FactoryCraft-Server/FactoryCraft/Inventory.cpp

#include "Inventory.h"

#include <InMemoryBuffer.h>

#include "Area.h"
#include "Constants.h"
#include "Entity.h"
#include "Game.h"
#include "ItemFilter.h"
#include "ItemSlot.h"
#include "ItemStack.h"
#include "NetworkMessage.h"

using namespace Framework;

InventoryInteraction::InventoryInteraction(
    Inventory* current, Inventory* other, Direction dir)
    : current(current),
      other(other),
      dir(dir)
{
    lock();
}

InventoryInteraction::InventoryInteraction(
    const InventoryInteraction& interaction)
    : InventoryInteraction(
          interaction.current, interaction.other, interaction.dir)
{}

InventoryInteraction::~InventoryInteraction()
{
    unlock();
}

void InventoryInteraction::lock()
{
    if (!current || !other) return;
    if (current->location.x < other->location.x)
    {
        current->cs.lock();
        other->cs.lock();
        return;
    }
    else if (current->location.x == other->location.x)
    {
        if (current->location.y < other->location.y)
        {
            current->cs.lock();
            other->cs.lock();
            return;
        }
        else if (current->location.y == other->location.y)
        {
            if (current->location.z < other->location.z)
            {
                current->cs.lock();
                other->cs.lock();
                return;
            }
        }
    }
    other->cs.lock();
    current->cs.lock();
}

void InventoryInteraction::unlock()
{
    if (!current || !other) return;
    if (current->location.x < other->location.x)
    {
        current->cs.unlock();
        other->cs.unlock();
        return;
    }
    else if (current->location.x == other->location.x)
    {
        if (current->location.y < other->location.y)
        {
            current->cs.unlock();
            other->cs.unlock();
            return;
        }
        else if (current->location.y == other->location.y)
        {
            if (current->location.z < other->location.z)
            {
                current->cs.unlock();
                other->cs.unlock();
                return;
            }
        }
    }
    other->cs.unlock();
    current->cs.unlock();
}

void InventoryInteraction::transaction(Inventory* zSource,
    Inventory* zTarget,
    ItemFilter* zFilter,
    Direction sourceView,
    Direction targetView,
    int count)
{
    for (auto sourceSlot = zSource->pullSlotsOrder->begin(); sourceSlot;)
    {
        while (sourceSlot
               && (sourceSlot->getNumberOfItems() == 0
                   || (zFilter && !zFilter->matchSourceSlot(sourceSlot))))
            sourceSlot++;
        if (!sourceSlot) break;
        // TODO: use target cache ot get list of slots that already contains the
        // source item
        bool needNext = 1;
        for (auto targetSlot = zTarget->pushSlotsOrder->begin(); targetSlot;)
        {
            while (targetSlot
                   && (targetSlot->isFull()
                       || (zFilter && !zFilter->matchTargetSlot(targetSlot))))
                targetSlot++;
            if (!targetSlot) break;
            needNext &= !Inventory::unsafeMove(zSource,
                zTarget,
                sourceSlot,
                targetSlot,
                sourceView,
                targetView,
                count);
            if (count == 0) return;
            if (sourceSlot->getNumberOfItems() == 0) break;
        }
        if (needNext) sourceSlot++;
    }
}

InventoryInteraction& InventoryInteraction::operator=(
    const InventoryInteraction& data)
{
    if (&data == this) return *this;
    unlock();
    current = data.current;
    other = data.other;
    dir = data.dir;
    lock();
    return *this;
}

void InventoryInteraction::endInteraction()
{
    unlock();
    current = 0;
    other = 0;
}

void InventoryInteraction::pullItems(int count, ItemFilter* zFilter)
{
    if (!current || !other) return;
    transaction(other, current, zFilter, getOppositeDirection(dir), dir, count);
}

void InventoryInteraction::pushItems(int count, ItemFilter* zFilter)
{
    if (!current || !other) return;
    transaction(current, other, zFilter, dir, getOppositeDirection(dir), count);
}

