Wall

io.write("Enter Length: ")
length = io.read()
io.write("Enter Height: ")
height = io.read()

local SLOT_COUNT = 16
local FUEL_CHEST = 15
local WOOD_CHEST = 16
local FILL_SLOT_COUNT = 4

function countItems(itemToCount)
    local itemCount = 0
    for slot = 1, SLOT_COUNT, 1 do
        item = turtle.getItemDetail(slot)
        if(item ~= nil) then
            if(item.name == itemToCount) then
                itemCount = itemCount + turtle.getItemCount(slot)
            end
        end
    end

    return itemCount
end



function refuel()
    fuel_level = turtle.getFuelLevel()
    if fuel_level < 1000 then
        turtle.select(FUEL_CHEST)
        turtle.digUp()
        turtle.placeUp()

        slot = 9
        turtle.select(slot)
        turtle.suckUp(64)
        turtle.refuel(64)

        turtle.select(FUEL_CHEST)
        turtle.digUp()
    end
end


function checkWOOD()
    if (countItems("minecraft:cobblestone") < 64) then
        turtle.select(WOOD_CHEST)
        turtle.digUp()
        turtle.placeUp()

        for slot = 1, FILL_SLOT_COUNT, 1 do
            turtle.select(slot)
            turtle.suckUp()
        end

        turtle.select(WOOD_CHEST)
        turtle.digUp()
    end
end

function getItemIndex(itemName)
    for slot = 1, SLOT_COUNT, 1 do
        local item = turtle.getItemDetail(slot)
        if(item ~= nil) then
            if(item["name"] == itemName) then
                return slot
            end
        end
    end
end

function moveForward()
    turtle.forward()
end

function moveBackward()
    turtle.back()
end

function placeBlock()
    turtle.placeDown()
end


function turnAround()
    turtle.turnRight()
    turtle.turnRight()
    turtle.up()
end

repeat
    for i = 1,tonumber(length) -1 do
        checkWOOD()
        refuel()
        turtle.select(getItemIndex("minecraft:cobblestone"))
        placeBlock()
        moveForward()

        if i == tonumber(length) - 1 then
            placeBlock()
            turnAround()
            height = height - 1
        end
    end
until height == 0