Piston Door Controller

local integrators = {
    redstone_integrator_788 = "north",
    redstone_integrator_790 = "east"
}
local screen = peripheral.find "monitor"
local side = "north"
local button_side = "front"
local modem = peripheral.find "modem"
modem.open(49961)
os.pullEvent = function(filter)
    while true do
        local ev = {coroutine.yield(filter)}
        if ev[1] == filter then
            return unpack(ev)
        end
    end
end
local w, h = screen.getSize()

screen.setTextScale(1.5)
screen.setBackgroundColor(colors.black)
screen.clear()

local function set_open(state)
    for i, side in pairs(integrators) do
        peripheral.call(i, "setOutput", side, not state)
    end
end

local scramble = {}
for i = 1, ((w * h) - 2) do
    table.insert(scramble, string.char(47 + i))
end

local function shuffle()
    for i = 1, (#scramble - 1) do
        local j = math.random(i, #scramble)
        local a = scramble[i]
        local b = scramble[j]
        scramble[j] = a
        scramble[i] = b
    end
end

local function draw_display()
    screen.setTextColor(colors.black)
    for i = 0, ((w * h) - 3) do
        local x = i % w
        local y = math.floor(i / w)
        screen.setCursorPos(x + 1, y + 1)
        local c = scramble[i + 1]
        screen.setBackgroundColor(2 ^ ((string.byte(c) - 48) % 15))
        screen.write(c)
    end
    screen.setTextColor(colors.white)
    screen.setBackgroundColor(colors.black)
    screen.write "CE"
end

local function flash_display(color)
    screen.setBackgroundColor(color)
    screen.clear()
    sleep(0.1)
    draw_display()
end

set_open(false)
draw_display()

local can_open = false

local function monitor_ui()
    local inp = ""
    while true do
        local _, _, x, y = os.pullEvent "monitor_touch"
        if y == h and x == w then
            print "E"
            flash_display(colors.blue)
            shuffle()
            inp = ""
            if can_open then set_open(true) sleep(1) set_open(false) end
            draw_display()
        elseif y == h and x == (w - 1) then
            print "C"
            flash_display(colors.red)
            shuffle()
            draw_display()
            inp = ""
        else
            flash_display(colors.lime)
            local i = (x - 1) + (y - 1) * w
            inp = inp .. string.char(i + 48)
        end
    end
end
local function comms()
    while true do
        local _, _, c, rc, open = os.pullEvent "modem_message"
        can_open = open
    end
end
local function button()
    while true do
        os.pullEvent "redstone"
        set_open(rs.getInput(button_side))
    end
end

parallel.waitForAll(monitor_ui, button, comms)