MultipleInventoryLock::MultipleInventoryLock(Inventory** inventories, int count)
    : inventories(new Inventory*[count]),
      count(count),
      locked(0)
{
    // sort given inventories in locking order
    bool* used = new bool[count];
    memset(used, 0, count);
    // TODO: use a performant sorting algorithm
    for (int i = 0; i < count; i++)
    {
        Inventory* min = 0;
        int minJ = 0;
        for (int j = 0; j < count; j++)
        {
            if (!used[j])
            {
                if (!min)
                {
                    min = inventories[j];
                    minJ = j;
                    continue;
                }
                if (inventories[j]->location.x < min->location.x)
                {
                    min = inventories[j];
                    minJ = j;
                    continue;
                }
                if (inventories[j]->location.x == min->location.x)
                {
                    if (inventories[j]->location.y < min->location.y)
                    {
                        min = inventories[j];
                        minJ = j;
                        continue;
                    }
                    if (inventories[j]->location.y == min->location.y)
                    {
                        if (inventories[j]->location.z < min->location.z)
                        {
                            min = inventories[j];
                            minJ = j;
                            continue;
                        }
                    }
                }
            }
        }
        this->inventories[i] = min;
        used[minJ] = 1;
    }
    lock();
    delete[] used;
}

MultipleInventoryLock::~MultipleInventoryLock()
{
    unlock();
    delete[] inventories;
}

void MultipleInventoryLock::unlock()
{
    if (locked)
    {
        locked = 0;
        for (int i = count - 1; i >= 0; i--)
        {
            inventories[i]->cs.unlock();
        }
    }
}

void MultipleInventoryLock::lock()
{
    if (!locked)
    {
        locked = 1;
        for (int i = 0; i < count; i++)
        {
            inventories[i]->cs.lock();
        }
    }
}

Inventory::Inventory(
    const Framework::Vec3<float> location, int dimensionId, bool hasInventory)
    : ReferenceCounter(),
      nextSlotId(1),
      dimensionId(dimensionId),
      location(location)
{
    if (hasInventory)
    {
        pullSlotsOrder = new Framework::RCArray<ItemSlot>();
        pushSlotsOrder = new Framework::RCArray<ItemSlot>();
        itemCache = new Framework::HashMap<int, Framework::Array<ItemSlot*>*>(
            ITEM_CACHE_SIZE, [](int key) { return key; });
    }
    else
    {
        pullSlotsOrder = 0;
        pushSlotsOrder = 0;
        itemCache = 0;
    }
}

Inventory::~Inventory()
{
    if (pullSlotsOrder) pullSlotsOrder->release();
    if (pushSlotsOrder) pushSlotsOrder->release();
    if (itemCache) itemCache->release();
}

void Inventory::updateCache(ItemSlot* zSlot, int beforeKey)
{
    if (!itemCache) return;
    int key
        = zSlot->zStack() ? zSlot->zStack()->zItem()->zItemType()->getId() : -1;
    if (key == beforeKey) return;
    if (beforeKey >= 0)
    {
        auto tmp = itemCache->safeGet(key, 0);
        if (tmp) tmp->removeValue(zSlot);
    }
    if (zSlot->zStack())
    {
        auto tmp = itemCache->safeGet(key, 0);
        if (!tmp)
        {
            tmp = new Array<ItemSlot*>();
            itemCache->put(key, tmp);
        }
        tmp->add(zSlot, 0);
    }
}

void Inventory::addSlot(ItemSlot* slot)
{
    cs.lock();
    ((ItemSlotIDSetter*)slot)->setId(nextSlotId++);
    int pullPrio = slot->getPullPriority();
    int pushPrio = slot->getPushPriority();
    int index = 0;
    for (auto stack : *pullSlotsOrder)
    {
        if (stack->getPullPriority() > pullPrio) break;
        index++;
    }
    pullSlotsOrder->add(dynamic_cast<ItemSlot*>(slot->getThis()), index);
    index = 0;
    for (auto stack : *pushSlotsOrder)
    {
        if (stack->getPushPriority() > pushPrio) break;
        index++;
    }
    pushSlotsOrder->add(slot, index);
    updateCache(slot, -1);
    cs.unlock();
}

