function init()
    setmode(1)
    setchar(94, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
    piano = { "_____", "\143\143\143\154\154", "     ", "\143\143\143\154\154", "^^^^^", "_____",
        "\143\143\143\154\154", "     ", "\143\143\143\154\154", "     ", "\143\143\143\154\154", "^^^^^" }
    notes = {"C ", "C#", "D ", "D#", "E ", "F ", "F#", "G ", "G#", "A ", "A#", "B "}
    pnotes = {"c", "c#", "d", "d#", "e", "f", "f#", "g", "g#", "a", "a#", "b"}

    piano_pos=18
    mousewait=0
    compas = 0
    compasos = {}
    for i=0,31 do compasos[i] = 108 end
    compasos[0] = 49
    compasos[1] = 49
    compasos[2] = 49
    compasos[7] = 50
    compasos[8] = 50
    compasos[9] = 50
    compasos[10] = 50

    old_mouse_x,old_mouse_y = 0,0
end

function update()
    color(COLOR_WHITE, COLOR_BLACK)
    cls()
    for i=0,11 do
        local k = 11-i
        local pos = ((piano_pos+i)%12)+1
        local oct = flr((piano_pos+i)/12)+1
        color(COLOR_WHITE, COLOR_BLACK)
        print(notes[pos], 1, 10+k)
        color(COLOR_BLACK, COLOR_WHITE)
        print(piano[pos], 3, 10+k)
        color(COLOR_BLACK, COLOR_LIGHT_GRAY+flr(oct%2))
        print("_______\003_______\003_______\003_______\003", 8, 10+k)
        color(COLOR_BLACK, oct)
        if pos==6 then
            print(tostr(oct), 0, 10+k)
        else
            print(" ", 0, 10+k)
        end
    end

    piano_pos = mid(0, piano_pos+mousewheel(), 96)

    if mousewait>0 then mousewait=mousewait-1 end
    if mousebutton(1) and mousewait==0 then
        if mousex()<8 and mousey()>=10 and mousey()<=21 then
            local note = piano_pos+(11-(mousey()-10))
            play("l4o"..tostr(note/12)..pnotes[(note%12)+1])
            mousewait=10
        end
    end

    for i=0,31 do
        local n = compasos[i]
        if n>=piano_pos and n<=piano_pos+11 then
            if i>0 and n~=compasos[i-1] then
                local oct = flr(n/12)+1
                color(COLOR_BLACK, COLOR_LIGHT_GRAY+flr(oct%2))
                print("\003",7+i,10+11-(n-piano_pos))
            end
            color(COLOR_BLACK,COLOR_LIGHT_RED)
            if i==31 or compasos[i+1]~=n then
                print("\003",8+i,10+11-(n-piano_pos))
            else
                print("_",8+i,10+11-(n-piano_pos))
            end
        end
    end
    
    if mousex()>=8 and  mousey()>=10 and mousey()<=21 then
        if mousebutton(1) then
            compasos[mousex()-8] = piano_pos+11-(mousey()-10)
            if old_mouse_x ~= mousex() or old_mouse_y ~= mousey() then
                local note = piano_pos+11-(mousey()-10)
                play("l4o"..tostr(note/12)..pnotes[(note%12)+1])
            end    
            old_mouse_x,old_mouse_y = mousex(),mousey()
        else
            old_mouse_x,old_mouse_y = 0,0
            if mousebutton(3) then
                compasos[mousex()-8] = 108
            end
        end
    end

    if btnp(KEY_RETURN) then play_song() end

    color(15,0)print("\143",0,0)
    color(14,0)print("\143",1,0)
    color(12,0)print("\143",2,0)
    color(6,0)print("\143",3,0)
    color(4,0)print("\143",4,0)
    color(5,4)print("\143",5,0)
    color(9,0)print("\143",6,0)
    color(1,0)print("\143",7,0)
    color(0,0)print("\143",8,0)

end

function play_song()
    local note_size = {1,2,3,4,6,8,12,16,24,32}
    local note_names = {"c","c#","d", "d#","e","f","f#","g","g#","a","a#","b"}
    local song = ""

    local current_note = 255
    local current_octave = 4
    local p=0
    while p<32 do
        current_note = compasos[p]
        local d=0
        while current_note == compasos[p] do d=d+1 p=p+1 end
        local o = flr(current_note/12)
        if o<9 and current_octave~=o then
            current_octave=o
            song=song.."o"..tostr(o)
        end
        local n = current_note%12
        local note = note_names[n+1]
        while d>0 do
            local i=1
            while d>note_size[i] do i=i+1 end
            if note_size[i]>d then i=i-1 end
            d=d-note_size[i]
            if current_length~=i-1 then
                current_length = i-1
                song=song.."l"..tostr(i-1)
            end
            if o<9 then
                song=song..note
            else
                song=song.."r"
            end
        end
    end
    play(song)
end