rnd

lengths = {["C418 - 13"]=180, ["C418 - cat"]=186, ["C418 - blocks"]=347, ["C418 - chirp"]=186, ["C418 - far"]=172, ["C418 - mall"]=197, ["C418 - mellohi"]=98, ["C418 - stal"]=151, ["C418 - strad"]=191, ["C418 - ward"]=250, ["C418 - 11"]=70}
--config
local side = "right"
local ejectOutput = "bottom"
local insertOutput = "left"

function clear()
  term.clear()
  term.setCursorPos(1,1)
end


--show name and time left while playing
function show(name, length, endTime)
  clear()
  print("Playing: ", name)
  local untilEnd = math.floor(endTime - os.clock())
  print("Time left: ", untilEnd, " seconds")
end

--start change function
function change()
    print("inserting new random music disc..")
    --to eject music disc from disk drive
    redstone.setOutput(ejectOutput, true)
    sleep(1)
    redstone.setOutput(ejectOutput, false)
    while disk.isPresent(side) do
        clear()
        print("waiting for auto-eject..")
        sleep(1)
    end

    --to insert music disc to disk drive
    redstone.setOutput(insertOutput, true)
    sleep(1)
    redstone.setOutput(insertOutput, false)
    while disk.isPresent(side) do
        clear()
        print("waiting for disc..")
        sleep(1)
    end
    return
end

-- start work function
function work()
  if disk.isPresent(side) then
    if disk.hasAudio(side) then

      local diskName = disk.getLabel(side)
      local diskLength = lengths[diskName]
      local timer = os.startTimer(diskLength)
      local endTime = os.clock() + diskLength
      show(diskName,diskLength,endTime)
      --start playing
      disk.playAudio(side)
      local tick = os.startTimer(1)
      while true do

        local evt, arg = os.pullEvent()

        if evt == "disk_eject" then
          print("disk was ejected")
          error("bye")
        end

        if evt == "timer" then
          if arg == timer then
            change()
            return
          end
          --end if arg timer

        end
        --end if evt timer

        if evt == "timer" then
          if arg == tick then
            show(diskName,diskLength,endTime)
            tick = os.startTimer(1)
          end
        end
        --end if evt tick

        if evt == "key" then
          if arg == keys.right then
             change()
             return
          end
        end
      end
      --end while

    else
    --else for disk.hasAudio()
      clear()
      print("this is not a music disc")
      sleep(1)
    end
  else
    --else for disk.isPresent()
    clear()
    print("nothing in disk drive")
    sleep(1)
  end
end
--end work function
while true do
    work()
end