getSource(), $action->getCount()); //output discarded - we allow CraftingTransaction to verify the balance
 
        }elseif($action instanceof CraftingCreateSpecificResultStackRequestAction){
            $this->assertDoingCrafting();
 
            $nextResultItem = $this->craftingResults[$action->getResultIndex()] ?? null;
            if($nextResultItem === null){
                throw new ItemStackRequestProcessException("No such crafting result index: " . $action->getResultIndex());
            }
            $this->setNextCreatedItem($nextResultItem);
        }elseif($action instanceof DeprecatedCraftingResultsStackRequestAction){
            //no obvious use
        }else{
            throw new ItemStackRequestProcessException("Unhandled item stack request action");
        }
    }
 
    public function generateInventoryTransaction() : InventoryTransaction{
        foreach($this->request->getActions() as $k => $action){
            try{
                $this->processItemStackRequestAction($action);
            }catch(ItemStackRequestProcessException $e){
                throw new ItemStackRequestProcessException("Error processing action $k (" . (new \ReflectionClass($action))->getShortName() . "): " . $e->getMessage(), 0, $e);
            }
        }
        $this->setNextCreatedItem(null);
        $inventoryActions = $this->builder->generateActions();
 
        $transaction = $this->specialTransaction ?? new InventoryTransaction($this->player);
        foreach($inventoryActions as $action){
            $transaction->addAction($action);
        }
 
        return $transaction;
    }
 
    public function buildItemStackResponse() : ItemStackResponse{
        $builder = new ItemStackResponseBuilder($this->request->getRequestId(), $this->inventoryManager);
        foreach($this->requestSlotInfos as $requestInfo){
            $builder->addSlot($requestInfo->getContainerName()->getContainerId(), $requestInfo->getSlotId());
        }
 
        return $builder->build();
    }
}