/**
 * MaNGOS is a full featured server for World of Warcraft, supporting
 * the following clients: 1.12.x, 2.4.3, 3.3.5a, 4.3.4a and 5.4.8
 *
 * Copyright (C) 2005-2018  MaNGOS project <https://getmangos.eu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * World of Warcraft, and all World of Warcraft or Warcraft art, images,
 * and lore are copyrighted by Blizzard Entertainment, Inc.
 */

#include "Common.h"
#include "WorldPacket.h"
#include "WorldSession.h"
#include "World.h"
#include "ObjectAccessor.h"
#include "Log.h"
#include "Opcodes.h"
#include "Player.h"
#include "Item.h"
#include "Spell.h"
#include "SocialMgr.h"
#include "DBCStores.h"

void WorldSession::SendTradeStatus(const TradeStatusInfo& info)
{
    WorldPacket data(SMSG_TRADE_STATUS, 13);
    data << uint32(info.Status);

    switch (info.Status)
    {
        case TRADE_STATUS_BEGIN_TRADE:
            data << info.TraderGuid;                        // CGTradeInfo::m_tradingPlayer
            break;
        case TRADE_STATUS_CLOSE_WINDOW:
            data << uint32(info.Result);                    // InventoryResult
            data << uint8(info.IsTargetResult);             // bool isTargetError; used for: EQUIP_ERR_BAG_FULL, EQUIP_ERR_CANT_CARRY_MORE_OF_THIS, EQUIP_ERR_MISSING_REAGENT, EQUIP_ERR_ITEM_MAX_LIMIT_CATEGORY_COUNT_EXCEEDED
            data << uint32(info.ItemLimitCategoryId);       // ItemLimitCategory.dbc entry
            break;
        case TRADE_STATUS_WRONG_REALM:
            data << uint8(info.Slot);                       // Trade slot; -1 here clears CGTradeInfo::m_tradeMoney
            break;
        default:
            break;
    }

    SendPacket(&data);
}

void WorldSession::HandleIgnoreTradeOpcode(WorldPacket& /*recvPacket*/)
{
    DEBUG_LOG("WORLD: Ignore Trade %u", _player->GetGUIDLow());
    // recvPacket.print_storage();
}

void WorldSession::HandleBusyTradeOpcode(WorldPacket& /*recvPacket*/)
{
    DEBUG_LOG("WORLD: Busy Trade %u", _player->GetGUIDLow());
    // recvPacket.print_storage();
}

void WorldSession::SendUpdateTrade(bool trader_state /*= true*/)
{
    TradeData* view_trade = trader_state ? _player->GetTradeData()->GetTraderData() : _player->GetTradeData();

    WorldPacket data(SMSG_TRADE_STATUS_EXTENDED, (100));    // guess size
    data << uint8(trader_state ? 1 : 0);                    // send trader or own trade windows state (last need for proper show spell apply to non-trade slot)
    data << uint32(TRADE_SLOT_COUNT);                       // trade slots count/number?, = next field in most cases
    data << uint32(TRADE_SLOT_COUNT);                       // trade slots count/number?, = prev field in most cases
    data << uint32(view_trade->GetMoney());                 // trader gold
    data << uint32(view_trade->GetSpell());                 // spell casted on lowest slot item

    for (uint8 i = 0; i < TRADE_SLOT_COUNT; ++i)
    {
        data << uint8(i);                                   // trade slot number, if not specified, then end of packet

        if (Item* item = view_trade->GetItem(TradeSlots(i)))
        {
            data << uint32(item->GetProto()->ItemId);       // entry
            data << uint32(item->GetProto()->DisplayInfoID);// display id
            data << uint32(item->GetCount());               // stack count

            // wrapped: hide stats but show giftcreator name
            data << uint32(item->HasFlag(ITEM_FIELD_FLAGS, ITEM_DYNFLAG_WRAPPED) ? 1 : 0);
            data << item->GetGuidValue(ITEM_FIELD_GIFTCREATOR);

            data << uint32(item->GetEnchantmentId(PERM_ENCHANTMENT_SLOT));
            data << item->GetGuidValue(ITEM_FIELD_CREATOR);
            data << uint32(item->GetSpellCharges());        // charges
            data << uint32(item->GetItemSuffixFactor());    // SuffixFactor
            data << uint32(item->GetItemRandomPropertyId());// random properties id
            data << uint32(item->GetProto()->LockID);       // lock id
            // max durability
            data << uint32(item->GetUInt32Value(ITEM_FIELD_MAXDURABILITY));
            // durability
            data << uint32(item->GetUInt32Value(ITEM_FIELD_DURABILITY));
        }
        else
        {
            for (uint8 j = 0; j < 15; ++j)
                { data << uint32(0); }
        }
    }

