aetnaosmenu

os.pullEvent = os.pullEventRaw

local w,h = term.getSize()

function printCentered( y,s )
   local x = math.floor((w - string.len(s)) / 2)
   term.setCursorPos(x,y)
   term.clearLine()
   term.write( s )
end

local nOption = 1

local function drawMenu()
    term.clear()
    term.setCursorPos(1,1)
    term.write("AetnaOS Alpha // ")
    term.setCursorPos(1,2)
    shell.run("id")
    term.setCursorPos(w-11,1)

    if nOption == 1 then
        local optionName = "Command"
        term.setCursorPos(w - string.len(optionName),1)
        term.write(optionName)
    elseif nOption == 2 then
        local optionName = "Programs"
        term.setCursorPos(w - string.len(optionName),1)
        term.write(optionName)
    elseif nOption == 3 then
        local optionName = "Shutdown"
        term.setCursorPos(w - string.len(optionName),1)
        term.write(optionName)
    elseif nOption == 4 then
        local optionName = "Uninstall"
        term.setCursorPos(w - string.len(optionName),1)
        term.write(optionName)
    end
 end

--GUI
term.clear()
local function drawFrontend()
   printCentered( math.floor(h/2) - 3, "")
   printCentered( math.floor(h/2) - 2, "Start Menu" )
   printCentered( math.floor(h/2) - 1, "")
   printCentered( math.floor(h/2) + 0, ((nOption == 1) and "-> Command ") or "Command " )
   printCentered( math.floor(h/2) + 1, ((nOption == 2) and "-> Programs ") or "Programs" )
   printCentered( math.floor(h/2) + 2, ((nOption == 3) and "-> Shutdown") or "Shutdown" )
   printCentered( math.floor(h/2) + 3, ((nOption == 4) and "-> Uninstall") or " Uninstall" )
   printCentered( math.floor(h/2) + 4, "")
end

--Display
drawMenu()
drawFrontend()

while true do
    local e,p = os.pullEvent()
    if e == "key" then
         local key = p
        if key == keys.up then
            if nOption > 1 then
                nOption = nOption - 1
                drawMenu()
                drawFrontend()
            end
        elseif key == keys.down then
            if nOption < 4 then
                nOption = nOption + 1
                drawMenu()
                drawFrontend()
            end
        elseif key == keys.enter then
            if nOption  == 1 then
                    shell.run("command")
                elseif nOption == 2 then
                    shell.run("osprogramlist")
                elseif nOption == 3 then
                    os.shutdown()
                else
                    shell.run("delete osprogramlist")
                    shell.run("delete osmenu")
                    shell.run("delete startup")
                    term.clear()
                    term.setCursorPos(1,1)
                    print("AetnaOS Uninstalled")
                    term.setCursorPos(1,2)
                    return
            end
        end
    end
end
term.clear()