function isFocused(cid, t)
    for i, v in pairs(t) do
        if(v == cid) then
            return true
        end
    end
    return false
end

function addFocus(cid, t)
    if(not isFocused(cid, t)) then
        table.insert(t, cid)
    end
end

function removeFocus(cid, t)
    for i, v in pairs(t) do
        if(v == cid) then
            table.remove(t, i)
            break
        end
    end
end

function lookAtFocus(t)
    for i, v in pairs(t) do
        if(isPlayer(v)) then
            doNpcSetCreatureFocus(v)
            return
        end
    end
    doNpcSetCreatureFocus(0)
end

function msgcontains(msg, ...)
    local function checkstring(msg, key)
      return (" " .. msg .. " "):find("%s+" .. key .. "[%s%p]+") and true or false
    end
    for _, key in ipairs(arg) do
        if checkstring(tostring(msg):lower(), tostring(key):lower()) then
          return true
        end
    end
  return false
end
local focuses = {}
function onCreatureDisappear(cid)
    if isFocused(cid, focuses) then
     removeFocus(cid, focuses)
        if isPlayer(cid) then
         closeShopWindow(cid)
        end
    end
end

local onBuy = function(cid, item, subType, amount, ignoreCap, inBackpack,sellPrice,price,buyPrice)
      local it = items[item]
      for i,v in pairs(it) do
      print(i,v)
      end
end
local onSell = function(cid, item, subType, amount, ignoreCap, inBackpacks)
      return
end

function onCreatureSay(cid, type,msg)
items = {}
    if msgcontains(msg, "hi", "hello") and not isFocused(cid, focuses) and getDistanceToCreature(cid) < 4 then
     selfSay("Hiho " .. getCreatureName(cid)..". Say {offers} to see my offers.", cid)
     addFocus(cid, focuses)
     selfFocus(cid)
    elseif msgcontains(msg, "offers") and isFocused(cid, focuses) then
     selfSay("Here are the places that I can take you.", cid)
     text = "--==## id | Price | name | ##==-- \n"
      for index, info in pairs(readyResellerItems()) do
        local itemname = getItemDescriptionsById(info.itemid).name
        text = ""..text.."\n".. info.item_uid.." | ".. info.price.." | ".. itemname .."."
        items[info.item_uid] = {id = info.itemid, price = info.price, info.playerid}

      end
      text = ""..text.."\n \n Para comprar diga (buy + id do o item)."
        doPlayerPopupFYI(cid, text)
     elseif msgcontains(msg, "buy") and isFocused(cid, focuses) then
     local item = tonumber(string.find (msg, "(.%d)"))
     print(item)
     item = items[item]
     print(item)
    elseif msgcontains(msg, "bye") and isFocused(cid, focuses) then
     selfSay("Goodbye!", cid)
     closeShopWindow(cid)
     removeFocus(cid, focuses)
     lookAtFocus(focuses)
    end
end

function onThink()
    for _, focus in pairs(focuses) do
        if not isCreature(focus) then
         removeFocus(focus, focuses)
        else
         local distance = getDistanceTo(focus) or 5
            if distance > 4 then
                selfSay("Hmpf!", focus)
                closeShopWindow(focus)
                removeFocus(focus, focuses)
            end
        end
    end
    lookAtFocus(focuses)
end