Chunk Cleaner

local args = {...}

-- Check if there 3 arguments
if #args ~= 3  then
  print("Usage: chunkclear <L/R> <length> <width>")
  return
end

local dir, length, width = "L", 0, 0
dir = args[1]

if dir == "l" or dir == "L" then
    dir = "L"
else
    dir = "R"
end
length = tonumber(args[2])
width = tonumber(args[3])

local function tryDig()
    while turtle.detect() do
        if turtle.dig() then
            sleep(0.3)
        else
            return false
        end
    end
    return true
end

local function tryDigUp()
    while turtle.detectUp() do
        if turtle.digUp() then
            sleep(0.3)
        else
            return false
        end
    end
    return true
end

local function refuel()
    local fuelLevel = turtle.getFuelLevel()
    if fuelLevel == "unlimited" or fuelLevel > 0 then
        return
    end

    local function tryRefuel()
        for n=1,16 do
            if turtle.getItemCount(n) > 0 then
                turtle.select(n)
                if turtle.refuel(1) then
                    turtle.select(1)
                    return true
                end
            end
        end
        turtle.select(1)
        return false
    end

    if not tryRefuel() then
        print( "Add more fuel to continue." )
        while not tryRefuel() do
            sleep(1)
        end
        print( "Resuming Tunnel." )
    end
end

local function tryDown()
    refuel()
    while not turtle.down() do
        if turtle.detectDown() then
            if not tryDigDown() then
                return false
            end
        elseif turtle.attackDown() then
            -- collect()
        else
            sleep( 0.3 )
        end
    end
    return true
end

local function tryForward()
    refuel()
    while not turtle.forward() do
        if turtle.detect() then
            if not tryDig() then
                return false
            end
        elseif turtle.attack() then
            -- collect()
        else
            sleep( 0.3 )
        end
    end
    return true
end

-- dig
for i=1,2 do
    for n=1, length do
        turtle.placeDown()
        tryDigUp()

        if n<length then
            tryDig()
            if not tryForward() then
                print( "Aborting Tunnel." )
                break
            end
        else
            print( "Segment complete." )
        end

    end
    if dir == "L" then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
    for n=1, width do
        turtle.placeDown()
        tryDigUp()

        if n<width then
            tryDig()
            if not tryForward() then
                print( "Aborting Tunnel." )
                break
            end
        else
            print( "Segment complete." )
        end

    end
    if dir == "L" then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
end

print( "Chunk cleared." )