local keywordHandler = KeywordHandler:new()
local npcHandler = NpcHandler:new(keywordHandler)
NpcSystem.parseParameters(npcHandler)
local talkState = {}
function onCreatureAppear(cid) npcHandler:onCreatureAppear(cid) end
function onCreatureDisappear(cid) npcHandler:onCreatureDisappear(cid) end
function onCreatureSay(cid, type, msg) npcHandler:onCreatureSay(cid, type, msg) end
function onThink() npcHandler:onThink() end
function creatureSayCallback(cid, type, msg)
if(not npcHandler:isFocused(cid)) then
return false
end

local talkUser = NPCHANDLER_CONVBEHAVIOR == CONVERSATION_DEFAULT and 0 or cid
local msg = msg:lower()

local refineItem = 8306
local playerItem = 9693


    if (msgcontains(msg, 'trade') or msgcontains(msg, 'help')) then   
	    selfSay("So, you want to trade your ".. getItemNameById(playerItem) .." for my ".. getItemNameById(refineItem) .. "... Are you sure that?", cid)
	    talkState[talkUser] = 1
    elseif msgcontains(msg, 'yes') and talkState[talkUser] == 1 then
	    if getPlayerItemCount(cid, playerItem) <= 0 then	   
		  selfSay("You don't have the ".. getItemNameById(playerItem) ..", go back when you get that!", cid)
		  talkState[talkUser] = 0
		  return true
	    end
	    doPlayerRemoveItem(cid, playerItem, 1)
	    doPlayerAddItem(cid, refineItem, 1)
	    selfSay("So thats it, if you have more go back and talk to me!", cid)
	    talkState[talkUser] = 0
	    return true
    end

return true
end

npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, creatureSayCallback)
npcHandler:addModule(FocusModule:new())		    

<?xml version="1.0" encoding="UTF-8"?>

<npc name="NOME DO NPC" script="NOME DO SCRIPT ALI DECIMA.lua" walkinterval="3000" floorchange="0" access="5" level="1" maglevel="1">

<health now="150" max="150"/>

<look type="LOOK DO NPC" head="114" body="119" legs="114" feet="114" corpse="2212"/>

<parameters>

<parameter key="message_greet" value="Welcome |PLAYERNAME|, what you want?"/>

</parameters>

</npc>