Trade Items per Item

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

-- [[ START THE SETTINGS ]] ---
local knives = {
    ["name1"] = {id = xxxx, tradeid = 2152, tradecount = 10},
    ["name2"] = {id = xxxx, tradeid = xxxx, tradecount = 100},
    ["name3"] = {id = xxxx, tradeid = xxxx, tradecount = 100},
}
-- [[ END FROM SETTINGS THINGS ]] ---

function creatureSayCallback(cid, type, msg)
if(not npcHandler:isFocused(cid)) then
return false
end
local talkUser = NPCHANDLER_CONVBEHAVIOR == CONVERSATION_DEFAULT and 0 or cid
knife = knives[""..msg..""]
if knife then
    selfSay('You really wanna trade '..knife.tradecount..' '..getItemNameById(knife.tradeid)..' for a '..msg..'?', cid)
    talkState[talkUser] = 1

    -- [[ CONFIRMANDO BROADCASTMESSAGES ]] --
elseif talkState[talkUser] == 1 then
    if (msgcontains(msg, 'sim') or msgcontains(msg, 'yes')) then
        if getPlayerItemCount(cid, knife.tradeid) >= knife.tradecount then
            doPlayerRemoveItem(cid, knife.tradeid, knife.tradecount)
            doPlayerAddItem(cid, knife.id, 1)
            selfSay('Here are your item.', cid)
            talkState[talkUser] = 0
        else
            selfSay('Sorry, but you don\'t have '..knife.tradecount..' '..getItemNameById(knife.tradeid)..'s.', cid)
            talkState[talkUser] = 0
        end
    else
        selfSay('Okay, see u later.', cid)
        talkState[talkUser] = 0
    end
else
    local str = ''
    for index, result in pairs(knives) do
        str = str.."{"..index.."}, "
    end
    selfSay('Sorry, but have to say a knife name: '..str..'.', cid)
    talkState[talkUser] = 0
end
  return true
end
npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, creatureSayCallback)
npcHandler:addModule(FocusModule:new())