Noteblock Studio (.nbs) player for the Iron Noteblock

-- Noteblock Studio file (.nbs) player for MiscPeripherals (a ComputerCraft mod)
-- version 2
-- You are free to copy, alter, and distribute this under the following conditions:
-- 1) You leave these comments and credits attached
-- 2) You do not make money off of this
-- Program by James0x57 - http://www.youtube.com/watch?v=ro4EK8smULQ
-- Noteblock Studio by _Davve_ - http://www.minecraftforum.net/topic/136749-minecraft-note-block-studio-150000-downloads/
-- MiscPeripherals by RichardG867 - http://www.computercraft.info/forums2/index.php?/topic/4587-cc1481mc146-miscperipherals-23/
-- ComputerCraft by Dan - http://www.computercraft.info/
-- If you use this in anything you create, please show credit where due, and let me know because I'd love to see it used!! =)
-- ComputerCraft command to add this program: pastebin get NkUXF3Ee play

local args = {...};
local menu = {};
local box = nil;
local song = nil;
local action = 'mainList';
local isPlaying = false;
local stopFlag = false;
local settings = { rptMode = "allRandom"; }; -- "repeat" is reserved in lua
local maxtoshow = 15;

if turtle ~= nil then
    maxtoshow = 9;
end

function mountIronNoteblock()
    for _,side in ipairs({"left"; "right"; "back"; "bottom"; "top"; "front"}) do
        if peripheral.getType(side) == "note" then
            box = peripheral.wrap(side);
            return side;
        end
    end
    return nil;
end

function newSong(x, selectedIndex)
    return {
        fh = x;
        index = selectedIndex;
        length = 0;
        height = 0;
        name = "";
        author = "";
        originalAuthor = "";
        description = "";
        tempo = 10.00; --tks per second
        autoSaving = 0;
        autoSaveDur = 0;
        timeSig = 4;
        minSpent = 0;
        leftClicks = 0;
        rightClicks = 0;
        blocksAdded = 0;
        blocksRemoved = 0;
        midi = "";
        music = { wait={}; inst={}; note={}; };
    };
end

function loadMenu(fromDir)
    if fs.isDir(fromDir) then
        for _, file in ipairs(fs.list(fromDir)) do
          if fs.isDir(file) == false and string.find(file, ".nbs", -4, true) ~= nil then -- if file and ends in ".nbs"
            menu[#menu+1] = { d=fromDir; fn=file };
          end
        end
    end
    return #menu;
end

function readInt(fh) --little endian, fh is open in rb mode
    local ret = 0;
    local x = fh.read();
    if x == nil then return nil; end
    ret = x;
    x = fh.read();
    if x == nil then return nil; end
    ret = (x * 0x100) + ret;
    x = fh.read();
    if x == nil then return nil; end
    ret = (x * 0x10000) + ret;
    x = fh.read();
    if x == nil then return nil; end
    ret = (x * 0x1000000) + ret;
    return ret;
end

function readShort(fh) --little endian, fh is open in rb mode
    local ret = 0;
    local x = fh.read();
    if x == nil then return nil; end
    ret = x;
    x = fh.read();
    if x == nil then return nil; end
    ret = (x * 0x100) + ret;
    return ret;
end

function readString(fh, len) --fh is open in rb mode
    local ret = "";
    local x = 0;
    for i = 1, len do
        x = fh.read();
        if x == nil then return nil; end
        ret = ret .. string.char(x);
    end
    return ret;
end

function readHeader()
    song.length         = readShort(song.fh);
    song.height         = readShort(song.fh);
    song.name           = readString(song.fh, readInt(song.fh));
    song.author         = readString(song.fh, readInt(song.fh));
    song.originalAuthor = readString(song.fh, readInt(song.fh));
    song.description    = readString(song.fh, readInt(song.fh));
    song.tempo          = 1.000 / ( readShort(song.fh) / 100.00 );
    song.autoSaving     = song.fh.read();
    song.autoSaveDur    = song.fh.read();
    song.timeSig        = song.fh.read();
    song.minSpent       = readInt(song.fh);
    song.leftClicks     = readInt(song.fh);
    song.rightClicks    = readInt(song.fh);
    song.blocksAdded    = readInt(song.fh);
    song.blocksRemoved  = readInt(song.fh);
    song.midi           = readString(song.fh, readInt(song.fh));
end

function readNotes()
    local curtk = 1;
    local tk = -1;
    local layer = -1;
    local inst = 0;
    local note = 33; -- MC is 33 to 57