bool Inventory::allowPullStack(ItemSlot* zSlot, Direction dir) const
{
    return pullSlotsOrder;
}

bool Inventory::allowPushStack(
    ItemSlot* zSlot, Direction dir, const Item* zItem, int& count) const
{
    return pushSlotsOrder;
}

void Inventory::afterPullStack(
    ItemSlot* zSlot, Direction dir, const Item* zItem, int count)
{
    NetworkMessage* msg = new NetworkMessage();
    char* message = new char[9];
    message[0] = 1; // set count of items
    *(int*)(message + 1) = zSlot->getId();
    *(int*)(message + 5) = zSlot->getNumberOfItems();
    msg->setMessage(message, 9);
    notifyObservers(msg);
    for (auto call : afterPullStackCalls)
        call(zSlot, dir, zItem, count);
}

void Inventory::afterPushStack(
    ItemSlot* zSlot, Direction dir, const Item* zItem, int count)
{
    updateSlot(zSlot);
    for (auto call : afterPushStackCalls)
        call(zSlot, dir, zItem, count);
}

void Inventory::updateSlot(ItemSlot* zSlot)
{
    NetworkMessage* msg = new NetworkMessage();
    char* message = new char[9];
    message[0] = 1; // set count of items
    *(int*)(message + 1) = zSlot->getId();
    *(int*)(message + 5) = 0;
    msg->setMessage(message, 9);
    notifyObservers(msg);
    if (zSlot->getNumberOfItems() > 0)
    {
        const Item* zItem = zSlot->zStack()->zItem();
        NetworkMessage* msg = new NetworkMessage();
        char* message = new char[30 + zItem->getName().getLength()];
        message[0] = 2; // add new stack
        *(int*)(message + 1) = zSlot->getId();
        *(int*)(message + 5) = zSlot->getNumberOfItems();
        *(float*)(message + 9) = zItem->getHp();
        *(float*)(message + 13) = zItem->getMaxHp();
        *(float*)(message + 17) = zItem->getDurability();
        *(float*)(message + 21) = zItem->getMaxDurability();
        *(int*)(message + 25) = zItem->zItemType()->getId();
        *(message + 29) = (char)zItem->getName().getLength();
        memcpy(message + 30,
            zItem->getName().getText(),
            zItem->getName().getLength());
        msg->setMessage(message, 30 + zItem->getName().getLength());
        notifyObservers(msg);
    }
}

void Inventory::loadInventory(Framework::StreamReader* zReader)
{
    if (itemCache)
    {
        for (auto stack : *pushSlotsOrder)
        {
            int size = 0;
            zReader->lese((char*)&size, 4);
            if (size != 0)
            {
                int id = 0;
                zReader->lese((char*)&id, 4);
                Item* item = Game::INSTANCE->zItemType(id)->loadItem(zReader);
                stack->addItems(new ItemStack(item, size), NO_DIRECTION);
            }
        }
    }
}

void Inventory::saveInventory(Framework::StreamWriter* zWriter)
{
    if (itemCache)
    {
        for (auto slot : *pushSlotsOrder)
        {
            const ItemStack* stack = slot->zStack();
            int value = 0;
            if (!stack || !stack->zItem())
            {
                zWriter->schreibe((char*)&value, 4);
            }
            else
            {
                value = stack->getSize();
                zWriter->schreibe((char*)&value, 4);
                value = stack->zItem()->zItemType()->getId();
                zWriter->schreibe((char*)&value, 4);
                stack->zItem()->zItemType()->saveItem(stack->zItem(), zWriter);
            }
        }
    }
}

void Inventory::notifyObservers(NetworkMessage* msg)
{
    observable.notifyObservers(msg);
}

void Inventory::lock()
{
    cs.lock();
}

void Inventory::unlock()
{
    cs.unlock();
}

const ItemSlot* Inventory::zSlot(int id) const
{
    if (itemCache)
    {
        for (auto slot : *pushSlotsOrder)
        {
            if (slot->getId() == id) return slot;
        }
    }
    return 0;
}