    SendPacket(&data);
}

//==============================================================
// transfer the items to the players

void WorldSession::moveItems(Item* myItems[], Item* hisItems[])
{
    Player* trader = _player->GetTrader();
    if (!trader)
        { return; }

    for (int i = 0; i < TRADE_SLOT_TRADED_COUNT; ++i)
    {
        ItemPosCountVec traderDst;
        ItemPosCountVec playerDst;
        bool traderCanTrade = (myItems[i] == NULL || trader->CanStoreItem(NULL_BAG, NULL_SLOT, traderDst, myItems[i], false) == EQUIP_ERR_OK);
        bool playerCanTrade = (hisItems[i] == NULL || _player->CanStoreItem(NULL_BAG, NULL_SLOT, playerDst, hisItems[i], false) == EQUIP_ERR_OK);
        if (traderCanTrade && playerCanTrade)
        {
            // Ok, if trade item exists and can be stored
            // If we trade in both directions we had to check, if the trade will work before we actually do it
            // A roll back is not possible after we stored it
            if (myItems[i])
            {
                // logging
                DEBUG_LOG("partner storing: %s", myItems[i]->GetGuidStr().c_str());
                if (_player->GetSession()->GetSecurity() > SEC_PLAYER && sWorld.getConfig(CONFIG_BOOL_GM_LOG_TRADE))
                {
                    sLog.outCommand(_player->GetSession()->GetAccountId(), "GM %s (Account: %u) trade: %s (Entry: %d Count: %u) to player: %s (Account: %u)",
                                    _player->GetName(), _player->GetSession()->GetAccountId(),
                                    myItems[i]->GetProto()->Name1, myItems[i]->GetEntry(), myItems[i]->GetCount(),
                                    trader->GetName(), trader->GetSession()->GetAccountId());
                }

                // store
                trader->MoveItemToInventory(traderDst, myItems[i], true, true);
            }

            if (hisItems[i])
            {
                // logging
                DEBUG_LOG("player storing: %s", hisItems[i]->GetGuidStr().c_str());
                if (trader->GetSession()->GetSecurity() > SEC_PLAYER && sWorld.getConfig(CONFIG_BOOL_GM_LOG_TRADE))
                {
                    sLog.outCommand(trader->GetSession()->GetAccountId(), "GM %s (Account: %u) trade: %s (Entry: %d Count: %u) to player: %s (Account: %u)",
                                    trader->GetName(), trader->GetSession()->GetAccountId(),
                                    hisItems[i]->GetProto()->Name1, hisItems[i]->GetEntry(), hisItems[i]->GetCount(),
                                    _player->GetName(), _player->GetSession()->GetAccountId());
                }

                // store
                _player->MoveItemToInventory(playerDst, hisItems[i], true, true);
            }
        }
        else
        {
            // in case of fatal error log error message
            // return the already removed items to the original owner
            if (myItems[i])
            {
                if (!traderCanTrade)
                    { sLog.outError("trader can't store item: %s", myItems[i]->GetGuidStr().c_str()); }
                if (_player->CanStoreItem(NULL_BAG, NULL_SLOT, playerDst, myItems[i], false) == EQUIP_ERR_OK)
                    { _player->MoveItemToInventory(playerDst, myItems[i], true, true); }
                else
                    { sLog.outError("player can't take item back: %s", myItems[i]->GetGuidStr().c_str()); }
            }
            // return the already removed items to the original owner
            if (hisItems[i])
            {
                if (!playerCanTrade)
                    { sLog.outError("player can't store item: %s", hisItems[i]->GetGuidStr().c_str()); }
                if (trader->CanStoreItem(NULL_BAG, NULL_SLOT, traderDst, hisItems[i], false) == EQUIP_ERR_OK)
                    { trader->MoveItemToInventory(traderDst, hisItems[i], true, true); }
                else
                    { sLog.outError("trader can't take item back: %s", hisItems[i]->GetGuidStr().c_str()); }
            }
        }
    }
}

//==============================================================
static void setAcceptTradeMode(TradeData* myTrade, TradeData* hisTrade, Item** myItems, Item** hisItems)
{
    myTrade->SetInAcceptProcess(true);
    hisTrade->SetInAcceptProcess(true);

