autoRefuel

local ARMSG__IM_NOT_LABELED          = 1;
local ARMSG__GIVE_ME_FUEL_MORE       = 2;
local ARMSG__REFUELING_WAS_COMPLETED = 3;

local floppySource =
[[
local function setMsg(armsg)
  rs.setAnalogOutput("bottom", armsg);
end

local function freeze()
  while true do
    sleep(60);
  end
end

turtle.turnLeft();
turtle.turnLeft();

if nil == os.getComputerLabel() then
  print("I'm not labeled turtle.");
  setMsg(ARMSG__IM_NOT_LABELED);
  freeze();
end

local lastSlot = -1;
local selSlot;
while true do
  sleep(0);
  if ARG_FUEL_LEVEL <= turtle.getFuelLevel() then
    print("Refueling was completed.");
    setMsg(ARMSG__REFUELING_WAS_COMPLETED);
    freeze();
  end

  print("Give me fuel more.");
  setMsg(ARMSG__GIVE_ME_FUEL_MORE);

  selSlot = 1;
  if -1 ~= lastSlot and 1 <= turtle.getItemCount(lastSlot) then
    selSlot = lastSlot;
  else
    for i = 1, 16 do
      if 1 <= turtle.getItemCount(i) then
        selSlot = i;
        break;
      end
    end
  end

  local itemCnt = turtle.getItemCount(selSlot);
  if 1 <= itemCnt then
    turtle.select(selSlot);
    local beforeLv = turtle.getFuelLevel();
    local rslt     = turtle.refuel(1);
    local afterLv  = turtle.getFuelLevel();
    local unitFLv  = afterLv - beforeLv;

    print("[status] : ARG_LV  = " .. ARG_FUEL_LEVEL);
    print("           afterLv = " .. afterLv);

    if not rslt then
      print("This is not fuel.");
      turtle.drop();
    else
      if 1 == turtle.getItemCount(selSlot) and 1 == itemCnt then
        -- Probably empty bucket.
        turtle.drop();
      else
        itemCnt = turtle.getItemCount(selSlot)
        if afterLv + unitFlv * itemCnt < ARG_FUEL_LEVEL then
          turtle.refuel(itemCnt);
        else
          local useCnt = (ARG_FUEL_LEVEL - afterLv) / unitFlv + 1;
          turtle.refuel(useCnt);
        end
      end
    end
  end
end
]];

local SLOT_CHEST  = 1;
local SLOT_FLOPPY = 2;
local SLOT_DRIVE  = 3;

print("slot1 : chest       x 2");
print("slot2 : floppy disk x 1");
print("slot3 : disk drive  x 1");
print("left  side : chest for fuels");
print("right side : chest for turtles");

local fuelLV;
while true do
  print("Input fuel level to start the script.");
  term.write("fuel level >");
  local input = read();
  fuelLV = tonumber(input);
  if nil == fuelLV then
    print("Wrong input. Please retry.");
  else
    break;
  end
end

turtle.digUp();
turtle.up();

turtle.turnRight();
turtle.select(SLOT_CHEST);

turtle.place();
turtle.turnLeft();
turtle.turnLeft();
turtle.place();

turtle.turnRight();
turtle.select(SLOT_DRIVE);
turtle.placeUp();
turtle.select(SLOT_FLOPPY);
turtle.dropUp();

local diskPath = disk.getMountPath("top");

-- backup original startup.
local stPath = "/" .. diskPath .. "/startup";
local bkPath = "/" .. diskPath .. "/startup_bk_by_autoRefuel";
fs.delete(bkPath);
if fs.exists(stPath) then
  fs.move(stPath, bkPath)
end

local hFile = fs.open(stPath, "w");
hFile.writeLine("local ARMSG__IM_NOT_LABELED          = " .. ARMSG__IM_NOT_LABELED          .. ";");
hFile.writeLine("local ARMSG__GIVE_ME_FUEL_MORE       = " .. ARMSG__GIVE_ME_FUEL_MORE       .. ";");
hFile.writeLine("local ARMSG__REFUELING_WAS_COMPLETED = " .. ARMSG__REFUELING_WAS_COMPLETED .. ";");
hFile.writeLine("local ARG_FUEL_LEVEL = " .. fuelLV .. ";");
hFile.writeLine(floppySource);
hFile.close();

turtle.turnRight();
turtle.down();

local unlabeledFlg = false;

while true do
  turtle.down();
  turtle.select(1);
  turtle.suck();

  if 0 == turtle.getItemCount(1) then
    break;
  end

  turtle.placeUp();

  if "turtle" ~= peripheral.getType("top") then
    print("not turtle.");
    turtle.digUp();
    turtle.up();
    for i = 1, 16 do
      if 1 <= turtle.getItemCount(i) then
        turtle.select(i);
        turtle.drop();
      end
    end
    turtle.down();
  else
    print("turnOn.");
    peripheral.call("top", "turnOn");

    for i = 1, 16 do
      if 1 <= turtle.getItemCount(i) then
        turtle.select(i);
        turtle.drop();
      end
    end

    turtle.turnLeft();
    turtle.turnLeft();

    local lastSlot = -1;

    while true do
      sleep(0);
      local rcvdMsg = rs.getAnalogInput("top");
      if rcvdMsg == ARMSG__IM_NOT_LABELED then
        unlabeledFlg = true;
        print("Unlabeled turtle.");
        break;

      elseif rcvdMsg == ARMSG__GIVE_ME_FUEL_MORE then
        print("Fueling mode.");

        if not turtle.suck() then
          print("<< Chest for fuels is empty. >>");
          sleep(3);
        end

        if -1 ~= lastSlot and 1 <= turtle.getItemCount(lastSlot) then
          turtle.dropUp();
        else
          for i = 1, 16 do
            if 1 <= turtle.getItemCount(i) then
              turtle.select(i);
              lastSlot = i;
              turtle.dropUp();
              break;
            end
          end
        end

      elseif rcvdMsg == ARMSG__REFUELING_WAS_COMPLETED then
        print("Surplus fuel capture mode.");
        for i = 1, 16 do
          turtle.suckUp();
        end
        for i = 1, 16 do
          if 1 <= turtle.getItemCount(i) then
            turtle.select(i);
            turtle.drop();
          end
        end
        break;
      end
    end

    turtle.turnRight();
    turtle.turnRight();

    turtle.digUp();
    turtle.up();
    turtle.drop();
  end
end

-- restore original startup.
fs.delete(stPath);
if fs.exists(bkPath) then
  fs.move(bkPath, stPath)
end
fs.delete(bkPath);

turtle.down();

turtle.turnLeft();
print("autoRefuel was completed.");
if unlabeledFlg then
  print("* unlabeled turtle was not refueled.");
end