--Int--

local w,h = term.getSize()
local running = true
local selectedMenu = "MainMenu"
local selectedItem = 1

--Menu Functions--

function Choice1()
	selectedMenu = "Programs"
end

function Choice2()
	selectedMenu = "Control"
end

function Choice3()
	selectedMenu = "Redstone"
end

function exit()
	running = false
end

--Menu Int--

local MainMenu = {
	[1] = {text = "Programs", handler = Choice1},
	[2] = {text = "Control Options", handler = Choice2},
	[3] = {text = "Redstone Options", handler = Choice3},
	[4] = {text = "Exit", handler = exit}
}

--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[selectedItem].text.." ]",i+5)
		else
			centerPrint(menu[selectedItem].text,i+5)
		end
	end
end

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

--Main Function--

term.clear()
term.setCursorPos(1,1)
while running do
	local event, key = os.pullEvent("key")
	Input(key, selectedMenu)
	PrintMenu(selectedMenu)
end
term.clear()
term.setCursorPos(1,1)