    // store items in local list and set 'in-trade' flag
    for (int i = 0; i < TRADE_SLOT_TRADED_COUNT; ++i)
    {
        if (Item* item = myTrade->GetItem(TradeSlots(i)))
        {
            DEBUG_LOG("player trade %s bag: %u slot: %u", item->GetGuidStr().c_str(), item->GetBagSlot(), item->GetSlot());
            // Can return NULL
            myItems[i] = item;
            myItems[i]->SetInTrade();
        }

        if (Item* item = hisTrade->GetItem(TradeSlots(i)))
        {
            DEBUG_LOG("partner trade %s bag: %u slot: %u", item->GetGuidStr().c_str(), item->GetBagSlot(), item->GetSlot());
            hisItems[i] = item;
            hisItems[i]->SetInTrade();
        }
    }
}

static void clearAcceptTradeMode(TradeData* myTrade, TradeData* hisTrade)
{
    myTrade->SetInAcceptProcess(false);
    hisTrade->SetInAcceptProcess(false);
}

static void clearAcceptTradeMode(Item** myItems, Item** hisItems)
{
    // clear 'in-trade' flag
    for (int i = 0; i < TRADE_SLOT_TRADED_COUNT; ++i)
    {
        if (myItems[i])
            { myItems[i]->SetInTrade(false); }
        if (hisItems[i])
            { hisItems[i]->SetInTrade(false); }
    }
}

void WorldSession::HandleAcceptTradeOpcode(WorldPacket& recvPacket)
{
    recvPacket.read_skip<uint32>();

    TradeData* my_trade = _player->m_trade;
    if (!my_trade)
        { return; }

    Player* trader = my_trade->GetTrader();

    TradeData* his_trade = trader->m_trade;
    if (!his_trade)
        { return; }

    Item* myItems[TRADE_SLOT_TRADED_COUNT]  = { NULL, NULL, NULL, NULL, NULL, NULL };
    Item* hisItems[TRADE_SLOT_TRADED_COUNT] = { NULL, NULL, NULL, NULL, NULL, NULL };

    // set before checks to properly undo at problems (it already set in to client)
    my_trade->SetAccepted(true);

    TradeStatusInfo info;
    if (!_player->IsWithinDistInMap(trader, TRADE_DISTANCE, false))
    {
        info.Status = TRADE_STATUS_TARGET_TO_FAR;
        SendTradeStatus(info);
        my_trade->SetAccepted(false);
        return;
    }

    // not accept case incorrect money amount
    if (my_trade->GetMoney() > _player->GetMoney())
    {
        info.Status = TRADE_STATUS_CLOSE_WINDOW;
        info.Result = EQUIP_ERR_NOT_ENOUGH_MONEY;
        SendTradeStatus(info);
        my_trade->SetAccepted(false, true);
        return;
    }

    // not accept case incorrect money amount
    if (his_trade->GetMoney() > trader->GetMoney())
    {
        info.Status = TRADE_STATUS_CLOSE_WINDOW;
        info.Result = EQUIP_ERR_NOT_ENOUGH_MONEY;
        trader->GetSession()->SendTradeStatus(info);
        his_trade->SetAccepted(false, true);
        return;
    }

    // not accept if some items now can't be trade (cheating)
    for (int i = 0; i < TRADE_SLOT_TRADED_COUNT; ++i)
    {
        if (Item* item = my_trade->GetItem(TradeSlots(i)))
        {
            if (!item->CanBeTraded())
            {
                info.Status = TRADE_STATUS_TRADE_CANCELED;
                SendTradeStatus(info);
                return;
            }
        }

        if (Item* item  = his_trade->GetItem(TradeSlots(i)))
        {
            if (!item->CanBeTraded())
            {
                info.Status = TRADE_STATUS_TRADE_CANCELED;
                SendTradeStatus(info);
                return;
            }
        }
    }

    if (his_trade->IsAccepted())
    {
        setAcceptTradeMode(my_trade, his_trade, myItems, hisItems);

        Spell* my_spell = NULL;
        SpellCastTargets my_targets;

        Spell* his_spell = NULL;
        SpellCastTargets his_targets;

