Minecraft Computer Craft Advanced Tunnel

shell.run("clear")

while tunnelLength == nil do
    term.setCursorPos(1, 1)
    term.clearLine()
    term.write("Tunnel Length: ")
    tunnelLength = tonumber(read())
end

while tunnelWidth == nil do
    term.setCursorPos(1, 2)
    term.clearLine()
    term.write("Tunnel Width: ")
    tunnelWidth = tonumber(read())
end

while tunnelHeight == nil do
    term.setCursorPos(1, 3)
    term.clearLine()
    term.write("Tunnel Height: ")
    tunnelHeight = tonumber(read())
end

while skipedRows == nil do
    term.setCursorPos(1, 4)
    term.clearLine()
    term.write("Skip Rows: ")
    skipedRows = tonumber(read())
end

if tunnelHeight > 1 then
    while lightSpacing == nil do
        term.setCursorPos(1, 5)
        term.clearLine()
        term.write("Light spacing (0 for no lights): ")
        lightSpacing = tonumber(read())
        if lightSpacing == 1 then
            print(" - Must be greater then 1")
            lightSpacing = nil
        end
    end
else
    lightSpacing = 0
end

local estimatedFuelUsage = tunnelWidth*2*tunnelLength*tunnelHeight
estimatedFuelUsage = tunnelHeight*2*tunnelLength + estimatedFuelUsage + tunnelLength
estimatedFuelUsage = skipedRows*2 + estimatedFuelUsage
estimatedFuelUsage = math.ceil(estimatedFuelUsage)

term.clear()
term.setCursorPos(1,1)
print(""..tunnelLength.." blocks long, "..tunnelWidth.." blocks wide, and "..tunnelHeight.." blocks tall")
if lightSpacing == 0 then
    print("No lights will be placed")
else
    print("A light will be placed from slot 16 every "..lightSpacing.." blocks, place a chest to the right to refill")
end
print("")
print("Current fuel: "..turtle.getFuelLevel())
print("Estimated fuel usage: "..estimatedFuelUsage)
if turtle.getFuelLevel() < estimatedFuelUsage then
    print("!!! Turtle may run out of fuel before finishing !!!")
end
print("")
print("Press ENTER to confirm or type <restart> to start over or type <exit> to exit program")
term.write("Confirm: ")
confirmStart = read()
if confirmStart == "restart" then
    shell.exit()
    shell.run(shell.getRunningProgram())
    return
end
if confirmStart == "exit" then
    term.clear()
    term.setCursorPos(1,1)
    return
end
term.clear()
term.setCursorPos(1, 1)

local fuelUsed = 0
local blocksBroken = 0
local blocksToBreak = tunnelWidth*tunnelHeight*tunnelLength
local currentTunnelLength = 1
local turtlePosX = 1
local turtlePosY = 1
local turtlePosZ = 0
local notification = ""
local startTime = os.epoch("utc")/1000

function digWidth(w)
    for u = 1, w-1 do
        if shouldPlaceLight() then
            placeLight()
        end
        while turtle.dig() == true do
            blocksBroken = blocksBroken + 1
            sleep(0.6)
        end
        if turtle.forward() == false then
            turtle.dig()
            blocksBroken = blocksBroken + 1
        end

        if turtlePosY%2 == 1 then
            turtlePosX = turtlePosX + 1
        else
            turtlePosX = turtlePosX - 1
        end
        fuelUsed = fuelUsed + 1
        printTurtleStats()
    end
end

function reverse(w)
    for u = 1, w-1 do
        turtle.back()
        turtlePosX = turtlePosX - 1
        fuelUsed = fuelUsed + 1
        printTurtleStats()
    end
end

function prepForNextRow()
    while turtle.digUp() == true do
        blocksBroken = blocksBroken + 1
        sleep(0.6)
    end
    if turtle.up() == false then
        turtle.digUp()
        blocksBroken = blocksBroken + 1
    end

    turtlePosY = turtlePosY + 1
    fuelUsed = fuelUsed + 1
    turtle.turnLeft()
    turtle.turnLeft()
end

function digOutNextSection()
    while turtle.dig() == true do
        blocksBroken = blocksBroken + 1
        sleep(0.6)
    end
    if turtle.forward() == false then
        turtle.dig()
        blocksBroken = blocksBroken + 1
    end

    turtlePosZ = turtlePosZ + 1
    fuelUsed = fuelUsed + 1
    printTurtleStats()

