--config
local amountOfButtons = 8
local buttonWidth = 11
local buttonHeight = 3
local verticalButtonSpace = 2
local
--end of config

local screenSizeX,screenSizeY = term.getSize()

local buttons = {}
for i=1,amountOfButtons do
	buttons[i] = {xPos=0, yPos=0, width=buttonWidth, height=buttonHeight, name="", color=colors.red, action=function()}
end

local calculatePositions = function()
	for i=1,math.floor(amountOfButtons/2 + 0.5) do
		if amountOfButtons > 1 then
			buttons[i].xPos = math.floor((screenSizeX - 2 * buttonWidth)/3) + 1
		else
			buttons[i].xPos = math.floor((screenSizeX - buttonWidth)/2) + 1
		end
		buttons[i].yPos = 3 + (i-1) * verticalButtonSpace + (i-1) * buttonHeight
	end
	for i=1,math.floor(amountOfButtons/2) do
		buttons[i + math.floor(amountOfButtons/2)].xPos = math.floor(buttonWidth + 2 * (screenSizeX - 2 * buttonWidth)/3) + 1
		buttons[i + math.floor(amountOfButtons/2)].yPos = 3 + (i-1) * verticalButtonSpace + (i-1) * buttonHeight
	end
end

local isClicked = function(button, xClick, yClick)
	if xClick >= buttons.xPos and xClick < buttons.xPos + buttons.width and yClick >= buttons.yPos and yClick < buttons.yPos + buttons.height then
		return true
	else
		return false
	end
end

local event,mouseButton,xPos,yPos
local handleInput = function()
	event,mouseButton,xPos,yPos = os.pullEventRaw()
	if event = "mouse_click" then
		for i=1,amountOfButtons do
			if isClicked(buttons[i],xPos,yPos) then
				buttons[i].action()
			end
		end
	end
end

local draw = function()
	for i=1,amountOfButtons do
		term.setBackgroundColor(buttons[i].color)
		for j=1,buttons[i].height do
			for k=1,buttons[i].width do
				term.setCursorPos(buttons[i].xPos + k -1, buttons[i].yPos + j -1)
				term.write(" ")
			end
		end
		term.setCursorPos(buttons[i].xPos + math.floor((buttons[i].width - string.len(buttons[i].name))/2), buttons[i].yPos + math.floor(buttons[i].height/2))
		term.write(buttons[i].name)
	end
end

local loop = function()
	while true do
		draw()
		handleInput()
	end
end


--actually running the program
calculatePositions()

loop()