TechOS

-- -- TechOS -- --

-- Local Variables --

local nScreenWidth, nScreenHeight = term.getSize()
local nSelection = 1
local menustate = "Boot"

-- End Local Variables --

-- Local Tables --

local tMenus = {
    [ "Boot" ] = {
    options = { "Inventory", "Turtles", "Reactor" },
    draw = drawBoot
    },
    [ "Inventory" ] = {
    options = { "Raw Materials", "Refined Materials" },
    draw = drawInventory
    },
    [ "Turtles" ] = {
    options = { "Mining" },
    draw = drawTurtles  },
    [ "Reactor" ] = {
    options = { "Control" },
    draw = drawReactor
    }
}

-- End Local Tables --

-- -- Draw Functions -- --

-- Base Draw Functios --

function ClearScreen()
    term.clear()
    term.setCursorPos( 1, 1 )
end

function PrintCentered( nHeight, sString )
    term.setCursorPos( nScreenWidth/2 - #sString/2, nHeight )
    term.write( sString )
end

function PrintLeft( nHeight, sString )
    term.setCursorPos( 1, nHeight )
    term.write( sString )
end

function PrintRight( nHeight, sString )
    term.setCursorPos( ( nScreenWidth + 1 ) - #sString, nHeight )
    term.write( sString )
end

function PrintTitle( sName )
    PrintCentered( 1, string.rep( "-", ( nScreenWidth + 1 ) ) )
    PrintCentered( 2, string.rep( "-", ( nScreenWidth + 1 ) ) )
    PrintLeft( 3, "-" )
    PrintCentered( 3, sName )
    PrintRight( 3, "-" )
    PrintCentered( 4, string.rep( "-", ( nScreenWidth + 1 ) ) )
    PrintCentered( 5, string.rep( "-", ( nScreenWidth + 1 ) ) )
    for i = 6, ( nScreenHeight - 1 ) do
        PrintLeft( i, "-" )
        PrintRight( i, "-" )
    PrintCentered( nScreenHeight, string.rep( "--", ( nScreenWidth + 1 ) ) )
end
end

-- End Base Draw Functions

-- Menu Draw Functions --

function drawBoot()
    PrintTitle( "Boot Menu" )
    for j = 1, 3 do
        if j == nSelection then
            PrintCentered( 11 + ( j - 1 ), "[" .. tMenus["Boot"].options[j] .. "]" )
        else
            PrintCentered( 11 + ( j - 1 ), " " .. tMenus["Boot"].options[j] .. " " )
        end
    end
end

function drawInventory()
    PrintTitle( "Inventory Menu" )
    for k = 1, 2 do
        if k == nSelection then
            PrintCentered( 11 + ( k - 1 ), "[" .. tMenus["Inventory"].options[k] .. "]" )
        else
            PrintCentered( 11 + ( k - 1 ), " " .. tMenus["Inventory"].options[k] .. " " )
        end
    end
end

-- End Menu Draw Functions --

-- -- End Draw Functions -- --

while true do
    ClearScreen()

    -- -- Problem lies here -- --

    -- drawBoot() -- shows changing of selections
    tMenus[menustate].draw() -- doesn't show changing of selections

    local id, nKey = os.pullEvent("key")
    if nKey == 200 and nSelection > 1 then
        nSelection = nSelection - 1
    elseif nKey == 208 and nSelection < #tMenus[menustate].options then
        nSelection = nSelection + 1
    elseif nKey == 28 then
        menustate = tMenus[menustate].options[nSelection]

    end
end