#include "inventorystore.hpp"

#include <iterator>
#include <algorithm>

#include "../mwmechanics/npcstats.hpp"

#include "class.hpp"

void MWWorld::InventoryStore::copySlots (const InventoryStore& store)
{
    // some const-trickery, required because of a flaw in the handling of MW-references and the
    // resulting workarounds
    for (std::vector<ContainerStoreIterator>::const_iterator iter (
        const_cast<InventoryStore&> (store).mSlots.begin());
        iter!=const_cast<InventoryStore&> (store).mSlots.end(); ++iter)
    {
        std::size_t distance = std::distance (const_cast<InventoryStore&> (store).begin(), *iter);

        ContainerStoreIterator slot = begin();

        std::advance (slot, distance);

        mSlots.push_back (slot);
    }
}

void MWWorld::InventoryStore::initSlots (TSlots& slots)
{
    for (int i=0; i<Slots; ++i)
        slots.push_back (end());
}

MWWorld::InventoryStore::InventoryStore()
{
    initSlots (mSlots);
}

MWWorld::InventoryStore::InventoryStore (const InventoryStore& store)
: ContainerStore (store)
{
    copySlots (store);
}

MWWorld::InventoryStore& MWWorld::InventoryStore::operator= (const InventoryStore& store)
{
    ContainerStore::operator= (store);
    mSlots.clear();
    copySlots (store);
    return *this;
}

void MWWorld::InventoryStore::equip (int slot, const ContainerStoreIterator& iterator)
{
    if (slot<0 || slot>=static_cast<int> (mSlots.size()))
        throw std::runtime_error ("slot number out of range");

    if (iterator.getContainerStore()!=this)
        throw std::runtime_error ("attempt to equip an item that is not in the inventory");

    if (iterator!=end())
    {
        std::pair<std::vector<int>, bool> slots = Class::get (*iterator).getEquipmentSlots (*iterator);

        if (std::find (slots.first.begin(), slots.first.end(), slot)==slots.first.end())
            throw std::runtime_error ("invalid slot");
    }

    /// \todo restack item previously in this slot (if required)

    /// \todo unstack item pointed to by iterator if required)

    mSlots[slot] = iterator;

    flagAsModified();
}

MWWorld::ContainerStoreIterator MWWorld::InventoryStore::getSlot (int slot)
{
    if (slot<0 || slot>=static_cast<int> (mSlots.size()))
        throw std::runtime_error ("slot number out of range");

    if (mSlots[slot]==end())
        return end();

    if (mSlots[slot]->getRefData().getCount()<1)
    {
        // object has been deleted
        mSlots[slot] = end();
        return end();
    }

    return mSlots[slot];
}

void MWWorld::InventoryStore::autoEquip (const MWMechanics::NpcStats& stats,
    const Environment& environment)
{
    TSlots slots;
    initSlots (slots);

    for (ContainerStoreIterator iter (begin()); iter!=end(); ++iter)
    {
        Ptr test = *iter;
        int testSkill = MWWorld::Class::get (test).getEquipmentSkill (test, environment);

        std::pair<std::vector<int>, bool> itemsSlots =
            MWWorld::Class::get (*iter).getEquipmentSlots (*iter);

        for (std::vector<int>::const_iterator iter2 (itemsSlots.first.begin());
            iter2!=itemsSlots.first.end(); ++iter2)
        {
            bool use = false;

            if (slots.at (*iter2)==end())
                use = true; // slot was empty before -> skill all further checks
            else
            {
                Ptr old = *slots.at (*iter2);

                if (!use)
                {
                    // check skill
                    int oldSkill =
                        MWWorld::Class::get (old).getEquipmentSkill (old, environment);

                    if (testSkill!=-1 || oldSkill!=-1 || testSkill!=oldSkill)
                    {
                        if (stats.mSkill[oldSkill].getModified()>stats.mSkill[testSkill].getModified())
                            continue; // rejected, because old item better matched the NPC's skills.

                        if (stats.mSkill[oldSkill].getModified()<stats.mSkill[testSkill].getModified())
                            use = true;
                    }
                }

                if (!use)
                {
                    // check value
                    if (MWWorld::Class::get (old).getValue (old)>=
                        MWWorld::Class::get (test).getValue (test))
                    {
                        continue;
                    }

                    use = true;
                }
            }

            /// \todo unstack, if reqquired (itemsSlots.second)

            slots[*iter2] = iter;
            break;
        }
    }

    bool changed = false;

    for (std::size_t i=0; i<slots.size(); ++i)
        if (slots[i]!=mSlots[i])
        {
            changed = true;
        }

    if (changed)
    {
        mSlots.swap (slots);
        flagAsModified();
    }
}