Portal Song Player - PC

--[[ Startup file for the computer,
    sends signal to turtle to receive
    table of names of the discs,
    then creates a menu of which to play
    ]]

--[[ Variables ]]--
rednet.open("left")
turtleID = 4
t_songs = {}
sX, sY = term.getSize()
running = true
-- Tables
t_songPlaying = {"Stop", "Replay"}

local function colorW(...)
  local curColor
  for i=1, #arg do -- arg is ...
    if type(arg[i]) == 'number' then
      curColor = arg[i]
    else
      if curColor then
        term.setTextColor(curColor)
      end
      write(arg[i])
    end
  end
end

local function menu(_table)
    local sel = 1
    while true do
        tempSpace = 0
        yPos = 7
        if sel > #_table then sel = 1 end
        if sel < 1 then sel = #_table end
        for i = 1,#_table do
            if i == 10 then tempSpace = 23 yPos = 7 end
            term.setCursorPos(3 + tempSpace, yPos)
            yPos = yPos + 1
            if sel == i then
                colorW(colours.red, "[  ", colours.lightBlue, _table[i], colours.red, "  ]")
            else
                colorW("   ", colours.lightBlue, _table[i], "   ")
            end
        end
        local e, key = os.pullEvent("key")
        if key == 200 then -- up key
            sel = sel-1
        elseif key == 208 then -- down key
            sel = sel+1
        elseif key == 28 then
            return _table[sel], sel
        end
    end
end

function cWrite(text, x, y, colour)
    colour = colour or colours.black
    term.setTextColour(colour)
    term.setCursorPos(x, y)
    write(text)
end

function drawBackground()
    -- Print background
    term.setBackgroundColour(colours.black)
    term.setTextColour(colours.white)
    term.clear()
    term.setCursorPos(1,1)
    bg = paintutils.loadImage("background")
    paintutils.drawImage(bg, 1, 1)
    t = "Music disk player"
    term.setCursorPos( (sX - #t)/2, 2)
    term.setTextColour(colours.lime)
    term.setBackgroundColour(colours.cyan)
    write(t)
    term.setBackgroundColour(colours.grey)
end

function songPlaying(songName)
    drawBackground()
    text = "Playing " .. songName
    cWrite(text, (sX-#text)/2, 5, colours.red)
    nSelected = 1
    while true do
        for i = 1, #t_songPlaying do
            term.setCursorPos(i*15, 7)
            if nSelected == i then
                colorW(colours.red, "[", colours.lime, t_songPlaying[i], colours.red, "]")
            else
                colorW(" ", colours.lime, t_songPlaying[i], " ")
            end
        end
        e, key = os.pullEvent("key")
        if key == keys.left and nSelected > 1 then nSelected = nSelected - 1
        elseif key == keys.right and nSelected < #t_songPlaying then nSelected = nSelected + 1
        elseif key == keys.enter then break end
    end
    if nSelected == 1 then
        -- Code to stop playing the song
        rednet.send(turtleID, "stop")
        drawBackground()
        text = "Last played song: " .. songName
        cWrite(text, (sX - #text)/2, 5, colours.red)
    elseif nSelected == 2 then
        -- Code to restart the disk
        rednet.send(turtleID, "restart")
        sleep(1)
        return songPlaying(songName)
    end
end

function getDiskTitles()
    drawBackground()
    t_songs = {} -- reset the table of songs
    term.setBackgroundColour(colours.grey)
    cWrite("Getting information from turtle...", 3, 5, colours.black)
    rednet.send(turtleID, "getDiskTitles")
    repeat id, message = rednet.receive() until id == turtleID
    if message == "no discs" then
        cWrite("No disks in turtle.               ", 3, 5, colours.black)
        term.setCursorPos(3, 6)
        colorW(colours.lightBlue, "[Try again]")
        repeat e, k = os.pullEvent() until k == keys.enter
        return getDiskTitles()
    else
        t_songs = textutils.unserialize(message)
        table.insert(t_songs, "Exit")
        table.insert(t_songs, "Get Titles")
    end
    drawBackground()
end

drawBackground()
getDiskTitles()

while running do
    term.setBackgroundColour(colours.grey)
    songName, songNumber = menu(t_songs)
    if songName == "Exit" then
        term.setBackgroundColour(colours.black)
        term.setTextColour(colours.white)
        term.setCursorPos(1, 1)
        term.clear()
        running = false
    elseif songName == "Get Titles" then
        getDiskTitles()
    else
        drawBackground()
        cWrite("Attempting to play " .. songName, 3, 5, colours.red)
        rednet.send(turtleID, songName)
        repeat id, message = rednet.receive() until id == turtleID
        if message == "songFound" then
            songPlaying(songName)
        elseif message == "songNotFound" then
            drawBackground()
            text = "Unable to find " .. songName
            cWrite(text, (sX-#text)/2, 5, colours.red)
        end
    end
end