Builder

local lenth = 4         -- lenth
local width = 5         -- width
local height = 2        -- height of walls
local floors = 1        -- how many floors+walls to build
local walls = true      -- do you need walls or just floor
local ceiling = true    -- do you need to build roof
-------------------------------------------------------
local t = turtle
local currentSlot = 1

t.placeDownOld = t.placeDown

lenth = lenth - 2
width = width - 2

function t.placeDown()
    CheckSlot()
    t.placeDownOld()
end

function CalcBlocks()
    local blocks = 0

    local w = width+2
    local l = lenth+2

    blocks = blocks + w*l*floors
    blocks = blocks + (walls and (w+l-2)*2*floors*height or 0)
    blocks = blocks + (ceiling and w*l or 0)

    return blocks
end

function CheckSlot()
    if t.getItemCount(currentSlot) == 0 then
        if currentSlot == 16 then
            print("WAITING FOR BLOCKS")
            currentSlot = 1
            t.select(1)
            while t.getItemCount() == 0 do
                sleep(1)
            end
        else
            currentSlot = currentSlot + 1
            t.select(currentSlot)
            CheckSlot()
        end
    end
end

function BuildFloor()
    local side = 0

    t.up()

    if not(walls) then
        width = width - 2
        lenth = lenth - 2
    end

    for i = 1, width+2 do
        for i = 1, lenth+1 do
            t.placeDown()
            t.forward()
        end
        t.placeDown()

        if i ~= width+2 then
            if side == 0 then
                t.turnRight()
                t.forward()
                t.turnRight()
            elseif side == 1 then
                t.turnLeft()
                t.forward()
                t.turnLeft()
            end
            side = 1 - side
        end
    end
end

function BuildWalls()
    if width%2 == 0 then
        t.turnLeft()
        t.turnLeft()
        for i = 1, lenth+1 do
            t.forward()
        end
    end
    t.turnLeft()
    t.forward()

    for i = 1, height do
        t.up()
        for i = 1, 2 do
            for i = 1, width do
                t.placeDown()
                t.forward()
            end
            t.placeDown()
            t.turnLeft()
            t.forward()
            for i = 1, lenth do
                t.placeDown()
                t.forward()
            end
            t.placeDown()
            t.turnLeft()
            t.forward()
        end
    end

    for i = 1, width do
        t.forward()
    end
    t.turnLeft()
    for i = 1, lenth+1 do
        t.forward()
    end
    t.turnLeft()
    t.turnLeft()
end

if t ~= nil then
    term.clear()
    term.setCursorPos(1, 1)

    print("PICKAR'S BUILDER v1.0")
    print("YOU WILL NEED "..CalcBlocks().." BLOCKS")
    print("ITS ".. (CalcBlocks()-CalcBlocks()%64)/64 .." STACK AND ".. CalcBlocks()%64 .." BLOCKS")
    if walls then
        if floors == 1 then
            BuildFloor()
            BuildWalls()
        else
            for i = 1, floors do
                BuildFloor()
                BuildWalls()
            end
        end
        if ceiling then
            BuildFloor()
            BuildFloor()
        end
    else
        BuildFloor()
    end
end