platform

io.write("Enter Length: ")
length = io.read()
io.write("Enter Width: ")
width = io.read()
io.write("Build off in what direction? Left or Right?: ")
direction = io.read()

local SLOT_COUNT = 16
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 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 turnRight()
    turtle.turnRight()
    turtle.forward()
    turtle.turnRight()
end

function turnLeft()
    turtle.turnLeft()
    turtle.forward()
    turtle.turnLeft()
end

function turnAround()
    if direction == "Right" then turnRight()
    elseif direction == "Left" then turnLeft()
    end
end

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

        if i == tonumber(length) - 1 then
            placeBlock()
            turnAround()
            width = width - 1

            if i == tonumber(length) - 1 and direction == "Right"
                then direction = "Left"
                elseif i == tonumber(length) - 1 and direction == "Left"
                    then direction = "Right"
            end
        end
    end
until width == 0