    while true do
        tk = readShort(song.fh);
        if tk == nil then return false; end
        if tk == 0 then break; end
        while true do
            song.music.wait[curtk] = (tk * song.tempo) * 0.965; -- * 0.965 to speed it up a bit because lua slow
            layer = readShort(song.fh); --can't do anything with this info (yet?)
            if layer == nil then return false; end
            if layer == 0 then break; end
            song.music.inst[curtk]=song.fh.read();
            if song.music.inst[curtk] == 0 then
                song.music.inst[curtk] = 0;
            elseif song.music.inst[curtk] == 2 then
                song.music.inst[curtk] = 1;
            elseif song.music.inst[curtk] == 3 then
                song.music.inst[curtk] = 2;
            elseif song.music.inst[curtk] == 4 then
                song.music.inst[curtk] = 3;
            elseif song.music.inst[curtk] == 1 then
                song.music.inst[curtk] = 4;
            end
            song.music.note[curtk]=song.fh.read()-33;
            tk = 0;
            curtk = curtk + 1;
        end
    end
    return true;
end

function showInfo()
    term.clear();
    print("Now Playing: \n\n\n\n\n\n          " .. song.name);
    print("\n\n\n\n\n\nAuthor: " .. song.author);
    print("Original Author: " .. song.originalAuthor);
    print("Description: ");
    print(song.description);
    parallel.waitForAny(function()
        _, key = os.pullEvent("key");
    end, function()
        while true do
            if not isPlaying then break; end
            os.sleep(0.125);
        end
    end);
    if settings.rptMode == "none" or isPlaying then --song finished in single play mode or key pressed exit
        action = 'mainList';
    end
end

function getRepeateMode() -- returns the name of currently selected repeat mode
    local rptText = "";

    if settings.rptMode == "allRandom" then
        rptText = "All (Random)";
    elseif settings.rptMode == "allOrdered" then
        rptText = "All (In Order)";
    elseif settings.rptMode == "one" then
        rptText = "One (Loop Song)";
    elseif settings.rptMode == "none" then
        rptText = "None";
    end

    return rptText;
end

function changeRepeatMode() -- cycles to next repeat mode and returns its name
    if settings.rptMode == "allRandom" then
        settings.rptMode = "allOrdered";
    elseif settings.rptMode == "allOrdered" then
        settings.rptMode = "one";
    elseif settings.rptMode == "one" then
        settings.rptMode = "none";
    elseif settings.rptMode == "none" then
        settings.rptMode = "allRandom";
    end

    return getRepeateMode();
end

function options()
    local selectedIndex = 1;
    while true do
        term.clear();
        local opts = {};
        opts[1] = "Show Now Playing";
        opts[2] = "Repeat: " .. getRepeateMode();
        opts[3] = "Next Song";
        opts[4] = "Stop";
        opts[5] = "Back To Song List";
        -- "Load Playlist" --> default song lists & any saved lists
        -- "Add " .. selected main menu song .. " to a playlist"
        -- "Queue " .. selected main menu song -- takes priority over repeat mode
        -- "Load songs from ..." -- prompts for folder path, erases current queue

        for i = 1, #opts do
            if i == selectedIndex then
                print("> " .. opts[i]);
            else
                print("  " .. opts[i]);
            end
        end
        print("----------------------\nUse Arrow keys and Enter to navigate.\n");
        _, key = os.pullEvent("key");

        if key == 208 or key == 31 then -- down or s
            selectedIndex = selectedIndex + 1;
            if selectedIndex > #opts then selectedIndex = 1; end
        elseif key == 200 or key == 17 then -- up or w
            selectedIndex = selectedIndex-1;
            if selectedIndex < 1 then selectedIndex = 1; end
        elseif key == 28 or key == 57 then -- enter or space
            if selectedIndex == 1 and isPlaying then
                action = 'nowPlaying';
                break;
            elseif selectedIndex == 2 then
                changeRepeatMode();
            elseif selectedIndex == 3 then
                skipSong();
                break;
            elseif selectedIndex == 4 then
                stopSong();
                action = 'mainList';
                break;
            else
                action = 'mainList';
                break;
            end
        end
    end
end

function mainList(startat, selectedIndex)
    term.clear();
    for i = startat, #menu do
        if startat + maxtoshow <= i then break end
        if i == selectedIndex then
            print("> " .. menu[i].fn);
        else
            print("  " .. menu[i].fn);
        end
    end
    print("----------------------\nUse Arrow keys and Enter to navigate.");
    print("Press m to access options.")
    _, key = os.pullEvent("key");

