dig.lua

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

local currentSlot = 1
local maxSlot = robot.inventorySize()

local enableIC = component.isAvailable("inventory_controller")

local itemName = 'ignore'

function getItemName(slot)
    if not enableIC then
        return ''
    end

    local item = component.inventory_controller.getStackInInternalSlot(slot)
    if item then
        return item.name
    else
        return ''
    end
end

function up()
    local can, type = robot.detectUp()
    if can then
        robot.swingUp()
        up()
    else
        robot.up()
    end
end

function down()
    local can, type = robot.detectDown()
    if can then
        robot.swingDown()
        down()
    else
        robot.down()
    end
end

function forward()
    local can, type = robot.detect()
    if can then
        robot.swing()
        forward()
    else
        robot.forward()
    end
end

function findItem()
    for s = 1, maxSlot, 1 do
        if getItemName(s) ~= '' then
            return s
        end
    end
    return 0
end

function checkSlot()
    local newItemName = getItemName(currentSlot)
    if newItemName ~= '' then
        robot.select(currentSlot)
        return true
    else
        currentSlot = findItem()
        if currentSlot ~= 0 then
            robot.select(currentSlot)
            return true
        end
        return false
    end
end

function placeDown()
    local can, type = robot.detectDown()
    if can then
        robot.swingDown()
        placeDown()
    else
        if itemName ~= '' then
            if checkSlot() then
                robot.placeDown()
            end
        end
    end
end

function placeUp()
    local can, type = robot.detectUp()
    if can then
        robot.swingUp()
        placeUp()
    else
        if itemName ~= '' then
            if checkSlot() then
                robot.placeUp()
            end
        end
    end
end

function place()
    local can, type = robot.detect()
    if can then
        robot.swing()
        place()
    else
        if itemName ~= '' then
            if checkSlot() then
                robot.place()
            end
        end
    end
end

function dig()
    forward()

    placeDown()

    robot.turnLeft()

    place()
    up()

    place()
    up()

    place()
    up()

    place()

    placeUp()

    robot.turnLeft()
    robot.turnLeft()

    place()
    down()

    place()
    down()

    place()
    down()

    place()

    robot.turnLeft()
end

function main()
    while true do
        dig()
    end
end

main()