function getItemList ()

    local itemList = {}

    for i = 1, 16, 1 do
        itemList[i] = turtle.getItemDetail(i)
    end

    return itemList

end

function checkSlot ( _item, _slot )

    if type(_item) ~= "string" then
        print("Invalid item")
        return nil
    end
    if type(_slot) ~= "number" or _slot < 1 or _slot > 16 then
        print("Invalid slot")
        return nil
    end

    local item = turtle.getItemDetail(_slot)
    if item ~= nil then
        return item.name == _item
    else
        return false
    end

end

function checkEmptySlot ()

    local itemList = getItemList()
    local emptySlot = 0

    for i = 1, 16, 1 do
        if itemList[i] == nil then
            emptySlot = i
            break
        end
    end

    return emptySlot

end


function checkForItem ( _item )

    local itemSlot = 0

    for i = 1, 16, 1 do
        if checkSlot(_item, i) then
            itemSlot = i
            break
        end
    end

end

function dropIfItems ( _itemList, _slot )

    local currentSelectedSlot = turtle.currentSelectedSlot()
    local currentItem = turtle.getItemDetail(_slot)
    local itemFound = false

    if currentItem == nil then return true end

    for i = 1, #_itemList, 1 do
        if _itemList[i] == currentItem.name then
            itemFound = true
            break
        end
    end

    if itemFound = false then return true end

    turtle.select(_slot)
    local success = turtle.dropDown()
    turtle.select(currentSelectedSlot)
    return success

end

function moveItem ( _slot )

    local item = turtle.getItemDetail(_slot)
    if item == nil then return true end

    local currentSelectedSlot = turtle.currentSelectedSlot()
    turtle.select(_slot)
    local potentialSpot = 0

    potentialSpot = checkForItem(item.name)

    if potentialSpot ~= 0 then
        local success = turtle.transferTo(potentialSpot)
        local itemAfterTransfer = turtle.getItemDetail()

        if success and itemAfterTransfer == nil then
            turtle.select(currentSelectedSlot)
            return true
        end
    end

    potentialSpot = checkEmptySlot()

    if potentialSpot ~= 0 then
        local success = turtle.transferTo(potentialSpot)

        if success then
            turtle.select(currentSelectedSlot)
            return true
        end
    end

    return false

end