        // not accept if spell can't be casted now (cheating)
        if (uint32 my_spell_id = my_trade->GetSpell())
        {
            SpellEntry const* spellEntry = sSpellStore.LookupEntry(my_spell_id);
            Item* castItem = my_trade->GetSpellCastItem();

            if (!spellEntry || !his_trade->GetItem(TRADE_SLOT_NONTRADED) ||
                    (my_trade->HasSpellCastItem() && !castItem))
            {
                clearAcceptTradeMode(my_trade, his_trade);
                clearAcceptTradeMode(myItems, hisItems);

                my_trade->SetSpell(0);
                return;
            }

            my_spell = new Spell(_player, spellEntry, true);
            my_spell->m_CastItem = castItem;
            my_targets.setTradeItemTarget(_player);
            my_spell->m_targets = my_targets;

            SpellCastResult res = my_spell->CheckCast(true);
            if (res != SPELL_CAST_OK)
            {
                my_spell->SendCastResult(res);

                clearAcceptTradeMode(my_trade, his_trade);
                clearAcceptTradeMode(myItems, hisItems);

                delete my_spell;
                my_trade->SetSpell(0);
                return;
            }
        }

        // not accept if spell can't be casted now (cheating)
        if (uint32 his_spell_id = his_trade->GetSpell())
        {
            SpellEntry const* spellEntry = sSpellStore.LookupEntry(his_spell_id);
            Item* castItem = his_trade->GetSpellCastItem();

            if (!spellEntry || !my_trade->GetItem(TRADE_SLOT_NONTRADED) ||
                    (his_trade->HasSpellCastItem() && !castItem))
            {
                delete my_spell;
                his_trade->SetSpell(0);

                clearAcceptTradeMode(my_trade, his_trade);
                clearAcceptTradeMode(myItems, hisItems);
                return;
            }

            his_spell = new Spell(trader, spellEntry, true);
            his_spell->m_CastItem = castItem;
            his_targets.setTradeItemTarget(trader);
            his_spell->m_targets = his_targets;

            SpellCastResult res = his_spell->CheckCast(true);
            if (res != SPELL_CAST_OK)
            {
                his_spell->SendCastResult(res);

                clearAcceptTradeMode(my_trade, his_trade);
                clearAcceptTradeMode(myItems, hisItems);

                delete my_spell;
                delete his_spell;

                his_trade->SetSpell(0);
                return;
            }
        }

        // inform partner client
        info.Status = TRADE_STATUS_TRADE_ACCEPT;
        trader->GetSession()->SendTradeStatus(info);

        // test if item will fit in each inventory
        TradeStatusInfo myCanCompleteInfo, hisCanCompleteInfo;
        hisCanCompleteInfo.Result = trader->CanStoreItems(myItems, TRADE_SLOT_TRADED_COUNT);
        myCanCompleteInfo.Result = _player->CanStoreItems(hisItems, TRADE_SLOT_TRADED_COUNT);

        clearAcceptTradeMode(myItems, hisItems);

        // in case of missing space report error
        if (myCanCompleteInfo.Result != EQUIP_ERR_OK)
        {
            clearAcceptTradeMode(my_trade, his_trade);

            myCanCompleteInfo.Status = TRADE_STATUS_CLOSE_WINDOW;
            trader->GetSession()->SendTradeStatus(myCanCompleteInfo);
            myCanCompleteInfo.IsTargetResult = true;
            SendTradeStatus(myCanCompleteInfo);
            my_trade->SetAccepted(false);
            his_trade->SetAccepted(false);
            return;
        }
        else if (hisCanCompleteInfo.Result != EQUIP_ERR_OK)
        {
            clearAcceptTradeMode(my_trade, his_trade);

            hisCanCompleteInfo.Status = TRADE_STATUS_CLOSE_WINDOW;
            SendTradeStatus(hisCanCompleteInfo);
            hisCanCompleteInfo.IsTargetResult = true;
            trader->GetSession()->SendTradeStatus(hisCanCompleteInfo);
            my_trade->SetAccepted(false);
            his_trade->SetAccepted(false);
            return;
        }

        // execute trade: 1. remove
        for (int i = 0; i < TRADE_SLOT_TRADED_COUNT; ++i)
        {
            if (Item* item = myItems[i])
            {
                item->SetGuidValue(ITEM_FIELD_GIFTCREATOR, _player->GetObjectGuid());
                _player->MoveItemFromInventory(item->GetBagSlot(), item->GetSlot(), true);
            }
            if (Item* item = hisItems[i])
            {
                item->SetGuidValue(ITEM_FIELD_GIFTCREATOR, trader->GetObjectGuid());
                trader->MoveItemFromInventory(item->GetBagSlot(), item->GetSlot(), true);
            }
        }

