OC Robot Excavator

local component = require("component")
local term = require("term")
local robot = require("robot")

term.write("Enter length (number): ")
local length = term.read()

term.write("Enter width (number): ")
local width = term.read()

term.write("Enter depth (number): ")
local depth = term.read()

local right = true

function turn()
    if (right) then robot.turnRight() else robot.turnLeft() end
end

function trySwing()
    if (robot.durability() and robot.durability() == 0) then
        term.write("Tool durability is low! Mining stopped.\n")
        trySwing()
    else
        robot.swing()
    end
end

function trySwingDown()
    if (robot.durability() and robot.durability() == 0) then
        term.write("Tool durability is low! Mining stopped.\n")
        trySwingDown()
    else
        robot.swingDown()
    end
end

function tryForward()
    trySwing()
    if (not robot.forward()) then tryForward() end
end

function tryDown()
    trySwingDown()
    if (not robot.down()) then tryDown() end
end


function mineX(j)
    for i = length, 1, -1 do
        trySwingDown()
        if (i > 1) then
            tryForward()
        elseif (j > 1) then
            turn()
            trySwingDown()
            tryForward()
            turn()
        end
    end
end

function mineY(j)
    for i = width, 0, -1 do
        if (i > 0) then
            mineX(i)
            right = not right
        elseif (j > 1) then
            tryDown()
            robot.turnAround()
            right = not right
        end
    end
end

for i = depth, 1, -1 do
    mineY(i)
end

tryDown()
term.write("Done mining! Going back to original position.\n")
if (depth % 2 == 0) then
    robot.turnAround()
elseif (width % 2 == 0) then
    robot.turnRight()
    for i = width, 2, -1 do
        tryForward()
    end
    robot.turnRight()
else
    robot.turnAround()
    for i = length, 2, -1 do
        tryForward()
    end
    robot.turnRight()
    for i = width, 2, -1 do
        tryForward()
    end
end
term.write("Done.\n")