    if key == 208 or key == 31 then -- down or s
        selectedIndex = selectedIndex + 1;
        if selectedIndex >= startat + maxtoshow then startat = startat + maxtoshow; end
        if selectedIndex > #menu then selectedIndex = 1; startat = 1; end
    elseif key == 200 or key == 17 then -- up or w
        selectedIndex = selectedIndex-1;
        if selectedIndex < 1 then selectedIndex = 1; end
        if selectedIndex < startat then startat = startat - maxtoshow; end
        if startat < 1 then startat = 1; end
    elseif key == 205 or key == 32 then -- right or d
        selectedIndex = startat + maxtoshow;
        if selectedIndex > #menu then selectedIndex = 1; end
        startat = selectedIndex;
    elseif key == 203 or key == 30 then -- left or a
        selectedIndex = startat - maxtoshow;
        startat = startat - maxtoshow;
        if selectedIndex < 1 then selectedIndex = 1; end
        if startat < 1 then startat = 1; end
    elseif key == 28 or key == 57 then -- enter or space
        action = 'playSong';
    elseif key == 50 or key == 19 then -- m or r
        action = 'options';
    end

    return startat, selectedIndex;
end

function continueWith() -- returns a menu index of the next song based on the selected repeat mode
    local contWith = 1;
    if #menu > 0 then
        if settings.rptMode == "allRandom" then
            contWith = math.random(#menu);
        elseif settings.rptMode == "allOrdered" then
            contWith = song.index + 1;
            if contWith > #menu then
                contWith = 1;
            end
        elseif settings.rptMode == "one" then
            contWith = song.index;
        end
    end
    return contWith;
end

function playNotes(doReturn)
    while true do
        if action == 'songReady' then
            isPlaying = true;
            action = 'nowPlaying';
            os.queueEvent("playStarted");
            for i = 1, #song.music.wait - 1 do
                if song.music.wait[i] ~= 0 then
                    os.sleep(song.music.wait[i]);
                    if stopFlag then break; end
                end
                pcall(box.playNote, song.music.inst[i], song.music.note[i]);
            end
            isPlaying = false;
            os.queueEvent("playEnded");
            if not stopFlag then --song finished (instead of controller terminated)
                if #menu > 0 and settings.rptMode ~= "none" then
                    menuAt(continueWith()); --continue playing songs based on current repeat mode
                end
            end
        end
        if doReturn ~= nil and doReturn == true then break; end
        os.sleep(0.25);
    end
end

function stopSong()
    if isPlaying then
        stopFlag = true;
        parallel.waitForAny(function()
            while true do
                if not isPlaying then break; end
                os.sleep(0.125);
            end
        end);
        stopFlag = false;
    end
end

function menuAt(x) -- plays the song on the menu at index x
    stopSong();
    song = newSong(fs.open(menu[x].d .. "/" .. menu[x].fn, "rb"), x);
    readHeader();
    readNotes();
    song.fh.close();
    action = 'songReady';
end

function skipSong()
    if #menu > 0 and settings.rptMode ~= "none" then
        menuAt(continueWith()); --continue playing songs based on current repeat mode
    else
        stopSong();
    end
end

function controller() --handles actions
    local startat = 1;
    local selectedIndex = 1;
    while true do
        if action == 'mainList' then
            startat, selectedIndex = mainList(startat, selectedIndex);
        elseif action == 'playSong' then
            menuAt(selectedIndex);
            action = 'songReady';
        elseif action == 'songReady' then
            os.sleep(0.125);
        elseif action == 'nowPlaying' then
            showInfo();
        elseif action == 'options' then
            options();
        end
    end
end

function clearMenu()
    menu = {};
end

function menuTable() -- returns all the loaded songs that would show up in the menu
    return menu;
end

function launchUI()
    if box == nil then
        print("No Iron Noteblock Detected");
        return;
    end

    if args[1] == nil or fs.isDir(args[1]) == false then
        args[1] = "songs";
        if fs.isDir("songs") == false then
            fs.makeDir("songs");
        end
    elseif args[1] ~= nil and fs.isDir(args[1]) == true then
        loadMenu(args[1]);
    end

    clearMenu();
    loadMenu("songs");
    loadMenu("rom/songs"); -- \Desktop\MindCrack\minecraft\mods\ComputerCraft\lua\rom\songs (ComputerCraft folder inside \mods\ must be created, it is not there by default)

    parallel.waitForAll(playNotes, controller);
end

function current() -- returns convinient 'song' table with complete header info, notes, and etc, --OR-- nil if nothing is playing (useful)
    if isPlaying == true then
        return song; --full song table, has everything
    else
        return nil;
    end
end

mountIronNoteblock();
if shell ~= nil then --ran normally, not loaded as API
    launchUI();
else --else it was loaded as an api so don't do anything else automatically
    settings.rptMode = "none";
end