--Int--

local w,h = term.getSize()
local running = true
local selectedItem = 1
local selectedMenu
local MainMenu = { }
--Menu Int--

local Programs = {
	[1] = {text = "Test", handler = function() end}
	[2] = {text = "Back", handler = function() selectedMenu = MainMenu end}
}


local Control = {
	[1] = {text = "Test", handler = function() end}
	[2] = {text = "Back", handler = function() selectedMenu = MainMenu end}
}


local Redstone = {
	[1] = {text = "Test", handler = function() end}
	[2] = {text = "Back", handler = function() selectedMenu = MainMenu end}
}

MainMenu = {
    [1] = {text = "Programs", handler = function() selectedMenu = Programs end},
    [2] = {text = "Control Options", handler = function() selectedMenu = Control end},
    [3] = {text = "Redstone Options", handler = function() selectedMenu = Redstone end},
    [4] = {text = "Exit", handler = function() running = false end}
}

--Functions--

function centerPrint(string,ypos)
        term.setCursorPos(w/2-#string/2,ypos)
        write(string)
end

function PrintMenu(menu)
        for i=1,#menu do
                if i == selectedItem then
                        centerPrint("[ "..menu[i].text.." ]",i+5)
                else
                        centerPrint("  "..menu[i].text.."  ",i+5)
                end
        end
end

function Input(key, menu)
        if key == keys.enter then
        		selectedItem = 1
                menu[selectedItem].handler
        elseif key == keys.down and selectedItem < #menu then
                selectedItem = selectedItem + 1
        elseif key == keys.up and selectedItem > 1 then
                selectedItem = selectedItem - 1
        end
end

--Main Function--
selectedMenu = MainMenu
term.clear()
term.setCursorPos(1,1)
while running do
		term.clear()
        PrintMenu(selectedMenu)
        local event, key = os.pullEvent("key")
        Input(key, selectedMenu)
        sleep(0.1)
end
term.clear()
term.setCursorPos(1,1)