/*
 * MIDI Player - Command line tool
 * 
 * Usage: cell run examples/player.ce <midi_file> <soundfont_file>
 */

var io = use('cellfs')
var audio = use('sokol/audio')
var midi = use('midi')

var blob = use('blob')
var os = use('os')

if (length(args) < 2) {
  log.console("Usage: cell run examples/player.ce <midi_file> <soundfont_file>")
  log.console("Example: cell run examples/player.ce invent8.mid harpsichord.sf2")
  $stop()
}

var midi_file = args[0]
var sf_file = args[1]

log.console("Loading soundfont: " + sf_file)
var sf_blob = io.slurp(sf_file)
if (!sf_blob) {
  log.console("Error: Could not load soundfont: " + sf_file)
  $stop()
}

var soundfont = midi.Soundfont(sf_blob)
log.console("Soundfont loaded, " + text(soundfont.preset_count()) + " presets")

log.console("Loading MIDI: " + midi_file)
var midi_blob = io.slurp(midi_file)
if (!midi_blob) {
  log.console("Error: Could not load MIDI file: " + midi_file)
  $stop()
}

var song = midi.parse(midi_blob)
log.console("MIDI loaded: " + text(song.note_count) + " notes, " + text((song.duration_ms / 1000)) + " seconds")

var player = midi.Player(soundfont, song)

// Setup audio with push model
var SAMPLE_RATE = 44100
var BUFFER_FRAMES = 1024

audio.setup({
  sample_rate: SAMPLE_RATE,
  num_channels: 2,
  buffer_frames: BUFFER_FRAMES * 4
})

if (!audio.is_valid()) {
  log.console("Error: Failed to initialize audio")
  $stop()
}

log.console("Playing... Press Ctrl+C to stop")
log.console("Sample rate: " + text(audio.sample_rate()) + " Hz")
player.play()

// Audio pump - push samples to audio device
function pump() {
  // Push audio when buffer has room
  var expect = audio.expect()
  var rendered = null
  while (expect >= BUFFER_FRAMES) {
    rendered = player.render(BUFFER_FRAMES)
    if (rendered) {
      audio[] = rendered
    }
    expect = audio.expect()
  }
  
  // Check if done
  if (!player.is_playing() && soundfont.active_voices() == 0) {
    log.console("\nPlayback finished")
    audio.shutdown()
    soundfont.close()
    $stop()
    return
  }
  
  $delay(pump, 0.1) // ~200Hz pump rate
}

// Progress display
function progress() {
  if (!player.is_playing() && soundfont.active_voices() == 0) {
    return
  }
  
  var pos = player.position_ms() / 1000
  var dur = player.duration_ms() / 1000
  var pct = text(pos / dur * 100)
  log.console(`\r${text(pos)}s / ${dur}s (${pct}%) - ${soundfont.active_voices()} voices  `, false)
  $delay(progress, 0.1)
}

pump()
progress()