Minecraft - Waterboy

local bRedNet = false
local nBatterySlot = 1
-- ----------------------------------------------------------
local function say(message)
        if bRedNet == true then
                rednet.send(nMasterComputerID, message)
        end
        print(message)
        -- sleep(0.2)
end
-- ----------------------------------------------------------
local function turnLeft()
        turtle.turnLeft()
end
-- ----------------------------------------------------------
local function turnRight()
        turtle.turnRight()
end
-- ----------------------------------------------------------
local function getFreeSlots()
    local nSpace = 0
    for invloop=1,16 do
        local items = turtle.getItemCount(invloop)
        if items == 0 then
            nSpace = nSpace + 1
        end
    end
    return nSpace
end
-- ----------------------------------------------------------
local function tryForwards()
    local nMaxTries = 10
    local nTries = 0
    while not turtle.forward() do
        sleep(0.8)
        nTries = nTries + 1
        if nTries >= nMaxTries then
                return false
        end
    end
    return true
end
-- ----------------------------------------------------------

local function recharge()
        say("trying to recharge")
        turtle.select(nBatterySlot)
        local e = turtle.getFuelLevel()
        turtle.refuel()
        nEnergy = turtle.getFuelLevel()
        say("fuel: "..e.." -> "..nEnergy)
        if nEnergy > e then
                return true
        end
        return false
end

-- ----------------------------------------------------------
-- ----------------------------------------------------------
local function waitForEnergy()
        local count = 0
        local hasEnergy = false
        say("Waiting for energy in Slot "..nBatterySlot)

        while not hasEnergy do
                if recharge() == true then
                        hasEnergy = true
                        return true
                else
                        sleep(5)
                        count = count + 1
                        if count == 5 then
                                say("Waiting for energy in Slot "..nBatterySlot)
                                count = 0
                        end
                end
        end
        return true
end
-- ----------------------------------------------------------
local function isOperational()
        -- get energy
        local nEnergyLevel = turtle.getFuelLevel()
        local required = 20
        if nEnergyLevel <= required then
        waitForEnergy()
        end
        -- all cool
        return true
end
-- ----------------------------------------------------------
local function loopi()
isOperational()

while not turtle.suck() do
    sleep(2)
end

turnRight()
turnRight()
tryForwards()
tryForwards()
tryForwards()
turnLeft()
tryForwards()
turnRight()
tryForwards()
tryForwards()
tryForwards()
tryForwards()
turnLeft()
tryForwards()
turtle.select(2)
turtle.drop()
turnLeft()
turnLeft()
tryForwards()
turnRight()
tryForwards()
tryForwards()
tryForwards()
tryForwards()
turnLeft()
tryForwards()
turnRight()
tryForwards()
tryForwards()
tryForwards()
turtle.select(2)
turtle.drop()

return true
end

local done = false
while not done do
   loopi()
end