# emit.ludic - the only calls into the runtime's playback: aud_play, under aud_emit and aud_ui, is the ONE
# place a float crosses into Audio.play_at's Q16.16 - handed over unconverted, 0.94 as a pitch clamped to 4x
# and -0.85 as a pan to hard left, and every sound in a valley played fast out of one speaker
export state AudioState {
  last_gain: float = 0.0
  last_pitch: float = 0.0
  last_pan: float = 0.0
  emitted: int = 0
  tried: int = 0
  live: int = 0
  ch_gain: []float = [1.0, 1.0, 1.0, 1.0]   # per channel (channels.ludic), under the master
}

export function aud_emit(audio_st: mut AudioState, h: int, gain: float, pitch: float, pan: float) -> void {
  if h == 0 { return }
  audio_st.last_gain = gain
  audio_st.last_pitch = pitch
  audio_st.last_pan = pan
  audio_st.emitted += 1
  aud_play(h, gain, pitch, pan)
}

# the ONE call into the runtime's playback, and the one place a float becomes its Q16.16
function aud_play(h: int, gain: float, pitch: float, pan: float) -> void { Audio.play_at(h, fixed(gain), fixed(pitch), fixed(pan)) }

# a sound at a place in the world, heard within `range` metres: false (and nothing played) when the
# listener is out of earshot
export function aud_emit_at(audio_st: mut AudioState, h: int, x: float, z: float, range: float) -> bool {
  let g = aud_gain_at(x, z, range)
  if g == 0.0 { return false }
  aud_emit(audio_st, h, g, aud_pitch_at(g), aud_pan_at(x, z))
  return true
}

# a click, a chime, a shutter, a warning: in the player's head, flat
export function aud_ui(audio_st: mut AudioState, h: int) -> void {
  if h == 0 { return }
  audio_st.emitted += 1
  aud_play(h, aud_channel(audio_st, AUD_CH_UI), 1.0, 0.0)
}

export function aud_music(h: int) -> void { if h != 0 { Audio.play_music(h) } }
export function aud_stop_music() -> void { Audio.stop_music() }
export function aud_master(v: float) -> void { Audio.volume(fixed(Math.clamp(v, 0.0, 1.0))) }

# what the last emit handed the runtime, and how many shots so far: Audio.* is a no-op headless, so
# the numbers are the only thing a test can hear
export function aud_last_gain(audio_st: AudioState) -> float { return audio_st.last_gain }
export function aud_last_pitch(audio_st: AudioState) -> float { return audio_st.last_pitch }
export function aud_last_pan(audio_st: AudioState) -> float { return audio_st.last_pan }
export function aud_emitted(audio_st: AudioState) -> int { return audio_st.emitted }