Button API

local mon = peripheral.wrap("top")
mon.setTextScale(1)
mon.setTextColor(colors.white)
local button={}
mon.setBackgroundColor(colors.black)

function clearTable()
   button = {}
   mon.clear()
end

-- Creates a new button with a name
function initButton(name, func, xmin, xmax, ymin, ymax)
   button[name] = {}
   button[name]["func"] = func
   button[name]["active"] = false
   button[name]["xmin"] = xmin
   button[name]["ymin"] = ymin
   button[name]["xmax"] = xmax
   button[name]["ymax"] = ymax
end

function fredClicked()
   print("You clicked Fred")
end

function demoButton()
   initButton("I am Fred", buttonClicked, 5, 25, 4, 8)
end

-- Fills the button with color and text
function fillButton(text, color, bData)
   mon.setBackgroundColor(color)
   -- The vertical center of the button
   local yspot = math.floor((bData["ymin"] + bData["ymax"]) /2)
   -- The horizontal space where the text should start
   local xspot = math.floor((bData["xmax"] - bData["xmin"] - string.len(text)) /2) +1
   for j = bData["ymin"], bData["ymax"] do
      mon.setCursorPos(bData["xmin"], j)
      if j == yspot then
         for k = 0, bData["xmax"] - bData["xmin"] - string.len(text) +1 do
            if k == xspot then
               mon.write(text)
            else
               mon.write(" ")
            end
         end
      else
         for i = bData["xmin"], bData["xmax"] do
            mon.write(" ")
         end
      end
   end
   mon.setBackgroundColor(colors.black)
end

-- Refreshes the screen
function screen()
   local currColor
   for name,data in pairs(button) do
      local isOn = data["active"]
      if isOn then currColor = colors.lime else currColor = colors.red end
      fillButton(name, currColor, data)
   end
end

-- Button functions --

-- Toggles a button between active an inactive
function toggleButton(name)
   button[name]["active"] = not button[name]["active"]
   screen()
end

-- Causes a button to toggle for a short pulse
function flash(name)
   toggleButton(name)
   sleep(0.15)
   toggleButton(name)
end

-- Determines which button was clicked, if any
function checkxy(x, y)
   for name, data in pairs(button) do
      if y>=data["ymin"] and  y <= data["ymax"] then
         if x>=data["xmin"] and x<= data["xmax"] then
            data["func"]()
            return true
            --data["active"] = not data["active"]
            --print(name)
         end
      end
   end
   return false
end

-- End button functions --

-- Sets a header on the top center of the monitor
function heading(text)
   w, h = mon.getSize()
   mon.setCursorPos((w-string.len(text))/2+1, 1)
   mon.write(text)
end

-- Sets a text label at a specified position
function label(w, h, text)
   mon.setCursorPos(w, h)
   mon.write(text)
end