local gpu = require("component").gpu
local event = require("event")

local objects = {}

local function object.new(x, y, w, h,visible,shouldAutoUpdate)
  local obj = {
    type = "object",
    x = x,
    y = y,
    w = w,
    h = h,
    visible = visible,
    shouldAutoUpdate = shouldAutoUpdate,
    update = function() obj.drawNextFrame = true end,
    _drawNextFrame = false
  }

  return obj
end

local function button(x,y,w,h,label,color,textColor,shouldAutoUpdate,callback)
  local obj = object.new(x,y,w,h,true,shouldAutoUpdate)
  obj.label = label
  obj.color = color
  obj.textColor = textColor
  obj.callback = callback

  table.insert(objects,obj)
  return #objects
end

local function frame(x,y,w,h,color,textColor,text,shouldAutoUpdate)
  local obj = object.new(x,y,w,h,true,shouldAutoUpdate)
  obj.type = "frame"
  obj.color = color
  obj.textColor = textColor
  obj.text = text
  table.insert(objects, obj)
  return #objects
end

local function draw(bg)
  bg = bg or 0x333333
  gpu.setBackground(bg)
  gpu.setForeground(0xFFFFFF)
  gpu.fill(1,1,resx,resy," ")
  for i,v in ipairs(objects) do
    local object = v

    if object.shouldAutoUpdate or object._drawNextFrame then
      object._drawNextFrame = false
      if object.type == "button" and object.visible == true then
        gpu.setBackground(object.color)
        gpu.setForeground(object.textColor)
        gpu.fill(object.x,object.y,object.w,object.h," ")
        gpu.set(object.x+math.floor(object.w/2)-math.floor(#object.label/2),object.y+math.floor(object.h/2),object.label)
      elseif object.type == "frame" and object.visible == true then
        gpu.setBackground(object.color)
        gpu.setForeground(object.textColor)
        gpu.fill(object.x,object.y,object.w,object.h," ")
        gpu.set(object.x+math.floor(object.w/2)-math.floor(#object.text/2),object.y+math.floor(object.h/2),object.text)
      end
    end
  end
end

event.listen("touch",function(_,_,x,y)
  for i,v in ipairs(objects) do
    if v.type == "button" then
      if x>=v.x and x<=v.x+v.w-1 and y>=v.y and y<=v.y+v.h-1 then
        v.callback()
      end
    end
  end
end)

while true do
  os.sleep(0.2)

  draw()
end