startup

local monitor1 = peripheral.wrap('top')
local monWidth, monHeight
local buttCount = 0
local buttLoc = {}
local buttSize = {}

local function nextLine()
 x, y = monitor1.getCursorPos()
 monitor1.setCursorPos(1 ,y+1)
 a, b = term.getCursorPos()
 term.setCursorPos(1 , y+1)
end

local function monStart()
 monitor1.clear()
 monWidth, monHeight = monitor1.getSize()
 monitor1.setCursorPos(1,1)
 monitor1.setTextScale(.5)
 monitor1.setTextColor(colors.black)
 monitor1.setBackgroundColor(colors.white)
 monitor1.clear()
end

local function center(str)
 local len = string.len(str)
 x = monWidth/2 - len/2
 y = monHeight/2
 if monWidth%2 ~= 0 and len%2 ~= 0 then
  x = x + 1
 end
 return x,y
end

local function drawButt(a, b, c)
 monitor1.setTextColor(colors.white)
 monitor1.setBackgroundColor(colors.black)
 monitor1.setCursorPos(a, b)
 monitor1.write(c)
 buttCount = buttCount + 1
 buttLoc[buttCount] = {}
 buttLoc[buttCount]["x"] = a
 buttLoc[buttCount]["y"] = b
 local buttLength = string.len(c)
 buttSize[buttCount] = buttLength
end

--Returns 0 if no button coord found, 1 if found
local function checkButt(a, b)
term.write(a..b)
 local i = 1
 while i <= buttCount do
  if buttLoc[i]["x"] == a and buttLoc[i]["y"] == b then
      return 1, i
  elseif buttLoc[i]["y"] == b and buttLoc[i]["x"] ~= a then
   for j=1,buttSize[i],1 do
    if buttLoc[i]["x"] == a - j then
     return 1, i
    else
    end
   end
   i = i + 1
  else
   i = i + 1
  end
 end
 return 0, 0
end

local function monWriteCen(c)
 monitor1.setTextColor(colors.black)
 monitor1.setBackgroundColor(colors.white)
 local d, e = center(c)
 monitor1.setCursorPos(d,e)
 monitor1.write(c)
end

local function monWrite(a, b, c)
 monitor1.setTextColor(colors.black)
 monitor1.setBackgroundColor(colors.white)
 monitor1.setCursorPos(a,b)
 monitor1.write(c)
end

monStart()
local screenText = "Right Click Monitor To Begin"
monWriteCen(screenText)

--Wait for click
os.pullEvent("monitor_touch")

monStart()
screenText = "Thanks! Welcome!"
monWriteCen(screenText)

--Draw Buttons
drawButt(8,3," Button1 ")
drawButt(8,8," Button2 ")

--Wait for click
local event,side,x,y = os.pullEvent("monitor_touch")

local buttStatus, buttNumber = checkButt(x,y)
if buttStatus == 1 then
 monStart()
 screenText = "Button #"..buttNumber.." Pressed!"
 monWriteCen(screenText)
else
 monStart()
 screenText = "No Button Pressed!"
 monWriteCen(screenText)
end
--Debug
--monWrite(1,8,x)
--monWrite(1,11,y)
--monWrite(1,9,buttStatus)
--monWrite(1,11,buttNumber)