Vertical Digger

local blackList = {
    ["minecraft:stone"] = true,
    ["minecraft:cobblestone"] = true,
    ["minecraft:gravel"] = true,
    ["minecraft:dirt"] = true,
}
local useFuel = true
local backFill = true
local fuelLevel = 0

local function checkSlots()
    local emptySlots = 0
    local enderChestSlot = 0
    for slotNum = 1, 16 do
        local itemData = turtle.getItemDetail(slotNum)
        if itemData then
            if itemData.name == "EnderStorage:enderChest" then
                enderChestSlot = slotNum
            end
        else
            emptySlots = emptySlots + 1
        end
    end
    if emptySlots < 5 then
        if enderChestSlot > 0 then
            turtle.select(enderChestSlot)
            if turtle.placeUp() then
                for slotNum = 1, 16 do
                    local itemData = turtle.getItemDetail(slotNum)
                    if itemData and not blackList[itemData.name] then
                        turtle.select(slotNum)
                        turtle.dropUp()
                        local attempts = 1
                        while turtle.getItemCount(slotNum) > 0 do
                            if attempts > 30 then
                                turtle.digUp()
                                return false
                            end
                            sleep(1)
                            turtle.dropUp()
                            attempts = attempts + 1
                        end
                    end
                end
                turtle.select(1)
                turtle.digUp()
            end
        else
            return false
        end
    end
    return true
end

local function checkFuelLevel()
    fuelLevel = turtle.getFuelLevel()
    if type(fuelLevel) == "string" then
        fuelLevel = math.huge
    end
end

--taken from refuel program
local function refuel(nLimit)
    for n=1,16 do
        local nCount = turtle.getItemCount(n)
        if nLimit > 0 and nCount > 0 and turtle.getFuelLevel() < turtle.getFuelLimit() then
            local nBurn = math.min( nLimit, nCount )
            turtle.select( n )
            if turtle.refuel( nBurn ) then
                local nNewCount = turtle.getItemCount(n)
                nLimit = nLimit - (nCount - nNewCount)
            end
        end
    end
    turtle.select(1)
    checkFuelLevel()
    return nLimit <= 0
end

local function tryBackFill(turtlePlace)
    for slotNum = 1, 16 do
        local itemData = turtle.getItemDetail(slotNum)
        if itemData and blackList[itemData.name] then
            turtle.select(slotNum)
            turtlePlace()
            break
        end
    end
    turtle.select(1)
end

local function main()
    local keepGoingDown = true
    local distanceMoved = 0
    while keepGoingDown do
        local blockBelow, blockData = turtle.inspectDown()
        if blockBelow and blockData.name == "minecraft:bedrock" then
            keepGoingDown = false
        else
            if fuelLevel > distanceMoved or (useFuel and refuel(1)) then
                if blockBelow then
                    turtle.digDown()
                end
                local attempts = 0 --just in case of hitting natural cobble gen
                while not turtle.down() and keepGoingDown do
                    attempts = attempts + 1
                    if attempts >= 5 then
                        keepGoingDown = false
                    end
                    turtle.digDown()
                end
                distanceMoved = distanceMoved + 1
                fuelLevel = fuelLevel - 1
                if keepGoingDown then
                    for i = 1, 4 do
                        local isBlock, data = turtle.inspect()
                        if isBlock then
                            if not blackList[data.name] and turtle.dig() then
                                if backFill then
                                    tryBackFill(turtle.place)
                                end
                            end
                        elseif backFill then
                            tryBackFill(turtle.place)
                        end
                        if i < 4 then
                            turtle.turnLeft()
                        end
                    end
                    if not checkSlots() then
                        keepGoingDown = false
                    end
                end
            else
                keepGoingDown = false
            end
        end
    end

    for i = 1, distanceMoved do
        while not turtle.up() do
            sleep(1)
        end
        tryBackFill(turtle.placeDown)
    end
end

checkFuelLevel()
main()