-- Windows screensaver with love2d

function love.load()
  love.graphics.setDefaultFilter("nearest", "nearest")

  -- get screen size
  wdw_w, wdw_h = love.graphics.getDimensions()

  -- Check command line options
  ssmode = ""
  for k, v in pairs(arg) do
    lv = string.lower(v)
    if lv == "/s" then
      ssmode = "fullscreen"
    elseif lv == "/c" then
      ssmode = "config"
    elseif lv == "/p" then
      ssmode = "preview"
    elseif lv == "/a" then
      ssmode = "passwordlock"
    end
  end

  if ssmode == "" then
    ssmode = "none"
  end

  if ssmode == "config" then love.event.quit() end
  if ssmode == "preview" then love.event.quit() end
  if ssmode == "passwordlock" then love.event.quit() end
  if ssmode == "none" then love.event.quit() end
  
  -- hide mouse cursor 
  love.mouse.setVisible(false)

  min_dt = 1 / 60
  next_time = love.timer.getTime()

  dx = wdw_w / 2
  dy = dx / 3
  x = wdw_w / 2
  y = wdw_h / 2
  r = wdw_w / 100
end

function love.update(dt)
  next_time = next_time + min_dt
  if dt > 0.75 then return end

  -- move ball
  x = x + dx * dt
  y = y + dy * dt
  if (x - r) < 0 or (x + r) > wdw_w then dx = dx * -1 end
  if (y - r) < 0 or (y + r) > wdw_h then dy = dy * -1 end
end

function love.draw()
  -- clear screen
  love.graphics.setCanvas()
  love.graphics.clear(0, 0, 0, 1.0)

  -- draw ball
  love.graphics.setColor(0.1, 0.3, 1.0, 1.0)
  love.graphics.circle("fill", x, y, r)

  -- draw FPS
  love.graphics.setColor(0.5, 0.5, 0.5, 1.0)
  love.graphics.print("FPS: "..tostring(love.timer.getFPS()), 10, 10)

  if love.system.getOS() == "Windows" then
    -- wait
    local cur_time = love.timer.getTime()
    if next_time <= cur_time then
      next_time = cur_time
    else
      love.timer.sleep(next_time - cur_time)
    end
  end
end

function love.keypressed(key, isrepeat)
  -- Pressed any key to exit
  love.mouse.setVisible(true)
  love.event.quit()
end

function love.mousemoved( x, y, dx, dy, istouch )
  -- Moved the mouse cursor a lot to exit
  if dx * dx + dy * dy >= 16 * 16 then
    love.mouse.setVisible(true)
    love.event.quit()
  end
end