void Inventory::localTransaction(Array<ItemSlot*>* zSourceSlots,
    Array<ItemSlot*>* zTargetSlots,
    ItemFilter* zFilter,
    int count,
    Direction outDir,
    Direction inDir)
{
    if (itemCache)
    {
        cs.lock();
        auto sourceSlot
            = zSourceSlots ? zSourceSlots->begin() : pullSlotsOrder->begin();
        while (true)
        {
            while (sourceSlot
                   && (sourceSlot->getNumberOfItems() == 0
                       || (zFilter && !zFilter->matchSourceSlot(sourceSlot))))
                sourceSlot++;
            if (!sourceSlot)
            {
                cs.unlock();
                return;
            }
            bool needNext = 1;
            for (auto targetSlot = zTargetSlots->begin(); targetSlot;)
            {
                while (
                    targetSlot
                    && (targetSlot->isFull()
                        || (zFilter && !zFilter->matchTargetSlot(targetSlot))))
                    targetSlot++;
                if (!targetSlot) break;
                needNext &= !Inventory::unsafeMove(
                    this, this, sourceSlot, targetSlot, outDir, inDir, count);
                if (count == 0)
                {
                    cs.unlock();
                    return;
                }
                if (sourceSlot->getNumberOfItems() == 0) break;
            }
            if (needNext) sourceSlot++;
        }
        cs.unlock();
    }
}

void Inventory::addItems(ItemStack* zItems, Direction dir, ItemFilter* zFilter)
{
    if (itemCache && zItems && zItems->getSize() > 0)
    {
        cs.lock();
        for (auto targetSlot = pushSlotsOrder->begin(); targetSlot;
            targetSlot++)
        {
            if (!targetSlot->isFull()
                && (!zFilter || zFilter->matchTargetSlot(targetSlot)))
            {
                if (targetSlot->zStack())
                {
                    if (targetSlot->zStack()->zItem()->canBeStackedWith(
                            zItems->zItem()))
                    {
                        int number = MIN(targetSlot->numberOfAddableItems(
                                             zItems->zItem(), dir),
                            zItems->getSize());
                        int tmp = number;
                        if (number > 0
                            && allowPushStack(
                                targetSlot, dir, zItems->zItem(), tmp))
                        {
                            number = MIN(number, tmp);
                            ItemStack* stack = zItems->split(number);
                            if (stack)
                            {
                                targetSlot->addItems(stack, dir);
                                afterPushStack(targetSlot,
                                    dir,
                                    targetSlot->zStack()->zItem(),
                                    number);
                                if (stack->getSize()) throw stack;
                                stack->release();
                                if (!zItems->getSize()) break;
                            }
                        }
                    }
                }
                else
                {
                    int number = MIN(
                        targetSlot->numberOfAddableItems(zItems->zItem(), dir),
                        zItems->getSize());
                    int tmp = number;
                    if (number > 0
                        && allowPushStack(
                            targetSlot, dir, zItems->zItem(), tmp))
                    {
                        number = MIN(number, tmp);
                        ItemStack* stack = zItems->split(number);
                        if (stack)
                        {
                            targetSlot->addItems(stack, dir);
                            updateCache(targetSlot, -1);
                            afterPushStack(targetSlot,
                                dir,
                                targetSlot->zStack()->zItem(),
                                number);
                            if (stack->getSize()) throw stack;
                            stack->release();
                            if (!zItems->getSize()) break;
                        }
                    }
                }
            }
        }
        cs.unlock();
    }
}

void Inventory::addItems(ItemSlot* zSlot, ItemStack* zItems, Direction dir)
{
    if (zSlot->zStack()
        && !zSlot->zStack()->zItem()->canBeStackedWith(zItems->zItem()))
        return;
    bool needUpdate = !zSlot->zStack();
    int number = MIN(
        zSlot->numberOfAddableItems(zItems->zItem(), dir), zItems->getSize());
    int tmp = number;
    if (number > 0 && allowPushStack(zSlot, dir, zItems->zItem(), tmp))
    {
        number = MIN(number, tmp);
        ItemStack* stack = zItems->split(number);
        if (stack)
        {
            zSlot->addItems(stack, dir);
            if (needUpdate) updateCache(zSlot, -1);
            afterPushStack(zSlot, dir, zSlot->zStack()->zItem(), number);
            if (stack->getSize()) throw stack;
            stack->release();
        }
    }
}

