mana

local idleStep = 8
local rechargeStep = 4
--mana
local target = 14 --/15
--comparator
local compSide = "front"
---cakeChest
local chestSide = "bottom"
local reverse = "up"
--turtle
local buffer = 16
local cakeSlot = 1

local chest = peripheral.wrap(chestSide)
print(chest.getInventoryName().." found.")

function lowCake()
  return turtle.getItemCount(cakeSlot) < (buffer/2)
end

function round(n)
  return n % 1 >= 0.5 and math.ceil(n) or math.floor(n)
end

function refillCake()
  if lowCake() then
    print("Cake level is low(inf. "..(buffer/2)..")")
    local as = chest.getAllStacks(false)
    for i,slot in pairs(as) do
      if slot ~= nil and slot.name == "cake" and lowCake() then
        print(chest.pushItem(reverse,i,(buffer-turtle.getItemCount(cakeSlot)),cakeSlot).." cakes retrieved from slot "..i..".")
      end
    end
  end
end

function getLevel()
  local lvl = rs.getAnalogInput(compSide)
  print("Mana level is "..round(lvl*100/15).."%")
  return lvl
end

while true do

  while getLevel() < target do
    print("RECHARGING!")
    if not turtle.detectUp() then
      turtle.select(cakeSlot)
      refillCake()
      if not turtle.placeUp() then
        print("Error placing cake!")
      end
    else
      print("Previous cake still present!")
    end
    sleep(rechargeStep)
  end

  print("IDLE")
  sleep(idleStep)

end