Furnace x4 loader

local function home()
    while true do
        while turtle.forward() do
        end
        turtle.turnLeft()
        local success, data = turtle.inspectDown()
        if success and data.name=="ironchest:iron_chest" then
            turtle.turnLeft()
            return
        end
    end
end



local function load()
    turtle.select(1)
    for i=1,4 do
        turtle.suckDown()
    end
end

local function unload(f)
    for i=1,4 do
        turtle.forward()
        turtle.select(f[i][1])
        turtle.dropDown(f[i][2])
        turtle.forward()
        turtle.turnRight()
    end
    for i=1,4 do
        turtle.select(i)
        turtle.dropDown()
    end
end

home()


while true do
    load()
    if turtle.getItemCount(4)>0 then
        unload({{1,64},{2,64},{3,64},{4,64}})
        sleep(10)
    elseif turtle.getItemCount(3)>0 then
        unload({{1,64},{2,64},{3, math.ceil(turtle.getItemCount(3)/2) },{3,64}})
        sleep(10)
    elseif turtle.getItemCount(2)>0 then
        unload({{1, math.ceil(turtle.getItemCount(1)/2) },{1,64},{2, math.ceil(turtle.getItemCount(2)/2) },{2,64}})
        sleep(10)
    elseif turtle.getItemCount(1)>0 then
        unload({    {1, math.ceil(turtle.getItemCount(1)/4) },
                    {1, math.ceil(turtle.getItemCount(1)/4) },
                    {1, math.ceil(turtle.getItemCount(1)/4) },
                    {1,64}
                })
        sleep(10)
    else
        sleep(10)
    end
end