crafting turtle

recipe = {
    [6] = true,  [7] = true, [8] = true,
    [10] = true, [12] = true,
    [14] = true, [15] = true, [16] = true,
}

do
    local itemsRequired = 0
    slotMap = {}
    for k, v in pairs(recipe) do
        if v == true then
            itemsRequired = itemsRequired + 1
            slotMap[k] = true
        end
    end

    recipe[ "itemsRequired" ] = itemsRequired
end

function balanceSlot( slot , source , amount ) -- toSlot, take fromSlot, how much to take?
    --print("balanceslot")
    if turtle.getItemCount(source) >= amount then
        turtle.select( source );
        turtle.transferTo( slot, amount )

        return true
    else
        print(turtle.getItemCount(source).. "<" .. tostring(amount))
    end

    return false
end

function suckFillSlot() -- suck to fill first slot, and distribute exceeding items from the 2 slot
    print("suckfillslot")
    turtle.suckDown()
    if turtle.getItemCount(2) ~= 0 then
        turtle.select(2)

        for k, v in pairs(slotMap) do
            if turtle.getItemCount(2) ~= 0 then
                turtle.select(2);
                turtle.transferTo(k, math.floor(turtle.getItemCount(2) / recipe.itemsRequired))
            else
                break
            end
        end
        if turtle.getItemCount(2) ~= 0 then turtle.dropDown() end -- if one item remained
    end
end


function main()
    suckFillSlot()
    turtle.select(1)

    --balance all crafting slots
    for k, v in pairs( slotMap ) do
        if v then
            --print("stack1")
            local nextKey = next( slotMap, k)

            if nextKey == nil then nextKey = 1 end
            print("* ["..k.."]"..turtle.getItemCount( k ) .." - ["..k.."]"..turtle.getItemCount( nextKey ))
            if turtle.getItemCount( k ) > turtle.getItemCount( nextKey ) then -- balance the next slot out
                print("Stack 1:1")
                sleep(1)
                if balanceSlot( nextKey , 1, turtle.getItemCount(k) - turtle.getItemCount( nextKey ) )==false then
                    print("Not enough source items, aborting")
                    break
                end

            elseif turtle.getItemCount( k ) < turtle.getItemCount( nextKey ) then
                print("Stack 1:2")
                sleep(1)
                if balanceSlot( k , 1, turtle.getItemCount( nextKey ) - turtle.getItemCount(k) )==false then
                    print("Not enough source items, aborting")
                    break
                end

            end
        end
    end

    if turtle.getItemCount(1) > recipe.itemsRequired then
        print("stack2")
        local craftingItemPerSlot = math.floor( turtle.getItemCount(1) / recipe.itemsRequired)

        for k, v in pairs( slotMap ) do
            if v == true then
                balanceSlot( k , 1 , craftingItemPerSlot )
            end
        end

        turtle.select(1); turtle.transferTo(6, turtle.getItemCount(1))
        turtle.craft(craftingItemPerSlot)
        turtle.drop()
    else
        print("Not enough items!")
    end
end

main()