        // execute trade: 2. store
        moveItems(myItems, hisItems);

        // logging money
        if (sWorld.getConfig(CONFIG_BOOL_GM_LOG_TRADE))
        {
            if (_player->GetSession()->GetSecurity() > SEC_PLAYER && my_trade->GetMoney() > 0)
            {
                sLog.outCommand(_player->GetSession()->GetAccountId(), "GM %s (Account: %u) give money (Amount: %u) to player: %s (Account: %u)",
                                _player->GetName(), _player->GetSession()->GetAccountId(),
                                my_trade->GetMoney(),
                                trader->GetName(), trader->GetSession()->GetAccountId());
            }
            if (trader->GetSession()->GetSecurity() > SEC_PLAYER && his_trade->GetMoney() > 0)
            {
                sLog.outCommand(trader->GetSession()->GetAccountId(), "GM %s (Account: %u) give money (Amount: %u) to player: %s (Account: %u)",
                                trader->GetName(), trader->GetSession()->GetAccountId(),
                                his_trade->GetMoney(),
                                _player->GetName(), _player->GetSession()->GetAccountId());
            }
        }

        // update money
        _player->ModifyMoney(-int32(my_trade->GetMoney()));
        _player->ModifyMoney(his_trade->GetMoney());
        trader->ModifyMoney(-int32(his_trade->GetMoney()));
        trader->ModifyMoney(my_trade->GetMoney());

        if (my_spell)
            my_spell->prepare(&my_targets);

        if (his_spell)
            his_spell->prepare(&his_targets);

        // cleanup
        clearAcceptTradeMode(my_trade, his_trade);
        delete _player->m_trade;
        _player->m_trade = NULL;
        delete trader->m_trade;
        trader->m_trade = NULL;

        // desynchronized with the other saves here (SaveInventoryAndGoldToDB() not have own transaction guards)
        CharacterDatabase.BeginTransaction();
        _player->SaveInventoryAndGoldToDB();
        trader->SaveInventoryAndGoldToDB();
        CharacterDatabase.CommitTransaction();

        info.Status = TRADE_STATUS_TRADE_COMPLETE;
        trader->GetSession()->SendTradeStatus(info);
        SendTradeStatus(info);
    }
    else
    {
        info.Status = TRADE_STATUS_TRADE_ACCEPT;
        trader->GetSession()->SendTradeStatus(info);
    }
}

void WorldSession::HandleUnacceptTradeOpcode(WorldPacket& /*recvPacket*/)
{
    TradeData* my_trade = _player->m_trade;
    if (!my_trade)
        { return; }

    my_trade->SetAccepted(false, true);
}

void WorldSession::HandleBeginTradeOpcode(WorldPacket& /*recvPacket*/)
{
    TradeData* my_trade = _player->m_trade;
    if (!my_trade)
        { return; }

    TradeStatusInfo info;
    info.Status = TRADE_STATUS_OPEN_WINDOW;
    my_trade->GetTrader()->GetSession()->SendTradeStatus(info);
    SendTradeStatus(info);
}

void WorldSession::SendCancelTrade()
{
    if (m_playerRecentlyLogout)
        { return; }

    TradeStatusInfo info;
    info.Status = TRADE_STATUS_TRADE_CANCELED;
    SendTradeStatus(info);
}

void WorldSession::HandleCancelTradeOpcode(WorldPacket& /*recvPacket*/)
{
    // sent also after LOGOUT COMPLETE
    if (_player)                                            // needed because STATUS_LOGGEDIN_OR_RECENTLY_LOGGOUT
        { _player->TradeCancel(true); }
}

void WorldSession::HandleInitiateTradeOpcode(WorldPacket& recvPacket)
{
    ObjectGuid otherGuid;
    recvPacket >> otherGuid;

    if (GetPlayer()->m_trade)
        { return; }

    TradeStatusInfo info;
    if (!GetPlayer()->IsAlive())
    {
        info.Status = TRADE_STATUS_YOU_DEAD;
        SendTradeStatus(info);
        return;
    }

    if (GetPlayer()->hasUnitState(UNIT_STAT_STUNNED))
    {
        info.Status = TRADE_STATUS_YOU_STUNNED;
        SendTradeStatus(info);
        return;
    }

    if (isLogingOut())
    {
        info.Status = TRADE_STATUS_YOU_LOGOUT;
        SendTradeStatus(info);
        return;
    }

    if (GetPlayer()->IsTaxiFlying())
    {
        info.Status = TRADE_STATUS_TARGET_TO_FAR;
        SendTradeStatus(info);
        return;
    }

