on=true
local mon=peripheral.wrap("monitor_0")
local width, height=mon.getSize()
print(width.." "..height)
print 'setting "on" to true'
mon.setCursorPos(1,1)
mon.write("Current state: OFF          ")
mon.setCursorPos(5,5)
mon.write("Click to turn ON power      ")
function draw(x,y)
  --what will happen after click
  if (on==true) then
  on=false
  print 'setting "on" to false'
  elseif (on==false) then
  on=true
  print 'setting "on" to true'
  end
  if (on==true) then
  mon.setCursorPos(1,1)
  mon.write("Current state: OFF     ")
  mon.setCursorPos(5,5)
  mon.write("click to turn ON power      ")
  rs.setOutput("left",false)
  elseif (on==false) then
  mon.setCursorPos(1,1)
  mon.write("Current state: ON      ")
  mon.setCursorPos(5,5)
  mon.write("click to turn OFF power    ")
  rs.setOutput("left",true)
  end
end

while true do
  local event, side, x, y=os.pullEvent("monitor_touch")
  draw(x,y)
end