Make XyTank

-- Tank Builder
-- Fenthis

-- Slot 1 = Frame
-- Slot 2 = Sides

args = { ... }
forward = tonumber(args[1])
right = tonumber(args[2])
up = tonumber(args[3])

if not (forward and right and up) then
    print("Usage: maketank forward right up")
    print(" Slot 1: Base and Frame")
    print(" Slot 2: Sides and Top")
    print(" The space must be clear, plus, one extra level above the tank.")
    error("Invalid usage.")
end

if not (forward > 2 and right > 2 and up > 2) then
    error("Minimum dimensions are 3x3x3.")
end

if (forward > 12 and right > 12 and up > 12) then
    error("Maximum dimensions are 12x12x12.")
end

glass = ((right-2)*(up-2)*2) + ((forward-2)*(up-2)*2) + ((forward-2) * (right-2))
frame = (up * 4) + ((forward-2) * 4) + ((right-2) * 4) + ((forward-2) * (right-2))

print("Required blocks:")
print("Base + Frame (slot 1): " .. frame)
print("Sides + Top (slot 2):  " .. glass)
print("Estimated fuel use:    " .. glass + frame + right + 2)

print("")
print("Press Q to quit, or any other key to start.")

e, c = os.pullEvent("char")
if c == "Q" or c == "q" then
    return
end

if not act then
    os.loadAPI("act")
    if not act then
        print("act api required.")
        exit()
    end
end

function do_left_or_right(dir)
    if dir then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
end

function is_odd(n)
    return ((n % 2) == 1)
end

function try_n(times)
    for i = 1, times do
        act.try()
    end
end

function do_to_or_botton(top)
    turtle.up()
    for r = 1,right do
        for x = 1,forward do
            -- Frame or side
            if (not top) or r == 1 or r == right or
                x == 1 or x == forward then
                act.select(1)
            else
                act.select(2)
            end
            act.placeDown()
            if x ~= forward then
                act.try()
            end
        end

        if r ~= right then
            do_left_or_right(not is_odd(r))
            act.try()
            do_left_or_right(not is_odd(r))
        end
    end

    -- Movve to opisit of starting corner
    if not is_odd(right) then
        turtle.turnLeft()
        turtle.turnLeft()
        try_n(forward - 1)
    end

    -- Turn around
    turtle.turnLeft()
    turtle.turnLeft()
end

function do_wall(length)
    for i = 1, length do
        if i == 1 or i == length then
            act.select(1)
        else
            act.select(2)
        end

        act.placeDown()

        if i ~= length then
            act.try()
        end
    end

    turtle.turnRight()
end

function do_walls()
    for level = 1, (up - 2) do
        turtle.up()
        do_wall(forward)
        do_wall(right)
        do_wall(forward)
        do_wall(right)
    end
end

do_to_or_botton(false)
do_walls()
do_to_or_botton(true)