Better Simple Quarry Code

--[[
    Quarry code for a turtle
    Digs an WIDTH by WIDTH hole, DEPTH blocks deep; specified by the input
    Calculates fuel efficiency
    Recognises a full inventory & dumps excess into ender chest
    TODO:
    - Move setup into a single function, maybe even allow values to be passed in before runtime as an option?
    - Make code support rectangular paths
    - Change the way it calculates a full inventory, as currently it slows down mining a lot
]]

os.loadAPI("commonUtils")

RETURNCOND = 0
DEPTH = 0
WIDTH = 0
UPWARDS = false
ECPRESENT = false

function setDimensions()
    print("Enter quarry depth: ")
    DEPTH = tonumber(read())
    print("Enter quarry width: ")
    WIDTH = tonumber(read())
    if WIDTH%2 == 0 then
        EVENWIDTH = true
    end
    -- Shall I go up , or down?
    print("Shall I go up, or down?")
    local directionChoice = string.lower(tostring((read())))
    local acceptedResponses = {"up","down",
                                "u","d"}

    for index,value in pairs(acceptedResponses) do -- find out what they said
        if directionChoice == value then
            if index%2==1 then
                UPWARDS = true
                return
            else
                UPWARDS = false
                return
            end
        end
    end
end

function setReturnCond()
    print("Shall I return to the original height?")
    local returnResponse = string.lower(tostring(read()))
    local acceptedConditions = {"yes","no",
                                "true","false",
                                "1","0",
                                "y","n",
                                "yeah","nah"}
    for k,v in pairs(acceptedConditions) do
        if returnResponse == v then
            if k%2==1 then
                RETURNCOND = 1
                return
            end
        end
    end
end

local function calculateFuelExpenditure() -- Calculate how much fuel will be taken from the quarry volume
    local distance = DEPTH*WIDTH*WIDTH

    if RETURNCOND == true then
        distance = distance + DEPTH
    end

    if turtle.getFuelLevel() > distance then
        return true
    else
        return false
    end
end

function minesquare(layer)

    local reverse,right

    if layer%2 == 0 and not EVENWIDTH then
        -- if the width is odd and the current layer count is even
        reverse = true
    end

    for n = 1,WIDTH,1 do -- Theoretically should be easy to make rectuangular
        -- The first block in a line is mined differently, as the turtle needs to move into said ine.
        if n == 1 then -- if its the first iteration, then the turtle needs to move down a layer
            if UPWARDS then
                turtle.digUp()
                turtle.up()
            else
                turtle.digDown()
                turtle.down()
            end
        end
        commonUtils.digForward(WIDTH-1) -- mine out the rest of the line
        if n < WIDTH then -- if the turtle hasn't finished this layer yet
            -- There was a huge bug with odd width quarries, so I'm trying out a boolean "am I turning right or left" value
            if reverse then
                right = false
            else
                right = true
            end
            if n%2 == 0 then
                right = not right
            end
            if right then -- alternate between turning right and left at the end of a line
                turtle.turnRight()
                commonUtils.digForward()
                turtle.turnRight()
            else
                turtle.turnLeft()
                commonUtils.digForward()
                turtle.turnLeft()
            end
            if reverse then
                right = not right
            end
        else
            if not EVENWIDTH and not reverse then
                turtle.turnLeft()
            else
                turtle.turnRight()
            end
        end
    end
end

function main()
    term.clear()
    for i = 1,DEPTH,1 do
        minesquare(i)
    end

    if RETURNCOND == 1 then
        for _ = 1, DEPTH, 1 do
            if UPWARDS then
                turtle.down()
            else
                turtle.up()
            end
        end
    end
    commonUtils.dumpItems()
    write("Execution complete, fuel remaining: ")
    print(turtle.getFuelLevel())
end

setDimensions()
setReturnCond()

if calculateFuelExpenditure() == true then -- I know about the '== true' but it doesn't work otherwise so shut up
    main()
else
    if commonUtils.refuelChestSafe() == true then
        if calculateFuelExpenditure() == true then
            main()
        else
            print("Refuel attempt insufficient, shutting down...")
        end
    else
        print("Failed refuel attempt, shutting down...")
    end
end