Pong ComputerCraft

local sx, sy = term.getSize()
local pong1pos, pong2pos, ballxpos, ballypos, ballxvelocity, ballyvelocity, p1score, p2score = math.ceil(sy / 2), math.ceil(sy / 2), math.ceil(sx / 2), math.ceil(sy / 2), math.ceil(math.random() - 1), math.ceil(math.random() - 1), 0, 0

if ballxvelocity == 0 then
    ballxvelocity = -1
end

if ballyvelocity == 0 then
    ballyvelocity = -1
end

local function gameGraphics()
    term.setBackgroundColor(colors.black)
    term.clear()
    term.setBackgroundColor(colors.white)

    for a = -1, 1 do
        term.setCursorPos(4, pong1pos + a)
        io.write(" ")
        term.setCursorPos(sx - 3, pong2pos + a)
        io.write(" ")
    end

    term.setCursorPos(ballxpos, ballypos)
    io.write(" ")
    term.setCursorPos(1, 1)
    io.write(p1score)
    term.setCursorPos(sx, 1)
    io.write(p2score)
end

local function gameTime()
    local timer = os.startTimer(0.07)
    local input1, input2

    while true do
        local event, par1 = os.pullEvent()

        if event == "timer" and par1 == timer then
            if input1 == "up" then
                pong1pos = pong1pos - 2
            elseif input1 == "down" then
                pong1pos = pong1pos + 2
            end

            if input2 == "up" then
                pong2pos = pong2pos - 2
            elseif input2 == "down" then
                pong2pos = pong2pos + 2
            end

            break
        elseif event == "key" then
            if par1 == keys.up and pong1pos > 2 then
                input2 = "up"
            elseif par1 == keys.down and pong1pos < sy - 1 then
                input2 = "down"
            end

            if par1 == keys.w and pong2pos > 2 then
                input1 = "up"
            elseif par1 == keys.s and pong2pos < sy - 1 then
                input1 = "down"
            end
        end
    end
end

local function gameFunctions()
    ballxpos, ballypos = ballxpos + ballxvelocity, ballypos + ballyvelocity

    if ballypos == 1 then
        ballyvelocity = 1
    elseif ballypos == sy then
        ballyvelocity = -1
    end

    if ballxpos == 5 and ballypos >= pong1pos - 1 and ballypos <= pong1pos + 1 then
        ballxvelocity = 1
    elseif ballxpos == sx - 4 and ballypos >= pong2pos - 1 and ballypos <= pong2pos + 1 then
        ballxvelocity = -1
    end
end

while true do
    while true do
        gameGraphics()
        gameFunctions()
        gameTime()

        if ballxpos == 1 then
            p2score = p2score + 1
            pong1pos, pong2pos, ballxpos, ballypos, ballxvelocity, ballyvelocity = math.ceil(sy / 2), math.ceil(sy / 2), math.ceil(sx / 2), math.ceil(sy / 2), math.ceil(math.random() - 1), math.ceil(math.random() - 1)

            if ballxvelocity == 0 then
                ballxvelocity = -1
            end

            if ballyvelocity == 0 then
                ballyvelocity = -1
            end
        elseif ballxpos == sx then
            p1score = p1score + 1
            pong1pos, pong2pos, ballxpos, ballypos, ballxvelocity, ballyvelocity = math.ceil(sy / 2), math.ceil(sy / 2), math.ceil(sx / 2), math.ceil(sy / 2), math.ceil(math.random() - 1), math.ceil(math.random() - 1)

            if ballxvelocity == 0 then
                ballxvelocity = -1
            end

            if ballyvelocity == 0 then
                ballyvelocity = -1
            end
        end
    end
end