    turtle.turnRight()
    for h = 1, tunnelHeight do
        notification = "Digging width"
        digWidth(tunnelWidth)
        if h < tunnelHeight then
            prepForNextRow()
        end
    end
    if turtlePosY%2 == 1 then
        notification = "Reversing"
        reverse(tunnelWidth)
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
    for h = 1, tunnelHeight-1 do
        while turtle.digDown() == true do
            blocksBroken = blocksBroken + 1
            sleep(0.6)
        end
        if turtle.down() == false then
            turtle.digDown()
            blocksBroken = blocksBroken + 1
        end
        turtlePosY = turtlePosY - 1
        fuelUsed = fuelUsed + 1
        printTurtleStats()
    end
end

function moveTurtleToChest()
    turtle.turnRight()
    turtle.turnRight()
    for i = 1, currentTunnelLength do
        turtle.forward()
        turtlePosZ = turtlePosZ - 1
        fuelUsed = fuelUsed + 1
        printTurtleStats()
    end
end

function moveTurtleBackToFront()
    turtle.turnLeft()
    turtle.turnLeft()
    for i = 1, currentTunnelLength do
        turtle.forward()
        turtlePosZ = turtlePosZ + 1
        fuelUsed = fuelUsed + 1
        printTurtleStats()
    end
end

function emptyTurtleToChest()
    for i = 1, 15 do
        turtle.select(i)
        turtle.drop()
    end
    turtle.select(1)
end

function turtleShouldEmpty()
    local occupiedSlots = 0
    for i = 1, 16 do
        if turtle.getItemCount(i) > 0 then
            occupiedSlots = occupiedSlots + 1
        end
        i = i + 1
    end
    return 16 - occupiedSlots <= 4
end

function shouldPlaceLight()
    if turtlePosX%lightSpacing == 0 and turtlePosZ%lightSpacing == 0 and turtlePosY == 2 then
        return true
    else
        return false
    end
end

function hasLights()
    return turtle.getItemCount(16) > 0
end

function placeLight()
    if not hasLights() then return end
    turtle.select(16)
    turtle.placeDown()
    turtle.select(1)
end

function lightChestAtStart()
    i,cd = turtle.inspect()
    return cd["tags"]["forge:chests"] == true
end

function takeLights()
    turtle.select(16)
    turtle.suck(turtle.getItemSpace())
    turtle.select(1)
end

function disp_time(time)
    local days = math.floor(time/86400)
    local hours = math.floor(math.mod(time, 86400)/3600)
    local minutes = math.floor(math.mod(time,3600)/60)
    local seconds = math.floor(math.mod(time,60))
    return string.format("%d:%02d:%02d:%02d",days,hours,minutes,seconds)
end

function printTurtleStats()
    term.clear()
    term.setCursorPos(1, 1)
    local percent = math.ceil(blocksBroken/blocksToBreak*100)
    local checkTime = os.epoch("utc")/1000
    print("Time Elapsed: "..disp_time(checkTime-startTime))
    print("Progress "..percent.."% complete ("..blocksBroken.."/"..blocksToBreak..")")
    print("Fuel used: "..fuelUsed.."/"..estimatedFuelUsage)
    print("Remaining estimated fuel usage: "..estimatedFuelUsage-fuelUsed)
    print("Fuel remaining: "..turtle.getFuelLevel())
    print("X: "..turtlePosX)
    print("Y: "..turtlePosY)
    print("Z: "..turtlePosZ)
    print(notification)
end

for tl = 1, tunnelLength+skipedRows do
    if currentTunnelLength > skipedRows then
        digOutNextSection()
        printTurtleStats()

        if turtleShouldEmpty() and currentTunnelLength ~= tunnelLength then
            notification = "Going to empty inventory"
            moveTurtleToChest()
            emptyTurtleToChest()
            if lightSpacing > 0 then
                turtle.turnLeft()
                if lightChestAtStart() then
                    takeLights()
                end
                turtle.turnRight()
            end
            notification = "Moving back from chest"
            moveTurtleBackToFront()
        end
    else
        turtle.forward()
        turtlePosZ = turtlePosZ + 1
        fuelUsed = fuelUsed + 1
    end
    currentTunnelLength = currentTunnelLength + 1
end
currentTunnelLength = currentTunnelLength - 1
moveTurtleToChest()
printTurtleStats()
emptyTurtleToChest()
turtle.turnLeft()
turtle.turnLeft()