ItemStack* Inventory::takeItemsOut(ItemSlot* zSlot, int count, Direction dir)
{
    if (allowPullStack(zSlot, dir))
    {
        ItemStack* stack = zSlot->takeItemsOut(count, dir);
        if (stack)
        {
            updateCache(zSlot, stack->zItem()->zItemType()->getId());
            if (stack->getSize() > 0)
                afterPullStack(zSlot, dir, stack->zItem(), stack->getSize());
        }
        return stack;
    }
    return 0;
}

InventoryInteraction Inventory::interactWith(
    Inventory* zInventory, Direction dir)
{
    return InventoryInteraction(this, zInventory, dir);
}

void Inventory::unsaveAddItem(
    ItemStack* zStack, Direction dir, ItemFilter* zFilter)
{
    addItems(zStack, dir, zFilter);
}

int Inventory::numberOfAddableItems(const Item* zItem, Direction dir) const
{
    int count = 0;
    for (auto targetSlot = pushSlotsOrder->begin(); targetSlot; targetSlot++)
    {
        int maxCount = targetSlot->numberOfAddableItems(zItem, dir);
        int allowed = maxCount;
        if (allowPushStack(targetSlot, dir, zItem, allowed))
            count += MIN(maxCount, allowed);
    }
    return count;
}

int Inventory::numberOfAddableItems(
    const Item* zItem, Direction dir, const Framework::Text& slotName) const
{
    int count = 0;
    for (auto targetSlot = pushSlotsOrder->begin(); targetSlot; targetSlot++)
    {
        if (targetSlot->getName().istGleich(slotName))
        {
            int maxCount = targetSlot->numberOfAddableItems(zItem, dir);
            int allowed = maxCount;
            if (allowPushStack(targetSlot, dir, zItem, allowed))
                count += MIN(maxCount, allowed);
        }
    }
    return count;
}

bool Inventory::isAllAvailable(Framework::RCArray<RecipieInput>& inputs,
    const Framework::Text& slotName) const
{
    int* used = new int[pullSlotsOrder->getEintragAnzahl()];
    memset(used, 0, sizeof(int) * pullSlotsOrder->getEintragAnzahl());
    for (RecipieInput* input : inputs)
    {
        int found = 0;
        for (int i = 0; i < pullSlotsOrder->getEintragAnzahl(); i++)
        {
            ItemSlot* slot = pullSlotsOrder->get(i);
            if (slot && slot->zStack() && slot->zStack()->zItem()
                && slot->getNumberOfItems() > used[i]
                && slot->getName().istGleich(slotName)
                && input->zFilter()->matchItem(slot->zStack()->zItem()))
            {
                int usable = slot->getNumberOfItems() - used[i];
                if (found + usable >= input->getAmount())
                {
                    used[i] += input->getAmount() - found;
                    found = input->getAmount();
                    break;
                }
                else
                {
                    used[i] += usable;
                    found += usable;
                }
            }
        }
        if (found < input->getAmount())
        {
            delete[] used;
            return 0;
        }
    }
    delete[] used;
    return 1;
}

void Inventory::consume(
    Framework::RCArray<RecipieInput>& inputs, const Framework::Text& slotName)
{
    for (RecipieInput* input : inputs)
    {
        int consumed = 0;
        for (int i = 0; i < pullSlotsOrder->getEintragAnzahl(); i++)
        {
            ItemSlot* slot = pullSlotsOrder->get(i);
            if (slot && slot->zStack() && slot->zStack()->zItem()
                && slot->getName().istGleich(slotName)
                && input->zFilter()->matchItem(slot->zStack()->zItem()))
            {
                if (consumed + slot->getNumberOfItems() >= input->getAmount())
                {
                    takeItemsOut(
                        slot, input->getAmount() - consumed, NO_DIRECTION)
                        ->release();
                    consumed = input->getAmount();
                    break;
                }
                else
                {
                    consumed += slot->getNumberOfItems();
                    takeItemsOut(slot, slot->getNumberOfItems(), NO_DIRECTION)
                        ->release();
                }
            }
        }
    }
}