    Player* pOther = ObjectAccessor::FindPlayer(otherGuid);

    if (!pOther)
    {
        info.Status = TRADE_STATUS_NO_TARGET;
        SendTradeStatus(info);
        return;
    }

    if (pOther == GetPlayer() || pOther->m_trade)
    {
        info.Status = TRADE_STATUS_BUSY;
        SendTradeStatus(info);
        return;
    }

    if (!pOther->IsAlive())
    {
        info.Status = TRADE_STATUS_TARGET_DEAD;
        SendTradeStatus(info);
        return;
    }

    if (pOther->IsTaxiFlying())
    {
        info.Status = TRADE_STATUS_TARGET_TO_FAR;
        SendTradeStatus(info);
        return;
    }

    if (pOther->hasUnitState(UNIT_STAT_STUNNED))
    {
        info.Status = TRADE_STATUS_TARGET_STUNNED;
        SendTradeStatus(info);
        return;
    }

    if (pOther->GetSession()->isLogingOut())
    {
        info.Status = TRADE_STATUS_TARGET_LOGOUT;
        SendTradeStatus(info);
        return;
    }

    if (pOther->GetSocial()->HasIgnore(GetPlayer()->GetObjectGuid()))
    {
        info.Status = TRADE_STATUS_IGNORE_YOU;
        SendTradeStatus(info);
        return;
    }

    if (!sWorld.getConfig(CONFIG_BOOL_ALLOW_TWO_SIDE_INTERACTION_TRADE) && pOther->GetTeam() != _player->GetTeam())
    {
        info.Status = TRADE_STATUS_WRONG_FACTION;
        SendTradeStatus(info);
        return;
    }

    if (!pOther->IsWithinDistInMap(_player, TRADE_DISTANCE, false))
    {
        info.Status = TRADE_STATUS_TARGET_TO_FAR;
        SendTradeStatus(info);
        return;
    }

    // OK start trade
    _player->m_trade = new TradeData(_player, pOther);
    pOther->m_trade = new TradeData(pOther, _player);

    info.Status = TRADE_STATUS_BEGIN_TRADE;
    info.TraderGuid = _player->GetObjectGuid();
    pOther->GetSession()->SendTradeStatus(info);
}

void WorldSession::HandleSetTradeGoldOpcode(WorldPacket& recvPacket)
{
    uint32 gold;

    recvPacket >> gold;

    TradeData* my_trade = _player->GetTradeData();
    if (!my_trade)
        { return; }

    // gold can be incorrect, but this is checked at trade finished.
    my_trade->SetMoney(gold);
}

void WorldSession::HandleSetTradeItemOpcode(WorldPacket& recvPacket)
{
    // send update
    uint8 tradeSlot;
    uint8 bag;
    uint8 slot;

    recvPacket >> tradeSlot;
    recvPacket >> bag;
    recvPacket >> slot;

    TradeData* my_trade = _player->m_trade;
    if (!my_trade)
        { return; }

    TradeStatusInfo info;
    // invalid slot number
    if (tradeSlot >= TRADE_SLOT_COUNT)
    {
        info.Status = TRADE_STATUS_TRADE_CANCELED;
        SendTradeStatus(info);
        return;
    }

    // check cheating, can't fail with correct client operations
    Item* item = _player->GetItemByPos(bag, slot);
    if (!item || (tradeSlot != TRADE_SLOT_NONTRADED && !item->CanBeTraded()))
    {
        info.Status = TRADE_STATUS_TRADE_CANCELED;
        SendTradeStatus(info);
        return;
    }

    // prevent place single item into many trade slots using cheating and client bugs
    if (my_trade->HasItem(item->GetObjectGuid()))
    {
        // cheating attempt
        info.Status = TRADE_STATUS_TRADE_CANCELED;
        SendTradeStatus(info);
        return;
    }

    my_trade->SetItem(TradeSlots(tradeSlot), item);
}

void WorldSession::HandleClearTradeItemOpcode(WorldPacket& recvPacket)
{
    uint8 tradeSlot;
    recvPacket >> tradeSlot;

    TradeData* my_trade = _player->m_trade;
    if (!my_trade)
        { return; }

    // invalid slot number
    if (tradeSlot >= TRADE_SLOT_COUNT)
        { return; }

    my_trade->SetItem(TradeSlots(tradeSlot), NULL);
}