charge

local fuel_types = {"charcoal", "coal"}
local container_types = {"mcp_mobius_betterbarrel", "container_chest"}
local side="bottom"
local reverse ="up"
local p=peripheral.wrap(side)

function isFull()
  if turtle.getFuelLevel() > turtle.getFuelLimit()-100 then
    print("Turtle charged!")
    return true
  else
    return false
  end
end

function validWithList(type,list)
  for i=1,#list do
    if list[i]==type then
      return true
    end
  end
  return false
end

function isFuel(slot)
  if validWithList(slot.name, fuel_types) then
    print("fuel found.")
    return true
  else
    return false
  end
end

function isFuelSource(type)
  if validWithList(type, container_types) then
    print("Sitting on a fuel source.")
    return true
  else
    print("No fuel source down there.")
    return false
  end
end

function eatFuel(cont)
  turtle.select(1)
  local stacks = cont.getAllStacks()
  for i, slot in pairs(stacks) do
    if not isFull() and isFuel(slot) then
      cont.pushItemIntoSlot(reverse,i,16,1)
      turtle.refuel()
    end
  end
end

function getFuel()
  local charge = turtle.getFuelLevel()
  local max= turtle.getFuelLimit()
  local percent = charge * 100 / max
  print("charge level : "..percent.." ( "..charge.."/ "..max..")")
  return charge
end

if isFuelSource(peripheral.getType(side),container_types) then
  print("CHARGING FROM")
  print("name : "..p.getInventoryName())
  print("size : "..p.getInventorySize())
  local lastState = turtle.getFuelLevel()
  while not isFull() do
    eatFuel(p)
    if not ( getFuel() > lastState ) then
      print("Fuel source empty, Stop charging.")
      break
    end
    sleep(1)
  end
end