Framework::ArrayIterator<ItemSlot*> Inventory::begin()
{
    return pullSlotsOrder->begin();
}

Framework::ArrayIterator<ItemSlot*> Inventory::end()
{
    return pullSlotsOrder->end();
}

void Inventory::inventoryApi(Framework::StreamReader* zRequest,
    NetworkMessage* zResponse,
    Entity* zSource)
{
    char type;
    zRequest->lese(&type, 1);
    switch (type)
    {
    case 0: // request inventory
        {
            char idLen;
            zRequest->lese(&idLen, 1);
            char* id = new char[idLen + 1];
            zRequest->lese(id, idLen);
            id[(int)idLen] = 0;
            int processor;
            zRequest->lese((char*)&processor, 4);
            zResponse->addressUIElement(id, processor);
            observable.addObserver(zSource, id, processor);
            delete[] id;
            char filterLen;
            zRequest->lese(&filterLen, 1);
            char* filter = new char[filterLen + 1];
            if (filterLen) zRequest->lese(filter, filterLen);
            filter[(int)filterLen] = 0;
            InMemoryBuffer buffer;
            int count = 0;
            for (ItemSlot* slot : *this)
            {
                if (filterLen == 0 || slot->getName().istGleich(filter))
                {
                    count++;
                    int id = slot->getId();
                    buffer.schreibe((char*)&id, 4);
                    int itemCount = slot->getNumberOfItems();
                    buffer.schreibe((char*)&itemCount, 4);
                    if (itemCount > 0)
                    {
                        float f = slot->zStack()->zItem()->getHp();
                        buffer.schreibe((char*)&f, 4);
                        f = slot->zStack()->zItem()->getMaxHp();
                        buffer.schreibe((char*)&f, 4);
                        f = slot->zStack()->zItem()->getDurability();
                        buffer.schreibe((char*)&f, 4);
                        f = slot->zStack()->zItem()->getMaxDurability();
                        buffer.schreibe((char*)&f, 4);
                        int id = slot->zStack()->zItem()->zItemType()->getId();
                        buffer.schreibe((char*)&id, 4);
                        char len = (char)slot->zStack()
                                       ->zItem()
                                       ->getName()
                                       .getLength();
                        buffer.schreibe((char*)&len, 1);
                        buffer.schreibe(
                            slot->zStack()->zItem()->getName().getText(),
                            slot->zStack()->zItem()->getName().getLength());
                    }
                }
            }
            delete[] filter;
            char* msg = new char[5 + buffer.getSize()];
            msg[0] = 0;
            *(int*)(msg + 1) = count;
            buffer.lese(msg + 5, (int)buffer.getSize());
            zResponse->setMessage(msg, 5 + (int)buffer.getSize());
            break;
        }
    case 1: // remove Observer
        {
            char idLen;
            zRequest->lese(&idLen, 1);
            char* id = new char[idLen + 1];
            zRequest->lese(id, idLen);
            id[(int)idLen] = 0;
            int processor;
            zRequest->lese((char*)&processor, 4);
            observable.removeObserver(zSource, id, processor);
            delete[] id;
            break;
        }
    case 2: // request item tooltip
        {
            char idLen;
            zRequest->lese(&idLen, 1);
            char* id = new char[idLen + 1];
            zRequest->lese(id, idLen);
            id[(int)idLen] = 0;
            int processor;
            zRequest->lese((char*)&processor, 4);
            zResponse->addressUIElement(id, processor);
            delete[] id;
            int slotId;
            zRequest->lese((char*)&slotId, 4);
            Text uiml;
            for (ItemSlot* slot : *pullSlotsOrder)
            {
                if (slot->getId() == slotId)
                {
                    if (slot->zStack() && slot->zStack()->zItem())
                        uiml = slot->zStack()->zItem()->getTooltipUIML();
                }
            }
            short len = (short)uiml.getLength();
            char* buffer = new char[uiml.getLength() + 7];
            buffer[0] = 3;
            *(int*)(buffer + 1) = slotId;
            *(short*)(buffer + 5) = len;
            memcpy(buffer + 7, uiml, len);
            zResponse->setMessage(buffer, len + 7);
            break;
        }
    }
}

