# audio.ludic — the Audio.* standard library (#22). Sound effects and music over
# the platform audio backend (AVAudioPlayer on macOS). A sound is loaded once
# into a handle; sfx fire one-shot, music loops on a single channel; master
# volume and pitch apply across everything, and Audio.play_at fires one shot with
# its own gain, pitch and stereo position without touching them.
#
# Playback is out-of-band — the audio device is real-time, not part of the
# deterministic simulation — but every trigger is an ordinary frame-driven call,
# so a recorded run replays the same sounds at the same frames. Headless (no
# window) every call is a safe no-op: load returns 0 and is_playing returns
# false, so the same code runs under the test harness. A full headless run:
#   bin/ludic examples/library/audio.ludic  ->  0 0 0 0 1
program AudioDemo {
  function bi(b: bool) -> int { if b { return 1 };  return 0 }

  entry {
    let sfx = Audio.load("assets/sfx/blip.wav")     # 0 headless (no audio device)
    let mus = Audio.load("assets/music/theme.ogg")  # 0 headless
    print(sfx)                                       # 0
    print(mus)                                       # 0

    Audio.volume(0.8)                                # master volume, 0.0..1.0
    Audio.pitch(1.25)                                # playback rate / pitch
    Audio.play(sfx)                                  # one-shot sound effect
    # the per-voice version: a sound placed in the world rather than the master settings.
    # This is what distance attenuation is made of - work out how far away and which side
    # it is, and say so. gain rides on top of the master volume, so the options screen wins.
    Audio.play_at(id: sfx, gain: 0.35, pitch: 0.9, pan: -0.6)
    Audio.play_at(sfx, 0.35, 0.9, -0.6)              # or positionally, which a tight loop prefers
    Audio.play_music(mus)                            # looping background music
    print(bi(Audio.is_playing(sfx)))                 # 0 headless

    Audio.stop(sfx)                                  # stop one sound
    Audio.stop_music()                               # stop the music channel
    Audio.stop_all()                                 # stop everything
    print(bi(Audio.is_playing(mus)))                 # 0
    print(1)                                          # 1 — every call returned cleanly
  }
}