ComputerCraft Tutorial: auto_refuel

-- #########################################
-- auto refuel
-- version 0.1
-- http://hevohevo.hatenablog.com/

-- You must prepare many many fuel items.

-- Config
local suck = turtle.suckDown
local drop = turtle.dropDown

-- Functions
function myGetFuelLevel()
    local tmp = turtle.getFuelLevel()
    print("Fuel Level: "..tmp)
    return tmp
end

function dropAll()
    for i=1,16 do
        if turtle.getItemCount(i) > 0 then
            turtle.select(i)
            drop()
        end
    end
end

-- main
local limit_level = turtle.getFuelLimit()

-- see ComputerCraft.cfg
if not limit_level or limit_level == 0 then
    error("no FuelLimit")
end


local args = {...}
local goal_level = tonumber(args[1])

if #args == 0 then
    print("FuelLimit is ",limit_level)
    myGetFuelLevel()
    while true do
        write("\nReally? (y/n): ")
        local str = read()
        if str == "n" or str == "N" then
            error("terminated")
        elseif str=="Y" or str=="y" then
            goal_level = limit_level
            break
        end
    end
end

turtle.select(1)
while (goal_level > myGetFuelLevel()) and suck() do
    local status, error_msg = turtle.refuel()
    if not status then
        print(error_msg)
        break
    end
end
dropAll()