void Inventory::registerAfterPullStackCall(std::function<void(
        ItemSlot* zSlot, Direction dir, const Item* zItem, int count)> call)
{
    afterPullStackCalls.add(call);
}

void Inventory::registerAfterPushStackCall(std::function<void(
        ItemSlot* zSlot, Direction dir, const Item* zItem, int count)> call)
{
    afterPushStackCalls.add(call);
}

void Inventory::registerObserverAddedCall(
    std::function<void(Entity* zSource, Framework::Text id, int processor)>
        call)
{
    observable.registerOnObserverAddedCall(call);
}

int Inventory::getDimensionId() const
{
    return dimensionId;
}

Framework::Vec3<float> Inventory::getLocation() const
{
    return location;
}

bool Inventory::unsafeMove(Inventory* zSource,
    Inventory* zTarget,
    ArrayIterator<ItemSlot*>& sourceSlot,
    ArrayIterator<ItemSlot*>& targetSlot,
    Direction outDir,
    Direction inDir,
    int& count)
{
    if (targetSlot->zStack())
    {
        if (sourceSlot->zStack()->zItem()->canBeStackedWith(
                targetSlot->zStack()->zItem()))
        {
            int number = MIN(targetSlot->numberOfAddableItems(
                                 sourceSlot->zStack()->zItem(), outDir),
                count);
            int tmp = number;
            if (number > 0 && zSource->allowPullStack(sourceSlot, outDir)
                && zTarget->allowPushStack(
                    targetSlot, inDir, sourceSlot->zStack()->zItem(), tmp))
            {
                number = MIN(number, tmp);
                ItemStack* stack = sourceSlot->takeItemsOut(number, outDir);
                if (stack)
                {
                    targetSlot->addItems(stack, inDir);
                    zSource->updateCache(sourceSlot,
                        targetSlot->zStack()->zItem()->zItemType()->getId());
                    zSource->afterPullStack(sourceSlot,
                        outDir,
                        targetSlot->zStack()->zItem(),
                        number);
                    zTarget->afterPushStack(targetSlot,
                        inDir,
                        targetSlot->zStack()->zItem(),
                        number);
                    if (stack->getSize()) throw stack;
                    stack->release();
                    count -= number;
                    return 1;
                }
                else
                    targetSlot++;
            }
            else
                targetSlot++;
        }
        else
            targetSlot++;
    }
    else
    {
        int number = MIN(targetSlot->numberOfAddableItems(
                             sourceSlot->zStack()->zItem(), outDir),
            count);
        int tmp = number;
        if (number > 0 && zSource->allowPullStack(sourceSlot, outDir)
            && zTarget->allowPushStack(
                targetSlot, inDir, sourceSlot->zStack()->zItem(), tmp))
        {
            number = MIN(number, tmp);
            if (number > 0)
            {
                ItemStack* stack = sourceSlot->takeItemsOut(number, outDir);
                if (stack)
                {
                    targetSlot->addItems(stack, inDir);
                    zSource->updateCache(sourceSlot,
                        targetSlot->zStack()->zItem()->zItemType()->getId());
                    zTarget->updateCache(targetSlot, -1);
                    zSource->afterPullStack(sourceSlot,
                        outDir,
                        targetSlot->zStack()->zItem(),
                        number);
                    zTarget->afterPushStack(targetSlot,
                        inDir,
                        targetSlot->zStack()->zItem(),
                        number);
                    if (stack->getSize()) throw stack;
                    stack->release();
                    count -= number;
                    return 1;
                }
                else
                    targetSlot++;
            }
            else
                targetSlot++;
        }
        else
            targetSlot++;
    }
    return 0;
}