Turtle Mine Program

local function checkFuel()
    if turtle.getFuelLevel() < 16 then
        turtle.refuel()
    end
end

local function moveForward(steps)
    for i=1, steps do
        turtle.forward()
        checkFuel()
        sleep(0)
    end
end

local function digForward()
    turtle.dig()
    turtle.forward()
    turtle.digUp()
    turtle.digDown()
    checkFuel()
    sleep(0)
end

local function printUsages()
    print("Usages:")
    print("mine hollow <squareSize>")
    print("mine strip <innerSquareSize> <totalSize>")
end

local tArgs = { ... }
if #tArgs < 1 then
    printUsages()
    return
end

local function digInnerStripSquare(size)
    for direction = 1, 4 do
        for i=1,size-1 do
            digForward()
        end
        turtle.turnRight()
    end
    moveForward(size-1)
end

local function moveBackward(steps)
    for i=1, steps do
        turtle.back()
        checkFuel()
        sleep(0)
    end
end

local function digStripSquare(inner, repetitions)
    for j = 1, repetitions do
        for i=1, repetitions do
            digInnerStripSquare(inner)
        end
        turtle.turnRight()
        moveForward(inner - 1)
        turtle.turnLeft()
        moveBackward((inner -1) * repetitions)
    end
    turtle.turnRight()
    moveBackward((inner -1) * repetitions)
    turtle.turnLeft()
end

local function digHollowSquare(size)
    for j = 1, size do
        for i=1, size-1 do
            digForward()
        end
        if j < size then
            if  j % 2 == 0 then
                turtle.turnLeft()
                digForward()
                turtle.turnLeft()
            else
                turtle.turnRight()
                digForward()
                turtle.turnRight()
            end
            sleep(0)
        end
    end
    if size % 2 == 0 then
        turtle.turnLeft()
        for i=1, size-1 do
            turtle.back()
            checkFuel()
            sleep(0)
        end
        turtle.turnLeft()
    else
        turtle.turnRight()
        for i=1, size-1 do
            turtle.back()
            checkFuel()
            sleep(0)
        end
        turtle.turnLeft()
        for i=1, size-1 do
            turtle.back()
            checkFuel()
            sleep(0)
        end
    end
end

local sCommand = tArgs[1]
if sCommand == "hollow" then
    digHollowSquare(tonumber(tArgs[2]))
elseif sCommand == "strip" then
    digStripSquare(tonumber(tArgs[2]), math.ceil(tonumber(tArgs[3])/tonumber(tArgs[2])))
else
    printUsages()
end