local sbc = term.setBackgroundColor
local stc = term.setTextColor
local scp = term.setCursorPos
local pa = paintutils
local running = true
local w,h = term.getSize()
local states = {
	inHelp = false,
	inMain = true,
	inMenu = false,
}
function expandBox(fx,fy,tx,ty,col)
	for i =1, tx-fx do
	  pa.drawFilledBox(fx,fy,i,ty,col)
	  sleep(0.1)
	end
end
function despandBox(fx,fy,tx,ty,col)
	for i =fx-tx, 1 do
	  pa.drawFilledBox(fx-i,fy,tx,ty,col)
	  sleep(0.1)
	end
end
function cwrite(t,y)
	scp((w/2) - #t/2, y)
	write(t)
end
function drawhelp()
	if(not states.inHelp)then
		despandBox(1,2,12,19,colors.white)
		states.inMain = true
		return 
	end
	scp(1,1)
	sbc(colors.gray)
	term.clearLine()
	cwrite("Help Menu",1)
	expandBox(1,2,12,19,colors.gray)
	drawbuttons()
end

function drawmenu()
	if(not states.inMenu)then
		despandBox(1,2,12,19,colors.white)
	else
		expandBox(1,2,12,19,colors.gray)
		drawbuttons()
	end
end

local buttons = {
	{n="Start",x=1,y=1,depends='inMain' or 'inMenu',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.lightGray,click=function()
		 states.inMenu = not states.inMenu
		 drawmenu()
	end},
	{n="Help      ",x=2,y=3,depends='inMenu',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.lightGray,click=function()
		states.inHelp = true
		states.inMain = false
		states.inMenu = false
		drawmenu()
		drawhelp()
	end},
	{n="Reboot    ",x=2,y=4,depends='inMenu',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.lightBlue,click=function()
		os.reboot()
	end},
	{n="Quit      ",x=2,y=5,depends='inMenu',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.red,click=function()
	end},
	{n="Topic 1   ",x=2,y=3,depends='inHelp',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.lightGray,click=function()
	end},
	{n="Topic 2   ",x=2,y=4,depends='inHelp',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.lightBlue,click=function()
	end},
	{n="Quit      ",x=2,y=5,depends='inHelp',tc=colors.white,bc=colors.gray,fbc=colors.black,ftc=colors.red,click=function()
		 states.inHelp = false
		 drawhelp()
		 redraw()
		 drawbuttons()
		 states.inMenu = not states.inMenu
		 drawmenu()
	end},
}

function drawbuttons()
	-- Draw buttons based on state dependances
	for i = 1, #buttons do
		if(buttons[i].depends == nil or states[buttons[i].depends])then
			-- Draw button
			sbc(buttons[i].bc)
			stc(buttons[i].tc)
			scp(buttons[i].x,buttons[i].y)
			write(buttons[i].n)
		end
	end
end

function flashbutton(n)
	sbc(buttons[n].fbc)
	stc(buttons[n].ftc)
	scp(buttons[n].x,buttons[n].y)
	write(buttons[n].n)
	sleep(0.2)
	sbc(buttons[n].bc)
	stc(buttons[n].tc)
	scp(buttons[n].x,buttons[n].y)
	write(buttons[n].n)
end
function updatebuttons(e)
	if(e[1] == "mouse_click")then
	-- Update buttons based on state dependances
		for i = 1, #buttons do
			if(buttons[i].depends == nil or states[buttons[i].depends])then
				-- Update button
				local x,y = e[3], e[4]
				if(x >= buttons[i].x and x <= buttons[i].x+#buttons[i].n and y == buttons[i].y)then
					 flashbutton(i)
					 buttons[i].click()
					 return
				end
			end
		end
	end
end
function redraw()
	sbc(colors.white)
	term.clear()
	scp(1,1)
	sbc(colors.gray)
	term.clearLine()
	scp(1,1)
	drawbuttons()
end

function loop()
	redraw()
	while running do
		-- Manage screen states (States that change the entire screen layout)
		local e = {os.pullEvent()}
		updatebuttons(e)
	end
end
loop()