chef

local amounts = {}
local furnaces = 8

function selectNext()
    for i = 1, 16 do
        if turtle.getItemCount(i) ~= 0 then
            turtle.select(i)
            return true
        end
    end
    return false
end

function getOre()
    for i = 2, furnaces do
        table.insert(amounts, 0)
        if not turtle.suck() then break end
    end
end

function putOre()
    for k, v in pairs(amounts) do
        turtle.back()
        amounts[k] = turtle.getItemCount()
        turtle.dropDown()
    end
    while turtle.forward() do end
end

function getFuel()
    turtle.select(1)
    turtle.down()
    for k, v in pairs(amounts) do
        turtle.suck(math.ceil(v/8))
    end
end

function putFuel()
    turtle.down()
    for k, v in pairs(amounts) do
        turtle.back()
        turtle.dropUp(math.ceil(v/8))
    end
end

function harvest()
    local biggestStack = 0
    for k, v in pairs(amounts) do
        if v > biggestStack then
            biggestStack = v
        end
    end
    sleep(biggestStack*10)
    for k, v in pairs(amounts) do
        turtle.suckUp()
        turtle.forward()
    end
    while selectNext() do turtle.drop() end
    turtle.up()
    turtle.up()
    turtle.select(1)
end

while turtle.suck() do
    getOre()
    putOre()
    getFuel()
    putFuel()
    harvest()
end