Turtle Builder

local empty={}
local x,y,z,d= 0,0,0,0
local FUEL,FRAME,FILLER,WINDOW,FLOOR,TRASH = 1,2,3,4,5,6

print "Welcome to TeddyJ's turtle builder"
print "Please ensure your chests and turtles are"
print "arranged as follows:"
print "            [T]"
print "[5][4][3][2][1]"
print "T=turtle, 1..5 chests containing Floor/Window/Filler/Frame/Fuel materials"
print ""
print "How big is the gap between chests (0 for no gap)?"
local chest_gap=io.read()
print "How many panels long would you like the building?"
local length=io.read()
print "How many panels wide would you like the building?"
local width=io.read()
print "How many storeys high would you like the building?"
local storeys=io.read()

function goUp(n)
    checkFuel()
    if n==nil then n=1 end
    y=y+n
    for _=1,n do
        turtle.digUp()
        turtle.up()
    end
end

function placeDown(n)
    if turtle.detectDown() then
        turtle.select(TRASH)
        turtle.digDown()
        turtle.drop()
    end
    turtle.select(n)
    if turtle.getItemCount(n)==0 then
        refill(n)
    end
    turtle.placeDown()
end

function refill(n)
    if not(empty[n]) then
        goToChestAndRestock(n)
        goToLastPlace()
    end
end

function goToChestAndRestock(n)
    for _=1,6 do
        turtle.digUp()
        turtle.up()
    end
    for _=1,d+3 do
        turtle.turnLeft()
    end
    for _=1,x do
        turtle.dig()
        turtle.forward()
    end
    turtle.turnRight()
    for _=0,z do
        turtle.dig()
        turtle.forward()
    end
    for _=1,(y+5) do
        turtle.down()
    end
    turtle.turnRight()
    if n>1 then
        for _=2,n do
            for i=0,chest_gap do
                turtle.forward()
            end
        end
        content=turtle.suckDown()
        for _=2,n do
            for i=0,chest_gap do
                turtle.back()
            end
        end
    else
        content=turtle.suckDown()
    end
    if not(content) then empty[n]=true end
    turtle.turnRight()
end

function goToLastPlace()
    for _=1,(y+5) do
        turtle.up()
    end
    for _=0,z do
        turtle.forward()
    end
    turtle.turnLeft()
    for _=1,x do
        turtle.forward()
    end
    for _=1,6 do
        turtle.down()
    end
    for _=1,d+5 do
        turtle.turnRight()
    end
end

function goDown(n)
    checkFuel()
    if n==nil then n=1 end
    y=y-n
    for _=1,n do
        turtle.digDown()
        turtle.down()
    end
end

function turnLeft()
    d=d-1
    if d==-1 then d=3 end
    turtle.turnLeft()
end

function turnRight()
    d=d+1
    if d==4 then d=0 end
    turtle.turnRight()
end

function checkFuel()
    if tonumber(turtle.getFuelLevel())~= nil and turtle.getFuelLevel()<80 then
        print "Fuel low"
        if turtle.getItemCount(FUEL)==0 then
            print "No fuel available, restocking"
            refill(FUEL)
        end
        print "Refueling"
        turtle.select(FUEL)
        if not(turtle.refuel()) then
            print "No fuel in slot 1! Press enter when filled"
            io.read()
        end
    end
end

function goForward(n)
    checkFuel()
    if n==nil then n=1 end
    if d==0 then z=z+n end
    if d==1 then x=x-n end
    if d==2 then z=z-n end
    if d==3 then x=x+n end
    for _=1,n do
        turtle.dig()
        turtle.forward()
    end
end

function goBack(n)
    if n==nil then n=1 end
    if d==0 then z=z-n end
    if d==1 then x=x+n end
    if d==2 then z=z+n end
    if d==3 then x=x-n end
    for _=1,n do
        turtle.back()
    end
end


function getBlockType(i,j)
    if i==5 or j==5 then
        return FRAME
    end
    if j==2 or j==3 then
        if (i==2 or i==3) then
            return WINDOW
        else
            return FILLER
        end
    end
    return FILLER
end

function doSide(panels, isFinalSide)
    for _=1,panels do
        doPanel()
    end
    if not(isFinalSide) then
        turnLeft()
        goForward()
        turnLeft()
        goForward()
        turnRight()
    end
end

function doPanel()
    checkFuel()
    for i=1,5 do
        goUp()
        for j=1,5 do
            b=getBlockType(i,j)
            placeDown(b)
            goForward()
        end
        if i<5 then
            goBack(5)
        end
    end
    goDown(5)
end

function doFloor()
    turnLeft()
    goForward()
    turnRight()
    floor_width=(width*5)-1
    floor_length=(length*5)-1
    for i=1,floor_width do
        for i=1,floor_length do
            placeDown(FLOOR)
            goForward()
        end
        goBack(floor_length)
        turnLeft()
        goForward()
        turnRight()
    end
    turnRight()
    goForward(floor_width+1)
    turnLeft()
end

function doStorey()
    goForward()
    doFloor()
    doSide(length)
    doSide(width)
    doSide(length)
    doSide(width,true)
    goUp(6)
    goBack()
    turnLeft()
    goDown()
end

goForward()
for _=1,storeys do
    doStorey()
end
goForward()
doFloor()