function init()
    -- mode 1: 40x30 characters
    setmode(1)
    -- prepare everything for the match
    reset_match()
    p1,p2=0,0   -- reset scores
end

function update()
    cls()

    -- ball movement
    -- 'wait' is a counter to skip some cycles before moving the ball, so it starts slower
    -- 'speed' defines how many cycles to skip. Every 5 hits to the paddles 'speed' goes down by 1, effectively increasing the ball's speed
    -- 'speed' is reset every point
    wait=wait-1
    if wait==0 then
        wait=speed
        -- move ball
        bx=bx+dx
        by=by+dy
        -- if ball hits top or down walls, bounce
        if by==0 or by==29 then
            dy=-dy
            if playing then play("a") end   -- if we are not playing, be quiet
        end

        -- during a match, paddles bounce the ball and left and right walls award points
        -- but before or after a match the ball just bounces around
        if playing then
            -- if ball hits left or right ball, reset the ball and award a point to the opposing paddle
            if bx==0 then p2=p2+1 reset_ball() end
            if bx==39 then p1=p1+1 reset_ball() end
            -- if ball hits paddle, bounce
            if (bx==1 and by>=y1 and by<=y1+4) or (bx==38 and by>=y2 and by<=y2+4) then
                play("c")
                dx=-dx
                -- also, increase hits. Every 5 hits the ball will speed up (only if it's not already as fast as possible)
                hits=hits+1
                if (hits%5 == 0) and (speed>0) then speed=speed-1 end 
            end
        else
            -- when not playing, just bounce freely
            if bx==0 or bx==39 then dx=-dx end
        end
    end

    -- player 1 controls
    if btn(KEY_Q) and y1>0 then y1=y1-1 end
    if btn(KEY_A) and y1<25 then y1=y1+1 end

    -- player 2 controls
    if btn(KEY_UP) and y2>0 then y2=y2-1 end
    if btn(KEY_DOWN) and y2<25 then y2=y2+1 end

    -- draw net
    if playing then for i=0,29 do print("\145",20,i) end end

    -- draw score
    print(p1,18,3)
    print(p2,22,3)

    -- draw ball
    print("\143",flr(bx),flr(by))

    -- draw paddles
    for i=0,4 do
        print("\143",1,y1+i)
        print("\143",38,y2+i)
    end

    if not playing then
        -- while not playing show the messages
        if p1==10 then print("PLAYER 1 WINS!", 14, 8)
        elseif p2==10 then print("PLAYER 2 WINS!", 14, 8) 
        else print("PONG!", 18, 10) end

        print("Press SPACE to play", 11, 20)
        if btn(KEY_SPACE) then
            start_match()
        end
    end

end

function start_match()
    playing=true
    p1,p2=0,0   -- reset scores
end

function reset_match()
    play("l2drl2d#l4e>l2crr<e>crr<l4e>crrrl2r cl4dl2d#l4el2cl4del2r<b>l4dl2rl4crrrl2r< drl2d#l4e>l2crr<e>crr<l4e>crrrl2r< l2argl4f#l2a>l4cl2errdl4cl2<al4>drrrl2r< l2drl2d#l4e>l2crr<e>crr<l4e>crrrl2r cl4dl2d#l4el2cl4del2r<b>l4dl2rl4crrrl2r<")

    playing=false
    bx,by=20,15 -- init ball's position
    dx,dy=1,1   -- init ball's direction
    y1,y2=14,14 -- init paddle's y coordinate
    wait=1      -- reset wait counter
    speed=4     -- reset speed
    hits=0      -- reset hits counter
end

function reset_ball()
    play("l0o3bagfedc") -- play sad tune
    bx,by=20,15         -- reset ball's position
    speed=4             -- reset speed
    hits=0              -- reset hits counter
    dx=-dx              -- invert x direction

    -- si algu arriba a 10, la partida acaba
    if p1==10 or p2==10 then
        playing=false
        play("o5l1crl0ergrl4o6c")
    end
end